Laetitia Tosoni
email: laetitia.tosoni@thalesgroup.com

Minh Tu Pham

Paolo Massioni

Elliot Broussard
email: elliot.broussard@thalesgroup.com

Rapid transfer alignment for large and time-varying attitude misaligment angles*

Transfer alignment is an effective method to estimate the attitude difference between two inertial platforms. Traditional transfer alignment methods are either meant for small misalignments or use nonlinear filtering. Linear methods for large misalignments use quaternion attitude representation, but their performance degrades when the misalignment is not constant or slowly varying. This work proposes to apply rapid transfer alignment to the inertial stabilization of a Satcom On The Move antenna. In this application case, the two inertial platforms are connected by a kinematic chain, meaning the attitude difference between the inertial platforms is both large and time-varying. This work proposes a method to estimate this attitude difference. A Kalman filter is used for the estimation of the unknown angles. To that effect, a new propagation model is developed to take into account the misalignment variations using master and slave rotation rates. Simulation results show the performance of the proposed solution in a Satcom antenna inertial stabilization case.

I. INTRODUCTION

Inertial navigation algorithms provide an effective means to compute the attitude and position of vehicles (aircraft, ships, etc.) [START_REF] Yüksel | Design and analysis of transfer aligment algorithms[END_REF]. In some applications, a subpart of the vehicle can be equipped with its own navigation system: the most common example is weapons carried by an aircraft.

In a projectile application [START_REF] Yüksel | Design and analysis of transfer aligment algorithms[END_REF], the final objective is for the projectile to follow its intended trajectory. The aircraft's aiming systems rely on the main inertial navigation system (INS) information to calculate said trajectory. As a consequence, the projectile's own inertial measurement unit (IMU) must be aligned with the main INS to follow that trajectory after launch. Transfer alignment algorithms have been originally developed to ensure that the projectile's navigation system worked in the same reference frame as the aiming system. To do so, transfer alignment algorithms estimate the misalignment between a high-grade INS, located on the carrier vehicle, and a low-cost IMU, located on the missile.

In addition to the original projectile applications, other applications exist, such as aircraft carried by a ship as in [START_REF] Lu | Random misalignment and lever arm vector online estimation in shipborne aircraft transfer alignment[END_REF], remote sensors carried by an aircraft as in [START_REF] Gong | A conditional cubature Kalman filter and its application to transfer alignment of distributed position and orientation system[END_REF], or spacecraft launched from a mobile base as studied in [START_REF] Chaudhuri | Transfer alignment for space vehicles launched from a moving base[END_REF]. minh-tu.pham@insa-lyon.fr, paolo.massioni@insa-lyon.fr

The principle of transfer alignment is as follows. Two inertial measurement units, a master INS and a slave IMU, exist in different reference frames as part of a single vehicle. They both measure the same variable, each in their own reference frame. These two measurements are compared in order to deduce the orientation difference between their reference frames.

Several methods of transfer alignment exist, and they are usually classified based on the type of measurement the estimator uses as inputs. According to [START_REF] Yüksel | Design and analysis of transfer aligment algorithms[END_REF], rotation rate, attitude, velocity or acceleration are the most common methods. Combinations of several measurements are also used: the technique known as rapid transfer alignment, first described by [START_REF] Kain | Rapid transfer alignment for tactical weapon applications[END_REF], uses a combination of attitude and velocity measurements. It allows a very fast and very precise estimation (estimation error of less than 1 mrad within 10 seconds), and according to [START_REF] Xiong | Observability analysis of INS rapid transfer alignment[END_REF], it is regarded as the best transfer alignment technique. However, it estimates a small, constant misalignment angle, and it uses small angle approximation to linearize the model. As a consequence, the larger the misalignment, the more the algorithm's performances degrade. Furthermore, potential variations in the misalignment angle aren't taken into account by the model.

Following the advent of rapid transfer alignment, efforts were made to reduce the computational load of the algorithm, as done by [START_REF] Xu | A computationally efficient variational adaptive kalman filter for transfer alignment[END_REF], and to compensate the carrier flexure, as done by [START_REF] Chen | Integrated modeling of motion decoupling and flexure deformation of carrier in transfer alignment[END_REF]. Carrier flexure is the rapid change of misalignment angle due to vibrations and deformations between the master INS and the slave IMU, and it impacts the accuracy of the estimation when not taken in consideration. These methods are still applied to a small and constant misalignment angle, and suffer from the drawbacks previously mentioned.

Several methods exist to estimate large misalignment angles. Some use non-linear filtering, such as the unscented Kalman filter used by [START_REF] Cheng | Polar transfer alignment of shipborne SINS with a large misalignment angle[END_REF] or the extended Kalman filter used by [START_REF] Cui | A unified model for transfer alignment at random misalignment angles based on secondorder EKF[END_REF]. However, works such as [START_REF] Zhou | Novel rapid transfer alignment algorithm for strapdown inertial navigation system[END_REF] and [START_REF] Chen | New rapid transfer alignment method for SINS of airborne weapon systems[END_REF] managed to estimate a large misalignment angle with a linear Kalman filter, by using a quaternion attitude representation instead of Euler angles. In all these cases, however, the misalignment estimated remained constant, and the model wasn't built to take into account potential variations.

In the present work, transfer alignment is applied to the inertial stabilization of a satellite communication antenna (called Satcom On-The-Move, or SOTM). As presented by [START_REF] Debruin | Control systems for mobile Satcom antennas[END_REF], in order to obtain high data rates, the antenna must be directional, which means that the received and emitted electromagnetic waves are oriented in a specific direction of space, called the line of sight or boresight. The line of sight must be steered in order to be aligned with the satellite to ensure a sufficient data rate transfer. The accuracy with which the antenna must be pointed depends on the antenna size and the radiofrequency band used to communicate.

In order to keep the antenna pointed towards the satellite, it is mounted on an antenna positioning system (APS). The APS is made of several axes actuated by servomotors. In our application case, the APS has two axes: an azimuth axis, and an elevation axis. In order to control the APS, the line of sight's current direction must be known; as a consequence, a slave IMU is aligned with the antenna's line-of sight. Placing the IMU in the same reference frame as the line of sight minimizes the risks of assembly misalignment errors. The master INS is located on the vehicle. As seen from Fig. 1, the APS can create a large and time varying orientation difference between the master and the slave inertial sensors. In the currently existing transfer alignment algorithms, this variation is an important perturbation that isn't accounted for by the models.

The contribution of this method relies on the inclusion of the propagation model for the movements of the secondary IMU, namely the one that is connected to the antenna in our application. This makes the method directly applicable to all cases where large relative, time-varying angles are featured between the two platforms; this case is usually neglected in other transfer alignment methods, due to the fact that the two platforms are connected to the same rigid body.

Specifically, this does not mean that the former algorithms cannot be used for tracking antenna movements; it means though that they will need to be tuned in a way that the propagation dynamics is considered as an unknown disturbance, which is inefficient. Adding the propagation model makes it unnecessary to do this step, making an efficient and performant tuning of the filter quite easy and direct. This article is organized as follows. Section II specifies the quaternion properties and different reference frames that will be used in the model. Section III presents the measurement model, propagation model and lever arm compensation of the transfer alignment algorithm. The lever arm compensation is meant to take into consideration the physical distance between the master and slave systems, and its impact on velocity measurements. Section IV presents the simulation conditions and results that confirm the effectiveness of the proposed method for our purposes.

II. PRELIMINARIES

A. Nomenclature

• q j k : quaternion expressing the rotation from frame k to frame j • C j k : rotation matrix from frame k to frame j • q the quaternion conjugate of q • For a quaternion q, we write q 0 its scalar part and q its vector part such as q = q 0 q T T . The vector part is made of three terms such as q = q 1 q 2 q 3 T .

