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You are an expert at summarizing long articles. Proceed to summarize the following text: 
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The technical scope of the present invention is that of systems enabling the deployment of a modular bridge carried by a vehicle, able to be deployed over an obstacle to allow vehicles to get across. 
     2. Description of the Related Art 
     To cross a river, a ford or a ditch, it is well known to use a vehicle carrying girders that are to be deployed over the obstacle. The vehicle is namely equipped with means enabling the bridge to be deployed, motorization ensuring its autonomy on the field of operations and means reinforcing its resistance to attacks by various projectiles. It is thus generally a heavy and cumbersome vehicle, difficult to manoeuvre and only able to be used in zones of relatively easy access. 
     By way of example, reference may be made to French patents 2 637 300, 2 637 301, 2 731 447 and 2 731 448 in the name of the applicant. 
     All the bridges illustrated by these patents are generally carried by armored vehicles to ensure the protection of the crew and are of imposing mass. 
     SUMMARY OF THE INVENTION 
     The aim of the present invention is to supply a bridge laying system, for example a modular bridge, that only requires light, autonomous, remote-controlled means. 
     The invention thus relates to a system to lay a bridge between two banks, wherein it firstly comprises a bridge carrying vehicle constituted by a remote-controlled self-propelled platform incorporating means to deploy and retract the bridge, said platform being unmanned and armor-free, and secondly a control post comprising means to communicate with said platform. 
     According to one characteristic of the invention, the platform is motorized thus ensuring its autonomy over any terrain at a distance from the control post, such motorization being provided, for example, by a diesel engine. 
     According to another characteristic of the invention, the platform is of the tracked or wheeled type or is a combination of both. 
     Advantageously, the platform incorporates means to implement the bridge. 
     According to yet another characteristic of the invention, the platform comprises control means able to be actuated at a distance from a control post. 
     According to yet another characteristic of the invention, the communication means are constituted by a steering data transmission system for the platform and a system to control the bridge implementing means. 
     Advantageously, the communication means are of the fixed, ultrasound, sound, luminous beam, infrared link or radio wave type. 
     According to another characteristic of the invention, the platform is towed by a vehicle to the site the bridge is to be deployed. 
     According to yet another characteristic of the invention, the control post is located in an armored vehicle or technical shelter. 
     A first advantage of the system according to the invention lies in the safety it provides for the crew. Indeed, the platform carries no operators and its possible destruction does not endanger the crew. 
     Another advantage lies in the simplified design and production of the platform which no longer has to be protected against projectiles. 
     Yet another advantage lies in the fact that the platform may be produced using commercially-available components which don&#39;t have to be specifically designed for this type of military plant. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other characteristics, details and advantages of the invention will become more apparent from the description given hereafter by way of illustration in reference to the appended drawings, in which: 
         FIG. 1  is a side view of the platform, 
         FIG. 2  is a top view of the platform, 
         FIG. 3  is a side view of the platform equipped with the bridge, 
         FIGS. 4 to 8  show the different bridge implementing phases using the platform, 
         FIG. 9  shows a towed platform, and 
         FIG. 10  schematically illustrates a control post. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Bridge carrying vehicles currently used in the army are constituted by a self-propelled chassis with a crew of at least two. The protection constraints for the on-board crew generate masses of around 60 tons for a tracked vehicle and 50 tons for a wheeled vehicle. It is easy to understand that such vehicles require substantial motorization. 
     Both the mass and the high level of performance and cross-country mobility required means that in the design of these vehicles, specific components have to be created. Moreover, since the need for this type of equipment is not great, the production of new equipment is ruled out. 
       FIG. 1  shows a side view of a platform  1  in the form of a vehicle composed of a chassis  2  motorized by eight wheels  3  ( 3   a  to  3   d ). A heat engine  4 , of the diesel type, makes this platform mobile. As described previously, it goes without saying that the engine  4  enables the platform to be positioned as near as possible to the intervention site and makes it mobile over short distances. The platform is provided with reception and elevation means  5  and  6  placed at the two ends of the chassis and intended to receive the modular-type bridge. The Figure shows the spring parts  16  of the platform suspension and the stabilization elements  14  and  15 . 
     The platform  1  is shown alone and it can be distanced from the bridge after laying. This platform can either be kept at a close distance if the girders are to be recovered or can be guided to a storage area. 
       FIG. 2  shows a top view of the platform  1  where the wheels  3   d  can be seen to be driven by the engine  4 , a diesel engine for example, by means of a bridge  7  and in relation to a hydraulic pump  8 , and wheels  3   a  and  3   b  are equipped with linkage  9   a  and  9   b  to ensure steering. The hydraulic pump  8  provides the drive autonomy of the platform  1  and the implementing of the bridge thanks to a hydraulic network, not shown. The platform  1  is also provided with suspension elements  10  connecting it to the different bridges. 
