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

Abstract

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 The present invention relates to a method for calculating and / or monitoring the operation of a satellite positioning system of a vehicle in a geographical area comprising the following steps: - acquisition of spatial and temporal observation coordinates; - acquisition of spatio-temporal coordinates of the satellites; - acquisition of characteristics and spatio-temporal coordinates representative of known positions of interference sources; - acquisition of data representative of characteristics of the satellite positioning system;- calculation of an impact of interference sources on the operation of the satellite positioning system for each service and 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, the spatio-temporal coordinates representative of the known positions of the interference sources. Figure 2;

Description

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

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

[0002] The present invention also relates to a computer program product and an associated computing and / or monitoring device.

[0003] Vehicles of all types, in particular aerial, land or naval vehicles, are equipped with a so-called satellite positioning system because it is generally based on a satellite positioning receiver and an antenna. This system can also be equipped with other additional positioning assistance sensors such as inertial units, Doppler sensors, radio navigation, etc. in the event of loss of 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.In the field of civil aviation, satellite positioning receivers are essential for operational safety, as they allow aircraft to have permanent geolocation, time and navigation capacity in a precise and integrated manner with global and permanent coverage.

[0004] In the field of civil aviation, satellite positioning receivers are used at all levels: by aircraft for their navigation system, by aviation communication, navigation and surveillance (CNS) systems, by air traffic management (ATM).

[0005] Similarly, the use of drones (Unmanned Aerial Vehicle, UAV) equipped with satellite positioning receivers is constantly increasing. These drones make extensive use of the satellite positioning system. Their applications are increasingly numerous: commercial delivery, logistical support in surveillance, security or emergency services... and require surveillance and control by UAV Traffic Management (UTM).

[0006] The weakness of these satellite positioning receivers is their vulnerability to radio frequency interference. In the presence of interference, their performance and their ability to provide a valid and integral PNT depends on many parameters, such as the quality of the receiver itself, but also on the on-board protection devices (e.g. filtering), the power and number of satellite signals and interference received, the waveforms and frequencies of the interference, the positioning of the transmitters and the 4D trajectory of the vehicle.

[0007] In recent years, incidents of disruption to the satellite positioning system due to interference sources have increased sharply (in 2022, an increase of more than 2,000% compared to 2018), most of which affect en route flights.

[0008] The existence of interference sources (radio frequency interference; English Radio Frequency Interference, RFI) including unintentional interference sources and / or intentional protection jammers have 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, the use of an augmentation system (ABAS).... These interference sources, in particular intentional protection jammers, may be particularly numerous near certain conflict zones for example.

[0009] Even though aircraft can fly safely without satellite positioning systems thanks to additional sensors, the massive increase in interference sources rapidly reduces the efficiency of the entire aviation system, which imposes a greater workload on pilots and air traffic controllers (location verification, radar tracking), and requires the maintenance of additional communication, navigation and surveillance services to meet more stringent requirements. 38.5% of European en route traffic passes through regions intermittently but regularly affected by interference sources presenting a potential risk to flight safety.

[0010] Consequently, the sources of interference have a direct and harmful impact on an aeronautical world which nevertheless constantly aspires to guarantee better safety.

[0011] Document WO 2015 / 065664 A1 discloses a system for generating a visual representation of interference sources that impair the operation of a satellite positioning system. The visual representation may comprise a map covered with visual indicators indicating a location and magnitude of the interference.

[0012] However, the known system does not allow to determine the impact of interference sources on the operation of a particular satellite receiver and on the on-board positioning system, nor the impact on the performance and capabilities of the latter in a vehicle that must operate in a defined geographical area and at different altitudes. 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 allow 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 to be determined.Finally, such a system does not reduce the risks of malfunction by providing a flight plan or a 4D route ensuring proper operation of the on-board satellite positioning system.

[0013] The 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 when the vehicle must move in a geographical area, at various altitudes and in a given time range, in particular when the vehicle must follow a planned 4D route crossing the geographical area.

[0014] To this end, the invention relates to a method for calculating and / or monitoring the operation of a satellite positioning system for a vehicle in a geographical area, the operation of said positioning system including the integrity, capacities and performances of this system, the method comprising the following steps:

[0015] - acquisition of spatial and temporal observation coordinates, the coordinates spatial observation sites located in the geographic area;

[0016] - acquisition of spatio-temporal coordinates of satellites of a GNSS system for each observation time coordinate;

[0017] - acquisition of representative spatio-temporal characteristics and coordinates known positions of sources of interference of a GNSS system signal, located in or near the geographic area;

[0018] - acquisition of data representative of characteristics of the posi system satellite operation;

[0019] - calculation of an impact of interference sources on the operation of the system of satellite positioning for each service and 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 spatial temporal coordinates of the GNSS system satellites at the observation time coordinate, space-time coordinates representative of the known positions of interference sources at the observation time coordinate and data representative of characteristics of the satellite positioning system.

[0020] 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 interference on the operation and performance of the satellite positioning system of a vehicle moving in the geographical area. Thus, the method according to the invention makes it possible to predict or reduce the risks of malfunction of the satellite positioning system precisely when the vehicle follows the planned journey.

[0021] According to other advantageous aspects of the invention, the calculation and / or monitoring method comprises one or more of the following characteristics, taken in isolation or in all technically possible combinations:

[0022] - the method further comprises the following steps:

[0023] - obtaining a planned trajectory of the vehicle, the planned trajectory connecting a starting position at a vehicle destination and including a vehicle departure date or the planned trajectory from a current vehicle position to the vehicle destination and including a current date; and

[0024] - determination of the spatial and temporal coordinates of observation located on the planned trajectory of the vehicle at an estimated date from the vehicle's departure date or the current date and an estimated travel time for that spatial coordinate from the vehicle's departure position or from the current position to that spatial coordinate.

