Method for calculating and / or monitoring the operation of a satellite positioning system on board a vehicle, and associated device and computer program product

Abstract

Method for calculating and / or monitoring the operation of a satellite positioning system on board a vehicle, and associated device and computer program product The present invention relates to a method for calculating and / or monitoring the operation of a satellite positioning system of a main vehicle in a geographical area comprising the acquisition of spatial and temporal observation coordinates; the acquisition of spatio-temporal coordinates of the satellites of a GNSS system for each temporal observation coordinate; the acquisition of characteristics and spatio-temporal coordinates representative of known positions of sources of electromagnetic disturbance of a signal of the GNSS system; the acquisition of data representative of characteristics of the satellite positioning system of the main vehicle;calculation of the impact of electromagnetic disturbance sources on the operation of the main vehicle's satellite positioning system. Figure for abstract: figure 2;

Description

Title of the invention: Method for calculating and / or monitoring the operation of a satellite positioning system on board a vehicle, and associated device and computer program product

[0001] The present invention relates to a method for calculating and / or monitoring the operation of a positioning system using a satellite positioning receiver on board a vehicle which has to move in a geographical area and within a time range.

[0002] The present invention also relates to a computer program product and a calculation and / or monitoring device associated with this method.

[0003] Vehicles of all types, in particular aerial, land or naval vehicles, are equipped with a so-called satellite positioning system because it is generally based on a satellite positioning receiver and an antenna. This system can also be equipped with other additional positioning assistance sensors such as inertial units, Doppler sensors, radio navigation in the event of loss of integrity, capacity or performance of the satellite positioning receiver. The satellite positioning system is a set of components based on a constellation of satellites making it possible to provide a user, via the sensors constituting it, with its 3D position, its 3D speed and the time. The satellite positioning system thus allows positioning, navigation and time measurement (Positioning, Navigation, Time: PNT) and thus constitutes a so-called PNT system.

[0004] For missions involving the coordination of several vehicles, satellite positioning receivers are used at all levels, and in particular directly by air, land or naval vehicles for their navigation system, as well as directly or indirectly by operational command centers for piloting missions.

[0005] Similarly, the drones that can participate in these missions also make extensive use of the satellite positioning system.

[0006] The strategic nature of satellite positioning systems is no longer in doubt. Their advantages include global and permanent coverage of the PNT, operational security, and their performance.

[0007] The weakness of these satellite positioning systems lies in their vulnerability to electromagnetic disturbances, in particular radiofrequency interference, and in particular the vulnerability of the receiver to these disturbances. In the presence of such disturbances, their performance and their ability to provide a valid and integrated PNT depends on many parameters, such as the quality of the receiver itself, but also that of the on-board protection devices (e.g. filtering), the power and number of satellite and disturbing signals received, the waveforms and frequencies of the electromagnetic disturbances, the positioning of the sources of these disturbances and the 4D trajectory of the vehicle.

[0008] To prohibit the use of such an operational asset, and to contest space sovereignty, numerous jamming systems are thus used, these systems ranging from simple interference systems to very sophisticated jammers.

[0009] Sources of jamming are thus particularly numerous in and near conflict zones or areas requiring humanitarian intervention.

[0010] The existence of sources of involuntary and / or intentional electromagnetic disturbances has the effect of degrading the performance of the satellite positioning system, or even of making certain capabilities of the receivers used unavailable, such as acquisition, tracking, integrity, dual-frequency or multi-constellation processing, the use of an augmentation system (ABAS).

[0011] Even if the vehicles participating in a mission can move safely without satellite positioning systems thanks to the additional sensors, the massive increase in sources of electromagnetic disturbances is considered a threat because it can harm the success of any mission, or at least complicate the execution of missions, and imposes a greater workload both on the pilots of the vehicles on the ground and on the personnel of the operational control centers of these missions. The presence of these threats also requires the maintenance of additional communication, navigation and surveillance services to meet performance and success requirements.

[0012] Having to operate in an electromagnetically disturbed mission space while the integrity, capacity and / or performance of the PNT are required for the success of the mission poses numerous problems. In particular, it is necessary to anticipate threats to the integrity, performance and capacity of the satellite positioning system, their evolution, their impacts on the various systems and actors of the mission on the ground, in order to decide on the strategy(ies) for implementing the mission in terms of locations, dates, and means.

[0013] Document WO 2015 / 065664 A1 discloses a system for generating a visual representation of sources of interference that impair the operation of a satellite positioning system. The visual representation may comprise a map covered with visual indicators indicating a location and magnitude of the interference.

[0014] However, the known system does not make it possible to determine the impact of interference sources on the operation of a particular satellite receiver and on the on-board positioning system, nor the impact on the integrity, capabilities and performance of the latter in a vehicle that has to operate in a defined geographical area and at different altitude levels. The known system also does not make it possible to determine the impact of interference sources on the operation of a satellite receiver at a specific date and time. Thus, the system does not make it possible to predict or estimate the risks of malfunction of the on-board satellite positioning receiver when the vehicle is located at specific positions in the geographical area at a specific time.Similarly, the known system also does not make it possible to determine the impact of interference sources on the operation of a satellite positioning system on board a vehicle that has to follow a flight plan or a particular route at a specific date and time. Finally, such a system does not make it possible to reduce the risks of malfunction of the onboard satellite positioning system by proposing a flight plan or a 4D route that makes it possible to reduce, or even minimize, the risks of electromagnetic disturbances.

[0015] In order to partially or totally address these various issues, one aim of the invention is then to propose a calculation and / or monitoring method making it possible to predict or reduce the risks of malfunction of the satellite positioning system used by a vehicle that has to move in a geographical area, and to provide a precise view of the present and future situation in terms of the capacity and performance of the PNT adapted to each user, at any point in a geographical area, at various altitudes and in a given time range, or at any point on a planned 4D trajectory crossing the geographical area or even with a view to coordinating the movements of several vehicles, including the aforementioned vehicle, participating in a civil or military mission, both upstream of the mission and in real time during the mission.

[0016] An aim of the invention is also to alert the crew when approaching a loss of PNT capacity or a significant degradation of performance, and to detect any evolution of electromagnetic threats by monitoring the operation of the satellite positioning system during the course of the mission.

[0017] To this end, the invention relates to a method for calculating and / or monitoring the operation of a satellite positioning system for a main vehicle in a geographical area, the method comprising the following steps:

[0018] - acquisition of spatial and temporal observation coordinates, the coordinates spatial observation sites located in the geographical area;

[0019] - acquisition of spatio-temporal coordinates of the satellites of a GNSS system for each observation time coordinate;

[0020] - acquisition of spatio-temporal characteristics and coordinates representative of known positions of sources of electromagnetic disturbance of a GNSS system signal, located in or near the geographic area;

[0021] - acquisition of data representative of characteristics of the system of satellite positioning of the main vehicle;

[0022] - calculation of an impact of sources of electromagnetic disturbances on the operation, including the integrity, capabilities and performance, of the main vehicle satellite positioning system for each service and each constellation of the GNSS system and for each observation space and time coordinate as a function of the observation space coordinate, the observation time coordinate corresponding to this observation space coordinate, the space-time coordinates of the GNSS system satellites at the observation time coordinate, the space-time coordinates representative of the known positions of the sources of electromagnetic disturbances at the observation time coordinate and the data representative of characteristics of the satellite positioning system.

[0023] The method according to the invention thus makes it possible, for a journey defined in space and time, to precisely determine the impact of the sources of electromagnetic disturbances on the operation, in particular on the integrity, capacities and performances, of the receiver and the satellite positioning system of a vehicle moving in the geographical area. Thus, the method according to the invention makes it possible to predict or reduce the risks of malfunction of the receiver of the satellite positioning system precisely when the vehicle follows the journey and possibly the consequences of such malfunction on the whole of a mission in which the vehicle participates.

[0024] According to other advantageous aspects of the invention, the calculation and / or monitoring method comprises one or more of the following characteristics, taken in isolation or in all technically possible combinations:

[0025] - a step of acquiring characteristics and / or spatio-temporal coordinates representative of positions of at least one auxiliary vehicle, equipped with a satellite positioning system and located in or near the geographical area, and their use in said calculation of the impact of sources of electromagnetic disturbance;

[0026] - for at least one vehicle chosen from the main vehicle and, where applicable, the other least one auxiliary vehicle:

[0027] i) obtaining a planned trajectory of the respective vehicle, the planned trajectory connecting a starting position to a destination of the respective vehicle and comprising a departure date of the respective vehicle or the planned trajectory connecting a current position of the vehicle to the destination of the respective vehicle and comprising a current date; and

[0028] ii) determining the observation spatial and temporal coordinates lying on the planned trajectory of the respective vehicle at an estimated date from the departure date of the respective vehicle or from the current date and an estimated travel time for this spatial coordinate from the departure position of the respective vehicle or from the current position to this spatial coordinate;

[0029] optionally iii) dividing the planned trajectory into a plurality of sections determined according to the impact of the sources of electromagnetic disturbances on the operation of the satellite positioning system at each of the spatial and temporal observation coordinates located on the respective section;

[0030] - warning a driver and / or crew of the respective vehicle when the current position of the respective vehicle approaches a section with high disruption forecast, and / or in the event of loss of capacity and / or degradation of performance;

[0031] - the planned trajectory of the respective vehicle is in one embodiment of the process obtained:

[0032] a) by calculating several possible trajectories of the respective vehicle connecting either the starting position to the destination or the current position to the destination;