• C(q): rotation matrix representing the same orientation as the attitude quaternion q • ω l j/k : rotation rate of frame j relative to frame k expressed in coordinate frame l • a l j/k : acceleration of frame j relative to frame k expressed in coordinate frame l • v l j/k : velocity of frame j relative to frame k expressed in coordinate frame l • g n : gravity acceleration in coordinate frame n • f s : acceleration sensed by the slave IMU such as f s = a s s/n + g s • θ Az : rotation angle around the azimuth axis.

• θ El : rotation angle around the elevation axis.

• S( u): 3-by-3 skew-symmetric matrix associated with 3by-1 vector u • ẋ: derivative of variable x with respect to time • x: estimation of variable x

B. Quaternion attitude representation

Unit quaternions can be used to represent attitude [START_REF] Parwana | Quaternions and attitude representation[END_REF]. They are more compact than rotation matrices, and unlike Euler angles, they avoid gimbal lock issues.

Five properties are key for attitude quaternions. The first one is their derivative [START_REF] Parwana | Quaternions and attitude representation[END_REF]:

qj k = 1 2 q j k × ω k k/j (1)
where × is the Hamilton product between two quaternions, q j k is the attitude quaternion from frame k to frame j, ω l j/k is the rotation rate of j relative to k expressed in l, and for any rotation rate ω k k/j , ω k k/j is the associated quaternion such as

ω k k/j = 0 ω k k/j T T
. The second one is the use of attitude quaternion to change another quaternion's coordinate frame. For example, with rotation rates:

ω o j/k = q o l × ω l j/k × q l o (2)
The third one is the conjugate of an attitude quaternion, with q the conjugate of q :

qj k = q k j (3)
Therefore,

q j k × q k j = 1 0 0 0 T (4)
with 1 0 0 0 T being the multiplicative identity for the quaternion algebra.

The fourth one is the matrix form expression of quaternion multiplication. For any two quaternions q and p: γ(q) = q 0 -q T q q 0 I + S( q)

(5)

χ(p) = p 0 -p T p p 0 I -S( p) (6)
q × p = γ(q)p = χ(p)q (7)

The last property is the conversion from attitude quaternion to other attitude representations. A quaternion can be converted to a rotation matrix or to Euler angles for better readability. In this paper, we will display results in Euler angles using the ZYX convention.

C. Reference frames

The reference frames used in this paper are the same as in [START_REF] Chen | New rapid transfer alignment method for SINS of airborne weapon systems[END_REF]. They are illustrated in Fig. 1 Bearing body frame (b): Reference frame originating at the base of the azimuth joint, stemming from the rotation of (m) around the azimuth axis.

Slave IMU body frame (s): Orthogonal reference frame aligned with slave IMU axes.

Slave IMU body frame at the start time (s 0 ): It coincides with the slave INS body frame at the start of transfer alignment. This frame is non-rotating relative to inertial frame.

Earth frame (e): Geocentric frame. Inertial frame (i): Frame considered non-rotating and unmoving for the entirety of the transfer alignment.

III. RAPID TRANSFER ALIGNMENT ALGORITHM FOR SOTM

In traditional transfer alignment, the master INS and slave IMU measure the same variable in their respective reference frame. In this work's application case, the two inertial platforms are separated by a kinematic chain. This kinematic chain's motion will induce a specific velocity difference between the slave and the master, and will therefore need to be compensated. It can also cause large and time-varying attitude differences between the master frame and slave frame.

In this section, the algorithm's structure is described, then the measurement and propagation equations are given. Lever arm compensation and integration method for the measurement equation are taken into consideration.

A. Algorithm structure A linear system can be defined with a measurement matrix H and a propagation matrix A. Using these matrices and a measurement vector Y , it is possible to estimate the system's state vector X with linear equations:

Ẋ = AX Y = HX (8)
The state vector to be estimated is:

X = q n0 s0 q m s T (9)
with q n0 s0 being the attitude of frame (s) relative to frame (n) at t = 0, and q m s being the attitude of (s) relative to (m) at the current time.

The inputs of the algorithm are as follows:

• v n m/e :

B. Measurement equation

The method of this work is based on the pseudomeasurement equation explained in [START_REF] Chen | New rapid transfer alignment method for SINS of airborne weapon systems[END_REF]. This Section III.B briefly recaps the elements from this former reference that are needed in order to understand the rest of the paper.

The measurement model is a pseudo-measurement equation as all the terms of the measurement vector Y are zeros. In order to get to this, first we define two vectors α and β such as:

α(t) = v n0 n/e|comp (t) -v n0 n/e|comp (0) + t 0 C n0 n ((2 ω n e/i + ω n n/e ) × v n n/e -g n )dt (10) β(t) = t 0 C s0 s f s dt (11)
v n0 n/e|comp is the master INS velocity compensated for lever arm effect. Its calculation is detailed in Section III-C. The details of the real-time calculation of [START_REF] Zhou | Novel rapid transfer alignment algorithm for strapdown inertial navigation system[END_REF] are given in Section III-D. α(t) and β(t) are the quaternions associated with vectors α(t) and β(t). We can then write the pseudo-measurement equation:

(0 8×1 ) = γ(α(t)) -χ(β(t)) 0 4×4 χ(q s0 s ) -γ(q n0 m ) X (12)
As a conclusion,

H = γ(α(t)) -χ(β(t)) 0 4×4 χ(q s0 s ) -γ(q n0 m ) (13)
The details of the calculation of q s0 s are given in Section III-D.

C. Lever arm compensation

In [START_REF] Cui | A unified model for transfer alignment at random misalignment angles based on secondorder EKF[END_REF], v n0 n/e|comp refers to the velocity of the master INS in reference frame n 0 compensated for level arm effect. v n0 n/e|comp is an estimation of v n0 s/e , the velocity of the slave IMU in reference frame n 0 .

By decomposing v n0 s/e , we get the following:

v n0 s/e = C n0 n (v n s/m + v n m/e ) (14)
v n m/e is the master velocity in n frame and is given by the master INS. C n0 n can be calculated knowing the position of the vehicle and the curvature of the Earth. However, v n s/m is unknown and must be calculated. This calculation uses the measurements from the encoders located on the azimuth and elevation axes and the dimensions of the different parts of the APS. The APS configuration is illustrated in Fig. 1.

Let us define the following matrices:

• R z (θ) is the matrix expressing the rotation of angle θ about the z axis. • R y (θ) is the matrix expressing the rotation of angle θ about the y axis. In our application, the dimensions of the vectors M A, AE and ES are in the order of one meter.

v n s/m can then be computed through kinematic considerations. Because the azimuth and elevation rotation operate only on one axis, we have ω m b/m = 0 0 θAz T and ω b s/b = 0 θEl 0 T , yielding:

v n s/m = C n m (S(ω n m/n )( M A + R z (θ Az )( AE + R y (θ El ) ES))) + C n m R z (θ Az )(S(ω m b/m )( AE + R y (θ El ) ES)) + C n m R z (θ Az )R y (θ El )S(ω b s/b ) ES (15)
Using [START_REF] Cheng | A novel polar rapid transfer alignment for shipborne SINS under arbitrary misalignments[END_REF], the lever arm effect can be compensated knowing the system's dimensions, the vehicle position, and the angular positions and angular rates on the azimuth and elevation axes.

D. Integration

In modern transfer alignment, the computed slave velocity and attitude are accessible measurements, although they contain sensor errors [START_REF] Cheng | A novel polar rapid transfer alignment for shipborne SINS under arbitrary misalignments[END_REF], [START_REF] Cai | A polar rapid transfer alignment assisted by the improved polarized-light navigation[END_REF], [START_REF] Lyu | Adaptive UT-H∞ filter for sins' transfer alignment under uncertain disturbances[END_REF]. This is not the case in our application case: the slave IMU only provides rotation rates and acceleration. In order to compute q s0 s in ( 13) and t 0 C s0 s f s dt in [START_REF] Zhou | Novel rapid transfer alignment algorithm for strapdown inertial navigation system[END_REF]. these measurements have to be integrated in real time.

