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

Abstract

The present invention relates to a method for computing and / or for monitoring the operation of a satellite positioning system of a main vehicle in a geographical area, comprising acquiring spatial and temporal observation coordinates; acquiring spatiotemporal coordinates of the satellites of a GNSS system for each temporal observation coordinate; acquiring features and spatiotemporal coordinates representative of known positions of sources of electromagnetic disturbance on a signal of the GNSS system; acquiring data representative of features of the satellite positioning system of the main vehicle; computing an impact of the sources of electromagnetic disturbance on the operation of the satellite positioning system of the main vehicle.

Description

[0001] TITLE: Method for calculating and / or monitoring the operation of a satellite positioning system on board a vehicle, and associated device and computer program product

[0002] 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 is to move in a geographical area and within a time range.

[0003] The present invention also relates to a computer program product and a calculation and / or monitoring device associated with this method.

[0004] 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.

[0005] 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 mission control.

[0006] Similarly, drones that can participate in these missions also make extensive use of the satellite positioning system.

[0007] The strategic nature of satellite positioning systems is well established. Their advantages include global and permanent coverage of the PNT, operational safety, and performance.

[0008] The weakness of these satellite positioning systems lies in their vulnerability to electromagnetic disturbances, particularly 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 undamaged 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 interfering 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.

[0009] To prohibit the use of such an operational asset, and to challenge space sovereignty, numerous jamming systems are used, these systems ranging from simple interference systems to very sophisticated jammers.

[0010] Sources of interference are therefore particularly numerous in and near conflict zones or areas requiring humanitarian intervention.

[0011] 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 making certain capabilities of the receivers used unavailable, such as acquisition, tracking, integrity, dual-frequency or multi-constellation processing, use of an augmentation system (ABAS).

[0012] Even if vehicles participating in a mission can move safely without satellite positioning systems thanks to additional sensors, the massive increase in sources of electromagnetic disturbance is considered a threat because it can harm the success of any mission, or at least complicates the execution of missions, and imposes a greater workload both on the pilots of 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.

[0013] Having to operate in an electromagnetically disturbed mission space when the integrity, capacity and / or performance of the PNT are required for the success of the mission poses many challenges. 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 resources.

[0014] Document WO 2015 / 065664 A1 discloses a system for generating a visual representation of interference sources affecting the operation of a satellite positioning system. The visual representation may comprise a map overlaid with visual indicators indicating a location and magnitude of the interference.

[0015] However, the known system does not allow the impact of interference sources on the operation of a particular satellite receiver and on the on-board positioning system to be determined, nor the impact on the integrity, capabilities and performance of the latter in a vehicle that must operate in a defined geographical area and at different altitude levels. The known system also does not allow the impact of interference sources on the operation of a satellite receiver at a specific date and time to be determined. Thus, the system does not allow the risks of malfunction of the on-board satellite positioning receiver to be predicted or estimated 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 must 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 interference.

[0016] 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 having to operate 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 before the mission and in real time during the mission.

[0017] An aim of the invention is also to alert the crew when approaching a loss of PNT capacity or a significant degradation in performance, and to detect any change in electromagnetic threats by monitoring the operation of the satellite positioning system during the course of the mission.

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

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

[0020] - 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 geographical area;

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

[0022] - calculation of an impact of sources of electromagnetic disturbance on the operation, including the integrity, capabilities and performance, 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 disturbance at the observation temporal 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 over time 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 entire 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 individually or in all technically possible combinations:

[0025] - the result of the calculation of an impact of interference sources on the operation of the satellite positioning system includes at least one quantitative indicator representative of at least two capacities and / or performances chosen from a first acquisition capacity without initialization, a first acquisition capacity with initialization, a re-acquisition capacity, a tracking capacity without integrity, a tracking capacity with integrity, a hybridization capacity, a PNT precision and an integrity radius;

[0026] - the method comprises 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;

[0027] - the method comprises, for at least one vehicle selected from the main vehicle and, where applicable, the at least one auxiliary vehicle: 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 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 starting position of the respective vehicle or from the current position to this spatial coordinate;optionally iii) the division of 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;

[0028] - the method comprises warning a driver and / or a 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;