[0033] b) determining observation spatial and temporal coordinates lying on the several possible trajectories of the respective vehicle at an estimated date from the departure date of the respective vehicle or from the current date and an estimated travel time for this observation spatial coordinate and this possible trajectory from the departure position of the respective vehicle or from the current position to this observation spatial coordinate;

[0034] c) by acquiring the spatio-temporal coordinates of the satellites of the GNSS system for each observation temporal coordinate of each possible trajectory;

[0035] d) by calculating, for each possible trajectory, the impact of the sources of electromagnetic disturbances on the operation of the satellite positioning system of the respective vehicle at each of the spatial and temporal observation coordinates as a function of the spatial observation coordinate, the temporal observation coordinate associated with this spatial observation coordinate, the spatio-temporal coordinates of the satellites of the GNSS system at the temporal observation coordinate, the spatio-temporal coordinates representative of known positions of the sources of electromagnetic disturbances, the data representative of characteristics of the satellite positioning system, and where applicable, characteristics and / or spatio-temporal coordinates representative of positions of at least one other vehicle chosen from the main vehicle and at least one auxiliary vehicle;

[0036] e) determining the planned trajectory from among the possible trajectories based on the impact of the sources of electromagnetic disturbances on the operation of the satellite positioning system of the respective vehicle at each spatial and temporal observation coordinate located on the possible trajectory;

[0037] - in one embodiment, for each possible trajectory and / or for the planned trajectory or for any point in the geographical area, the calculation of the impact of sources of electromagnetic disturbance on the operation of the satellite positioning system includes the calculation of the distances, elevations and azimuths of each source of electromagnetic disturbance and of each satellite of the GNSS system at each of the spatial and temporal observation coordinates of the possible trajectory and / or of the planned trajectory and / or of the geographical area;

[0038] - in one embodiment, a planned trajectory is obtained for each vehicle among the main vehicle and at least one auxiliary vehicle;

[0039] - for at least one vehicle chosen from the main vehicle and, where applicable, the at least one auxiliary vehicle, the method comprises in one embodiment acquiring data representative of a category of the respective vehicle and / or a shape of the respective vehicle and / or a position of an antenna on the respective vehicle and / or movement characteristics of the respective vehicle; and the impact on the operation of the satellite positioning system at each of the observation spatial and temporal coordinates is calculated as a function of an antenna gain of the antenna of the respective vehicle estimated for each observation spatial and temporal coordinate, from the data representative of the category of the vehicle and / or the shape of the vehicle and / or the position of the antenna on the vehicle and / or an orientation of the vehicle at this observation spatial and temporal coordinate estimated on the basis of the data representative of the movement characteristics;

[0040] - for at least one vehicle chosen from the main vehicle and, where applicable, the at least one auxiliary vehicle, the method comprises in one embodiment the acquisition of data representative of a topography and obstacles of the geographical area; and in that the impact on the operation of the satellite positioning system of the respective vehicle at each of the spatial and temporal observation coordinates is further calculated as a function of data representative of a topography of the geographical area;

[0041] - the acquisition of spatial coordinates representative of known positions of sources of electromagnetic disturbances is repeated at regular intervals;

[0042] - the method further comprises verifying proper operation, in particular the integrity, performance and capabilities of the main vehicle positioning system at regular time intervals with respect to the predictions; and if the deviation from the predictions is greater than a threshold, generation of a message updating a database of spatial coordinates representative of the known positions of sources of electromagnetic disturbance in the geographical area;

[0043] - in one embodiment, the geographic area is divided into a plurality of boxes constituting a grid, the grid preferably comprising a predefined resolution, the spatial and temporal observation coordinates comprising a plurality of positions each located in one of the boxes constituting the grid, preferably located in the center of the box constituting the grid, the geographical area observed for the same instant in time, the spatial and temporal observation coordinates all referring to the same instant of observation;

[0044] The invention also relates to a computer program product comprising software instructions which, when executed by a computer, implement the calculation and / or monitoring method according to any one of the preceding embodiments.

[0045] The invention finally relates to a device for calculating and / or monitoring the operation of a satellite positioning system of a main vehicle in a geographical area, comprising technical means adapted to implement the calculation and / or monitoring method according to any one of the preceding embodiments.

[0046] The invention will appear more clearly on reading the description which follows, given solely by way of non-limiting example, and made with reference to the drawings in which:

[0047] [Fig-1] [Fig.l] is a schematic representation of a computing device and / or monitoring the operation of a vehicle satellite positioning system in a geographic area according to the present application;

[0048] [Fig.2] [Fig.2] is a schematic representation of several flight plans possible of a vehicle crossing a geographic area;

[0049] [Fig.3] [Fig.3] is a representation of a power received from a source of electromagnetic disturbances in the geographical area in a given frequency band and at a given time and a given altitude;

[0050] [Fig.4] [Fig.4] is a representation of a power received from the source of electromagnetic disturbances after application of the on-board satellite antenna diagram on the vehicle in the geographical area;

[0051] [Fig.5] [Fig.5] is a representation of the total power spectral density of noise present in a particular receiver (after rejection, filtering, correlation, etc.) with respect to three sources of electromagnetic disturbances in the geographical area for three services of a satellite positioning system;

[0052] [Fig 6A] [Fig 6A] is a representation of the estimated powers of the signals of the satellite positioning system received over time at a given spatial point in the geographic area and for a given service (e.g. L1 C / A);

[0053] [Fig 6B] [Fig 6B] is a representation of the antenna gain applied to each satellite signal received by the satellite positioning system at the point within the geographic area;

[0054] [Fig 6C] [Fig 6C] is a representation of the estimated post-antenna power of each signal received by the satellite positioning system at the point located in the geographic area;

[0055] [Fig.7] [Fig.7] is a representation of the estimated receiver capabilities of the satellite positioning system for three services and for the entire geographical area at a given time t and altitude;

[0056] [Fig.8] [Fig.8] is a schematic representation of a planned trajectory of the vehicle divided into a plurality of sections according to the estimated capacities;

[0057] [Fig.9] [Fig.9] is a representation of a power received at the antenna of a source of electromagnetic disturbances along a 4D trajectory crossing the geographic area;

[0058] [Fig. 10] [Fig. 10] is a representation of post-antenna power received from the electromagnetic disturbance source along the 4D trajectory crossing the geographic area;

[0059] [Fig. 11] [Fig. 11]: - part A is a representation of an estimated power of the satellite signals of a given service received at the antenna of a satellite positioning system of a vehicle moving along a 4D trajectory crossing the geographical area; - part B is a representation of the antenna gains applied to each satellite signal received along the 4D trajectory crossing the geographic area; - part C is a representation of the estimated post-antenna power of each GNSS system signal received along the 4D trajectory crossing the geographic area.

[0060] [Fig.l] illustrates a device 10 for calculating and / or monitoring the operation of a satellite positioning system for a vehicle in a geographical zone Z.

[0061] This device 10 is suitable for implementing a method of calculating and / or monitoring the operation of the vehicle's satellite positioning system in the geographical zone Z.

[0062] By operation of the vehicle's satellite positioning system, we mean both the integrity of this system, i.e. its ability to provide data on an output, but also its capabilities, including its ability to acquire a signal emitted by one or more satellites, its ability to track this signal or to find this signal, as well as its performance when it is capable of at least acquiring a signal, in particular in terms of precision of the PNT and speed of the measurement chain, this speed depending in particular on the time taken to lock onto a satellite signal as well as the response time of the system to an acquired signal.

[0063] The device 10 comprises an input module 20, a processing module 30 and an output module 40.

[0064] The input module 20 and the output module 40 each comprise at least one communication interface allowing an exchange of information with a data processing device such as a server or a user interface UI for example.

[0065] The processing module 30 is for example in the form of one or more software programs stored in a memory and executable by one or more processors. As a variant or in addition, the processing module 30 is at least partially in the form of a programmable logic circuit, such as an FPGA (Field-Programmable Gate Array) type circuit.

[0066] Alternatively, when the method is carried out in the form of one or more software programs, i.e. in the form of a computer program, also called a computer program product, it is furthermore capable of being recorded on a medium, not shown, that is readable by a computer. The computer-readable medium is, for example, a medium capable of storing electronic instructions and of being coupled to a bus of a computer system. For example, the readable medium is an optical disk, a magneto-optical disk, a ROM memory, a RAM memory, any type of non-volatile memory (for example FLASH or NVRAM) or a magnetic card. A computer program comprising software instructions is then stored on the readable medium.

[0067] The calculation and / or monitoring device 10 allows the implementation of the method for calculating and / or monitoring the operation of the satellite positioning system of the vehicle, and in particular of a receiver of this system, in the geographical zone Z.

[0068] The geographic zone Z may be a fixed, expandable or mobile geographic zone. It may also be a corridor around a flight plan or a trajectory. In the following, when we mention "in the vicinity of the geographic zone Z", we mean an extended geographic zone including the geographic zone Z. This extended geographic zone may for example be defined by a border distant from the border delimiting the geographic zone Z by a predetermined distance.

[0069] The geographic area Z may be divided into a plurality of boxes constituting a grid. The grid may have a predefined resolution. When the method performs a step for any point in the geographic area, the step may be performed, for each box, on a point located in the box, preferably in the center of the box. The geographic area may thus be rasterized.

[0070] The vehicle is provided with at least one satellite positioning system comprising a receiver, an antenna, optionally adaptive, connected to the receiver and in certain examples, one or more anti-disturbance robustness devices, in particular anti-jamming and / or anti-decoying devices.