[0025] - the planned trajectory of the vehicle is obtained:

[0026] - by calculating several possible trajectories of the vehicle connecting, either the position of departure to destination, or current position at destination;

[0027] - by determining spatial and temporal observation coordinates located on several possible trajectories of the vehicle at an estimated date from the vehicle's departure date or the current date and an estimated travel time for that observation spatial coordinate and that possible trajectory from the vehicle's departure position or from the current position to that observation spatial coordinate;

[0028] - by acquiring the spatio-temporal coordinates of the satellites of the GNSS system for each observation time coordinate of each possible trajectory;

[0029] - by calculating, for each possible trajectory, the impact of the interference sources on the operation of the satellite positioning system 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 system GNSS at the observation time coordinate, space-time coordinates representative of known positions of interference sources and data representative of characteristics of the satellite positioning system;

[0030] - by determining the planned trajectory among the possible trajectories as a function of the impact of interference sources on the operation of the satellite positioning system at each spatial and temporal observation coordinate located on the possible trajectory;

[0031] - for each possible trajectory and / or for the planned trajectory or for any point of the geographical area, the calculation of the impact of interference sources on the operation of the satellite positioning system includes the calculation of the distances, elevations and azimuths of each interference and of each satellite of the GNSS system at each of the spatial and temporal observation coordinates of the possible trajectory and / or the planned trajectory and / or the geographical area;

[0032] - the method further comprises the following step:

[0033] - acquisition of data representative of a category of the vehicle and / or of a shape of the vehicle and / or position of the antenna on the vehicle and / or movement characteristics of the vehicle;

[0034] - said impact on the operation of the satellite positioning system at each of the spatial and temporal observation coordinates is calculated based on an antenna gain of the 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;

[0035] - the method further comprises the following step:

[0036] - acquisition of data representative of a topography and obstacles of the area geographical;

[0037] - said impact on the operation of the satellite positioning system at each of the spatial and temporal observation coordinates is further calculated based on data representative of a topography of the geographic area;

[0038] - the vehicle being an aircraft, the method being characterized by the following step:

[0039] - acquisition of data representative of air corridors located in the area geographical;

[0040] - the possible trajectories of the aircraft connecting either the starting position to the des tination, or the current position at the destination, are further calculated from data representative of the air corridors, the possible trajectories essentially following the air corridors;

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

[0042] - the method further comprises the following step:

[0043] - division of the planned trajectory into a plurality of sections determined in depending on the impact of interference sources on the operation of the satellite positioning system at each of the spatial and temporal observation coordinates located on the respective section, in particular whether the section is a section with a high disturbance forecast or a section with a low disturbance forecast;

[0044] - the method further comprises the following step:

[0045] - warning a driver and / or vehicle crew when the position current vehicle approaching a section with high disruption forecast, and / or in case of loss of capacity and / or degradation of performance;

[0046] - the method further comprises the following steps:

[0047] - verification of proper operation, performance and capabilities of the system vehicle positioning at regular time intervals with respect to predictions;

[0048] - 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 interference sources in the geographic area.

[0049] - 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.

[0050] 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, as defined above.

[0051] The invention also relates to a device for calculating and / or monitoring the operation of a satellite positioning system for a vehicle in a geographical area, comprising technical means adapted to implement the calculation and / or monitoring method, as defined previously.

[0052] 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:

[0053] [Fig-1] [Fig.l] is a schematic representation of a computing device and / or monitoring the operation of a satellite positioning system of a vehicle in a geographic area according to the present application;

[0054] [Fig.2] [Fig.2] is a schematic representation of several flight plans possible of a vehicle crossing a geographical area;

[0055] [Fig.3] [Fig.3] is a representation of a power received from a source interference in the geographic area in a given frequency band and at a given time and altitude;

[0056] [Fig.4] [Fig.4] is a representation of a power received from the source interference after application of the on-board satellite antenna pattern on the vehicle in the geographic area;

[0057] [Fig.5] [Fig.5] is a representation of the total power spectral density of noise present in a particular receiver (after rejection, filtering, correlation, etc.) with respect to three sources of interference in the geographic area for three services of a satellite positioning system;

[0058] [Fig.6] the [Fig.6]:

[0059] - part A is a representation of the estimated powers of the system signals satellite positioning received over time at a given spatial point in the geographic area and for a given service (e.g. L1 C / A);

[0060] - part B is a representation of the antenna gain applied to each signal satellite received by the satellite positioning system at the point located in the geographic area;

[0061] - part C is a representation of the estimated power after antenna of each signal received by the satellite positioning system at the point located in the geographic area;

[0062] [Fig.7] [Fig.7] is a representation of the estimated receiver capabilities of the satellite positioning system for three services and for the entire geographical area at a given time t and altitude;

[0063] [Fig.8] [Fig.8] is a schematic representation of a planned trajectory of the vehicle divided into a plurality of sections according to the estimated capacities;

[0064] [Fig.9] [Fig.9] is a representation of a power received at the antenna of a source of interference along a 4D trajectory crossing the geographic area;

[0065] [Fig. 10] [Fig. 10] is a representation of an after-antenna power received from the interference source along the 4D trajectory crossing the geographic area; and

[0066] [Fig. 11] [Fig. 11]:

[0067] - 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;

[0068] - part B is a representation of the antenna gains applied to each signal satellite received along the 4D trajectory crossing the geographic area;

[0069] - part C is a representation of the estimated power after antenna of each GNSS system signal received along the 4D trajectory crossing the geographic area,

[0070] [Fig.l] illustrates a device 10 for calculating and / or monitoring the operation of a satellite positioning system for a vehicle in a geographical zone Z.