     The platform  1  also incorporates a radio system  11  for the transmission of steering and implementation control data and may also incorporate cameras (not shown) to monitor the terrain and the different maneuvers. These cameras must provide a full 360° C. field of vision around the platform. The radio system  11  is in relation with a remote reception and transmission unit  12 . 
     To ensure the rapid transportation of this platform  1 , it will be towed by an armored vehicle  17  or by a towing truck, as seen in  FIG. 9 . Naturally, these two means may be combined depending on the level of hostility. For its positioning on the bridging site, the platform  1  is autonomous and is able to move at a speed o around 15 km/h, for example, with the aid of the engine  4  cooperating with the hydraulic pump  8  in relation with the hydraulic motors that activate all or part of the wheels  3 . 
     It is easy to understand that such a platform  1  obviates the need for on-board crew and thus the requirements linked to mobility, or ballistic, laser, nuclear and chemical protection, heat and air-conditioning are reduced. 
     Furthermore, such a platform  1  can be produced at a much lower cost than a vehicle equipped according to prior art, since the components used are those used, for example, on trucks. Thus, autonomy can be provided by means of a 150 CV engine. The platform  1  thus designed has a much reduced cost of ownership and may incorporate neither armored cab, nor NBC insulation, nor air-conditioning. 
     The platform  1  according to the invention, equipped with its modular bridge may be a piece of plant of around 25 tons, that is to say having a mass of half that of plant used up to date. 
       FIG. 3  shows the platform  1  equipped with a bridge  13 , for example modular, constituted of three girders  13   a,    13   b,    13   c.  The platform  1  also incorporates forward  14  and rear  15  stabilization means which must be lowered when the bridge elements  13   a – 13   c  are being maneuvered. The bridge elements  13   a – 13   c  are brought into the raised position one after the other by forward  16  and rear  17  lifting means part of the launching means  18  activated by a cylinder  19  integral with a support  20 . The lifting means  17  may be extended by an antenna  21  that communicates with the control post. 
       FIGS. 4 to 8  show the positioning of the three bridge girders  13   a – 13   c  between banks  22  and  23 . The stabilization elements  14  and  15  are first lowered to the ground and the platform&#39;s stabilization may be reinforced by an additional mass  24 . The first girder  13   a  of the bridge  13  is made to slide ( FIG. 5 ) above the launching means. If this bridge girder  13   a  is enough to span the banks, it is lowered to the round. If the banks are too far apart, the other two girders  13   b  and  13   c  are raised ( FIG. 6 ) until girder  13   b  reaches the launching means  18 . The girders  13   a  and  13   b  are connected together ( FIG. 7 ) and may be used alone if the distance separating the banks has been spanned. The same process is used to bring the last girder  13   c  ( FIG. 8 ) into position above the launching means  18  and girders  13   b  and  13   c  are connected together. The first girder is able to span distances of less than 9 m. Two girders are able to span distances of less than 17 m and three girders are able to span distances of less than 25 m. 
     The remote-controlled implementation of the platform  1  is carried out using a control post  30  housed in a vehicle or technical shelter located at a distance behind the intervention site of the platform  1 . This control post is thus protected and cannot be seen by any observers. This post, shown schematically in  FIG. 10 , is composed of a steering control post  31  and a command post  32 . 
     Post  31  incorporates a monitoring screen  33 , for example a video screen, the remote steering controls  34  for the platform to control movements backwards and forwards, steering lock in one direction, etc. and an implementation monitor  35  for the bridge used to control the different control means for the deployment of said bridge. This essentially requires the control of the cylinders in a known sequence in the bridge carrying vehicles. 
     Post  32  is constituted of a video screen  36  on which the platform control data is displayed, a cartography system  37  to guide the platform over the ground, and an implementation monitor  38  for the bridge as explained above. 
     Lastly, the control post  30  incorporates means  39  to radio transmit data to the platform  1  in relation with its corresponding means. Implementation is as follows. The platform  1 , equipped with its bridge  13  and the control post  30 , is brought and placed in the vicinity of the intervention site in a sheltered spot. A towing truck can both transport the post  30  and tow the platform. The control post  30  is set into position and the bridge is made ready for deployment. The platform  1  may be positioned a few hundred meters from the site. The platform  1  is then radio-guided until it reaches the bridge laying site. The deployment phases are then activated as explained in reference to  FIGS. 4–8 , said deployment being performed classically. The platform  1  is then distanced from the deployed bridge. 
     It goes without saying that the linking means between the post  30  and the platform may be fixed, sound, ultrasound, by luminous beam, infrared link or radio waves. The control post  30  may be on-board the towing vehicle. The platform  1  may itself be part of a girder or constitute an access ramp. Lastly, manual control means may be provided for the platform that can be used outside the operational site.

Summary:
A system to lay a bridge between two banks, wherein said system firstly comprises a bridge carrying vehicle constituted by a remote-controlled self-propelled platform incorporating means to deploy and retract said bridge, said platform being unmanned and armor-free, and secondly a control post comprising means to communicate with said platform.