Using (1), we write:

qs0 s = 1 2 q s0 s × ω s s/s0 (16)
Since the frame (s0) is immobile relatively to the inertial frame, ω s s/s0 is the output measurement of the slave gyrometers. Equation ( 16) can therefore be integrated using q s0 s at the previous step to yield q s0 s at the current step. All that remains is the issue of initialization. Traditional rapid transfer alignment methods such as the one described in [START_REF] Kain | Rapid transfer alignment for tactical weapon applications[END_REF] calculate the slave attitude, making it necessary to approximate the initial slave attitude with the initial master attitude. Instead, we calculate the slave orientation between its initial attitude and its current attitude. At t = 0, the reference frames (s) and (s0) are aligned; therefore, by definition, q s0 s = 1 0 0 0 T .

C s0 s can be deduced from q s0 s . This allows the integration of the slave accelerometer output as done in [START_REF] Zhou | Novel rapid transfer alignment algorithm for strapdown inertial navigation system[END_REF]. It is initialized by β(0) = 0.

Notice that the errors on the measurement of ω s s/s0 and f s due to slave IMU imperfections will accumulate over time, and eventually they may cause these calculations of q s0 s and β(t) to drift from their real values. On the other hands, transfer alignment algorithms are commonly used for short period of times, which limits the extent of the drift due to error integration; in this work as well, we have verified that within the simulation time, no significant drift has been observed.

E. An innovative propagation equation [START_REF] Chen | New rapid transfer alignment method for SINS of airborne weapon systems[END_REF] made the hypothesis that any variation of X is due solely to process noise. While this is true of q n0 s0 by definition, it is not necessarily the case for q m s . In this work's application case, vehicle motion causes the APS to change the antenna's direction relative to (m) frame, so that the antenna's line of sight remains pointed towards the satellite. As a consequence, the (s) frame, aligned with the antenna's line of sight, changes its attitude relatively to (m) frame. Vehicle flexure also impacts the attitude of (s) relative to (m).

We will now develop a propagation model so that the observer can anticipate variations of q m s . According to (1), the derivative of q m s is as follows:

qm s = 1 2 q m s × ω s s/m (17)
The rotation rate ω s s/m is unknown, so we decompose it:

ω s s/m = ω s s/n -ω s m/n (18)
ω s s/n is the rotation rate provided by the slave IMU. However, ω s m/n is unknown. Using (2) in ( 18) yields:

ω s s/m = ω s s/n -q s m × ω m m/n × q m s (19)
ω m m/n is the rotation rate provided by the master INS. Rewriting ( 17) using ( 19) yields:

qm s = 1 2 q m s × (ω s s/n -q s m × ω m m/n × q m s ) (20)
We can then develop this equation. By using (4), we get:

qm s = 1 2 (q m s × ω s s/n -ω m m/n × q m s ) (21)
Using ( 5) and ( 6), we can put this equation in matrix form:

qm s = 1 2 (χ(ω s s/n )q m s -γ(ω m m/n )q m s ) (22)
By factorizing this, we can write the propagation model of this rapid transfer alignment algorithm applied to large variable angles:

Ẋ = 0 4×4 0 4×4 0 4×4 1 2 χ(ω s s/n ) -1 2 γ(ω m m/n ) X (23)
As a conclusion,

A = 0 4×4 0 4×4 0 4×4 1 2 χ(ω s s/n ) -1 2 γ(ω m m/n ) (24)
Equation ( 24) is an innovative propagation model expressing the misalignment quaternion's variations in time, thus extending the model developed by [START_REF] Chen | New rapid transfer alignment method for SINS of airborne weapon systems[END_REF] that only applied to constant misalignment angles. If the angle is constant,

( 1 2 χ(ω s s/n ) -1 2 γ(ω m m/n
))q m s = 0, yielding the trivial propagation model available in the literature.

IV. SIMULATION A. Simulation conditions

A simulation in a MATLAB Simulink environment is used to evaluate the performance of the proposed method.

The simulation model includes vehicle, APS and antenna simulation, and was developed by the company Thales.

The vehicle motion model is based on the work of [START_REF] Elkhouly | Standardized testing conditions for satellite communications on-the-move (SOTM) terminals[END_REF]. Two motion profiles have been simulated: relaxed and intense off-road conditions. An INS model in (m) frame, a two-axes APS and an IMU in (s) frame then use this motion information to calculate their respective outputs: master velocity, rotation rates and attitude, slave acceleration and rotation rate, and APS axis rotation angles. During the simulated scenario, the APS rotates the antenna until it points towards the satellite, then it keeps it inertially stabilized, causing a misalignement between (m) frame and (s) frame: it is this time-varying misalignement that the present work aims to estimate.

The slave IMU's specifications and noises are given in Table I. The slave IMU runs at 2000 Hz. The master INS is considered ideal and runs at 100 Hz. The Kalman Filter noise covariance matrices were determined through empirical testing. The structure of the algorithm, which includes calculation of the model matrices and Kalman filter, is given in Fig. 2.

The integration described in ( 16) and ( 11) are executed with a three-steps Adams-Bashforth method, more accurate than a forward Euler integration.

B. Simulation results

The initial convergence happens within 2.5 s in relaxed conditions and 15s in intense conditions (Fig. 3). This is accomplished without any specific manoeuver from the vehicle.

Two variables are of interest to examine the performance of the proposed solution. One is the estimation error (Fig. 3): the angle between the estimated antenna direction and the actual antenna direction. It is compared by the preexisting method developed in [START_REF] Chen | New rapid transfer alignment method for SINS of airborne weapon systems[END_REF]. Simulation results show that the estimation error stays beneath 0.22 • in relaxed off-road conditions, and beneath 1 • in intense off-road conditions. In both cases, for the same tuning, the proposed method performs better than the preexisting method. The other variable of interest is the pointing error: in a SOTM simulation similar to the one described in [START_REF] Broussard | Hybrid satellite position estimator using self-induced dither for SATCOM on the Move[END_REF], the algorithm results are used to control an APS and to point an antenna towards a satellite. The pointing error is the angle between the target satellite direction and the actual pointed direction, and its cumulative distribution over 200s is given in Fig. 4. Results show that 95% of the time, pointing error remains under 0.25 • in relaxed off-road conditions and 1.02 • in intense off-road conditions.

From the MIL-STD-188-164 standard [START_REF]Interoperability of SHF satellite communications Earth terminals[END_REF] and the formula given in [START_REF] Laine | 2D model-based step-track procedure[END_REF], we can conclude that this algorithm can be used to point antennas up to 82 cm in diameter.

V. CONCLUSION

This paper addresses the problem of estimating a large varying misalignment between two inertial platforms. The developed algorithm is an evolution of pre-existing algorithms using a linear model and quaternion representation, supplemented with a new propagation model for large timevarying misalignment variations. Simulation results show that the accuracy reached is sufficient for applications such as open-loop Satcom On-The-Move pointing and inertial stabilization.

Future research will look into experimental validation and adaptation of the algorithm to the specific Satcom application.

Fig. 1 .

 1 Fig. 1. Structure of the antenna positionning system

Fig. 3 .Fig. 4 .

 34 Fig. 3. Amplitude of the angle between estimated antenna direction and actual antenna direction, top: driving in relaxed off-road conditions, bottom: driving in intense off-road conditions

  and defined as follows: NED frame (n): Local North-East-Down frame. NED frame at start time (n 0 ): Local North-East-Down frame at the start of transfer alignment. This frame is nonrotating with regard to inertial frame.