[0071] This device 10 is suitable for implementing a method for calculating and / or monitoring the operation of the satellite positioning system of the vehicle in the geographical zone Z. The calculating and / or monitoring device 10 comprises an input module 20, a processing module 30 and an output module 40.

[0072] By operation of the satellite positioning system, we mean both the integrity of this system, that is to say its ability to provide data on an output, but also its capabilities, including its ability to acquire a signal emitted by one or more satellites, its ability to track this signal or to find this signal, as well as its performance when it is capable of at least acquiring a signal, in particular in terms of precision of the PNT and speed of the measurement chain, this speed depending in particular on the time taken to lock onto a satellite signal as well as the response time of the system to an acquired signal.

[0073] 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.

[0074] 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.

[0075] Alternatively, when the method is carried out in the form of one or more software programs, i.e. in the form of a computer program, also called a computer program product, it is furthermore capable of being recorded on a medium, not shown, that is readable by a computer. The computer-readable medium is, for example, a medium capable of storing electronic instructions and of being coupled to a bus of a computer system. For example, the readable medium is an optical disk, a magneto-optical disk, a ROM memory, a RAM memory, any type of non-volatile memory (for example FLASH or NVRAM) or a magnetic card. A computer program comprising software instructions is then stored on the readable medium.

[0076] The calculation and / or monitoring device 10 allows the implementation of the method calculating and / or monitoring the operation of the vehicle's satellite positioning system in the geographical area Z. The geographical area Z may be a fixed, expandable or mobile geographical area. It may also be a corridor around a flight plan or trajectory. In the following, when we mention "in the vicinity of the geographical area Z", we mean an extended geographical area including the geographical area Z. This extended geographical area may, for example, be defined by a border distant from the border delimiting the geographical area Z by a predetermined distance.

[0077] The geographic area Z may be divided into a plurality of boxes constituting a grid. The grid may have a predefined resolution. When the method performs a step for any point in the geographic area, the step may be performed, for each box, on a point located in the box, preferably in the center of the box. The geographic area may thus be rasterized.

[0078] The vehicle is provided with at least one satellite positioning system comprising a receiver, an antenna connected to the receiver and in certain examples, one or more anti-interference robustness devices. The receiver makes it possible to determine its position and / or its speed of movement, i.e. also the position of the vehicle and / or the speed of movement of the vehicle on the basis of GNSS signals that it receives from navigation satellites. Each receiver may have its own characteristics and exploit one or more GNSS services. In certain examples, the satellite positioning system further comprises one or more additional positioning assistance sensors such as inertial units, Doppler sensors, radio navigation, etc.

[0079] The navigation satellites are part of a GNSS system which 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.

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

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

[0082] Alternatively, the observation time slot may 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.

[0083] The user may be a driver of the vehicle, a member of the vehicle crew and / or a person in charge of route planning (route, flight plan) or traffic safety (air, naval) for example.

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

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

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

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

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

[0089] The calculation and / or monitoring method comprises a step of acquiring spatial coordinates representative of known positions of interference sources of a signal of the GNSS system covering the geographical zone Z. The spatial coordinates representative of known positions of interference sources can be acquired by retrieving them from a database where they have been previously deposited, such as an RFI BDRFI database. According to one possibility, the acquisition of the spatial coordinates representative of known positions of interference sources can be repeated at regular intervals.

[0090] The calculation and / or monitoring method may further comprise a step of acquiring the spectrum (central frequency, bandwidth) and the waveform and / or modulation type of the interference signal emitted by each known interference source and / or an average power of the interference signal emitted by each known interference source in the geographical area Z and / or a minimum power of the interference signal emitted by each known interference source in the geographical area Z and / or a maximum power of the interference signal emitted by each known interference source in the geographical area Z.The spectrum, waveform and modulation type of the interference signal and / or the average power of the interference signal and / or the minimum power of the interference signal and / or the maximum power of the interference signal can be acquired by retrieving it from a database where it has / have been previously deposited, such as the RFI database BDRFI.

[0091] The RFI database BDRFI can be supplied by a system for detecting / locating / counting / characterizing interference sources. The system for detecting / locating / counting / characterizing interference sources 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. This system could for example be managed by an international organization (e.g. European Organization for Civil Aviation Equipment: EUROCAE, CNS). This system may be able to analyze and consolidate data from multiple observations filed on a network via artificial intelligence processing based on data from known interference sources stored in the RFI database and / or information returned by the computing and / or monitoring device 10 in order to continuously generate / update the RFI database. This RFI database may be global or limited to a region and is directly used by the computing and / or monitoring device 10.

[0092] The interference sources may be stationary and / or emit the interference signal continuously. The interference sources may also be mobile and / or emit the interference 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 interference sources and / or data representative of the emission characteristics of the interference sources such as an expected emission chronology of the interference signal, a modulation of the interference signal and / or other dynamic characteristics.Data representative of expected movements of interference sources and / or data representative of the emission characteristics of interference sources can be acquired by retrieving them from a database where they have been previously deposited, such as the RFI BDRFI database.