[0071] The receiver makes it possible to determine its position and / or its speed of movement, i.e. also the position of the vehicle and / or the speed of movement of the vehicle on the basis of GNSS signals that it receives from navigation satellites. Each receiver can have its own characteristics and exploit one or more GNSS services.

[0072] In some examples, the satellite positioning system further comprises one or more additional positioning assistance sensors such as inertial units, Doppler sensors, radio navigation instruments, etc.

[0073] The space satellite positioning system, otherwise known as a GNSS system, may be a GPS, Galileo, Glonass, Beidou, SB AS system for example offering several services (for example L1 C / A, L2C) transmitted on different frequency bands.

[0074] The vehicle is one of the members of a group of vehicles dedicated to carrying out a mission and is referred to below as the “main” vehicle to distinguish it in the description from the other vehicles in the group, which are referred to as “auxiliary” vehicles. It should be noted that the distinction between main or auxiliary vehicle is only used for the purposes of intelligibility of the description and does not contain any notion of hierarchy or priority.

[0075] The group of vehicles may comprise one or more land vehicles and / or one or more naval vehicles and / or one or more aircraft, these vehicles being able to be autonomous or piloted by a human being.

[0076] Advantageously, at least one, preferably each, auxiliary vehicle of the group of vehicles comprises at least one satellite positioning system similar to that of the main vehicle.

[0077] The mission is controlled upstream and / or in real time from a control center. The control center can exchange information with all the vehicles of the mission. It is configured to coordinate the trajectories of the vehicles of the group of vehicles with a view to carrying out its mission. Thus, the control center can transmit and receive information on the trajectories of the main and auxiliary vehicles both upstream of the mission and, if necessary, in real time during the mission.

[0078] In a particular embodiment, the control center is located in one of the vehicles of the group.

[0079] The main and auxiliary vehicles and the control center advantageously communicate by means of a communication system dedicated to the group of vehicles, for example in terms of frequency bands.

[0080] The calculation and / or monitoring method comprises a step of acquiring spatial and temporal observation coordinates of the main vehicle, the spatial observation coordinates being located in the geographical zone Z.

[0081] The observation spatial and temporal coordinates comprise an observation spatial coordinate defining a point in the geographic area and an observation temporal coordinate associated with the observation spatial coordinate defining an instant in time. Preferably, the observation spatial coordinates are three-dimensional coordinates. The observation temporal coordinate among the acquired observation temporal coordinates occurring first in time and the observation temporal coordinate among the acquired observation temporal coordinates occurring last in time may define an observation time range. The observation spatial coordinate may correspond to a position of the vehicle expected for an instant corresponding to the observation temporal coordinate associated with this observation spatial coordinate.

[0082] Alternatively, the observation time range may be defined by the user by entering a time marking the start of the observation time range and a time marking the end of the observation time range.

[0083] The user may be a driver of the main vehicle, a member of the crew of the main vehicle and / or a person in charge of planning the journey (route, flight plan), in particular a member of the mission control center.

[0084] The calculation and / or monitoring method comprises a step of acquiring spatio-temporal coordinates of the satellites of the GNSS system for each observation time coordinate. The spatio-temporal coordinates of the satellites can be acquired by retrieving them from a GNSS database BDGNSS where they have been previously deposited. The spatio-temporal coordinates satellite temporal data can also be acquired by retrieving them from a memory of the receiver or a memory of the computing and / or monitoring device 10 where they have been previously deposited.

[0085] The space-time coordinates of the satellites may, for example, be almanac data or ephemeris data. The almanac data and the ephemeris data provide the position of the navigation satellites in the sky at a given date, such as one of the observation time coordinates. The ephemeris data provide more precise position data than the almanac data. The ephemeris data are generally stored in a database that is periodically updated to take into account changes affecting the orbit of the satellites.

[0086] The GNSS database BDGNSS may comprise a constellation management system collecting almanac data and / or ephemeris data. The constellation management system may also monitor and / or record the levels of the received GNSS signals in order to deduce the powers emitted for each service by each satellite (calibration) and thus improve the accuracy of the predictions of the levels of the received GNSS signals in the geographical zone Z.

[0087] From the almanac and / or ephemeris data, the calculation and / or monitoring method and the calculation and / or monitoring device 10 are capable of carrying out the forecast for each constellation of visible and healthy satellites, of the distance / elevation / azimuth of each from any point in the geographical zone Z and throughout the desired observation time range.

[0088] By determining the position of the visible satellites, and, where appropriate, the measurements taken that can serve as calibration, the method can implement a step of calculating the distance and the power received from each visible satellite at any point in the geographical zone Z and over the entire observation time range defined by using propagation models. In particular, the method can implement a step of calculating the distance and the power received from each visible satellite for each spatial and temporal observation coordinate. These propagation models can take into account a loss of intensity of the GNSS signal during the propagation of the GNSS signal depending on the presence of a free space located between the receiver and the satellite and / or ionospheric propagation phenomena and / or masking by the terrain and / or masking by buildings.

[0089] The calculation and / or monitoring method comprises a step of acquiring spatial coordinates representative of known positions of sources of electromagnetic disturbances of a signal from the GNSS system covering the geographical zone Z.

[0090] By source of electromagnetic disturbance, we mean any natural or artificial source of electromagnetic signal emitting an electromagnetic signal likely to disrupt the operation of the satellite positioning system itself or the GNSS signal to be received by this satellite positioning system. For example, this may be a GNSS signal jamming device, in particular a device operating by interference in the radio frequency domain, or a decoy device, or a destructive system which undermines the integrity of the system.

[0091] The spatial coordinates representative of known positions of sources of electromagnetic disturbances can be acquired by retrieving them from a database where they have been previously deposited, such as a BDRFI database of radiofrequency interference (RFI).

[0092] According to one possibility, the acquisition of spatial coordinates representative of known positions of sources of electromagnetic disturbances can be repeated at regular intervals.

[0093] The calculation and / or monitoring method may further comprise a step of acquiring the spectrum (central frequency, bandwidth) and the waveform and / or type of modulation of the electromagnetic signal emitted by each known source of electromagnetic disturbance and / or an average power of the electromagnetic signal emitted by each known source of electromagnetic disturbance in the geographical zone Z and / or a minimum power of the electromagnetic signal emitted by each known source of electromagnetic disturbance in the geographical zone Z and / or a maximum power of the electromagnetic signal emitted by each known source of electromagnetic disturbance in the geographical zone Z.The spectrum, waveform and modulation type of the electromagnetic signal and / or the average power of the electromagnetic signal and / or the minimum power of the electromagnetic signal and / or the maximum power of the electromagnetic signal can be acquired by retrieving it / them from a database where it / they have been previously deposited, such as the RFI database BDRFI.

[0094] The database of sources of electromagnetic disturbances, in particular the RFI database BDRFI, can be supplied by a system for detecting / locating / inventorying / characterizing sources of electromagnetic disturbances. The system for detecting / locating / inventorying / characterizing sources of electromagnetic disturbances can be capable of collecting data from multiple observations (ground, air, space), by various means such as radars, flight recordings (commercial, freight), boats, preferably located near or in the geographical zone Z, including the main vehicle itself or the auxiliary vehicles. This system could for example be managed by an international organization (e.g. European Organization for Civil Aviation Equipment: EUROCAE, CNS, NATO, etc.). This system may be capable of analyzing and consolidating data from multiple observations filed on a network, in particular a secure network, via artificial intelligence processing based on data from known sources of electromagnetic disturbance stored in the database and / or information returned by the computing and / or monitoring device 10 in order to continuously generate / update the database. This database of sources of electromagnetic disturbance may be global or limited to a region and is directly used by the computing and / or monitoring device 10. The sources of electromagnetic disturbance may be stationary and / or emit the electromagnetic signal continuously.The sources of electromagnetic disturbance may also be mobile and / or emit the disturbing electromagnetic signal intermittently and / or consist of different types of modulation and other dynamic characteristics. In this case, the method may comprise a step of acquiring data representative of expected movements of the sources of electromagnetic disturbance and / or data representative of the emission characteristics of the sources of electromagnetic disturbance such as an expected emission chronology of the electromagnetic signal, a modulation of the electromagnetic signal and / or other dynamic characteristics.The data representative of expected movements of the sources of electromagnetic disturbances and / or the data representative of the emission characteristics of the sources of electromagnetic disturbances can be acquired by retrieving them from a database where they have been previously deposited, such as the database of sources of electromagnetic disturbances, in particular the RFI BDRFI database.

[0095] The step of acquiring spatial coordinates representative of known positions of sources of electromagnetic disturbances may consist of acquiring spatial coordinates representative of known positions of sources of electromagnetic disturbances potentially harmful to the geographical zone Z and the observation time range concerned. This step makes it possible to limit the memory size of the database of sources of electromagnetic disturbances and to perform calculations only on sources of electromagnetic disturbances considered to be a risk for the safety and / or performance of the journey.

[0096] The calculation and / or monitoring method may further comprise a step of obtaining a desired result in terms of probability. The desired result in terms of probability may correspond to a worst case scenario, a best case scenario, an average case scenario, or a most likely scenario, for example. The desired result in terms of probability can for example be obtained by user input made using the UI or by retrieving it from a database where it has been previously deposited.

[0097] The calculation and / or monitoring method may further comprise a step of obtaining a weather forecast for the geographical area Z and the observation time range. The weather forecast may for example be obtained by retrieving it from a database where it has been previously deposited, such as a weather database.

[0098] The calculation and / or monitoring method comprises a step of acquiring data representative of the characteristics of the satellite positioning system. These characteristics include characteristics of the receiver and / or of the installed antenna and / or possibly of one or more additional sensors and / or of one or more anti-jamming robustness devices.