[0029] - the planned trajectory of the respective vehicle is in one embodiment of the method obtained: 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; b) by determining observation space and time 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 space coordinate and this possible trajectory from the starting position of the respective vehicle or from the current position to this observation space coordinate; c) by acquiring the space-time coordinates of the satellites of the GNSS system for each observation time coordinate of each possible trajectory;(d) by calculating, for each possible trajectory, 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 observation temporal coordinate associated with 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 known positions of the sources of electromagnetic disturbance, the data representative of characteristics of the satellite positioning system, and where appropriate, the characteristics and / or the spatio-temporal coordinates representative of positions of at least one other vehicle chosen from the main vehicle and the at least one auxiliary vehicle;(e) determining the planned trajectory from among the possible trajectories 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;

[0030] - 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 the sources of electromagnetic disturbance on the operation of the satellite positioning system comprises 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;

[0031] - in one embodiment, a planned trajectory is obtained for each vehicle among the main vehicle and the at least one auxiliary vehicle;

[0032] - for at least one vehicle chosen from the main vehicle and, where appropriate, the at least one auxiliary vehicle, the method comprises in one embodiment the 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 the impact on the operation of the satellite positioning system at each of the observation spatial and temporal coordinates is calculated based on an antenna gain of the respective vehicle antenna estimated for each observation spatial and temporal coordinate, from 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 an orientation of the vehicle at this observation spatial and temporal coordinate estimated on the basis of data representative of the movement characteristics;

[0033] - for at least one vehicle chosen from the main vehicle and, where appropriate, 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;

[0034] - the method comprises the acquisition of spatial coordinates representative of known positions of sources of electromagnetic disturbances is repeated at regular intervals;

[0035] - the method further comprises verifying proper operation, in particular the integrity, performance and capabilities, of the positioning system of the main vehicle at regular time intervals with respect to the predictions; and if the deviation with respect to the predictions is greater than a threshold, generating a message for updating a database of spatial coordinates representative of the known positions of sources of electromagnetic disturbance in the geographical area;

[0036] - in one embodiment, the geographical 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;

[0037] 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.

[0038] The invention finally relates to a device for calculating and / or monitoring an 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. 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: Figure 1 is a schematic representation of a device for calculating and / or monitoring an operation of a satellite positioning system of a vehicle in a geographical area according to the present application; Figure 2 is a schematic representation of several possible flight plans of a vehicle crossing a geographical area;Figure 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; Figure 4 is a representation of a power received from the source of electromagnetic disturbances after application of the satellite antenna diagram on board the vehicle in the geographical area; Figure 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;

[0039] In Figure 6, Figure 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); Figure 6B is a representation of the antenna gain applied to each satellite signal received by the satellite positioning system at the point in the geographic area; Figure 6C is a representation of the estimated post-antenna power of each signal received by the satellite positioning system at the point in the geographic area; Figure 7 is a representation of the estimated capabilities of the receiver of the satellite positioning system with respect to three services and for the entire geographic area at a given time t and altitude;Figure 8 is a schematic representation of a planned trajectory of the vehicle divided into a plurality of segments according to the estimated capacities; Figure 9 is a representation of a power received at the antenna of a source of electromagnetic disturbances along a 4D trajectory crossing the geographical area; Figure 10 is a representation of a power after antenna received from the source of electromagnetic disturbances along the 4D trajectory crossing the geographical area; in Figure 1 1:;

[0040] - 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;

[0041] - part B is a representation of the antenna gains applied to each satellite signal received along the 4D trajectory crossing the geographic area;

[0042] - 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.

[0043] Figure 1 illustrates a device 10 for calculating and / or monitoring the operation of a satellite positioning system for a vehicle in a geographical zone Z.

[0044] 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.

[0045] The operation of the vehicle satellite positioning system within the meaning of the present application can be described by one or more criteria, preferably at least two quantities, chosen from the integrity of this system, one or more capacities and one or more performances, these terms being defined as described below.

[0046] The integrity of the satellite positioning system is its ability to provide measurements (e.g. position, velocity, and / or time) on an output, associated with accuracy guarantees. Integrity can notably be defined as the capacity of the satellite positioning system to provide one or more geolocation data with a given level of confidence, the positioning system being able to optionally include the generation of an alert signal in the event of loss of integrity (invalid) or an integrity value exceeding an acceptable threshold. Reference may be made to the definition in Annex 10 to the Convention on International Civil Aviation, 8 ème edition, July 2023, volume I, supplement D, 3.3.1.