[0093] The step of acquiring spatial coordinates representative of known positions of interference sources may consist of acquiring spatial coordinates representative of known positions of interference sources 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 RFI database BDRFI and to perform calculations only on interference sources considered to be a risk for the safety of the route.

[0094] The calculation and / or monitoring method may further comprise a step of obtaining a desired result in terms of probability. The desired result in terms of probability may correspond to a worst case scenario, a best case scenario, an average case scenario, or a most likely scenario, for example. The desired result in terms of probability may, for example, be obtained by user input using the user interface (UI) or by retrieving it from a database where it has been previously deposited.

[0095] 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.

[0096] 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-interference robustness devices.

[0097] The characteristics of the vehicle antenna may in particular include an antenna pattern giving the gain for each azimuth / elevation. It is advisable that this antenna pattern be representative of the antenna pattern after installation on the vehicle (for example, taking into account masking, attenuations due to the vehicle (e.g. wings) and the ground plane).

[0098] The characteristics of the satellite positioning receiver on board the vehicle may in particular include the mathematical model and / or the performance and precision of the receiver, the constellations, services and frequency bands used, the robustness to interference 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.

[0099] The characteristics of the satellite positioning system on board the vehicle may in particular include the performance and precision of each additional sensor, their participation in the development of the PNT of the vehicle and their precision in particular when certain capacities of the GNSS receiver are lost (e.g. switching to Inertia or RadioNav mode when the position from the GNSS receiver is imprecise and / or not complete and / or invalid).

[0100] The data representative of characteristics of the satellite positioning system 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.

[0101] 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 vehicle and / or of a type of antenna corresponding to the antenna actually installed in the vehicle.

[0102] The calculation and / or monitoring method comprises a step of calculating the impact of each source of interference on the operation of the satellite positioning system for each spatial and temporal coordinate as a function of the spatial observation coordinate, the observation temporal coordinate corresponding to this spatial observation 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 interference sources and the data representative of the characteristics of the satellite positioning system.

[0103] The step of calculating the impact of each source of interference on the operation of the satellite positioning system may include calculating the distances, elevations, and / or azimuth in order to determine the power received from each source of interference for each spatial and temporal observation coordinate, i.e. either at each position on the path determined for the estimated date at which the 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 interference signal from this source of interference, considering, where appropriate, the wavelength of the interference signal and / or the weather forecast for the geographical zone Z and / or terrain masking.

[0104] The step of calculating an impact of each interference source on the operation of the satellite positioning system 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 interference source on the operation of the satellite positioning system may be based on the maximum power of the interference signal of the respective interference source, for example. When the desired outcome in terms of probability corresponds to the best-case scenario, the step of calculating an impact of each interference source on the operation of the satellite positioning system may be based on the minimum power of the interference signal of the respective interference source, for example.Where the desired outcome in terms of probability corresponds to the average and / or most likely scenario, the step of calculating an impact of each interference source on the operation of the satellite positioning system may be based on the average and / or most likely power of the interference signal from the respective interference source, for example.

[0105] The calculation and / or monitoring method may further comprise the following steps: - obtaining a planned trajectory TPR of the vehicle, the planned trajectory TPR connecting a starting position PD to a destination of the vehicle and comprising a vehicle departure date or the planned trajectory TPR connecting a current position PA of the vehicle to the destination of the vehicle and comprising a current date; and - determination of the spatial and temporal observation coordinates located on the planned TPR trajectory of the vehicle at a date estimated from the departure date of the vehicle or the current date and an estimated travel time for this spatial coordinate from the departure position of the vehicle or from the current position to this spatial coordinate.

[0106] The spatial coordinates defining the starting position PD, the current position PA of the vehicle and / or the destination may for example be acquired by a user input made using the user interface UI. These spatial coordinates may also be acquired by retrieving them from a database where they have been previously deposited. These spatial coordinates may for example be retrieved from an Air Traffic Services database BDSCA from a flight plan (FPLN) previously deposited in the latter. The spatial coordinates defining the current position PA of the vehicle may for example be acquired via the receiver.

[0107] The planned trajectory TPR may, for example, correspond to a previously defined or calculated vehicle path. The planned trajectory TPR may, for example, be obtained by user input using the user interface UI or by retrieving it from a database where it has been previously deposited. The planned trajectory TPR may be limited to a flight plan and, for example, be retrieved from the Air Traffic Services database BDSCA where it is stored as a deposited flight plan, or be a precise trajectory linked to the carrier's capabilities from a trajectory calculator or an FMS (Flight Management System).

[0108] 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 estimated 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 vehicle or by recovering it from the 4D trajectory.

[0109] The departure date and the estimated arrival date can define the observation time range.

[0110] 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.

[0111] The calculation and / or monitoring method may comprise a step of determining mination of several positions located on the planned trajectory TPR and, for each of these positions, determination of an estimated date on which the vehicle is located at the respective position. The dates and positions located on the planned trajectory can thus each constitute one of the spatial and temporary observation coordinates. The estimated date on which the vehicle is located at the respective position can 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 vehicle.

[0112] The positions located on the planned trajectory TPR can be equidistantly spaced from each other. The number of positions chosen allows a desired resolution to be defined. The desired resolution can be defined by a user, for example by entering the desired resolution in the user interface UI. The desired resolution can be defined in terms of time period or in terms of distance. Two consecutive positions can be spaced 10 seconds apart or 0.2 nautical miles apart, for example.