[0099] The characteristics of the antenna of the main vehicle may in particular include an antenna pattern giving the gain for each azimuth / elevation. It is advisable that this antenna pattern be representative of the antenna pattern after installation on the main vehicle (for example, taking into account masking, attenuations due to the vehicle (e.g. wings) and the ground plane).

[0100] The characteristics of the satellite positioning receiver on board the main vehicle may in particular include the mathematical model and / or the performance and precision of the receiver, the constellations, services and frequency bands used, the robustness to jamming and / or the onboard protection devices, the RF bandwidth, the capacity thresholds (for example, satellite acquisition capacity for a C / No > 36 dB-Hz, tracking capacity for a C / No > 28 dB-Hz), the satellite acquisition and re-acquisition times.

[0101] The characteristics of the satellite positioning system on board the vehicle may in particular include the performance and precision of each additional sensor, their participation in the development of the PNT of the vehicle and their precision in particular when certain capacities of the GNSS receiver are lost (e.g. switching to Inertia or RadioNav mode when the position from the GNSS receiver is imprecise and / or not complete and / or invalid).

[0102] The data representative of characteristics of the satellite positioning system of the main vehicle can be acquired by retrieving them from a database where they have been previously deposited, such as a database of known receivers BDRC and / or a database of known antennas BDAC. The data representative of characteristics of the receiver and / or the antenna can also be acquired by retrieving them from a memory of the receiver.

[0103] The data representative of characteristics of the receiver and / or of the antenna may correspond to characteristics of a standard receiver and / or of a standard antenna. Alternatively, the data representative of characteristics of the receiver and / or of the antenna may correspond to characteristics of a type of receiver corresponding to the receiver actually installed in the main vehicle and / or of a type of antenna corresponding to the antenna actually installed in the main vehicle.

[0104] The calculation and / or monitoring method comprises a step of calculating the impact of each source of electromagnetic disturbances on the operation of the satellite positioning system for each spatial and temporal coordinate as a function of the observation spatial coordinate, the observation temporal coordinate corresponding to this observation spatial coordinate, the spatio-temporal coordinates of the satellites at the observation temporal coordinate, the spatio-temporal coordinates representative of the known positions at the observation temporal coordinate of the acquired sources of electromagnetic disturbances and the data representative of the characteristics of the satellite positioning system.

[0105] Optionally, the calculation and / or monitoring method comprises a step of acquiring characteristics and / or spatial and temporal coordinates representative of positions of at least one auxiliary vehicle, advantageously of all the auxiliary vehicles located in or near the geographical zone Z.

[0106] The spatial and temporal coordinates representative of positions of the at least one auxiliary vehicle can be obtained, in particular in real time, by means of the satellite positioning system which equips the respective auxiliary vehicle and transmitted by the auxiliary vehicle either to the main vehicle or to the control center.

[0107] Part or all of these coordinates can be calculated upstream of the mission or in real time by means of an appropriate computerized device which equips the control center.

[0108] The data representative of characteristics of the at least one auxiliary vehicle may correspond to characteristics of the satellite positioning system of the auxiliary vehicle of the same type as those described previously for the main vehicle.

[0109] The data representative of characteristics of an auxiliary vehicle may relate to the mission. In particular, it may be a vehicle category, or an order of priority of the respective auxiliary vehicle in relation to the other auxiliary and / or main vehicles.

[0110] The calculation of the impact of each source of electromagnetic disturbance on the operation of the satellite positioning system of the main vehicle for each spatial and temporal coordinate is then advantageously also a function of the characteristics and / or the spatio-temporal coordinates representative of the positions of at least one auxiliary vehicle located in or near the geographical zone Z, preferably of all the auxiliary vehicles located in or near the geographical zone Z.

[0111] It is understood in particular that if the operation of the satellite positioning system of the main vehicle is degraded due to a source of electromagnetic disturbances emitting an electromagnetic signal in a given frequency band, if an auxiliary vehicle or the control center is able to communicate with the main vehicle for all or part of the duration of this degradation in an undisturbed frequency band, the data exchanged between the main vehicle and the auxiliary vehicle or the control center, which receives information from the different auxiliary vehicles, can make it possible to limit the degradation caused by the source of electromagnetic disturbances.The step of calculating the impact of each source of electromagnetic disturbance on the operation of the satellite positioning system of the main vehicle may include the calculation of the distances, elevations, and / or azimuth in order to determine the power received from each source of electromagnetic disturbance for each spatial and temporal observation coordinate, that is to say either at each position on the path determined for the estimated date on which the main vehicle is located at this position, or at any point in the geographical zone Z and over the entire defined observation time range, using propagation models taking into account a loss during the propagation of the electromagnetic signal from this source of electromagnetic disturbance considering, where appropriate, the wavelength(s) of the electromagnetic signal and / or the weather forecast for the geographical zone Z and / or terrain masking.

[0112] The step of calculating an impact of each source of electromagnetic disturbance on the operation of the satellite positioning system of the main vehicle may be performed based on the desired outcome in terms of probability. When the desired outcome in terms of probability corresponds to the worst-case scenario, the step of calculating an impact of each source of electromagnetic disturbance on the operation of the satellite positioning system may be based on the maximum power of the electromagnetic signal emitted by the respective source of electromagnetic disturbance, for example. When the desired outcome in terms of probability corresponds to the best-case scenario, the step of calculating an impact of each source of electromagnetic disturbance on the operation of the system satellite positioning system may be based on the minimum power of the electromagnetic signal emitted by the respective source of electromagnetic disturbance, for example. When the desired outcome in terms of probability corresponds to the average and / or most likely scenario, the step of calculating an impact of each source of electromagnetic disturbance on the operation of the satellite positioning system may be based on the average and / or most likely power of the electromagnetic signal emitted by the respective source of electromagnetic disturbance, for example.

[0113] The calculation and / or monitoring method may further comprise the following steps: - obtaining a planned trajectory TPR of the main vehicle, the planned trajectory TPR connecting a starting position PD to a destination of the main vehicle and comprising a departure date of the main vehicle or the planned trajectory TPR connecting a current position PA of the main vehicle to the destination of the main vehicle and comprising a current date; and - determination of the spatial and temporal observation coordinates located on the planned TPR trajectory of the main vehicle at a date estimated from the departure date of the main vehicle or the current date and an estimated travel time for this spatial coordinate from the departure position of the main vehicle or from the current position to this spatial coordinate.

[0114] The spatial coordinates defining the starting position PD, the current position PA of the main vehicle and / or the destination can for example be acquired by a user input made using the user interface UI. These spatial coordinates can also be acquired by retrieving them from a database where they have been previously deposited. These spatial coordinates can for example be retrieved from a database transmitted by the control center. The spatial coordinates defining the current position PA of the main vehicle can for example be acquired via the receiver of the main vehicle.

[0115] The planned trajectory TPR may for example correspond to a previously defined or calculated path of the main vehicle. The planned trajectory TPR may for example be obtained by a user input made using the user interface UI or received from the pilot center or retrieved from a database where it has been previously deposited. The planned trajectory TPR may be limited to a flight plan or be a precise trajectory linked to the capabilities of the carrier from a trajectory calculator or an FMS (English: Flight Management System).

[0116] The calculation and / or monitoring method comprises a step of calculating an estimated arrival date for the planned trajectory TPR. The estimated arrival date can be obtained by adding an estimated travel time to the departure date. The estimated travel time can be obtained from previous travel times following the same route or a similar route traveled by other vehicles or from simulations taking into account, among other things, the properties of the main vehicle or by recovering it from the 4D trajectory.

[0117] The departure date and the estimated arrival date can define the observation time range.

[0118] According to one possibility, the departure date can be the date of entry into the geographical zone Z and the arrival date can be the date of exit from the geographical zone.

[0119] The calculation and / or monitoring method may comprise a step of determining several positions located on the planned trajectory TPR and, for each of these positions, determining an estimated date on which the main vehicle is located at the respective position. The dates and positions located on the planned trajectory may thus each constitute one of the spatial and temporary observation coordinates. The estimated date on which the main vehicle is located at the respective position may be estimated from previous travel times following the same route or a similar route traveled by other vehicles or from a calculator taking into account, among other things, the properties of the main vehicle.

[0120] The positions located on the planned trajectory TPR can be spaced equidistantly from each other. The number of positions chosen allows a desired resolution to be defined. The desired resolution can be defined by a user, for example by entering the desired resolution in the user interface UI. The desired resolution can be defined in terms of time period or in terms of distance. Two consecutive positions can be spaced 10 seconds apart or 0.2 nautical miles apart, for example.

[0121] The mentioned method steps may be repeated, preferably repeated at regular intervals. The mentioned method steps may, for example, be repeated when the main vehicle has traveled part of its route. The mentioned method steps may then be repeated taking into account the current position of the main vehicle.