[0047] Integrity is for example described by a binary indicator (for example, validity or availability) or by a continuous indicator such as the level of confidence on each of one or more geolocation data;

[0048] The one or more capabilities of the satellite positioning system include, but are not limited to: a) the first acquisition capability, without or with initialization, i.e. the ability of the positioning system to acquire (or equivalently to capture or detect or lock on to) for the first time a signal transmitted by one or more satellites for a given GNSS service (e.g. GPS L1 C / A), in particular at the start of the operating system when no satellite signal has yet been captured, the possible initialization including the provision of assistance to the receiver to locate the satellite(s) to be searched for, for example an almanac and / or an approximate position of the satellite positioning system and / or a date-time;(b) the re-acquisition capacity, i.e. the capacity of the satellite positioning system to find a satellite signal first captured on a detection date and lost on a loss date subsequent to the detection date;(c) the tracking capability, with or without integrity, i.e. the ability of the satellite positioning system to continuously track over time a satellite signal first captured on a detection date, despite any relative movement of the receiver in relation to the satellite and / or its terrestrial or aerial environment. This capability may be unitary per satellite or consolidated in order to determine whether a PNT can be calculated and provided by the onboard GNSS receiver (for example, if at least four satellites are actually tracked), and with what precision and integrity. In the case of "with integrity", it is understood that the PNT is obtained with a confidence level higher than a predetermined confidence threshold or a precision value lower than a required threshold (for example, the capability of the satellite positioning system may be its ability to provide a position with an integrity of less than 0.3 nm).;

[0049] Advantageously, this ability to provide a valid and integrated PNT can be determined at the level of the on-board positioning system when it is implemented in combination with one or more additional positioning assistance sensors (such as inertial units (hybridization), Doppler sensors, radio navigation sensors).

[0050] The first acquisition capacity with or without initialization, the tracking capacity with or without integrity, the re-acquisition capacity and the hybridization capacity each depend on the intrinsic characteristics of the satellite positioning system, in particular the design of its measurement chain, its sensitivity or robustness to a disturbing electromagnetic environment, the positioning of its antenna on a vehicle with which it is equipped, the characteristics of the interference sources (in particular the power and / or spectrum of a signal emitted by such a source and / or the position over time of this source) acting on the vehicle and the satellites whose signals are to be detected (constellation and / or services used by the receiver, transmission power per service and per satellite, position over time).The re-acquisition capability may be unitary in the sense that this capability may be indicated as available if at least one previously lost satellite can be reacquired. This capability may also be an operational consolidation indicating that a satellite positioning system that has not provided valid PNT for a certain period of time has the capability at a given position and date (4D position) to re-acquire the number of satellites missing to provide valid PNT (for example, if the receiver is now tracking only two satellites, the re-acquisition capability may be indicated as available when it is determined that the satellite positioning system will be able to re-acquire at least two other missing satellites). Similarly,.

[0051] - the acquisition capacity can be considered individually per satellite and per GNSS service, but also as the capacity to acquire at least four satellites for a given service,

[0052] - tracking capacity can be considered individually per satellite and per GNSS service, but also as the capacity to track at least four satellites for a given service,

[0053] - tracking capability with integrity can be considered as the ability to track at least five satellites for a given service or the ability of the GNSS receiver to provide valid and intact PNT.

[0054] The performance of the satellite positioning system is defined when it is capable of at least acquiring a signal.

[0055] The performance of the satellite positioning system may include, but is not limited to, the accuracy of each parameter of positioning, navigation and synchronization (or equivalently time) (in English, "positioning, navigation and timing", PNT) and / or the integrity radius of each parameter of the PNT and / or the speed of the measurement chain.

[0056] The speed of the measurement chain may in particular be characterized by a time required for a first acquisition or a re-acquisition of a satellite signal, these times depending on the interaction of the receiver with the satellite in a given environment including potential sources of interference, uncertainty about the position and speed of the vehicle carrying the satellite positioning system, and / or the duration of loss of satellite signals, as well as by a response time of the system to a signal from its effective reception, which depends only on the intrinsic characteristics of the positioning system.

[0057] The accuracy of the PNT at a given position of the satellite positioning system is also a function of the intrinsic characteristics of the positioning system, the dynamics (in particular the attitude, roll and / or heading) of the vehicle carrying the satellite positioning system and the interaction of the satellite positioning system with its environment (including the satellites and any sources of interference).

[0058] The device 10 comprises an input module 20, a processing module 30 and an output module 40.

[0059] 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.

[0060] 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. Alternatively 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.

[0061] 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 also 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.

[0062] The calculation and / or monitoring device 10 allows the implementation of the method for calculating and / or monitoring the operation of the vehicle's satellite positioning system, and in particular of a receiver of this system, in the geographical zone Z.