[0113] The mentioned method steps may be repeated, preferably repeated at regular intervals. The mentioned method steps may, for example, be repeated when the vehicle has traveled part of its route. The mentioned method steps may then be repeated taking into account the current position of the vehicle.

[0114] According to one possibility, the planned trajectory TPR of the vehicle is obtained: - by calculating several possible trajectories TPO of the vehicle connecting either the starting position PD to the destination, or the current position PA to the destination; - by determining spatial and temporal observation coordinates located on the several possible trajectories TPO of the vehicle at a date estimated from the departure date of the vehicle or the current date and an estimated travel time for this spatial observation coordinate and this possible trajectory TPO from the departure position of the vehicle or from the current position to this spatial observation coordinate; - by calculating the space-time coordinates of the GNSS system satellites for each observation time coordinate of each possible TPO trajectory; - by calculating, for each possible TPO trajectory, the impact of each source of interference on the operation of the satellite positioning system 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 co spatial coordinates of the GNSS system satellites at the observation time coordinate, spatial coordinates representative of the known positions of the interference sources acquired at the observation time coordinate, characteristics of the interference sources and data representative of the characteristics of the satellite positioning system and / or the vehicle antenna; - by determining the recommended trajectory TPR among the possible trajectories TPO based on the impact of each source of interference on the operation of the satellite positioning system at each spatial and temporal observation coordinate located on each possible trajectory TPO.

[0115] This method thus makes it possible to propose and / or classify different TPO trajectories or flight plans to an operator according to the impact of the sources of interference on the operation and in particular on the capacities and performances of the receiver and / or location system on board the respective trajectory in order to be able to select a planned TPR trajectory from the possible TPO trajectories.

[0116] When the vehicle is an aircraft, the method allows the preparation of a flight plan (FPLN) taking into consideration the constraints of the presence of interference sources in the geographical zone Z and predictions of losses of receiver capacities during the flight according to the spatial configuration and the aircraft used.

[0117] According to one possibility, the trajectory recommended as TPR may correspond to the possible trajectory TPO having the lowest impact on the operation of the satellite positioning system. According to an alternative, the trajectory recommended as TPR may correspond to the possible trajectory TPO having an impact on the operation of the satellite positioning system below a predefined threshold (e.g. valid PNT, integrates with precision < 0.1nm at 95%) and having a minimum vehicle travel time and / or a minimum vehicle fuel consumption.

[0118] 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 interference on the operation of the satellite positioning system includes 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.

[0119] The method may further comprise a step of acquiring data representative of a category of the vehicle and / or a shape of the vehicle and / or a position of the antenna on the vehicle and / or movement characteristics of the vehicle (attitudes), the impact of each source of interference 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 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 a 3D orientation (attitudes) of the vehicle at this spatial and temporal observation coordinate on the basis of data representative of the movement characteristics and dynamic performances of the vehicle.

[0120] 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.

[0121] 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 interference 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.

[0122] The data representative of the topography of the geographical zone Z can be acquired in a database called a DEM (Digital Elevation Model) database DEM. The data representative of the topography of the geographical zone 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 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.

[0123] The step of calculating an impact of each source of interference on the operation of the receiver may include calculating the distances, elevations, and / or azimuth and the power received from each source of interference for each spatial and temporal observation coordinate, i.e. either at each position on the path determined for the estimated date at which the vehicle is located at this position, or at any point in the geographical zone Z and over the entire defined observation time range, using precise propagation models also taking into account the loss during the propagation of the interference signal from this interference source considering the topography of the terrain, by application of Fresnel equations for example.

[0124] When the vehicle is an aircraft, the method may further comprise a step of acquiring data representative of air corridors located in the geographical zone Z, the possible trajectories TPO of the aircraft connecting either the starting position PD to the destination, or the current position PA to the destination, being further calculated from the data representative of the air corridors, the possible trajectories TPO essentially following the air corridors.

[0125] As shown in [Fig.2], the possible trajectories TPO and / or the trajectory recommended as a planned trajectory TPR may comprise a plurality of waypoints PCI to PC7 constituting different flight plans. These flight plans may coincide with the air corridors. The starting position PD, the current position PA and / or the destination may constitute waypoints PCI to PC7. In [Fig.2], the waypoints PCI to PC7 are represented by stars.

[0126] As shown in [Fig. 2], the geographical area Z may comprise a low disruption risk area ZF, a medium disruption risk area ZM and / or a high disruption risk area ZE. The planned trajectory TPR may be determined from four possible trajectories TPO. In the example given by [Fig. 2], the planned trajectory TPR chosen (PCI - PC2 - PC3 - PC4) from the four possible trajectories TPO may cross the medium disruption risk area ZM for a short time. Alternatively, the planned trajectory TPR may be chosen so as to remain in the low disruption risk area ZF (PCI - PC2 - PC3 - PC5), i.e. without crossing the medium disruption risk area ZM or the high disruption risk area ZE by making a more significant detour.

[0127] The data representative of air corridors can be acquired by retrieving them from a database where they have been previously deposited, such as an air corridor database. The air corridor database can for example be a standard navigation database according to a so-called ARINC 424 format.

[0128] 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 interference on the operation of the receiver 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 forecast of average TPM disturbance.

[0129] The low disturbance prediction TPF may correspond to a high probability of proper receiver operation and / or a high probability of GNSS signal integrity, for example. The high disturbance prediction TPE may correspond to a high probability of receiver malfunction and / or a high probability of loss of GNSS PNT, for example. The medium disturbance prediction TPM may correspond to a high probability of receiver performance degradation and / or a high probability of loss of GNSS signal integrity, for example.