[0122] According to one possibility, the planned trajectory TPR of the main vehicle is obtained: - by calculating several possible trajectories TPO of the vehicle connecting either the starting position PD to the destination, or the current position PA to the destination; - by determining spatial and temporal observation coordinates located on the several possible TPO trajectories of the main vehicle to an estimated date from the main vehicle departure date or the current date and an estimated travel time for that observation spatial coordinate and that possible trajectory TPO from the main vehicle departure position or from the current position to that observation spatial coordinate; - by calculating the space-time coordinates of the GNSS system satellites for each observation time coordinate of each possible TPO trajectory; - by calculating, for each possible trajectory TPO, the impact of each source of electromagnetic disturbance on the operation of the satellite positioning system of the main vehicle at each of the spatial and temporal observation coordinates as a function of the spatial observation coordinate, the temporal observation coordinate associated with this spatial observation coordinate, the spatial coordinates of the satellites of the GNSS system at the temporal observation coordinate, the spatial coordinates representative of the known positions of the sources of interference acquired at the temporal observation coordinate, the characteristics of the sources of electromagnetic disturbance and the data representative of the characteristics of the satellite positioning system of the main vehicle, and optionally the characteristics and / or the spatio-temporal coordinates representative of the positions of at least one auxiliary vehicle; - by determining the recommended TPR trajectory among the possible TPO trajectories based on the impact of each source of electromagnetic disturbance on the operation of the satellite positioning system of the main vehicle at each spatial and temporal observation coordinate located on each possible TPO trajectory.

[0123] This method thus makes it possible to propose and / or classify different TPO trajectories or flight plans to an operator according to the impact of each source of electromagnetic disturbances on the operation of the satellite positioning system on board the respective trajectory in order to be able to select a planned TPR trajectory from the possible TPO trajectories.

[0124] In the case where the impact calculation takes into account the characteristics and the spatio-temporal coordinates representative of positions of at least one other auxiliary vehicle, the method makes it possible to propose and / or classify different TPO trajectories or flight plans to an operator in the context of the mission, taking into account the different vehicles to be coordinated. Advantageously, at least one planned trajectory TPR is obtained - mutatis mutandis - for at least one auxiliary vehicle, preference for all auxiliary vehicles located in or near geographic zone Z.

[0125] Advantageously, the planned TPR trajectories obtained for the auxiliary vehicles are obtained:

[0126] - by calculating several possible TPO trajectories of the auxiliary vehicle connecting, either the starting position PD at the destination, or the current position PA at the destination; - by determining spatial and temporal observation coordinates located on the several possible trajectories TPO of the auxiliary vehicle at a date estimated from the departure date of the auxiliary vehicle or from the current date and an estimated travel time for this spatial observation coordinate and this possible trajectory TPO from the departure position of the auxiliary vehicle or from the current position to this spatial observation coordinate; - by calculating the space-time coordinates of the GNSS system satellites for each observation time coordinate of each possible TPO trajectory; - by calculating, for each possible trajectory TPO, the impact of each source of electromagnetic disturbance on the operation of the satellite positioning system of the auxiliary vehicle at each of the spatial and temporal observation coordinates as a function of the spatial observation coordinate, the temporal observation coordinate associated with this spatial observation coordinate, the spatial coordinates of the satellites of the GNSS system at the temporal observation coordinate, the spatial coordinates representative of the known positions of the sources of electromagnetic disturbance acquired at the temporal observation coordinate, the characteristics of the sources of electromagnetic disturbance and the data representative of the characteristics of the satellite positioning system of the auxiliary vehicle,and optionally characteristics and / or spatio-temporal coordinates representative of positions of at least one other vehicle chosen from the main vehicle and the other auxiliary vehicles; - by determining the recommended trajectory TPR among the possible trajectories TPO based on the impact of each source of electromagnetic disturbance on the operation of the satellite positioning system of the auxiliary vehicle at each spatial and temporal observation coordinate located on each possible trajectory TPO.

[0127] In this case, the method may comprise determining groups of possible GTPO trajectories. Each group of possible GTPO trajectories comprises a possible trajectory TPO for each of the main and auxiliary vehicles, the different possible trajectories TPO of a given group of possible trajectories GTPO being compatible with each other and with the accomplishment of the mission. The method can further comprise the classification of the different groups of possible trajectories GTPO according to the overall impact of the sources of electromagnetic disturbance on the group of vehicles. In this way, the control center can determine the optimal group of possible trajectories GTPO from the point of view not of a given vehicle but of all the main and auxiliary vehicles dedicated to the mission.

[0128] The optimal GTPO group of possible trajectories may correspond to an optimum upstream of the mission or be determined iteratively during the exercise of the mission.

[0129] The calculation steps of the method can be implemented centrally at the control center or partially distributed over calculation means equipping each of the main and auxiliary vehicles.

[0130] In a particular embodiment, all trajectory calculations are carried out on calculation means equipping the control center, then movement instructions are generated on the basis of these trajectories and in particular of the groups of possible GTPO trajectories. The movement instructions are then transmitted to the different vehicles concerned.

[0131] In an alternative embodiment, the calculation of the recommended trajectory for a predetermined time interval is carried out by calculation means of the respective vehicle, on the basis of the data transmitted by the control center on the entire group of vehicles at the start of the time interval, a local adaptation of the trajectory of the main vehicle by its pilot being able to be authorized. Then the new data on the vehicle trajectories are transmitted by each vehicle to the control center at the end of the time interval, so as to repeat the process on the following time interval.

[0132] When the main or auxiliary vehicle is an aircraft, the method allows the preparation of a flight plan (FPLN) taking into consideration the constraints of the presence of sources of electromagnetic disturbance in the geographical zone Z and predictions of losses of capacities and performances of the satellite positioning system of the respective vehicle during the flight according to the spatial configuration and the aircraft used.

[0133] According to one possibility, the trajectory recommended as TPR may correspond to the possible trajectory TPO having the lowest impact on the operation of the satellite positioning system of the respective vehicle. According to one alternative, the trajectory recommended as TPR may correspond to the possible trajectory TPO having an impact on the operation of the satellite positioning system. satellites below a predefined threshold (e.g. valid PNT, integrates with accuracy < 0.1nm at 95%) and exhibiting a minimum respective vehicle travel time and / or minimum vehicle fuel consumption.

[0134] According to a preferred characteristic, for each possible trajectory TPO and / or for the planned trajectory TPR, the calculation of the impact of each source of electromagnetic disturbances on the operation of the satellite positioning system of the respective vehicle comprises the calculation of the elevations, azimuths and distances of each satellite of the GNSS system at each of the spatial and temporal observation coordinates of the possible trajectory TPO and / or of the planned trajectory TPR.

[0135] The method may further comprise a step of acquiring data representative of a category of the respective vehicle and / or a shape of the respective vehicle and / or a position of the antenna on the respective vehicle and / or movement characteristics of the respective vehicle (attitudes), the impact of each source of electromagnetic disturbances on the operation of the satellite positioning system at each of the spatial and temporal observation coordinates being calculated as a function of the antenna gain of the antenna of the respective vehicle estimated for each spatial and temporal observation coordinate,from data representative of the category of the respective vehicle and / or the shape of the respective vehicle and / or the position of the antenna on the respective vehicle and / or a 3D orientation (attitudes) of the respective vehicle at this spatial and temporal observation coordinate on the basis of data representative of the movement characteristics and dynamic performance of the vehicle.

[0136] The data representative of the vehicle category and / or the shape of the vehicle and / or the position of the antenna on the vehicle and / or the movement characteristics of the vehicle can be acquired by retrieving them from a database where they have been previously deposited, such as a vehicle database and / or from a flight simulator and / or trajectory calculator. By "vehicle category" is meant the type of vehicle chosen for example between land vehicle, airplane, helicopter, drone, etc.

[0137] The method may further comprise a step of acquiring data representative of a topography of the geographical zone Z, the impact of each source of electromagnetic disturbances on the operation of the satellite positioning system at each of the spatial and temporal observation coordinates being further calculated as a function of data representative of a topography of the geographical zone Z.

[0138] The data representative of the topography of the geographical zone Z can be acquired in a database called MNE (Digital Model) database. Elevation) BDMNE. Data representative of the topography of the geographical zone Z may include data representative of obstacles such as buildings and data from a digital terrain model (DTM). Data representative of the topography make it possible to evaluate masking and propagation losses of useful and harmful signals, such as GNSS signals or disturbing signals such as interference signals emitted by interference sources. These databases are particularly useful for drone or naval applications, i.e. when the vehicle is a drone or a boat. They are also useful in terrestrial and low-altitude flight applications.

[0139] The step of calculating an impact of each source of electromagnetic disturbances on the operation of the positioning system of the main or auxiliary vehicle may include the calculation of the distances, elevations, and / or azimuth and the power received from each source of electromagnetic disturbances for each spatial and temporal observation coordinate, i.e. either at each position on the path determined for the estimated date at which the respective vehicle is located at this position, or at any point in the geographical zone Z and over the entire defined observation time range, using precise propagation models also taking into account the loss during the propagation of the electromagnetic signal emitted by this source of electromagnetic disturbances considering the topography of the terrain, by applying Fresnel equations for example.

[0140] As shown in [Fig.2], the possible trajectories TPO and / or the trajectory recommended as a planned trajectory TPR may comprise a plurality of waypoints PCI to PC7 constituting different flight plans. The starting position PD, the current position PA and / or the destination may constitute waypoints PCI to PC7. In [Fig.2], the waypoints PCI to PC7 are represented by stars.

[0141] As shown in [Fig.2], the geographical area Z may include a low disruption risk area ZF, a medium disruption risk area ZM and / or a high disruption risk area ZE. The planned trajectory TPR may be determined from four possible trajectories TPO. In the example given by [Fig.2], the planned trajectory TPR chosen (PCI - PC2 - PC3 - PC4) from the four possible trajectories TPO may cross the medium disruption risk area ZM for a short time. Alternatively, the planned trajectory TPR may be chosen so as to remain in the low disruption risk area ZF (PCI - PC2 - PC3 - PC5), i.e. without crossing the medium disruption risk area ZM or the high disruption risk area ZE by making a more significant detour.