[0063] Geographic area Z may be a fixed, expandable, or mobile geographic area. It may also be a corridor around a flight plan or trajectory. In the following, when we mention "in the vicinity of geographic area Z", we mean an extended geographic area including geographic area Z. This extended geographic area may, for example, be defined by a border distant from the border delimiting geographic area Z by a predetermined distance.

[0064] 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 within the box, preferably at the center of the box. The geographic area may thus be rasterized.

[0065] 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.

[0066] The receiver allows 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.

[0067] 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.

[0068] The space satellite positioning system, otherwise known as GNSS system, can be a GPS, Galileo, Glonass, Beidou, SBAS system for example offering several services (for example L1 C / A, L2C) transmitted on different frequency bands.

[0069] The vehicle is one of the members of a group of vehicles dedicated to carrying out a mission and is referred to in the following as the "main" vehicle to distinguish it in the description from the other vehicles in the group, which are called "auxiliary" vehicles. It should be noted that the distinction between main or auxiliary vehicle is only used for the purpose of intelligibility of the description and does not contain any notion of hierarchy or priority.

[0070] The group of vehicles may include 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.

[0071] 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.

[0072] The mission is controlled upstream and / or in real time from a control center. The control center can exchange information with all the vehicles in the mission. It is configured to coordinate the trajectories of the vehicles in the vehicle group for the purpose of 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.

[0073] In a particular embodiment, the control center is located in one of the vehicles of the group. 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.

[0074] 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.

[0075] 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 predicted for an instant corresponding to the observation temporal coordinate associated with this observation spatial coordinate.

[0076] Alternatively, the observation time range can be defined by the user by entering a time point marking the start of the observation time range and a time point marking the end of the observation time range.

[0077] The user may be a driver of the main vehicle, a member of the main vehicle crew and / or a person in charge of route planning (route, flight plan), including a member of the mission control center.

[0078] 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 of the satellites can also be acquired by retrieving them from a memory of the receiver or a memory of the calculation and / or monitoring device 10 where they have been previously deposited.

[0079] Satellite space-time coordinates can be, for example, almanac data or ephemeris data. Almanac data and ephemeris data provide the position of navigation satellites in the sky at a given date, as one of the observation time coordinates. Ephemeris data provide more precise position data than almanac data. Ephemeris data are usually stored in a database that is periodically updated to account for changes in the satellite orbit.

[0080] The GNSS database BDGNSS may include 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 predictions of the levels of the received GNSS signals in the geographical area Z.

[0081] 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.

[0082] 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 of a signal 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 of a signal received (by GNSS service) 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.

[0083] The calculation and / or monitoring method comprises a step of acquiring spatial coordinates representative of known positions of sources of electromagnetic disturbance of a signal from the GNSS system covering the geographical zone Z.

[0084] A source of electromagnetic disturbance means 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 that undermines the integrity of the system. Spatial coordinates representative of known positions of sources of electromagnetic disturbance can be acquired by retrieving them from a database where they have been previously deposited, such as a BDRFI database of radio frequency interference (RFI).

[0085] According to one possibility, the acquisition of spatial coordinates representative of known positions of sources of electromagnetic disturbances can be repeated at regular intervals.

[0086] 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 area Z and / or a minimum power of the electromagnetic signal emitted by each known source of electromagnetic disturbance in the geographical area Z and / or a maximum power of the electromagnetic signal emitted by each known source of electromagnetic disturbance in the geographical area 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 from a database where it has / have been previously deposited, such as the RFI database BDRFI.

[0087] The database of sources of electromagnetic disturbance, in particular the RFI BDRFI database, can be fed by a system for detecting / locating / recording / characterizing sources of electromagnetic disturbance. The system for detecting / locating / recording / characterizing sources of electromagnetic disturbance can be capable of collecting data from multiple observations (ground, air, space), by various means such as radars, flight recordings (commercial, freight), ships, preferably located near or in the geographical zone Z, including the main vehicle itself or 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 deposited on a network, in particular a secure network, via artificial intelligence processing based on data from known sources of electromagnetic disturbances 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 disturbances may be global or limited to a region and is directly used by the computing and / or monitoring device 10. The sources of electromagnetic disturbances 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 disturbance and / or the data representative of the emission characteristics of the sources of electromagnetic disturbance can be acquired by retrieving them from a database where they have been previously deposited, such as the database of sources of electromagnetic disturbance, in particular the RFI BDRFI database.

