Abstract:
An aircraft wireless network in an aircraft includes a maintenance server, a cabin server, a radio switch, a network switch, and a cabin access point. The network switch and radio switch are configured to arrange the aircraft wireless network according to at least two distinct configurations. In a first configuration the cabin server is permitted to connect to the at least one cabin access point by the network switch and a first aircraft access point is connected to the external antenna by the radio switch. In a second configuration the maintenance server is permitted to connect to the at least one cabin access point by the network switch and a second aircraft access point is connected to the external antenna by the radio switch. In the first and second configurations the maintenance and cabin servers are prohibited from simultaneously connecting to the at least one cabin access point.

Description:
TECHNICAL FIELD OF THE INVENTION 
     The present invention relates in general to on-line maintenance operations for aircraft and more particularly to a switching device adapted to switch an aircraft wireless network from a maintenance configuration to a commercial configuration and vice versa. 
     To optimize the reliability of aircraft and increase their profitability, on-line maintenance operations are frequently performed between the flying phases. 
     PRIOR ART 
     In general, such operations, in the case of maintenance operators, for example, consist in analyzing data stored in memory during flight and in modifying certain parameters of the aircraft. The analyzed data are often obtained from transducers and stored in memory in a central diagnostic and storage device accessible via a man-machine interface of MCDU type (initials for Multi-Control Display Unit in English terminology) or of OMT type (initials for Onboard Maintenance Terminal in English terminology). This interface, via which interactive operations can be launched, makes it possible to analyze data stored in memory and to access parameters of the aircraft. By way of illustration, the Airbus A320, A330 and A340 are equipped with MCDUs and the Airbus A380 is equipped with an OMT (Airbus, A320, A330, A340 and A380 are trademarks). 
     Thus, when the aircraft is on the ground, a maintenance operator can board the aircraft to access and analyze the data stored in memory and if necessary to modify the parameters of the aircraft. 
     Alternatively, mobile stations are being used to respond to an increasing demand of the airline companies as regards shortening the time for on-line maintenance operations. Such stations, whose purpose is similar to that of the interfaces of MCDU or OMT type, are connected to the central diagnostic and storage device via connection outlets connected to the network of the aircraft. 
       FIG. 1  illustrates an example of an aircraft  100  comprising a central diagnostic and storage device  105  connected to connection outlets  110 - 1  to  110 - 3 . In this case, outlets  110 - 1  and  110 - 3  are accessible from the outside of aircraft  100 , while outlet  110 - 2  is accessible from the cockpit. 
     Device  105  is, for example, connected to control transducers (not illustrated) of the engines and to actuators of the landing gear and control surfaces. 
     An on-line mobile maintenance station  115  is connected to device  105  via outlet  110 - 1  and the communication network (not illustrated) of aircraft  100 . 
     Thus, when aircraft  100  is on the ground, a maintenance operator is able, by means of mobile station  115 , to analyze the flight data of the aircraft and to modify the parameters thereof. 
     Although this solution meets the expectations of the airline companies, it is necessary to use a hard-wired link between an aircraft and a station to achieve on-line maintenance operations. Such a constraint has the effect in particular of prolonging the duration of maintenance operations and consequently increasing the costs of operating the aircraft. 
     To alleviate these disadvantages, there exist diagnostic systems that use a wireless communication technology, wherein the data obtained from transducers can be transmitted directly to the mobile on-line maintenance station. For example European Patent 1306305 discloses a system in which the transducers are connected to data storage and transmission devices. In this way, a mobile station is able to obtain flight data on request. 
     However, such a system is limited to accessing data without permitting modification of the parameters of an aircraft, and it necessitates the use of several storage and transmission devices. 
     The invention is able to solve at least one of the problems mentioned in the foregoing. 
     OBJECT OF THE INVENTION 
     The object of the invention is therefore a switching device in an aircraft wireless network, the said aircraft comprising a maintenance server and a wireless network, whose infrastructure comprises at least one cabin access point connected to at least one internal antenna and one cabin server connected to the said access point, this device comprising network switching means making it possible to modify the configuration of the said wireless network according to at least two distinct configurations, a first of the said at least two configurations permitting establishment of a connection between the said cabin server and the said cabin access point and a second of the said at least two configurations permitting establishment of a connection between the said maintenance server and the said cabin access point, the said maintenance and cabin servers being unable to be connected simultaneously to the said cabin access point. 