[0142] The method may further comprise a step of dividing the planned trajectory TPR and / or the different trajectories TPO into a plurality of sections, and a step of determining, for each section, from the impact of each source of electromagnetic disturbances on the operation of the satellite positioning system of the respective vehicle at each of the spatial and temporal observation coordinates located on the respective section, whether the section is a section with a high disturbance forecast TPE or a section with a low disturbance forecast TPF or, where appropriate, a section with a medium disturbance forecast TPM.

[0143] The low disturbance prediction TPF may correspond to a high probability of proper operation of the satellite positioning system and / or a high probability of GNSS signal integrity, for example. The high disturbance prediction TPE may correspond to a high probability of malfunction of the satellite positioning system and / or a high probability of loss of GNSS PNT, for example. The medium disturbance prediction TPM may correspond to a high probability of performance degradation of the satellite positioning system and / or a high probability of loss of GNSS signal integrity, for example.

[0144] The method may further comprise a step of warning a driver (or pilot) of the main vehicle and / or a crew of the main vehicle when the current position of the vehicle approaches a section with a high TPE disturbance forecast or, where appropriate, a section with a medium TPM disturbance forecast. The step of warning the driver may comprise a warning of a loss of integrity, capacity and / or performance of the satellite positioning system of the vehicle.When the vehicle is an aircraft, the warning step may include an alert to warn the pilot as the driver of the aircraft and / or the crew of the aircraft of an imminent exceedance of RNP (Required Navigation Performance) and / or of an imminent loss of receiver capabilities (e.g. 2 minutes before the loss of acquisition capability) and / or of an imminent switch to a navigation mode without using the satellite positioning system (coasting) in order to be able to anticipate and manage the failure of imminent loss of availability of the GNSS PNT with complete peace of mind and improve flight safety. The receiver fault is likely to cause stress among the driver and / or crew.Thus, the possibility of being warned in advance of this defect allows the driver of the main vehicle and / or the crew of the main vehicle to prepare for this situation and thus reduce the risk of stress among the driver and / or the crew of the main vehicle.

[0145] If necessary, the warning can be transmitted to at least one other auxiliary vehicle.

[0146] The method may further comprise a monitoring function consisting of verifying the operation of the satellite positioning system and / or the signal-to-noise ratios, in real time or at regular time intervals, with respect to the predictions.For example, when a good functioning of the satellite positioning system is detected while the current position of the main vehicle is located on a section with a high disturbance forecast TPE or, where appropriate, on a section with a medium disturbance forecast TPM, or when a bad functioning of the satellite positioning system is detected while the current position of the vehicle is located on a section with a low disturbance forecast TPF, the method may comprise a step of generating a message for updating a database of spatial and temporal coordinates for the purpose of updating the known positions of interference sources in the geographical zone Z.When proper operation of the satellite positioning system is detected while the current position of the vehicle is located on a section with a forecast of high disturbance TPE or on a section with a forecast of medium disturbance TPM, this update message may include information indicating the disappearance of at least one source of electromagnetic disturbance and / or an attenuation of the electromagnetic signal emitted by at least one source of electromagnetic disturbance at the date / time of observation.When a malfunction of the satellite positioning system is detected while the current position of the vehicle is located on a section with a low TPF disturbance forecast, this update message may include information indicating the appearance of at least one source of electromagnetic disturbance and / or an amplification of the electromagnetic signal emitted by at least one source of disturbance at the date / time of observation.

[0147] Thus, the method monitors and compares in real time the measurements and the risks of disturbance and ensures a loopback to allow the database of sources of electromagnetic disturbances to be kept up to date. The disappearance of a predicted disturbance makes it possible to extrapolate a disappearance or attenuation of one of the known sources of interference. The presence of a disturbance occurring without having been predicted makes it possible to extrapolate an appearance of a new source of electromagnetic disturbances or an amplification of one of the known sources of interference. This information can then be transmitted so that a monitoring center can update the database of sources of electromagnetic disturbances after cross-checking the various pieces of information received.

[0148] The method may further be characterized in that the geographical area Z is divided into a plurality of boxes constituting a grid, the grid preferably comprising a resolution, the spatial and temporal observation coordinates comprising a plurality of positions each located in one of the boxes constituting the grid, preferably located in the center of the box constituting the grid, the geographical area observed for the same instant in time. Preferably, the spatial and temporal observation coordinates all refer to the same instant of observation.

[0149] According to one possibility, the plurality of boxes constituting the grid can be arranged in a three-dimensional manner. The grid can for example comprise a background layer located at ground level and at least one elevated layer corresponding to a defined altitude such as for example a cruising altitude of an airliner. The defined altitude can for example be defined by the user. The user can enter the desired defined altitude in the user interface UI.

[0150] The resolution may be a predefined resolution or a user-defined resolution, for example by entering the desired resolution in the UI.

[0151] Thus, the spatial and temporal observation coordinates can either correspond to positions located on a path defined by a planned trajectory TPR and / or a possible trajectory TPO or to positions defining the grid.

[0152] The method may further comprise a step of determining the signal level of the GNSS system satellites received for the service(s) used. The step of determining the signal level of the positioning system satellites may be carried out for all the acquired spatial and temporal observation coordinates, i.e. either for any position in the geographical zone Z and / or over the entire observation time range or for all the positions on the possible trajectories TPO and / or on the planned trajectory TPR and for all the dates corresponding to these positions. The method may further comprise a step of displaying the signal level of the GNSS system satellites received for a given position in the geographical zone during the defined observation duration and / or during the tracking of the trajectory.Such a graphical representation is given in [Fig 6A] (defined point) and Fig. 1 IA (during trajectory tracking) as an example.

[0153] The method may further comprise a step of determining the antenna gain of the respective vehicle antenna. The determination of the antenna gain may take into account the characteristics of the installed vehicle antenna and / or the position of the vehicle antenna and / or the shape of the vehicle, for example with a view to possible masking of the antenna by the vehicle. This determination step may further taking into account the vehicle's motion characteristics, such as maximum vehicle attitudes (e.g., roll, slope), when the vehicle is an aircraft for example. Alternatively or additionally, this determination step may further take into account the estimated vehicle attitudes at each position observed during the tracking of the TPR and / or TPO trajectory. For example, when the vehicle is an aircraft and when the aircraft is expected to travel in a straight line, such as a level flight, the determination step may further take into account that the aircraft has a horizontal attitude, in which the antenna is located above the aircraft's fuselage and takes a vertical orientation.

[0154] The step of determining the antenna gain can be carried out for all the acquired spatial and temporal observation coordinates, i.e. either for any position in the geographical zone Z and / or over the entire observation time range or for all the positions on the possible trajectories TPO and / or on the planned trajectory TPR and for all the dates corresponding to these positions. The method can further comprise a step of displaying the antenna gain for a given position in the geographical zone during the defined observation duration and / or during the tracking of the trajectory. Such a graphical representation is given in [Fig 6B] and FIG. 1 IB as an example.

[0155] The method may further comprise a step of determining the level of signals from the GNSS system satellites after the antenna received. The determination of the level of signals after the antenna received may take into account the characteristics of the installed vehicle antenna and / or the position of the vehicle antenna and / or the shape of the vehicle, with a view to possible masking of the antenna by the vehicle for example. This determination step may further take into account the movement characteristics of the vehicle, such as the maximum attitudes of the vehicle, when the vehicle is an aircraft for example.The step of determining the level of after-antenna signals received from the satellites of the GNSS system can be carried out for all the acquired observation time coordinates, i.e. either for any position in the geographical zone Z and / or over the entire observation time range or for all the positions on the possible trajectories TPO and / or on the planned trajectory TPR and for all the dates corresponding to these positions. The method can further comprise a step of displaying the level of after-antenna signals from the satellites of the GNSS system received for a given position in the geographical zone during the defined observation duration and / or during the tracking of the trajectory. Such a graphical representation is given in [Fig 6C] and figure 1 IC as an example.

[0156] Similarly, the method may further comprise a step of determining the level of electromagnetic signals received for each known source of electromagnetic disturbance. The step of determining the level of signals interference received can be carried out for all acquired observation time coordinates, i.e. either for any position in the geographical area Z and / or over the entire observation time range or for all positions on the possible trajectories TPO and / or on the planned trajectory TPR and for all dates corresponding to these positions. The method may further comprise a step of displaying the level of electromagnetic signals received for a known source of electromagnetic disturbances and / or for all sources of electromagnetic disturbances in a particular GNSS frequency band in which a graphical representation of the level of electromagnetic signals received is displayed to the user for the defined observation duration and / or during the tracking of the trajectory. Such a graphical representation is given in [Fig.3] (for area Z) and [Fig.9] (along the trajectory) as an example.

[0157] The method may further comprise a step of determining the antenna gain of the respective vehicle antenna with respect to each of the sources of electromagnetic disturbance. The determination of the antenna gain may take into account the characteristics of the installed vehicle antenna and / or the position of the vehicle antenna and / or the shape of the vehicle, with a view to possible masking of the antenna by the vehicle for example. When the antenna is an adaptive antenna making it possible to eliminate a limited number of sources of electromagnetic disturbance, the determination of the antenna gain applied to each electromagnetic signal originating from a source of electromagnetic disturbance may also take this fact into account and the new antenna pattern may be applied to the signals of the GNSS system satellites received.This determination step may further take into account the movement characteristics of the vehicle, such as maximum attitudes of the vehicle, when the vehicle is an aircraft for example. Alternatively or additionally, this determination step may further take into account the estimated attitudes of the vehicle at each position observed during the tracking of the TPR and / or TPO trajectory. In particular, when the aircraft has a horizontal attitude, the fuselage partially masks the electromagnetic signals emitted by sources of electromagnetic disturbance coming from a position below the aircraft.