[0088] The step of acquiring spatial coordinates representative of known positions of sources of electromagnetic disturbance may consist of acquiring spatial coordinates representative of known positions of sources of electromagnetic disturbance 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 disturbance and to perform calculations only on sources of electromagnetic disturbance considered to be a risk to the safety and / or performance of the route.

[0089] The calculation and / or monitoring method may further comprise a step of obtaining a desired outcome in terms of probability. The desired outcome 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 outcome in terms of probability may, for example, be obtained by user input using the UI or by retrieving it from a database where it has been previously deposited.

[0090] 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.

[0091] 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.

[0092] The characteristics of the antenna of the main vehicle may in particular include an antenna pattern giving the gain for each azimuth / elevation. Advantageously, this antenna pattern is representative of the antenna pattern after installation on the main vehicle so as to take into account the gain variations induced by the movement of the vehicle due to a specific position of the positioning system on this vehicle. For example, the antenna pattern may take into account possible masking, or attenuations due to the vehicle, in particular to a ground plane of the vehicle. For example, the installation of the antenna and the position of a wing of an aircraft relative to the satellite positioning system when it equips this aircraft may affect the antenna pattern compared to the antenna pattern obtained with this same satellite positioning system alone.

[0093] The characteristics of the satellite positioning receiver on board the main vehicle may include, in particular, 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.

[0094] The characteristics of the satellite positioning system on board the vehicle may include, in particular, the performance and precision of one or more additional sensors, their possible participation in the development of the vehicle's PNT and their precision, in particular when certain capabilities 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).

[0095] 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.

[0096] The data representative of characteristics of the receiver and / or the antenna may correspond to characteristics of a standard receiver and / or a standard antenna. Alternatively, the data representative of characteristics of the receiver and / or 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.

[0097] The calculation and / or monitoring method comprises a step of calculating the impact of each source of electromagnetic disturbance 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 space-time coordinates of the satellites at the observation temporal coordinate, the space-time coordinates representative of the known positions at the observation temporal coordinate of the acquired sources of electromagnetic disturbance and the data representative of the characteristics of the satellite positioning system.

[0098] The result of the calculation of the impact of the interference sources may include, for all the sources cumulatively, the provision of one or more quantitative indicators of criteria representative of the operation of the positioning system, in particular one or more capacities such as the first acquisition capacity without or with initialization, the re-acquisition capacity, the tracking capacity without or with integrity, the hybridization capacity and / or one or more indicators of the performance of the system, such as a precision of the PNT and / or an integrity radius, and / or a speed of the measurement chain.

[0099] The result of the calculation of the impact of interference sources may also include the provision of an absolute or relative variation of one or more of these quantitative indicators of criteria representative of the operation of the positioning system with respect to a respective nominal or predetermined reference value.

[0100] For example, the result of the calculation of the impact of the interference sources for each spatial and temporal coordinate may be presented in the form of a multiplet comprising at least two different capacities, for example a multiplet (PA, P, RA, PI, NC) where PA is a binary indicator representative of the capacity of first acquisition without initialization, P is a binary indicator of the capacity of tracking with integrity, RA is a binary indicator of the capacity of re-acquisition, PI is a binary indicator of the capacity of tracking with integrity at the confidence level NC.

[0101] The result of the calculation of the impact of interference sources can also be presented in the form of a numerical value for a given service, each bit of which represents a capacity (for example, the value 13 represented by the binary 00011 11 can indicate that the first four capacities are available), or in a unitary manner per satellite and per service (for example in the form of a table of 32 GPS satellites L1 C / A service (columns) whose acquisition (A), re-acquisition (R), and tracking (P) capacities are determined over the entire observation time range at a given position in the geographical area and / or along the 4D trajectory of the vehicle).

[0102] Unlike known methods, the impact calculation is made on the basis not only of characteristics extrinsic to the positioning system, such as the relative positions of the interference sources and the satellites, but also of characteristics intrinsic to the positioning system (for example the design of its measurement chain, as well as characteristics representative of the interaction between the positioning system and its direct environment, in particular the installation and position of the satellite positioning system and its antenna on the vehicle and the position and dynamics of the vehicle (including attitude, roll, heading, etc.)) relative to the satellites and the interference sources, which have a significant impact on the operation of the system.

[0103] The impact calculation according to the invention therefore makes it possible to go well beyond the provision of a jamming map.

[0104] 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.

[0105] The spatial and temporal coordinates representative of the 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.

[0106] Some or all of these coordinates can be calculated before the mission or in real time using an appropriate computerized device fitted to the control center.

[0107] 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.