     Thus the device according to the invention makes it possible to modify the use of the wireless network deployed in the cabin and dedicated to the use of the passengers in such a way that a maintenance station can take advantage of the wireless mobility during an intervention. This mobility is assured in the interior of the aircraft. 
     Advantageously, the said infrastructure comprises at least one aircraft access point connected to at least one external antenna, the device additionally comprising the following means,
         communication means adapted to establish a junction between a server and an antenna in order to establish a wireless connection; and   radio switching means making it possible to modify the configuration of the said wireless network according to at least two distinct arrangements, a first of the said at least two arrangements permitting establishment of a link between the said aircraft access point and the said at least one external antenna and a second of the said at least two arrangements permitting establishment of a link between the said communication means and the said at least one external antenna, the said aircraft access point and the said communication means being unable to be connected simultaneously to the said at least one external antenna.       

     The device according to the invention therefore permits a user to move around outside the aircraft in a nearby environment while still remaining connected. 
     According to a particular embodiment, the said at least one aircraft access point is connected to at least one second antenna independently of the said radio switching means to permit the said aircraft access point to exchange data regardless of the configuration of the said radio switching means. 
     Advantageously, the said first arrangement is associated with the said first configuration and the said second arrangement is associated with the said second configuration, in order to change over from a normal mode of use to a maintenance mode and vice versa. 
     According to a particular embodiment, the device additionally comprises alerting means adapted to alert at least one crew member of the said aircraft when the configuration of the said wireless network corresponds to the said second configuration and when a predetermined condition is satisfied. Advantageously, the said predetermined condition comprises a configuration duration. Thus, if the maintenance mode has been selected for a time exceeding a predetermined threshold, the said at least one crew member is forewarned that the normal mode of use is not selected. 
     According to another particular embodiment, the said wireless network is at least partly a network of WiFi type. 
     Another object of the invention is a method for employing the device described in the foregoing as well as an aircraft comprising the device described in the foregoing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other advantages, objectives and characteristics of the present invention will become apparent from the detailed description provided hereinafter by way of non-limitative example, with reference to the attached drawings, wherein: 
         FIG. 1  represents an aircraft and a mobile station making it possible to analyze the flight data thereof and to modify the parameters of those data according to a standard scheme; 
         FIG. 2  schematically illustrates a partial section of an aircraft  100  comprising elements of an infrastructure adapted for employment of the invention; 
         FIG. 3 , comprising  FIGS. 3   a  and  3   b , schematically represents a part of the infrastructure, partially illustrated in  FIG. 2 , for applying the invention according to a maintenance configuration and according to a commercial configuration respectively; 
         FIG. 4  illustrates some of the steps of an example of an algorithm that can be used to switch the infrastructure according to the invention from a maintenance mode to a commercial mode and vice versa; and 
         FIG. 5  schematically illustrates the zone of coverage of the wireless network in which a maintenance operator is able to access the central diagnostic and storage device. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     According to the invention, a shared infrastructure employed in an aircraft is used for maintenance operations and for commercial communications, or in other words for data transmissions involving the personal devices of the passengers. A switchable wireless network makes it possible to offer an access point exclusively either to the passengers or to the maintenance operators. 
       FIG. 2  schematically illustrates a partial section of an aircraft  200  comprising elements of an architecture adapted to employ the invention. In this case this infrastructure comprises two servers, one server  205  dedicated to maintenance operations, referred to as maintenance server, and one server  210  dedicated to commercial operations, referred to as cabin server. 
     The notion of server here is a general notion, and each of servers  205  and  210  may be a single server or a group of servers. 
     The infrastructure also comprises three access points  215 ,  220  and  225  for a wireless network, for example WiFi access points according to the 802.11a, b or g standard, and three antennas  230 ,  235  and  240 . In this case, antenna  230  is placed inside the aircraft, while antennas  235  and  240  are placed outside the latter. 
     The infrastructure also comprises a network switch  245 , such as an Ethernet switch, as well as a radio-frequency relay  250  also referred to as a radio switch. The positions or configurations of network switch  245  and of radio-frequency relay  250  are preferably controlled by a sole command accessible from the cockpit. Such a command may result, for example, from the position of a button, or be generated by an instruction originating from a calculator, if necessary by means of a user interface. 