[0158] The step of determining the antenna gain applied to the electromagnetic disturbances can be carried out for all the acquired spatial and temporal observation coordinates, i.e. either for any position in the geographical zone Z and / or over the entire observation time range or for all the positions on the possible trajectories TPO and / or on the planned trajectory TPR and for all the dates corresponding to these positions. The method can further comprise a step of displaying the antenna gain and / or antenna diagram for a position given in the geographic area during the defined observation period and / or during trajectory monitoring.

[0159] The method may further comprise a step of determining the level of the post-antenna electromagnetic signals received for each known source of electromagnetic disturbance. The determination of the level of post-antenna electromagnetic signals received may take into account the characteristics of the vehicle antenna and / or the position of the vehicle antenna and / or the shape of the vehicle, with a view to possible masking of the antenna by the vehicle, for example, during the observation period.

[0160] When the antenna is an adaptive antenna making it possible to eliminate a limited number of sources of electromagnetic disturbance, the determination of the level of the electromagnetic signals received after the antenna can also take this fact into account. This determination step can also take into account the movement characteristics of the vehicle, such as a maximum attitude of the vehicle, when the vehicle is an aircraft for example.

[0161] The step of determining the level of the received post-antenna electromagnetic signals for each source of electromagnetic disturbances can be carried out for all the acquired observation time coordinates, i.e. either for any position in the geographical zone Z and / or over the entire observation time range or for all the positions on the possible trajectories TPO and / or on the planned trajectory TPR and for all the dates corresponding to these positions. The method can further comprise a step of displaying the level of the received post-antenna electromagnetic signals for a known source of electromagnetic disturbances in which a graphical representation of the level of received post-antenna electromagnetic signals is displayed to the user. Such a graphical representation is given in [Fig.4] (for zone Z) and [Fig. 10] (along the trajectory) as an example.

[0162] The levels of the electromagnetic signals received after the antenna determined also make it possible to establish the destructive zones with respect to the vehicle receiver, for example as a function of the robustness of the receiver's protection diodes.

[0163] The method may, following the step of determining the level of signals from the satellites of the post-antenna satellite positioning system received and the step of determining the level of interference signals received for each known source of electromagnetic disturbance, take into account characteristics of the receiver used which may further include: the service of the GNSS system used (for example GNSS L1 C / A, L1 P(Y), GALILIEO El, SBAS), radiofrequency filtering of the receiver by frequency band, saturation / desaturation of a converter analog-digital (ADC) of the receiver, a behavior and response time of an automatic gain control (AGC) of the receiver, the presence of an anti-jamming device integrated into the receiver as well as the properties of such an anti-jamming device, a processing gain linked to a spread of the spectrum during correlation by a spread code, a threshold for acquisition of satellite signals of the receiver, a threshold for reacquisition of satellite signals of the receiver, a threshold for tracking satellite signals of the receiver, a time of acquisition and / or reacquisition of satellite signals.

[0164] The anti-jamming device may be, for example, of the monoammonium phosphate type, of the band-stop filter type, of the anti-carrier wave type or of the adaptive gain type. The properties of the anti-jamming device may include a rejection gain of the anti-jamming device. Depending on the type of anti-jamming device used, the properties of the anti-jamming device, the service of the satellite positioning system used (L1, L2, L5) and the characteristics of the interfering electromagnetic signal received after the antenna (waveform, spectral width, continuous / periodic), certain electromagnetic disturbances will lose effectiveness (partial or total rejection).

[0165] The process gain can vary depending on the spectral shape of the disturbing electromagnetic signal (narrow band, wide band, carrier wave, chirp, etc.), its type (Gaussian, AM / FM modulation, etc.) and the service code of the GNSS system used (C / A, C, P(Y), M).

[0166] The method may further comprise a step of developing the spectral sum of the interfering electromagnetic signals with thermal noise and / or a step of determining a power spectral density for each service and / or frequency band of the GNSS system used or activated.

[0167] As an example, [Fig.5] represents a table displaying the residual power - after antenna and receiver processing - of the different interfering electromagnetic signals received in the geographical area potentially affecting three services of a satellite positioning system (L1 C / A, L1 P(Y), L2 P(Y)). The left-hand column of the table represents the level of the interfering electromagnetic signals received after antenna at any point in the geographical area Z, each line of this column corresponding to a known source of electromagnetic disturbance. The three columns to the right of the table each relate to a level of the residual interfering electromagnetic signal after antenna and after a step of signal filtering, anti-jamming processing and correlation of the interference signal with the service of the respective GNSS system for each of the three services.The first column among these three columns concerns the Ll C / A service, the second column among these three columns concerns the Ll P(Y) service and the third column is- . i.e. the last column on the right, among these three columns concerns the L2 P(Y) service. For each of the three columns on the right of the table, the first row relates to a first known electromagnetic disturbance, the second row relates to a second known electromagnetic disturbance and the third row relates to a third known electromagnetic disturbance. For example, the box at the top right of the table represents the residual power of the signal received from the first source of electromagnetic disturbance after antenna, after filtering, after anti-jamming treatment and after correlation for the L2 P(Y) service. The bottom row represents the sum of the different residual disturbing electromagnetic signals for each of the services.For example, the box to the left of the last line represents the sum of the residual powers of the 3 interfering electromagnetic signals after antenna, after filtering, after anti-jamming treatment and after correlation for the L1C / A service.

[0168] The method may further comprise a step of calculating the ratio between the level of each signal from the satellites of the GNSS system received after the antenna and the residual sum of the levels of disturbing electromagnetic signals received after the antenna, after filtering, after anti-jamming processing and after correlation from each of the known sources of electromagnetic disturbance. This ratio may be called the signal / noise ratio. This step may be calculated for all the acquired spatio-temporal observation coordinates, i.e. either for any point in the geographical zone Z and over the entire observed time range or for all the positions on the possible trajectories TPO and / or on the planned trajectory TPR and for all the dates corresponding to these positions.

[0169] The method may further comprise a display step in which a graphical representation of the signal-to-noise ratio for each satellite and each service is displayed to the user.

[0170] The method may, following the step of determining the signal / noise ratio, further comprise a step of determining a prediction of proper operation of the receiver for each of the services of the GNSS system for all the acquired spatio-temporal observation coordinates, i.e. either for any point in the geographical zone Z and over the entire observed time range, or for all the positions on the possible trajectories TPO and / or on the planned trajectory TPR and for all the dates corresponding to these positions.

[0171] The method may further comprise a step of displaying the proper functioning of the satellite positioning system, in particular its integrity and its capacities and performances for each service used in which a graphical representation of the proper functioning of the respective service(s) is displayed to the user. This graphical representation of the proper functioning may comprise multiple layers. For example, for each of the services used, a first layer among the multiple layers can represent the receiver tracking capacity, a second layer among the multiple layers can represent the receiver tracking capacity with integrity, a third layer among the multiple layers can represent the re-acquisition capacity, a fourth layer among the multiple layers can represent the satellite signal acquisition capacity. Such a graphical representation is given in [Fig.7] as an example for a zone Z. Other layers can be added such as for example the representation of the tracking capacity in dual frequencies, in dual constellations, the representation of the estimated accuracy of positions and speeds. The graphical representation of the correct operation can include different cursors, for example an altitude level and a date / time.The graphical representation of the operation, including the capabilities and performance, of the receiver can be displayed to the user on a map background.

[0172] When the proper functioning step is calculated for all the positions on the possible trajectories TPO and / or on the planned trajectory TPR and for all the dates corresponding to these positions, the display step may comprise the display of proper functioning along a 4D trajectory corresponding to a possible trajectory TPO and / or the planned trajectory TPR. The capacities and performances along the 4D trajectory may be displayed to the user on a map background or on a horizontal view or on a vertical view or on a time line view. This display step makes it possible to present to the user a capacity view and performances of the receiver along and / or near the 4D trajectory. An example of a display of capacities of a receiver for a given service along such a 4D trajectory on a map background is given in [Fig.8].

[0173] The method may further comprise a step of calculating the impact of the present and future operation of the receiver on the on-board positioning system, in particular an estimator of the date or location at which the vehicle will lose its hybridization, switch to inertial mode or navigate using another location sensor (Doppler, radio navigation). In the same way, the capabilities and performance of the location system may be displayed to the user.

[0174] When the vehicle is an aircraft, the method may further comprise a step of displaying a representation of the operation, in particular the capacities and / or performances, of the receiver and / or positioning system around the 4D trajectory also giving its degree of latitude with respect to a modification of the planned trajectory TPR, or of the flight plan FPLN in the event of a potential diversion (weather, breakdown, etc.).

[0175] The method may further comprise a step of displaying the capacities and / or performances of the present and future situation of a set or a subset of the vehicles operating in the monitored geographical zone Z, also allowing sharing of information between different actors and assistance in the management of the control center).

[0176] The calculation and / or monitoring device 10 and the calculation and / or monitoring method 10 make it possible to improve the planning of a flight or a mission of any airplane or helicopter, to reduce the workload of the pilots and provide an improvement in the success rate of the mission and in air safety.

[0177] The calculation and / or monitoring device 10 and the calculation and / or monitoring method allow preparation of drone flights with secure trajectory calculation with a PNT solution always available.