Master INS body frame (m): Orthogonal reference frame aligned with master INS axes.

  the master velocity provided by the master INS • ω m m/n : the master rotation rate provided by the master INS • q n m : the master attitude provided by the master INS • f s : the slave accelerometers output provided by the slave IMU • ω s s/s0 : the slave rotation rate provided by the slave IMU • θ Az and θ El : azimuth and elevation angles provided by the APS encoders, which can yield θAz and θEl through derivation

	• C n0 n , ω n i/e and ω n e/n can be calculated from the vehicle
	position in earth frame given by a Global Navigation
	Satellite System (GNSS).
	Fig. 2 gives an overview of the algorithm structure. Each
	step described on this figure are further detailed in the
	following sections.
		Simulink simulation environment
	𝑞 𝑚 𝑛0	𝐶 𝑛 𝑛0 , 𝜔 𝑒/𝑖 𝑛 , 𝜔 𝑛/𝑒 𝑛 Lever arm 𝐶 𝑛 𝑛0 , 𝑣 𝑚/𝑒 𝑛 , 𝜃 𝐴𝑧 , 𝜃 𝐸𝑙 , ሶ 𝜃 𝐴𝑧 , ሶ 𝜃 𝐸𝑙 compensation (Section 3.2) 𝑣 𝑚/𝑒|𝑐𝑜𝑚𝑝	𝑓 𝑠	Conversion to matrix 𝐶 𝑠 𝑠0	Quaternion 𝜔 𝑠/𝑠0 𝑠 integration (17) 𝑞 𝑠 𝑠0	𝑚 𝜔 𝑚/𝑛
		Calculation of α (10)		Calculation of β (11)
		α(t)		β(t)	Calculation of A (24)
		Transformation into quaternion α(t), β(t)		𝐴
		Calculation of H (13)
			𝐻
				Kalman filter
				ො 𝑞 𝑠0 𝑛0		ො 𝑞 𝑠 𝑚

𝑛0 Fig. 2. Block diagram of the transfer alignment algorithm

Laetitia Tosoni, Minh Tu Pham and Paolo Massioni are with Univ Lyon, INSA Lyon, Université Claude Bernard Lyon 1, Ecole Centrale de Lyon, CNRS, Ampère, UMR5005, 69621 Villeurbanne, France.

*This work is supported by the company Thales and Association nationale de la recherche


discourse analyst, Maitre Valérie Bonnet

Paul Université

Sabatier

Toulouse

Sport in Films: Symbolism versus Verismo. A France-United States Comparative Analysis

Keywords: France, United States, film genre, sports values

3) as a member of team Psycom (social psychology of communication). Her research focuses on sports broadcasting as well as the political, activist discourse within the African-American community

This work is part of a larger study on film genre which I led in another context, and which started off during a symposium on sports in films organized by Y. Descamps and D. Durbin. The issue tackled in this themed section -the political dimension of the mediated representation of sports -can also be studied in great length though sports films for, as J.-M. Frodon 1 underlined: "There is a natural kinship between cinema and the nation which rests on a common mechanism which they are made ofprojection."

While sport is omnipresent in the American audiovisual landscape -one only has to watch cable networks in the United States or even in France, where American audiovisual productions are also widely broadcast -it is far from being the case as far as the French production is concerned. Some would answer that I am forgetting about soccer's omnipresence of French television, sports networks such as L'Équipe 21, and movies such as À mort l'arbitre or Coup de tête, but that would be putting two different things on the same level qualitatively and quantitatively. If we focus on the subject of this article -movie production -more specifically, the ratio of fictions dedicated to sports is very superior in North America.

Visiting websites dealing with cinema or listing movies such as Imdb and others allows to back this statement. Moreover, the corpus of scholarly work on the issue is far greater across the Atlantic. Since there is no precise figure to quote, and since it is complex to draw a quantitative comparison between industries which are structured differently, what these studies, rankings and analyses from both regular people and scholars show is the strong dominance of American productions in both French and American rankings. Above all, it shows that these productions are different. Indeed, it is quite difficult to compare À mort l'arbitre with Any Given Sunday, only to name a movie known by French audiences. However, both were made by renown, critically-acclaimed directors, and both tackle the dark side of these two countries' most popular sports. When the latter deals with society's flaws through the highlighting of athletes' mistreatment for the sake of profit, the former chooses to show violence from bewildered fans. And while the latter often shows some on-field action, the former only shows sports through the penalty kick which sparked controversy and drama. Also, comparing The Run -which features the struggle of an athlete facing both social and family issues -with La ligne droite -which tells the story of an ex-convict turned guide for a disabled athlete, and how her new role helps her rebuild herself -brings us to the same conclusions. The part played by sports is not the same: while it is an entry point in American cinema, it is somewhat of an element of contextualization in French cinema.

However, there was a wave of films dedicated to sports in these two countries during the same periodthe 1920s and 1930s. Those films focused on sports which were popular and whose practice was on the rise in these two societies -namely baseball and football in the United States, and soccer and cycling in France, with both countries sharing a common interest in boxing. During this same period, both these nations witnessed the rise of their first sports stars in baseball player Babe Ruth, Boxer Jack Dempsey, and football player Red Grange on the one hand, boxer George Carpentier -who was even more popular after he lost to the much heavier and taller Dempsey due to a fractured hand in the second round -cyclist André Leducq and soccer player Marcel Domergue on the other hand.

We shall tackle these different approaches based on aesthetics, socio-economics or ideology. But first of all, we shall define the sports film genre.

Film genre theory

Considering the genre as the product of the interaction between a language (in this case, cinema) and an institution (sports), we will question the social existence of the sports film genre (external criterion), and then try to define their attributes and properties (internal criteria). Those criteria, as written previously, include esthetical, ideological and socioeconomic dimensions.

Sports film as a genre

Contrary to literature, where genres are associated to some hypertextuality or regulating conventions (to write a sonnet, one must follow a few rules), cinema uses what we shall call a programmed hypertextuality that literature does not elude either if we consider page turners and other serial productions. On another aspect, cinematic genres are usually defined in regards to the relation between the context and the plot.

The notion of genre does raise many debates on the different categories as well as criteria to be applied.

Thus, American scholarly books offered the following list of famous, identifiable categories:

• Action, adventure, comedy, crime/gangster, drama, epics/historical, horror, musicals, science fiction, war, westerns.

Most of these genres were created at the end of the silent movie era: melodrama, western, horror movies, comedy, action and adventure, from swashbucklers to war movies. Musicals started with the era of talkies, and science fiction films appeared around the 1950s. The rise of the number of films and their diversity, linked to the different audiences, led analysts to go a step farther and come up with subcategories, thus stratifying the genres. These subcategories can also be identified through the narrative scheme -i.e. characters, plot, and context. One of the most referenced categorizations is the one formulated by Tim Dirk 2 : biographical films ("biopics"), 'chick' flicks (or gal films), detective/mystery films, disaster films, fantasy films, film noir, 'guy' films, melodramas or women's "weepers", romance films, sports films, supernatural films, thrillers/suspense films… This website even proposes to subdivide this subdivision: aviation films, buddy films, caper films, chase films, espionage films, "fallen" woman films, jungle films, legal films, martial arts films, medical films, military films, parody films, police films, political films, prison films, religious films, road films, slasher films, swashbucklers, etc.

We notice that the more we go down subcategories, the more they are classified according to content. The sports film genre does appear at an intermediary step, where the genre is not defined according to its plot or theme. If we take a look at the history of film production, we can see that the "sports film" genre exists in representations and categorizations formulated by popular sources (Wikipedia, Vodcaster, Top100, etc.), as well as institutional ones (an article from the e-Journal USA review edited by the State Department dedicated to film business dealt with this theme), or academic ones (Crawford, Erickson, Pearson and al., Miller, etc.). D. Pearsons and al. [START_REF] Pearson | Sport Films: Social Dimensions Over Time, 1930-1995[END_REF] released a quantitative study in which they identified 590 American movies over 65 years that they qualified as "sports films". Several books show the presence of the genre in the field of sports studies, in sociology and history, as well as in film studies.