[0108] The data representing characteristics of an auxiliary vehicle may be mission-related. In particular, it may be a vehicle category, or an order of priority of the respective auxiliary vehicle in relation to other auxiliary and / or main vehicles.

[0109] 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.

[0110] 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 disturbance 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 disturbance.

[0111] 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 thus 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,as well as characteristics of the satellite positioning system. The step of calculating the impact of each source of interference of the satellite positioning system may include calculating an estimated antenna gain, for example based on the calculated elevations and / or azimuths and vehicle attitudes.,

[0112] 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 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 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 determining the spatial and temporal observation coordinates located on the planned trajectory TPR 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 starting 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 user input made using the user interface UI or received from the control 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 computer 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 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] Positions along the TPR planned trajectory can be equidistantly spaced from each other. The number of positions chosen allows a desired resolution to be defined. The desired resolution can be set by a user, for example, by entering the desired resolution in the UI. The desired resolution can be defined in terms of time period or distance. Two consecutive positions can be spaced 10 seconds apart or 0.2 nautical miles apart, for example.

[0121] The mentioned process steps may be repeated, preferably at regular intervals. The mentioned process steps may, for example, be repeated when the main vehicle has traveled part of its route. The mentioned process 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:

[0123] - 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 trajectories TPO of the main vehicle at a date estimated from the departure date of the main vehicle or from the current date and an estimated travel time for this spatial observation coordinate and this possible trajectory TPO from the starting position of the main vehicle or from the current position to this spatial observation coordinate;

[0124] - 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 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 main vehicle at each spatial and temporal observation coordinate located on each possible trajectory TPO.;

[0125] This process 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 disturbance 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.

[0126] 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, preferably for all the auxiliary vehicles located in or near the geographical zone Z.

[0127] Advantageously, the TPR planned trajectories obtained for the auxiliary vehicles are obtained:

[0128] - by calculating several possible trajectories TPO of the auxiliary 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 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 starting position of the auxiliary vehicle or from the current position to this spatial observation coordinate;

[0129] - by calculating the space-time 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 each source of electromagnetic disturbance on the operation of the satellite positioning system of the auxiliary vehicle at each of the observation space and time coordinates as a function of the observation space coordinate, the observation time coordinate associated with this observation space coordinate, the spatial coordinates of the GNSS system satellites at the observation time coordinate, the spatial coordinates representative of the known positions of the sources of electromagnetic disturbance acquired at the observation time coordinate,characteristics of the sources of electromagnetic disturbance and data representative of the characteristics of the satellite positioning system of the auxiliary vehicle, and optionally characteristics and / or spatio-temporal coordinates representative of the positions of at least one other vehicle chosen from the main vehicle and the other auxiliary vehicles;,

[0130] - 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.

[0131] In this case, the method may comprise determining groups of possible GTPO trajectories. Each group of possible GTPO trajectories comprises a possible TPO trajectory for each of the main and auxiliary vehicles, the different possible TPO trajectories of a given group of possible GTPO trajectories being compatible with each other and with the accomplishment of the mission. The method may further comprise ranking the different groups of possible GTPO trajectories 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 GTPO trajectories from the point of view not of a given vehicle but of all the main and auxiliary vehicles dedicated to the mission.

[0132] The optimal GTPO group of possible trajectories may correspond to an optimum upstream of the mission or be determined iteratively during the mission exercise.

[0133] The calculation steps of the process can be implemented centrally at the control center or partially distributed across calculation resources equipping each of the main and auxiliary vehicles.

[0134] 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.

[0135] 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 driver 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.

[0136] When the main or auxiliary vehicle is an aircraft, the method allows the preparation of a flight plan (FPLN) taking into account 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.

[0137] Alternatively, the trajectory recommended as TPR may correspond to the possible trajectory TPO with the lowest impact on the operation of the satellite positioning system of the respective vehicle. Alternatively, the trajectory recommended as TPR may correspond to the possible trajectory TPO with an impact on the operation of the satellite positioning system below a predefined threshold (e.g. valid PNT, integrates with accuracy < 0.1 nm at 95%) and with a minimum travel time of the respective vehicle and / or a minimum fuel consumption of the vehicle.

[0138] 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.

[0139] 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 disturbance 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.,

[0140] 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.

[0141] 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 disturbance 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.

[0142] The data representative of the topography of the geographical area Z can be acquired in a database called a DEM (Digital Elevation Model) database BDMNE. The data representative of the topography of the geographical area Z can include data representative of obstacles such as buildings and data from a digital terrain model (DTM). The 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.