[0178] The calculation and / or monitoring device 10 can be subdivided into two entities:

[0179] - an upstream entity which takes into account all the characteristics of the system GNSS, sources of electromagnetic disturbances, topography of the geographic area Z, obstacles in the geographic area Z, 4D trajectory, relief, obstacles and time. The resulting data are generic or universal, and applicable for any user (antenna input).

[0180] - a downstream entity which will take into account the characteristics of the carrier, i.e. say of the vehicle, and its on-board system (antenna, receiver, carrier, positioning system, etc.) and translate this universal data into user data in terms of capacity and performance.

[0181] The upstream entity and the downstream entity provide directly operational information via a geographical and temporal representation (present and future) of the impacts of the sources of electromagnetic disturbance on the operation of the receiver and / or the positioning system adapted to each of the operators.

[0182] The calculation and / or monitoring device 10 and the calculation and / or monitoring method make it possible to provide a precise view of the present and future situation in terms of capacity and performance of the receiver and / or the positioning system along and around any trajectory of the vehicle or in the geographical zone Z and corresponding to the system / carrier used.

[0183] The calculation and / or monitoring device 10 and the calculation and / or monitoring method also make it possible to alert the crew of an aircraft in advance of any loss of PNT capacity or performance during the flight.

[0184] The calculation and / or monitoring device 10 and the calculation and / or monitoring method also make it possible to detect and inform of any modification of the electromagnetic disturbances in order to allow an update of the database of sources of electromagnetic disturbances.

[0185] The complete system thus allows multiple applications as set out previously and constitutes an asset for the success of a mission, the improvement of security, preventive information and assistance with decision-making / planning.

Claims

1. Claims Method for calculating and / or monitoring the operation of a satellite positioning system of a main vehicle in a geographical area (Z), the operation of said positioning system including the integrity, capacities and performances of this system, the method comprising the following steps: - acquisition of spatial and temporal observation coordinates, the spatial observation coordinates being located in the geographic zone (Z); - acquisition of spatio-temporal coordinates of the satellites of a GNSS system for each observation temporal coordinate; - acquisition of characteristics and spatio-temporal coordinates representative of known positions of sources of electromagnetic disturbances of a GNSS system signal, located in or near the geographic zone (Z); - acquisition of data representative of characteristics of the satellite positioning system of the main vehicle; - calculation of an impact of the sources of electromagnetic disturbances on the operation of the satellite positioning system of the main vehicle for each service and each constellation of the GNSS system and for each spatial and temporal observation coordinate as a function of the spatial observation coordinate, the observation temporal coordinate corresponding to this spatial observation coordinate, the spatio-temporal coordinates of the satellites of the GNSS system at the observation temporal coordinate, the spatio-temporal coordinates representative of the known positions of the sources of electromagnetic disturbances at the observation temporal coordinate and the data representative of characteristics of the satellite positioning system, said impact calculation comprising an estimation of a tracking capability, a tracking capability with integrity, a satellite signal acquisition capability and a satellite signal re-acquisition capability of a satellite positioning system receiver.

2. Calculation and / or monitoring method according to claim 1 further comprising the acquisition of characteristics and / or spatio-temporal coordinates representative of positions of at least one auxiliary vehicle, equipped with a satellite positioning system and located in or near the geographical zone (Z), and their use in said calculation of the impact of sources of electromagnetic disturbance.

3. Calculation and / or monitoring method according to any one of claims 1 and 2, characterized in that it further comprises the following steps for at least one vehicle chosen from the main vehicle and, where appropriate, the at least one auxiliary vehicle: - obtaining a planned trajectory (TPR) of the respective vehicle, the planned trajectory (TPR) connecting a starting position (PD) to a destination of the respective vehicle and comprising a departure date of the respective vehicle or the planned trajectory (TPR) connecting a current position (PA) of the vehicle to the destination of the respective vehicle and comprising a current date;and - determination of the spatial and temporal observation coordinates located on the planned trajectory (TPR) of the respective vehicle at an estimated date from the departure date of the respective vehicle or from the current date and an estimated travel time for this spatial coordinate from the departure position of the respective vehicle or from the current position to this spatial coordinate.;

4. Calculation and / or monitoring method according to claim 3, characterized in that it further comprises the following step: - division of the planned trajectory (TPR) into a plurality of sections determined as a function of the impact of the sources of electromagnetic disturbance on the operation of the satellite positioning system at each of the

5.

6. spatial and temporal observation coordinates located on the respective section. Calculation and / or monitoring method according to claim 4, characterized in that it further comprises the following step: - warning a driver and / or crew of the respective vehicle when the current position of the respective vehicle is approaching a section with high disruption forecast (TPE), and / or in the event of loss of capacity and / or degradation of performance. Calculation and / or monitoring method according to one of claims 3 to 5, characterized in that the planned trajectory (TPR) of the respective vehicle is obtained: - by calculating several possible trajectories (TPO) of the respective vehicle connecting either the starting position (PD) to the destination or the current position (PA) to the destination; - - by determining spatial and temporal coordinates observation point located on the several possible trajectories (TPO) of the respective vehicle at a date estimated from the departure date of the respective vehicle or from the current date and an estimated travel time for this observation spatial coordinate and this possible trajectory (TPO) from the departure position of the respective vehicle or from the current position to this observation spatial coordinate; - by acquiring the spatio-temporal coordinates of the GNSS system satellites for each observation time coordinate of each possible trajectory (TPO); - by calculating, for each possible trajectory (TPO), the impact of the sources of electromagnetic disturbance on the operation of the satellite positioning system of the respective vehicle at each of the spatial and temporal observation coordinates as a function of the spatial observation coordinate, the temporal observation coordinate associated with this spatial observation coordinate, the coordinates

7.

8.

9. spatio-temporal coordinates of the satellites of the GNSS system at the observation time coordinate, spatio-temporal coordinates representative of known positions of the sources of electromagnetic disturbances, data representative of characteristics of the satellite positioning system, and where appropriate, characteristics and / or spatio-temporal coordinates representative of positions of at least one other vehicle chosen from the main vehicle and at least one auxiliary vehicle; - by determining the planned trajectory (TPR) among the possible trajectories (TPO) based on the impact of electromagnetic disturbance sources on the operation of the satellite positioning system of the respective vehicle at each spatial and temporal observation coordinate located on the possible trajectory (TPO). Calculation and / or monitoring method according to one of claims 3 to 6, characterized in that, for each possible trajectory (TPO) and / or for the planned trajectory (TPR) or for any point in the geographical zone (Z), the calculation of the impact of the sources of electromagnetic disturbances on the operation of the satellite positioning system comprises the calculation of the distances, elevations and azimuths of each source of electromagnetic disturbances and of each satellite of the GNSS system at each of the spatial and temporal observation coordinates of the possible trajectory (TPO) and / or of the planned trajectory (TPR) and / or of the geographical zone (Z). Calculation and / or monitoring method according to claim 2 and any one of claims 3 to 7 in which a planned trajectory (TPR) is obtained for each vehicle among the main vehicle and the at least one auxiliary vehicle. Calculation and / or monitoring method according to any one of the preceding claims, characterized in that it further comprises the following step for at least one vehicle chosen from the main vehicle and, where appropriate, the at least one auxiliary vehicle: - acquisition of data representative of a category of the respective vehicle and / or a shape of the respective vehicle and / or a position of an antenna on the respective vehicle and / or movement characteristics of the respective vehicle; and in that said impact on the operation of the satellite positioning system at each of the spatial and temporal observation coordinates is calculated as a function of an antenna gain of the antenna of the respective vehicle estimated for each spatial and temporal observation coordinate, from the data representative of the category of the vehicle and / or the shape of the vehicle and / or the position of the antenna on the vehicle and / or an orientation of the vehicle at this spatial and temporal observation coordinate estimated on the basis of the data representative of the movement characteristics.

10. Calculation and / or monitoring method according to any one of the preceding claims, characterized in that it further comprises the following step for at least one vehicle chosen from the main vehicle and, where appropriate, the at least one auxiliary vehicle: - acquisition of data representative of a topography and obstacles of the geographical zone (Z); and in that said impact on the operation of the satellite positioning system of the respective vehicle at each of the spatial and temporal observation coordinates is further calculated as a function of data representative of a topography of the geographical zone (Z).

11. Calculation and / or monitoring method according to any one of the preceding claims, characterized in that the acquisition of spatial coordinates representative of known positions of sources of electromagnetic disturbances is repeated at regular intervals.

12. Calculation and / or monitoring method according to any one of the preceding claims, characterized in that it further comprises the following steps: - verification of proper operation of the main vehicle positioning system at regular time intervals with respect to the predictions; - if the deviation from the predictions is greater than a threshold, generation of a message updating a database of spatial coordinates representative of the known positions of sources of electromagnetic disturbance in the geographical zone (Z).

13. Calculation and / or monitoring method according to any one of the preceding claims, characterized in that the geographical area (Z) is divided into a plurality of boxes constituting a grid, the grid preferably comprising a predefined resolution, the spatial and temporal observation coordinates comprising a plurality of positions each located in one of the boxes constituting the grid, preferably located in the center of the box constituting the grid, the geographical area observed for the same instant in time, the spatial and temporal observation coordinates all referring to the same instant of observation.

14. A computer program product comprising software instructions which, when executed by a computer, implement the calculation and / or monitoring method according to any one of the preceding claims.

15. Device for calculating and / or monitoring the operation of a satellite positioning system of a main vehicle in a geographical zone (Z), comprising technical means adapted to implement the calculation and / or monitoring method according to any one of claims 1 to 13.

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