Sports films are often brought up in sociological and historical analyses as representations and constructs of social identities (they are relevant in terms of gender studies and racial studies) or intergroup relations (in the context of the Civil Rights struggle to represent the relations between African-Americans and the white majority, or the Cold War to tackle the USA-USSR divide), but also as representations of the history of sport itself. In any case, the genre is not studied as such. It is seized as a sui generis reality, while its characteristics virtually stand unquestioned.

Toward Defining Sports Films

In his own words, G. Jones [START_REF] Jones | In praise of an 'invisible genre'? An ambivalent look at the fictional sports feature film[END_REF] was very ambivalent while trying to define the "sports film" genre. D.

Pearsons and al. underlined the difficulty in framing this genre because of the variety of themes tackled.

Mosher [START_REF] Stephen | The white dreams of god": the mythology of sport films[END_REF] showed the diversity in plots from comedy to tragedy, romance or satire, while C. Summerlin 6 divided them into mythical, celebratory and biographical "genres". To conclude their studies, these authors wrote the following definition:

Our definition of a sport film, or film centrally focused on a sporting theme, consisted of themes or subjects focusing on a team, a sport saga, or a specific sport participant (i.e., athlete, coach, or agent) in which sporting events engaging the participants in athletics were the primary activity of the film and cognitive abilities predefined in a setting of ranking or winning or losing [START_REF] Pearson | Sport Films : Social Dimensions Over Time[END_REF] .

However, this definition does not reflect the state of research on this genre, which went beyond a certain kind of tautological definition (for instance, a western takes place in the Western part of America) for, as stated earlier, sport lies at the intermediary level of a definition which implies aspects of the plot and theme. To use a popular saying, one shall not mistake sports films with sports in films.

We have to go back to defining the numerous criteria of a film genre. R. Altman summed up the notion of film genre as it was defined in the literature. He brings out the following 7 characteristics: a genre has a social function, and it is characterized by a repeating strategy and a cumulative economy which mobilizes a dual structure, some kind of predictability, and privileges intertextual references. These characteristics could be found in sports films:

⎯ A dual structure based on a conflict of values leading the audience to focus on one character or the other alternately; the team (including or not the coach) could be considered as one single character.

⎯ A repeating strategy: The use of similar shots and stories (see Invictus), the creation of a genre iconography (with slow-motion sequences in track and field, boxing clubs filled with smoke and dust at dusk, footing on the beach, and triumphing home runs in baseball), conflicts solved by the same outcomes and messages (knowing the other, winning through facing obstacles together, going through adversity), i.e. every ideological dimension of sports in films.

⎯ A cumulative economy: The movies follow an inter-and intra-textual serial strategy, i.e. they accumulate gags, scenes of panic; they accumulate goals, points and dunks through pulsing editing [START_REF] Vernier | Nouvelle forme scénique des jeux TV[END_REF] .

⎯ Predictability: The pleasure in the genre lies in the reaffirming of conventions which the audience knows and identifies in the film, i.e. the positive value of sports.

⎯ A tendency for intertextual references: Sports films feature multiple references to great people and episodes in sports history, through the names of characters, cameos and so on [START_REF] For Instance | [END_REF] . Identifying them calls for a solid knowledge of sports history.

⎯ A symbolic dimension attached to sounds, situations and images: The strong reconciliatory dimension of the teams in Remember the Titans and Invictus are materialized through final handshakes in the former and hugs in the latter, while the fact of surpassing oneself and one's condition in boxing films is symbolized by the use of meat as hitting bags in Rocky 2.

⎯ A social function 10 allowing to fictionally resolve cultural or situational conflicts which society cannot settle. We can name racial reconciliation (Glory Road, 2006), self-respect and teamwork (Coach Carter, 2005), victory over adversity (We Are Marshall, 2006), the possibility of making dreams come true (Invincible, 2006), or the victory of (sports) values over (sports) commoditization (Any Given Sunday, 1999).

But this set of characteristics does not provide formal features which could be heuristic for our purpose. R. Altman proposes a definition which is a synthesis of the generic definitions founded on common traits (called semantic elements), and the generic definitions founded on relationships between placeholders (called syntax). Beyond the fact that this generic definition is unanimously accepted, the reason why we chose it is that it is not only based on the issue of theme, but also on construction, structural (syntactic) criteria which are linked to the part played by a genre within society [START_REF] Altman | Cinema and genre[END_REF] . If semantic criteria belong to social codes and representation, syntactic criteria are the support of the genre, its grammar and meaning.

For instance, western films are characterized by their characters, settings, filming modes, and how these elements reflect ideas of wilderness and civilization (through the relations between the characters, between characters and places, etc.). It is through this definition that we consider the existence of an autonomous "sports film" genre 12 . Beyond the film's format (a narrative) and length (a full-length film), the semantic criteria defined by R. Altman also apply to the characters (coaches/athletes), the actors' performances (realism, physical play, physical and psychological performances as the athlete showcases a competitive frame of mind), the soundtrack (in situ or media announcing as well as cheers and applauses from the crowd during sports scenes) 13 .

The syntactic criteria are the following: ⎯ Narrative strategy: drama/comedy in relation to the athletic performance and life lesson taught through the movie. Thus, if we refer to popular categories on the "sports movies" Wikipedia page, these movies are mainly classified as metagenre -dramas and comedies, with biopics as the third, less important category 14 .

⎯ Team/narrative relations: The unfolding story is linked to the team's cohesiveness, i. As it is said in endnote #13, this list of criteria needs a few adjustments to be applied to sports films. The semantic criteria are more or less shared -sporting characters, emblematic locations such as stadiums, the sporting props, paradigmatic situations such as competitions -but the syntactic criteria seem to differ in both countries.

Is the "Sports Film" Genre American?

As perceived as such, the "sports film" genre was only illustrated by American examples. It was also the case in the institutional and academic analyses quoted earlier. That would tend to prove the genre's Americanness. Indeed, it does not seem to have been adopted by other cultures, even though other countries and geographical zones have produced their own genres such as the martial art film in South-East Asia, or the lucha pelicula in Mexico. However, another criterion comes into play in regards to the definition of sports practices: the institutional framework 16 .

N. Mingant's work 17 tends to validate this hypothesis: to globalize their productions, the majors would avoid promoting sports films as a strategy, or at least they would maintain them as low-budget productions targeting the local, national market. A series of socioeconomic and sociocultural explanations supports this idea 18 .

First Explanation: the Studio Policy

The "sports film" genre is a product of studio policy by definition. A. Miller 19 showed that the 1926-1941 period saw the rise of American College Sports Movies. This genre was quite popular in the 1920s and 1930s. The author underlined that Hollywood's interest in sports films, and especially football films, was based on this pastime's popularity, which made it an attractive subject. In the meantime, the newly institutionalized sports world saw in cinema an opportunity to be broadcast to larger audiences 20 .

Because of smaller social barriers between genders than in boxing or baseball, football movies could attract female audience: the relationships between girls (cheering for their boyfriends) and boys were mapping out the storylines. Moreover, college football -a WASP, upper-class sport -was hit by a wave of democratization. This phenomenon gave another opportunity to sell plots showing poor students dealing with the social gap separating them from their teams and classmates. Most of all, it was another opportunity to attract a broader audience [START_REF] Altman Underlines | As genres gain coherence and win audiencs, their influence in all aspect of the cinema experience grows. For production teams, generic norms provide a welcome template facilitating rapide delivery of quality film products. Screen-writers increasingly conceive their efforts in relation to the plot formulas and character types associated with regular genres[END_REF] .