[0143] The step of calculating an impact of each source of electromagnetic disturbance 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 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 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 propagation of the electromagnetic signal emitted by this source of electromagnetic disturbance considering the topography of the terrain, by applying Fresnel equations for example.

[0144] As shown in Figure 2, the possible trajectories TPO and / or the trajectory recommended as a planned trajectory TPR may comprise a plurality of waypoints PC1 to PC7 constituting different flight plans. The starting position PD, the current position PA and / or the destination may constitute waypoints PC1 to PC7. In Figure 2, the waypoints PC1 to PC7 are represented by stars.

[0145] As shown in Figure 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 in Figure 2, the planned trajectory TPR chosen (PC1 - 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 (PC1 - 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.

[0146] 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.

[0147] The low disturbance forecast 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 forecast 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 forecast 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.

[0148] 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 disruption forecast or, where appropriate, a section with a medium TPM disruption 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.

[0149] If necessary, the warning can be transmitted to at least one other auxiliary vehicle.

[0150] The method may further comprise a monitoring function of verifying the operation of the satellite positioning system and / or signal-to-noise ratios, in real time or at regular time intervals, against the predictions.For example, when a good operation 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 operation 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 high disturbance forecast TPE or on a section with a medium disturbance forecast 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 forecast of low TPF disturbance, 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.

[0151] Thus, the method monitors and compares in real time the measurements and the risks of disturbance and ensures a loopback to keep the database of sources of electromagnetic disturbances 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 different information received.

[0152] 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.

[0153] 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.

[0154] The resolution can be a predefined resolution or a user-defined resolution, for example by entering the desired resolution in the UI. Thus, the observation spatial and temporal coordinates can either correspond to positions lying on a path defined by a planned trajectory TPR and / or a possible trajectory TPO or to positions defining the grid.

[0155] 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 Figure 6A (defined point) and Figure 11A (during trajectory tracking) as an example.

[0156] 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 take into account the movement characteristics of the vehicle, such as maximum attitudes of the vehicle (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 attitudes of the vehicle at each position observed during the tracking of the TPR and / or TPO trajectory.For example, where the vehicle is an aircraft and where the aircraft is intended to travel in a straight line, such as a level flight, the determining step may further take into account that the aircraft has a horizontal attitude, in which the antenna is located above the fuselage of the aircraft and takes a vertical orientation.

[0157] 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 1 B as an example.

[0158] 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 FIG. 1 1 C as an example.

[0159] In the same way, 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 interference signals received may 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 may further comprise a step of displaying the level of received electromagnetic signals for a known source of electromagnetic disturbance and / or for all sources of electromagnetic disturbance in a particular GNSS frequency band in which a graphical representation of the level of received electromagnetic signals 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 Figure 3 (for zone Z) and Figure 9 (along the trajectory) as an example. The method may further comprise a step of determining the antenna gain of the antenna of the respective vehicle 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, for example, with a view to possible masking of the antenna by the vehicle. When the antenna is an adaptive antenna making it possible to eliminate a limited number of sources of electromagnetic interference, the determination of the antenna gain applied to each electromagnetic signal originating from a source of electromagnetic interference 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 also 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.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.

[0160] 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, that is to say 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 given position in the geographical zone during the defined observation duration and / or during the tracking of the trajectory.

[0161] The method may further comprise a step of determining the level of the received post-antenna electromagnetic signals for each known source of electromagnetic disturbance. The determination of the level of received post-antenna electromagnetic signals may take into account the characteristics of the vehicle's antenna and / or the position of the vehicle's 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.

[0162] When the antenna is an adaptive antenna capable of eliminating a limited number of sources of electromagnetic disturbance, the determination of the level of the received electromagnetic signals after the antenna may also take this fact into account. This determination step may further 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.

[0163] The step of determining the level of the received post-antenna electromagnetic signals for each source of electromagnetic disturbance 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 disturbance 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 Figure 4 (for the zone Z) and Figure 10 (along the trajectory) as an example.

[0164] The levels of the electromagnetic signals received after the antenna also make it possible to establish the destructive zones with respect to the vehicle receiver, for example depending on the robustness of the receiver's protection diodes.

[0165] 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 E1, SBAS), radiofrequency filtering of the receiver by frequency band, saturation / desaturation of an analog-to-digital converter (ADC) of the receiver, 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 receiver satellite signal acquisition threshold, a receiver satellite signal re-acquisition threshold, a receiver satellite signal tracking threshold, a satellite signal acquisition and / or re-acquisition time.,

[0166] 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).