[0130] The method may further comprise a step of warning a driver (or pilot) of the vehicle and / or a crew of the vehicle when the current position of the vehicle approaches a section with a high TPE disturbance forecast or, where appropriate, a section with a medium TPM disturbance forecast. The step of warning the driver may comprise a warning of a loss of integrity, capacity and / or performance of the vehicle receiver.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 (for example 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 the crew. Thus, the possibility of being warned in advance of this fault allows the driver of the vehicle and / or the crew of the vehicle to prepare for this situation and thus reduce the risk of stress among the driver and / or the crew of the vehicle.

[0131] The method may further comprise a monitoring function consisting of checking the operation of the satellite positioning system and / or the signal-to-noise ratios, in real time or at regular time intervals, with respect to the predictions. For example, when proper operation of the receiver is detected while the current position of the 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 poor operation of the receiver 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 receiver operation 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 a disappearance of at least one source of interference and / or an attenuation of the interference signal of at least one source of interference at the date / time of observation. When a malfunction of the receiver is detected while the current position of the vehicle is located on a section with a low disturbance forecast TPF, this update message may include information indicating an appearance of at least one source of interference and / or an amplification of the interference signal of at least one source of interference at the date / time of observation.

[0132] Thus, the method monitors and compares in real time the measurements and the risks of disturbance and ensures a loopback to allow the RFI database to be kept up to date. The disappearance of a predicted disturbance makes it possible to extrapolate a disappearance or attenuation of one of the known sources of boiling. The presence of a disturbance occurring without having been predicted makes it possible to extrapolate an appearance of a new source of interference or an amplification of one of the known sources of boiling. This information can then be transmitted so that a monitoring center can update the RFI database after cross-checking the various information received.

[0133] 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.

[0134] 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.

[0135] The resolution may be a predefined resolution or a user-defined resolution, for example by entering the desired resolution in the UI.

[0136] Thus, the spatial and temporal observation coordinates can either correspond to positions located on a path defined by a planned trajectory TPR and / or a possible trajectory TPO or to positions defining the grid.

[0137] 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 1 IA (during trajectory tracking) as an example.

[0138] The method may further comprise a step of determining the antenna gain of the receiver. The determination of the antenna gain may take into account the characteristics of the installed vehicle antenna and / or the position of the vehicle antenna and / or the shape of the vehicle, with a view to possible masking of the antenna by the vehicle for example. 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.

[0139] The step of determining the antenna gain can be carried out for all the acquired spatial and temporal observation coordinates, i.e. either for any position in the geographical zone Z and / or over the entire observation time range or for all the positions on the possible trajectories TPO and / or on the planned trajectory TPR and for all the dates corresponding to these positions. The method can further comprise a step of displaying the antenna gain for a given position in the geographical zone during the defined observation duration and / or during the tracking of the trajectory. Such a graphical representation is given in FIG. 6B and FIG. 1 IB as an example.

[0140] The method may further comprise a step of determining the level of signals from the satellites of the GNSS system after the antenna received. The determination of the level of signals after the antenna received may take into account the characteristics of the antenna. of the vehicle installed 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 also take into account the vehicle's movement characteristics, such as the maximum attitudes of the vehicle, when the vehicle is an aircraft for example. The step of determining the level of signals after the antenna received from the GNSS system satellites may be carried out for all 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 positions on the possible trajectories TPO and / or on the planned trajectory TPR and for all dates corresponding to these positions.The method may further comprise a step of displaying the level of signals after the antenna of the satellites of the GNSS system received for a given position in the geographical area during the defined observation duration and / or during the tracking of the trajectory. Such a graphical representation is given in Figure 6C and Figure 1 IC as an example.

[0141] In the same way, the method may further comprise a step of determining the level of the interference signals received for each known interference source. The step of determining the level of the 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 interference signals received for a known interference source and / or for all interference sources in a particular GNSS frequency band in which a graphical representation of the level of interference signals received is displayed to the user for the defined observation duration and / or during the tracking of the trajectory. Such a graphical representation is given in [Fig.3] (for zone Z) and [Fig.9] (along the trajectory) as an example.

[0142] The method may further comprise a step of determining the antenna gain of the receiver with respect to each of the interference sources. The determination of the antenna gain may take into account the characteristics of the installed vehicle antenna and / or the position of the vehicle antenna and / or the shape of the vehicle, with a view to possible masking of the antenna by the vehicle for example. 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. 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. When the aircraft has an attitude horizontal, the fuselage partially masks interference signals coming from a position below the aircraft.

[0143] The step of determining the antenna gain applied to the interferences can be carried out for all the acquired spatial and temporal observation coordinates, i.e. either for any position in the geographical zone Z and / or over the entire observation time range or for all the positions on the possible trajectories TPO and / or on the planned trajectory TPR and for all the dates corresponding to these positions. The method can further comprise a step of displaying the antenna gain and / or antenna diagram for a given position in the geographical zone during the defined observation duration and / or during the tracking of the trajectory.

[0144] The method may further comprise a step of determining the level of post-antenna interference signals received for each known interference source. The determination of the level of post-antenna interference signals received may take into account the characteristics of the vehicle antenna and / or the position of the vehicle antenna and / or the shape of the vehicle, with a view to possible masking of the antenna by the vehicle, for example, during the observation period.