During this period, the birth of the first sports stars -Babe Ruth, Jack Dempsey, Knute Rockne, Red Grange -became a source of inspiration for the Athletic American Dream, and it caught the attention of the studios: numerous successful athletes and Olympic champions appeared in films as themselves or in different parts. As S. Crosson (2014) underlines:

Such recognizable sporting figures in some cases added considerably to the appeal of the films in which they appeared, particularly 'assigning low-keyed films a magnetic box office attraction they would never otherwise have had' (Umphlett, 1984: 29) [START_REF] Crosson | All this must come to an end. Through talking: dialogue and troubles cinema[END_REF] .

During the 1940s, these appearances turned into real parts, and several biopics dedicated to sporting figures were shot -Knut Rockne, All American (1940), Gentleman Jim (1942), The Pride of the Yankees (1942). S. Neales considers that these biopics are a linking cycle between sports considered as "an instance of popular culture to wartime populism and to martial values like fighting spirit, tactical awareness and the acceptance of loss and occasional defeat" [START_REF] Neale | Genre and Hollywood[END_REF] .

Far from the artistic views of early French cinema or the curiosity aroused by the magic screen, the first broadcasting of sporting events took place in the 1890s, and they had commercial purposes. The rising cinema industry used sport -which was itself on the rise. Also, the decline of sports films -which occurred in the 1960s according to D. Pearson and al. -coincided with the decline of the studios' industrial strategy.

Second Explanation: The Role of Sports in American Society

In American society, organized sport was actually an institution with a strong social dimension. Between the 1870s and 1940s, sports became the most popular cultural activity in the United States. Basketball was invented, college football turned into a mass spectacle, and baseball reached the status of America's pastime. Sports also became part of curricula -which illustrated Dickerson's emphasis on the importance of baseball as a tool for social integration teaching American values [START_REF] Gary E Dickerson | The cinema of baseball: Images of America[END_REF] . Both promoters and athletes linked countless virtues to it, defending the need for sports to assure the individual's vitality and the nation's grandeur through often-ideological speeches. Nowadays, the belief in sports' social role is still lasting, as many think it allows the teaching of and respect for values which are essential to Americanness, such as competitiveness, equality of chances, or social mobility. These are widely spread in society, and they solidify a close relation with "the imagined community who founded the nation" [START_REF] Marquis | La balle et la plume[END_REF] . The EJ (e-Journal USA) review's issue dedicated to the film industry allows to seize the part played by sports in institutional representations:

"Sports are part of the very fabric of American life, discourse, and lexicon (...) The centrality of sports in American life is amply reflected in contemporary American cinema, (with) films featuring virtually every major sport, from football, basketball, baseball, and hockey, to boxing, horse racing, and even surfing." [START_REF] Firestein | Fields of Dreams: American Sports Movies[END_REF] Cinema does reflect social issues. As Miller wrote, this is why college football films appeared in 1930s America, especially because of scholarships being more and more available to students from lower classes. The plots did reflect the potential part played by football as social equalizer (see above). As a college sport mostly played by middle-class young men who happened to go to the movies, football was perceived as a modern, industrial sport. This trend increased, leading to football dethroning during the 1950s older, rural baseball whose success was attached to its Americanness 27 .

As western movies reflect the opposition and complementarity of the wilderness and civilizationone of the US's founding myths -, sport films work on the duality and complementarity of the individual and the group, whatever the extend of this onefrom the athlete/coach couple to wider communities such as a team, a college, a village, a nation.

Myth and Community-Building Sports

As a form of entertainment and social and cultural development, sport was also one of the great 20 thcentury myth-builders according to authors, as it gave birth to the then-famous athletic American Dream [START_REF] Bryant | Sociological dynamics of sport and exercise[END_REF] . While sports and cinema were perceived as two tools for social integration in a period of immigration, they mixed in a film genre which was on the rise during the Great Depression. We can see that through the growing number of people playing community-building sports such as football (the first team sport to be featured in a movie), baseball, and basketball. The sports which were the most featured on the big screen were boxing (140), football (87), car racing (80), and baseball (72). They made up for about two thirds of sports films which were produced from 1930 to 1995. Basketball was featured in 27 total movies -20 of them being produced since 1970, while its number of players rose. Sports sociology finds in sports films a showcase of representations built by the American society for itself, as well as an entry point to examine and analyze its culture. Once more, institutional articles illustrate this, as the E Journal USA review clearly underlined: "Reflecting Americans' love for sports of all kinds, U.S. filmmakers turn repeatedly to sports themes to convey messages much larger than the stories themselves" [START_REF] Firestein | [END_REF] .

Pearsons & al. [START_REF] Pearson | Sport Films: Social Dimensions Over Time[END_REF] showed that, as prisms of the American culture, the scenarii and tones of sports films matched the social issues of their times: selflessness and character-building in the 1930s, hyperpatriotism and nationalism in the 1940s and 1950s, democratization and social awareness, as well as the rise of counter culture leading to the decline of traditional such as football and even boxing as a symbol of hope for social mobility 31 during the 1960s 32 and 1970s, the rise of antiheroes and non-ethical practices as well as the microcosmic representation of society in the 1980s and 1990s.

Thus, Markovitz [START_REF] Markovits | Pourquoi n'y a-t-il pas de football aux États-Unis ? L'autre "exceptionnalisme" américain[END_REF] showed that the American identity was partly built upon "its" sportsmeaning its three main sports allowing a distinction from England as they were local adaptations of English sportsbaseball for cricket, football for rugbyor creation of their own practices in the case of basketball. In fact, the three most quoted subgenres within the sports film category are football films, baseball films, and boxing films 34 .

Altman 35 defined the notion of generic community based on the common acceptance of a label attached to a group of films, this label implying that the audience shared a view on the world. It is unquestionably the case with American sports films, as their very existence is acknowledged by scholars and audiences who at least share a common view on the part played by sports in American society and culture.

A French School or an Authorial Logic?

The French situation is for the more different. If we consider so-called sports films, there are way less productions, and among these, we find social critics such as À mort l'arbitre, tall stories which vaguely tackle sports such as Les fous du stade, aesthetic projects such as Zidane, un portrait du XXI e siècle, and biopics such as Édith et Marcel. In regards to the diversity of these films, it is difficult to find them all as part of a single genre. Moreover, they are rarely described as "sports films", for sport is often only in the background, as a reference to lower classes through soccer and cycling, or part of the characters' construct -a Southerner will play rugby, while a tenacious character will practice a sports which requires stamina. In a nutshell, going back to Altman's criteria, those elements do not held any particular meaning in the inner structure of the text. However, sport is far from being totally missing in French society and films, as we remarked earlier. As it was the case in the United States, the golden age of sports in France took place between the two World Wars: as it was on the rise, French sport was celebrated in novels, poems, and statues, and it became an important part of French society [START_REF] Veray | Aux origines du spectacle sportif télévisé : le cas des vues Lumière[END_REF] . As in the United States, popular sports such as cycling and soccer played an important part in films 37 , as they allowed to build the myth of a French sports culture. The reasons for the non-creation of this genre in the French context lie elsewhere.

First Explanation: The Absence of Studio Policy and a Weak Production in the Genre

The first reason is the absence of a studio policy. France does not follow an industrial cultural strategy like the United States: "In this context, which is different from the studios', the process of genre-building also goes through expansion, but it adds new traits and characteristics, sometimes derived from a mix of national elements and American ones, to existing, national genres" 38 . The notion is not clearly delimited in the context of the French market. Thus, so-called "boxing films" refer to both comic fictions and broadcastings of bouts in theaters in the two weeks following the events [START_REF]These "film rights" were quite important in the cinema economy[END_REF] . Pierre Sorlin [START_REF] Sorlin | Le cinéma français a-t-il échappé à la tentation des genres ?[END_REF] wrote that there is only one genre we could qualify as a French genre: police films, also called "gangster movies" or "French film noir" which were made over four decades with an insistence on inter-individual relations, a particular care for the description of the atmosphere, a pessimistic tone, etc.