     It should be noted here that, except for network switch  245 , the radio-frequency relay and access point  215 , all the elements necessary for employment of the invention are already present in certain aircraft. 
       FIG. 3 , comprising  FIGS. 3   a  and  3   b , schematically represents part of the infrastructure, partially illustrated in  FIG. 2 , used to apply the invention according to a maintenance configuration and according to a commercial configuration respectively. 
     As illustrated, maintenance server  205  is connected to access point  215 , referred to as MWLU (initials for Maintenance Wireless Lan Unit in English terminology) and to network switch  245 , which in turn is connected to access point  220 , referred to as CWLU (initials for Cabin Wireless Lan Unit in English terminology) or cabin access point, whose antenna is antenna  230 . The cabin server is connected to access point  225 , referred to as TWLU (initials for Terminal Wireless Lan Unit in English terminology) and to network switch  245 . Thus, depending on the configuration of network switch  245 , access point  220  is connected to maintenance server  205  or to cabin server  210 . 
     Each of the antenna outputs of access points  215  and  225  is connected to an input of radio-frequency relay  250 , whose output is connected to antenna  235 . Thus, depending on the configuration of radio-frequency relay  250 , antenna  235  is connected to access point  215  or to access point  225 . The output of access point  225  is also connected to antenna  240 . 
     In this way, the infrastructure of the wireless network, which can be switched by means of two control elements, makes it possible to use partly, for the maintenance operations, the wireless network access points usable by the passengers. In other words, when the aircraft is in “commercial” use, the wireless network is configured to be usable by the passengers, and when the airplane is in maintenance phase, the wireless network is switched so as to be usable by the maintenance operators. In this latter configuration, the extension of the wireless network to the outside of the airplane can be achieved via the use of the additional MWLU element. 
       FIG. 3   a  represents the infrastructure of the wireless network used in a configuration that permits commercial use of the network. According to this configuration, the network switch is in a position such that cabin server  210  is connected to the CWLU, or in other words to access point  220 . Maintenance server  205  is then not connected to the CWLU. 
     Similarly, and still according to this configuration, the radio-frequency relay is in a position such that the antenna output of the TWLU, or in other words of access point  215 , is connected to antenna  235 . The antenna output of the MWLU is then not connected to antenna  235 . 
     Thus the infrastructure of the wireless network is configured in this case according to a standard scheme, permitting the passengers to access cabin server  210  via access point  220  and antenna  230 , the cabin server in turn being able to access a network outside the aircraft via access point  225  and antennas  235  and  240 . 
     As illustrated in  FIG. 3   b , after activation of the control command in the cockpit to change over to maintenance configuration, network switch  245  points the connection of maintenance server  205  toward the cabin wireless network, or in other words toward access point  220  or CWLU. A network monitoring software program advantageously takes over configuring the wireless network in standard manner, to permit only connection of stations compatible with previously defined network security rules for maintenance use. In this case, the passenger stations are no longer able to access the wireless network. 
     At the same time, the control command configures radio-frequency relay  250  in order to connect antenna  235  present outside the aircraft to the MWLU, or in other words to the antenna output of access point  215 . According to this configuration, it is still possible to effect data exchanges between the on-board devices and the ground via the TWLU, or in other words access point  225 , by using only antenna  240 . 
     MWLU  215  and CWLU  220  are advantageously configured by maintenance server  205  to be considered as the same wireless sub-network, thus permitting the mobile stations to function inside and outside the airplane without being disconnected. If necessary, it is also possible to adapt the output power of MWLU  215  to reduce the radio-frequency coverage to the close perimeter of the aircraft in order to minimize possible perturbations in the event that several aircraft of the same type are simultaneously in maintenance phase while being positioned close to one another. 
     As soon as the maintenance operations are terminated, the control command is used to reconfigure the infrastructure to the commercial configuration, such as illustrated in  FIG. 3   a.    
     In this way the network switch points the connection of cabin server  205  back to access point  220 , while the radio-frequency relay cuts the link between MWLU  215  and antenna  235 , in order to re-establish the link between TWLU  225  and antenna  235 . The cabin server then advantageously reconfigures the cabin access point, or in other words the CWLU, so that it can be used by the passengers. At the same time, the mobile maintenance stations no longer have access to the maintenance server and to the associated applications. 