[0145] 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. The step of determining the level of the post-antenna interference signals 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 the post-antenna interference signals received for a known interference source in which a graphical representation of the level of post-antenna interference signals received is displayed to the user. Such a graphical representation is given in [Fig.4] (for zone Z) and [Fig. 10] (along the trajectory) as an example.

[0146] The levels of the received post-antenna interference signals determined also make it possible to establish the destructive zones with respect to the vehicle receiver, for example as a function of the robustness of the receiver's protection diodes.

[0147] The method may, following the step of determining the level of signals from the satellites of the GNSS system received and the step of determining the level of interference signals received for each known source of interference, 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, L5C, GALILIEO El, SBAS), radiofrequency filtering of the receiver by frequency band, saturation / desaturation of a analog-to-digital converter (ADC) of the receiver, a behavior and response time of an automatic gain control (AGC) of the receiver, the presence of an anti-interference device integrated into the receiver as well as the properties of such an anti-interference device, a processing gain linked to a spread of the spectrum during correlation by a spread code, a threshold for acquisition of satellite signals of the receiver, a threshold for reacquisition of satellite signals of the receiver, a threshold for tracking satellite signals of the receiver, a time of acquisition and / or reacquisition of satellite signals.

[0148] The anti-interference 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-interference device may include a rejection gain of the anti-interference device. Depending on the type of anti-interference device used, the properties of the anti-interference device, the service of the GNSS system used (L1, L2, L5) and the characteristics of the interference received after the antenna (waveform, spectral width, continuous / periodic), certain interferences will lose effectiveness (partial or total rejection).

[0149] The process gain can vary depending on the spectral shape of the interference 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).

[0150] The method may further comprise a step of developing the spectral sum of the interference sources 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.

[0151] As an example, [Fig. 5] represents a table displaying the residual power - after antenna and receiver processing - of the different sources of interference received in the geographical area potentially affecting three services of a GNSS system (L1 C / A, L1C, L5C). The left column of the table represents the level of the interference signals received after antenna at any point in the geographical area Z, each row of this column corresponding to a known interference. The three columns to the right of the table each relate to a level of the residual interference signal after antenna and after a step of signal filtering, anti-interference processing and correlation of the interference signal with the service of the respective GNSS system for each of the three services.The first column among these three columns concerns the L1 C / A service, the second column among these three columns concerns the L1 C service and the third column, that is to say the last column on the right, among these three columns concerns the L5 C service. For each of the three columns on the right of the table, the first row relates to a first known interference, the . The second row refers to a second known interference and the third row refers to a third known interference. For example, the box at the top right of the table represents the residual power of the first interference after antenna, after filtering, after anti-interference treatment and after correlation for the L5C service. The bottom row represents the sum of the different residual interference signals for each of the services. For example, the box to the left of the last row represents the sum of the residual powers of the 3 interferences after antenna, after filtering, after anti-interference treatment and after correlation for the L1C / A service.

[0152] 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 interference signals received after the antenna, after filtering, after anti-interference processing and after correlation from each of the known interference sources. This ratio may be called the signal / noise ratio. This step may be calculated for all the acquired spatio-temporal observation coordinates, i.e. either for any point in the geographical zone Z and over the entire observed time range or for all the positions on the possible trajectories TPO and / or on the planned trajectory TPR and for all the dates corresponding to these positions.

[0153] 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.

[0154] The method may, following the step of determining the signal / noise ratio, further comprise a step of determining a prediction of proper operation of the receiver for each of the services of the GNSS system for all the acquired spatio-temporal observation coordinates, i.e. either for any point in the geographical zone Z and over the entire observed time range, or for all the positions on the possible trajectories TPO and / or on the planned trajectory TPR and for all the dates corresponding to these positions.

[0155] The method may further comprise a step of displaying the proper functioning of the receiver and its capabilities 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 capability of the receiver, a second layer among the multiple layers may represent the tracking capability of the receiver with integrity, a third layer among the multiple layers may represent the re-acquisition capability, a fourth layer among the multiple layers may represent the satellite signal acquisition capability. Such a graphical representation is given in [Fig.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 accuracy of positions and speeds. The graphical representation of the correct operation can include different cursors, for example an altitude level and a date / time. The graphical representation of the receiver's capacities and performances can be displayed to the user on a map background.

[0156] When the proper functioning step is calculated for all the positions on the possible trajectories TPO and / or on the planned trajectory TPR and for all the dates corresponding to these positions, the display step may comprise the display of proper functioning along a 4D trajectory corresponding to a possible trajectory TPO and / or the planned trajectory TPR. The capacities and performances along the 4D trajectory may be displayed to the user on a map background or on a horizontal view or on a vertical view or on a time line view. This display step makes it possible to present to the user a capacity view and performances of the receiver along and / or near the 4D trajectory. An example of a display of capacities of a receiver for a given service along such a 4D trajectory on a map background is given in [Fig.8].

[0157] 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.

[0158] When the vehicle is an aircraft, the method may further comprise a step of displaying a representation of the capabilities and / or performances of the satellite 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.).

[0159] The method may further comprise a step of displaying the capabilities and / or performances of the present and future situation of a set or subset of the vehicles operating in the monitored geographical zone Z, also allowing sharing of information between different actors and assistance with air traffic management (ATM, UTM).

[0160] 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 of any airplane or helicopter, to reduce the workload of pilots and / or air traffic management (pilots, ATM) and provide an improvement in air safety.

[0161] The calculation and / or monitoring device 10 and the calculation and / or monitoring method allow preparation of drone flights with secure trajectory calculation with a PNT solution always available.