The model for genre-creating in Hollywood -with a strategy of studio organization and competition between companies -or in the cultural spaces of an autonomous cinema production strong enough to digest outer influences is different from the one in non-autonomous cinema productions caring to maintain a cultural identity and resist the American cinema dominance since as early as World War I, and also during the 1950s [START_REF]Le roi de la pédale was promoted by[END_REF] . The concept of school or école was born during this period, establishing cinema as an art form, away from the American industrial ways, even though French cinema pondered following the American industrial model when it tried to recapture its lost dominance. Critics were working on the rise of productions linking artistic success with national identity (réussite artistique et identité nationale [START_REF] Gauthier | Le cinéma des nations : invention des écoles nationales et patriotisme cinématographique (années 1910-années 1930)[END_REF] ), based on the heritage and reappropriation of French authors and masterpieces. This cinéma des nations lasted until the 1930s and was also relayed by authorial logics mostly highlighted by the Nouvelle vague. Movies were then rated on the basis of an individual view, the director's, as he influenced the film's characters, aesthetic, and atmosphere with his or her vision: "As they wanted to be seen as authors and not mere film makers, French directors stayed away from genres which would hurt their reputation" [START_REF]les réalisateurs français, soucieux d'être considérés comme des auteurs et non comme de simples metteurs en images se sont tenus éloignés des genres qui nuiraient à leur réputation[END_REF] . As a result, the authorial logic undoubtedly went before the genre logic, making Million Dollar Baby a Clint Eastwood movie more than a boxing film in the eyes of the audience, while this latter genre somewhat did exist in France (see below).

Second Explanation: A Despicable Object

Going back to R. Altman's criteria, we shall consider the issue of reception. As P. Sorlin wrote, the French public is actually "less film-hating than film-loving" (moins cinéphage que cinéphile [START_REF] Sorlin | Le cinéma français a-t-il échappé à la tentation des genres ?[END_REF] ), while genre films are considered undignified by the French.

Sport is also considered as undignified in the French collective imagination. Films tackling sports are often used as an opportunity to denigrate a stupefying, corrupted environment, as in À mort l'arbitre, Coup de tête or Le vélo de Guislain Lambert. This phenomenon dates back a long time, since La fausse maîtresse (1942) showed how rugby kept men away from their homes and made them neglect their wives, and Rue des prairies (1959) denounced the corrupted world of professional cycling.

Very far from myth-building, symbols, and an emphasis on the values of sports, French movies reflect some distrust toward sports -which can be seen in scholarly works which went beyond academic circles such as books by J.-M. Brohm and M. Perelman [START_REF] Brohm | Les meutes sportives : critique de la domination[END_REF] -as well as toward genre films. Thus, French commentators prefer categorizing boxing films -an American subgenre which experienced somewhat of a golden era in France -as films noirs 46 over sports films. More generally, the French specialists in film genres do not take it into account, even as a subgenre.

In a context more prone to denounce athletes' misbehaviors -from errands by soccer players to doping scandals in cycling and corruption in any sports federation -sport is clearly not a theme on which the film industry, if we can call it this way, could capitalize. Moreover, even though movies do often highlight its values, sport does not have a nation-building power, as the French situation calls for identifying to a national identity rather than an identity in the process of being constructed [START_REF] Thus | icônes de l'utopie impériale dans la presse métropolitaine (1936-1944) ?[END_REF] . Furthermore, it is difficult to consider soccer as a national pastime, as popular as it is, for it was imported. Often despised, sports became a pretext to burlesque in movies showing some amateur lost in a sport he does not master... only to win by mistake, as it is the case in J. Tati's sports parodies (Oscar champion de tennis, 1932). Also, in early films, boxing is often part of a comic narrative (Soigne ton gauche, 1936).

A Language Not Matching the Genre's

These examples show the lack of compatibility with the genre's syntax. If the serial logic as well as the David-against-Goliath duel narrative are to be found in these films, the symbolic dimension of sports -or at least its social function -is often tarnished, as we have seen. In the absence of any genre logic, there are also only a few intertextual references. But above all, as it is left aside by film enthusiasts, sports predictability is not compatible with films which -for writing purposes -are built on luck [START_REF] Amy De La Bretèque | De Biscot à Gabin ; les héros sportifs dans le cinéma français, évolution du système du vedettariat et trajectoire d'héroïsation (1925 -1965[END_REF] as the main source for comedy as well as the best way to reproduce the glorious uncertainty of sports on the big screen.

More generally, if we focus on great movements following the cinéma des nations' aesthetic realism, F.

Truffaut's Qualité française and the Nouvelle vague, we note that both these two movements' film grammars were not compatible with sports. The former was based on dialogues, while the latter was based on studio-making, settings, scriptwriting, adaptations, and costumes. They did not match sports' modernity and need for outdoor action. The last movement was based on a light technical setting and it excluded realism. Once more, this did not allow the recreating and filming of the sports spectacle, which often calls for a heavier setting 49 .

In a nutshell, these explanations mirror the American situation. As it does not follow a serial logic, and as it denounces sports and its political use while criticizing it, the French socio-economic and intellectual context does not favor the exploitation of sports films. The films mentioned above follow a formal approach more than a symbolic one. F. Amy de la Bretèque 50 underlined that the spectacle of sportbeing it the Tour de France or a rugby match -came first, while the performance and its symbolic dimension only came second in terms of value in the first films featuring sports heroes.

Beyond these Explanations

At the end of this rather short excursus whose aim is to draw a comparison between the parts played by sports in the media and cultures of two societies which share a strong film culture with several exchanges in that regard [START_REF]Cinéma américain et théories françaises : images critiques croisées[END_REF] , it seems that beyond the explanations mentioned above, we should also tackle the difference between emotions which are conveyed through sports and films.

Indeed, as R. Moine underlined, "film genres bear with them and within them the mark of other literary or spectacular genres with which they sometimes share a degree of vagueness or preciseness" 52 . In the case of our study, the notion of spectacular genre would refer to sports contests -mediatized or not. This fact explains the totally different importance of sports films in the French and American cultures: when in the American culture, we shall talk about a sports film genre, in France, we shall consider a more or less heterogeneous collection of films. The criteria for making these films are different. Critics (such as Les cahiers du cinema) and academic reviews as well as testimonies from actors and spectators bring up a systematic comparison between films and sports broadcasting which always ends up in favor of the latter, as the poetic dimension is not associated with cinema in that regard. This view was already to be read in the 1920s and 1930s, our main period, which gave birth to the then-recurring use of game action in film editing [START_REF]See the « Rugby et cinéma[END_REF] . Representational movies gather actors and professional athletes [START_REF]Another aspect in the comparison with sports is the idea of a competition between films and sports: A racer arguably told Biscot, the leading role in Le roi de la pédale: « I don't like cinema[END_REF] , and strong ties were built between the film and sports industries. For instance, Descoins, scriptwriter of Le roi de la pédale, was a former sportswriter, and the chosen actors -Biscot, Préjean, and Gabin to a lesser extent -turned more or less professional. On the contrary, G. Carpentier shot his own biopic in as early as 1914 (Le roman de Carpentier) before starting his career as an actor once he hung up the gloves, to play parts of his making as a boxer, with images of his fights sometimes mixed with images from the shootings. As a movie unanimously acclaimed by the rugby-loving community, La grande passion (1928) owed its success to the help of the Stade Toulousain club, players and international players in writing and shooting the movie.

The French strategy of verismo does not match the genre system as it is linked with symbolism. Indeed, what makes the value of sports films and also allows to attract other audiences than aficionados -as it is the case with The Endless Summer -is the status of sports as an omnibus subject, as P. Bourdieu wrote [START_REF] Bourdieu | Sur la télévision[END_REF] .