[0167] The process gain can vary depending on the spectral shape of the disturbing electromagnetic signal (narrowband, wideband, 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).

[0168] 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.

[0169] As an example, Figure 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 column of the table represents the level of the interfering electromagnetic signals received after antenna at any point in the geographical area Z, each row 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 of these three columns concerns the L1 C / A service, the second column of these three columns concerns the L1 P(Y) service and the third column, i.e. the last column on the right, of 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 electromagnetic disturbance 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 L1 C / A service.

[0170] 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-to-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.

[0171] 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.

[0172] The method may, following the step of determining the signal / noise ratio, further comprise a step of determining a prediction of proper functioning 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.

[0173] 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 may represent the tracking capacity of the receiver, a second layer among the multiple layers may represent the tracking capacity of the receiver with integrity, a third layer among the multiple layers may represent the re-acquisition capacity, a fourth layer among the multiple layers may represent the satellite signal acquisition capacity.Such a graphical representation is given in Figure 7 as an example for a zone Z. Other layers can be added, such as the representation of the tracking capacity in dual frequencies, in dual constellations, the representation of the estimated precision 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, in particular the capacities and performances, of the receiver can be displayed to the user on a map background.

[0174] When the stage of good operation is calculated for all positions on the possible trajectories TPO and / or on the planned trajectory TPR and for all dates corresponding to these positions, the display stage may comprise the display of good operation 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 stage 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 figure 8.

[0175] 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.

[0176] 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.).

[0177] The method may further include a step of displaying the capabilities and / or performances of the present and future situation of a set or subset of vehicles operating in the monitored geographical zone Z, also allowing information to be shared between different actors and assistance in the management of the control center).

[0178] 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 aviation safety. The calculation and / or monitoring device 10 and the calculation and / or monitoring method allow for drone flight preparation with secure trajectory calculation with a PNT solution always available.

[0179] The computing and / or monitoring device 10 can be subdivided into two entities: an upstream entity which takes into account all the characteristics of the GNSS system, the sources of electromagnetic disturbances, the topography of the geographical zone Z, the obstacles in the geographical zone Z, the 4D trajectory, the relief, the obstacles and the time. The resulting data are generic or universal, and applicable for any user (antenna input). a downstream entity which will take into account the characteristics of the carrier, i.e. the vehicle, and its on-board system (antenna, receiver, carrier, positioning system, etc.) and translate these universal data into user data in the capacity and performance sense.

[0180] The upstream entity and the downstream entity provide directly operational information via a geographical and temporal representation (present and future) of the impacts of sources of electromagnetic disturbance on the operation of the receiver and / or the positioning system adapted to each of the operators.

[0181] 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.

[0182] 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.

[0183] 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.

[0184] The complete system thus allows multiple applications as previously explained and constitutes an asset for the success of a mission, the improvement of security, preventive information and assistance with decision-making / planning.

Claims

CLAIMS 1. 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, capabilities and performance of this system, the method comprising the following steps: acquisition of spatial and temporal observation coordinates, the spatial observation coordinates being located in the geographical area (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 geographical 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 disturbance 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 temporal observation coordinate corresponding to 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 the known positions of the sources of electromagnetic disturbance at the temporal observation coordinate and the data representative of characteristics of the satellite positioning system.

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 selected from the main vehicle and, if applicable, 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 determining the spatial and temporal observation coordinates lying 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 starting 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 according to the impact of sources of electromagnetic disturbance on the operation of the satellite positioning system at each of the spatial and temporal observation coordinates located on the respective section.

5. Calculation and / or monitoring method according to claim 4, characterized in that it further comprises the following step: warning a driver and / or a crew of the respective vehicle when the current position of the respective vehicle approaches a section with high disruption forecast (TPE), and / or in the event of loss of capacity and / or degradation of performance.

6. 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 observation coordinates 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 spatial observation coordinate and this possible trajectory (TPO) from the starting 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 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 disturbance, data representative of characteristics of the satellite positioning system, and where appropriate, the characteristics and / or the spatio-temporal coordinates representative of positions of at least one other vehicle chosen from the main vehicle and the 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).

7. 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).

8. 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.

9. 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 respective vehicle antenna estimated for each spatial and temporal observation coordinate, from 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 an orientation of the vehicle at this spatial and temporal observation coordinate estimated on the basis of 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 disturbance 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 correct 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 disturbances in the geographic 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. 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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