     If the control command is not activated to reconfigure the infrastructure after a maintenance operation, a warning preferably should be furnished to the pilot in order that the following flight may be operated under the optimal security conditions. 
     It should be noted that, although a single CWLU is illustrated in  FIGS. 2 and 3 , a plurality of CWLUs may be used. All the CWLUs are then connected to network switch  245 . Alternatively, a plurality of network switches may be used. 
       FIG. 4  illustrates some of the steps of an example of an algorithm that may be used to switch the infrastructure according to the invention from a maintenance mode to a commercial mode and vice versa. 
     When a control command is transmitted, a test is performed (step  400 ) to determine whether the infrastructure must be changed over to a commercial configuration or to a maintenance configuration. Such a test may consist in particular of testing the current configuration or in determining a state of the control command, such as 0 or 1. 
     If the infrastructure must be changed over to a commercial configuration, a variable t is initialized to a predetermined value, such as −1 (step  405 ). 
     The state of the network switch is then modified (step  410 ), if necessary, to adapt the infrastructure of the wireless network to the desired configuration according to the type of command. In the present case, the network switch is placed in the configuration in which the cabin server is connected to the CWLU(s). 
     Similarly, the state of the radio-frequency relay is modified (step  415 ), if necessary, to adapt the infrastructure of the wireless network to the desired configuration, again according to the type of command. In the present case, the radio-frequency relay is placed in the configuration in which the antenna output of the TWLU is connected to a second external antenna. 
     The adaptation of the configuration of the network switch and of that of the radio-frequency relay may be simultaneous or sequential. 
     The new network rules are then employed (step  420 ) as a function of the type of command. In the present case, it is the cabin server that adapts the network rules according to a standard algorithm. 
     If the infrastructure must be changed over to a maintenance configuration, the variable t is initialized to a value representing the present instant (step  425 ). 
     The state of the network switch is then modified (step  410 ), if necessary, to adapt the infrastructure of the wireless network to the desired configuration according to the type of command. In the present case, the network switch is placed in the configuration in which the maintenance server is connected to the CWLU(s). 
     Similarly, the state of the radio-frequency relay is modified (step  415 ), if necessary, to adapt the infrastructure of the wireless network to the desired configuration, again according to the type of command. In the present case, the radio-frequency relay is placed in the configuration in which the antenna output of the MWLU is connected to an external antenna. 
     Once again, the adaptation of the configuration of the network switch and of that of the radio-frequency relay may be simultaneous or sequential. 
     The new network rules are then employed (step  420 ) according to the type of command. In the present case, it is the maintenance server that adapts the network rules according to a standard algorithm. 
     In parallel, after the variable t has been initialized, a test is performed (step  430 ) to determine if the difference between the value representing the present instant and the variable t is greater than a predetermined threshold θ. In the affirmative, an alarm is generated (step  435 ) to indicate that the maintenance mode has been activated for too long and that it would be desirable to switch the wireless network to its commercial configuration. 
     Alternatively, if the difference between the value representing the present instant and the variable t is greater than a predetermined threshold θ, it is possible to switch the wireless network automatically to its commercial configuration by generating the appropriate control command. 
     If the difference between the value representing the present instant and the variable t is smaller than or equal to a predetermined threshold θ, or after an alarm has been generated, a test is performed (step  440 ) on the value of the variable t. The last three steps (steps  430  to  440 ) are repeated as long as the value of the variable t is different from the initialization value used when the wireless network is configured for commercial use. 
       FIG. 5  schematically illustrates the zone of coverage of the wireless network in which a maintenance operator is able to access the central diagnostic and storage device. 
     As represented, the zone of coverage of the wireless network comprises a first zone  500  inside the aircraft, where the operator is connected via the antenna or the antennas disposed inside the aircraft. 
     The zone of coverage of the wireless network also comprises a second zone  505  around the aircraft, where the operator is connected via the antenna or the antennas disposed outside the aircraft. 
     Naturally, to satisfy specific needs, a person skilled in the art of the invention will be able to apply modifications in the foregoing description.