[0162] The calculation and / or monitoring device 10 can be subdivided into two entities:

[0163] - an upstream entity which takes into account all the characteristics of the system GNSS, interference sources, topography of geographic area Z, obstacles in geographic area Z, 4D trajectory, relief, obstacles and time. The resulting data are generic or universal, and applicable for any user (antenna input).

[0164] - a downstream entity which will take into account the characteristics of the carrier, i.e. of the vehicle, and its on-board system (antenna, receiver, carrier, positioning system, etc.) and translate this universal data into user data in terms of capacity and performance.

[0165] The upstream entity and the downstream entity provide directly operational information via a geographical and temporal representation (present and future) of the impacts of interference sources on operation and in particular on the capacities and performances of the receiver and / or the positioning system adapted to each of the operators.

[0166] 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.

[0167] 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.

[0168] 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 interference in order to allow an update of the RFI database.

[0169] The complete system thus allows multiple applications as set out previously and constitutes an asset for improving security, preventive information and decision-making / planning assistance.

Claims

Claims

1. Method for calculating and / or monitoring an operation of a satellite positioning system of a vehicle in a geographical area (Z), the operation of said positioning system including an integrity, capabilities and performances of this system, the method comprising the following steps: - acquisition of spatial and temporal observation coordinates, the spatial observation coordinates being located in the geographical area (Z); - acquisition of spatio-temporal coordinates of the satellites of a GNSS system for each temporal observation coordinate; - acquisition of characteristics and spatio-temporal coordinates representative of known positions of sources of interference of a signal of the GNSS system, located in or near the geographical area (Z); - acquisition of data representative of characteristics of the satellite positioning system;- calculation of an impact of interference sources on the operation of the satellite positioning system for each service and 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 interference sources at the observation temporal coordinate and the data representative of characteristics of the satellite positioning system.;

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

3. Calculation and / or monitoring method according to claim 2, characterized in that the planned trajectory (TPR) of the vehicle is obtained: by calculating several possible trajectories (TPO) of the vehicle connecting either the starting position (PD) to the destination, or the current position (PA) to the destination; by determining spatial and temporal observation coordinates located on several possible trajectories (TPO) of the vehicle at an estimated date from the departure date of the vehicle or the current date and an estimated travel time for this spatial observation coordinate and this possible trajectory (TPO) from the departure position of the vehicle or from the current position to this spatial observation coordinate; by acquiring 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 interference sources on the operation of the satellite positioning system 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 space-time coordinates of the GNSS system satellites at the time coordinate observation, space-time coordinates representative of known positions of interference sources and data representative of characteristics of the satellite positioning system; - by determining the planned trajectory (TPR) among the possible trajectories (TPO) based on the impact of interference sources on the operation of the satellite positioning system at each space and time observation coordinate located on the possible trajectory (TPO).

4. Calculation and / or monitoring method according to claim 3, 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 interference sources on the operation of the satellite positioning system comprises the calculation of the distances, elevations and azimuths of each interference 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).

5. Calculation and / or monitoring method according to any one of claims 1 to 4, characterized in that it further comprises the following step: - acquisition of data representative of a category of the vehicle and / or a shape of the vehicle and / or a position of the antenna on the vehicle and / or movement characteristics of the 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 vehicle antenna estimated for each spatial and temporal observation coordinate, from the data representative of the category of the vehicle and / or the shape of the vehicle and / or the position of the antenna on the vehicle and / or an orientation of the vehicle at this spatial and temporal observation coordinate estimated on the basis of data representative of motion characteristics.

6. Calculation and / or monitoring method according to any one of claims 1 to 5, characterized in that it further comprises the following step: - 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 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).

7. Calculation and / or monitoring method according to any one of claims 1 to 6 taken in combination with claim 3, the vehicle being an aircraft, the method being characterized by the following step: - acquisition of data representative of air corridors located in the geographical zone (Z); and in that the possible trajectories (TPO) of the aircraft connecting either the starting position (PD) to the destination, or the current position (PA) to the destination, are further calculated from the data representative of the air corridors, the possible trajectories (TPO) essentially following the air corridors.

8. Calculation and / or monitoring method according to any one of claims 1 to 7, characterized in that the acquisition of spatial coordinates representative of known positions of interference sources is repeated at regular intervals.

9. Calculation and / or monitoring method according to any one of claims 1 to 8 taken in combination with claim 2, characterized in that it further comprises the following step: - division of the planned trajectory (TPR) into a plurality of sections determined as a function of the impact of the interference sources on the operation of the satellite positioning system at each of the spatial and temporal observation coordinates located on the respective section, in particular if the section is a section with a high disturbance forecast (TPE) or a section with a low disturbance forecast (TPF).

10. Calculation and / or monitoring method according to claim 9, characterized in that it further comprises the following step: - warning a driver and / or a crew of the vehicle when the current position of the vehicle approaches a section with the high disruption forecast (TPE), and / or in the event of loss of capacity and / or degradation of performance.

11. Calculation and / or monitoring method according to any one of claims 9 or 10, characterized in that it further comprises the following steps: - verification of proper operation, performance and capabilities of the vehicle positioning system at regular time intervals with respect to the predictions; - if the deviation with respect to the predictions is greater than a threshold, generation of a message for updating a database of spatial coordinates representative of the known positions of interference sources in the geographical zone (Z).

12. Calculation and / or monitoring method according to any one of claims 1 to 11, 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.

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

14. Device for calculating and / or monitoring the operation of a satellite positioning system of a 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 12.