The French audience is looking for a filmed sports contest, while the American audience is more attached to the symbolic and cultural dimension of sports. Thus, so-called cheerleading films can be categorized within the sports film genre 56 . In a way, the sports film genre implies another discourse on sports which allow real or fictitious storytelling through the values attached to sport in realistic or humanistic movies from mainstream film productions. While it does not find this in films, the French audience does find it in sports reporting, as reporters do not miss an opportunity to teach those life lessons.

12 R. Altman does not cite sports film as a genre, but he mentions boxing films as the product of a genrification process, and baseball and surfing films as minor genres.

13 If we compare this with R. Altman's work on musicals, sports scenes -which are metaphors for a psychological evolution which belong to diegesis with their images from diegetic media (see Any Given Sunday)would stand more as the equivalent of music scenes than the soundtrack itself.

14 However, we can question the status of biopics, which would stand as a metagenre more than a subgenre to me. 15 Jean-Marc Vernier, « Nouvelle forme scénique des jeux TV », Quaderni, 4, 1988, 57-63. 16 Depending on definitions, a physical practice is called sport on the basis of the following criteria: Thus, this definition implies to be affiliated to a federationwhich does not appear in the lucha peliculaand to be set in the framework of official competitionswhich is not to be found in martial art movies. American baseball teams and stars, movies, magazines, and radio programs, brought Canada close to the USA in the second and third decades of the twentieth century. Concerning Australia, R. Fotheringham is very cautious about Australian sports films. He demonstrates that there are few movies dedicated to sport in the Australian film industry -these productions trying to erase the Australian roots from their plots for exportation purposes. The most part of the corpus brought up by this author is made of racing movies, which are borderline cases -races are considered as a game more than a sport ; see # 16. Nowadays, there is a proper film industry in both these countries, partly producing sports films dedicated respectively to ice skating/hockey and surfing, but deeply rooted in the American seminal production. For the sake of the comparison, we shall focus on the USA. Culture, vol. 43, no. 6, 2010. 20 Andrew C. Miller, « The American Dream Goes to College: The Cinematic Student Athletes of College Football », 1226.

  e. the athlete(s)-coach(es) relation. The story follows the physical and psychological evolution of the characters and their close circles. ⎯ Sport/narrative relation: Sport is an active agent in the production of meaning around the team's cohesiveness (failure, success and the reasons why they happened). ⎯ Narrative/sport cycle relation: Practices and competitions are shown alternately as narrative stages which highlight a climax in every sequence. ⎯ Image/sound relation: This follows the hierarchy between preparation and actualization. The truly narrative moments are not the sports scenes, which are often summed up through a short, fastpaced video clip with music following an energetic regimen 15 .

⎯

  A set of motor situations, ⎯ A of rules, ⎯ Stakes related to competitiveness, ⎯ An institutional framework.

17

  Nolwenn Mingant, « Entre mondial et local : le jeu d'équilibriste des majors hollywoodiennes », Revue de recherche en civilisation américaine, 1, 2009, URL : http://rrca.revues.org/138 <accessed on September 19, 2016>. 18 It may be argued that there are numerous sports films in Australia or Canada. But, as Lorenz underlines: « Likewise, the United States gained a stranglehold on the Canadian movie market in the 1920s. Canada was regarded as Hollywood's "domestic" box office, and almost all of the movies Canadians watched were made in the United States » Stacy Lorenz, « A Lively Interest on the Prairies": Western Canada, the Mass Media, and a "World of Sport" 1870-1939 », Journal of sport history, 2000, 19.

19

  Andrew C. Miller, « The American Dream Goes to College: The Cinematic Student Athletes of College Football », The Journal of Popular


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Delphine ARAN & Florence MAUNOURY-DANGER

University of Lorraine -UFR Sciences Fondamentales et Appliquées -Département Sciences de la Vie et de la Terre Laboratoire Interdisciplinaire des Environnements Continentaux LIEC CNRS UMR 7360 8 rue du Général Delestraint, 57070 Metz, France / delphine.aran@univ-lorraine.fr / florence.maunoury-danger@univ-lorraine.fr

What is soil?

The first activity aims to get pupils/public thinking about a definition of what we call "soil".

Through open questions, they are encouraged to discuss what the word "soil" means to them : "the soil of my grandfather's garden", "the classroom floor", "the ground of the planet Mars!" (in French, all these concepts are called "sol").

The different proposals are discussed with the students supervising this activity (and the authors supervising the students) and a definition of soil is proposed by using little posters or drawings.

Particular attention is paid to the origin of the soils, their formation, their organization into horizons.

Created specifically for the International Year of Soil, a pedagogical project focused on soil sciences has been developed by the University of Lorraine. The aim of this project is to elaborate an educational activity about soils, through observations and experiments designed for a young audience and for a general public.

Therefore, the authors and students from bachelor to master levels have jointly developed this workshop and make it evolve every year. Students had thus the opportunity to practice and improve their learning in soil sciences, and also to debate about teaching methods and sharing their knowledge with different people. This kind of active learning is regarded as one of the effective educational methods (Filed et al., 2011). This trip through the soil is structured in 4 parts: the students guide the public between the different activities described hereafter.

To explain briefly what are the delimitations of the soil, a comparison is made with the skin of an orange "Worm stories" is always a favorite among the visitors

What is the soil made of?

Here the organization and constituents of soils are approached in order to show the great diversity of soils and their essential properties.

Participants can touch different types of soil texture in order to compare them, they can also perform the HCl test, as well as manipulation using eosin and methylene blue. These experiments enable the concepts of soil constituents, parent-material, exchange and retention properties to be addressed.

Finally, the observation of the organization of the soil at different scales provides an opportunity to evoke the notions of structure, aggregation, porosity and water circulation.

What is soil biodiversity?

What are human uses & impacts on the soil?

A final activity is based on a carpet representing the different types of land use: urban, forest, agricultural, etc. Small objects are placed on top, representing the services provided by the soil (toy vegetables, tractor, pieces of wood, etc.) or the dangers that threaten it (plastic waste, model of a building, etc.).

This workshop, led by authors and students from the University of Lorraine, has been experienced by over 700 pupils from schools since its creation. It allowed the young public to discover and manipulate soils in a playful way. It was also an opportunity to show their teachers many educational activities that can be carried out in soil sciences.

This workshop is also open to the general public (about 300 visitors) to raise awareness of the importance of soil conservation. In addition, the involvement of bachelor's and master's students in the creation and management of this workshop enables them to better integrate the major issues in soil sciences. A discussion takes place with the participants to identify these services and threats. Then they place a label with a green circle (services) or a red triangle (threat) near to the involved place.

The activity ends with a discussion on the simple things that everyone can do to protect soils (avoid using pesticides in the garden, do not throw waste into the environment, etc.). Another activity focuses on soil biology and ecology through the use of a terrarium containing soil, litter and soil fauna.

The pupils can thus directly go in search of the inhabitants of the soil: woodlice, millipeds and other bugs. They can also observe their morphological details with binocular loupes.

These observations allow to discuss biotic interactions (who eats who? …) and the role of these organisms in the soil functioning (organic matter recycling …).

Exploring the terrarium to search soil fauna

Since its creation in 2015 on the occasion of the International Year of Soils, a workshop for primary school pupils and the general public has regularly taken place at the University of Lorraine (in the city of Metz, France), except for the last two years due to the pandemic. It enabled the visitors to discover the major issues of soil knowledge and the students involved in this project to appropriate these questions.

Field

  , D. J., Koppi, A. J., Jarrett, L. E., Abbott, L. K., Cattle, S. R., Grant, C. D., McBratney, A. B., Menzies, N. W., & Weatherley, A. J. 2011 -Soil science teaching principles. Geoderma, 167, 9-14. Photo credits : Delphine ARAN, Adrien LE NAVENANT, Florence MAOUNOURY-DANGER, Sandrine PAIN-DEVIN