Method for calculating and / or monitoring the operation of a vehicle-mounted satellite positioning system, and associated computer program devices and products

Abstract

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

Description

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

[0001] The present invention relates to a method for calculating and / or monitoring the operation of a positioning system using a satellite positioning receiver mounted in a vehicle that is to operate in a geographical area and within a time range.

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

[0003] Vehicles of all types, particularly aerial, land, and naval vehicles, are equipped with a satellite positioning system, generally based on a satellite positioning receiver and an antenna. This system may also be equipped with other additional positioning aid sensors, such as inertial measurement units (IMUs), Doppler sensors, and radio navigation systems, in case of loss of integrity, capacity, or performance of the satellite positioning receiver. A satellite positioning system is a set of components based on a constellation of satellites that provides a user, via its constituent sensors, with their 3D position, 3D velocity, and time. The satellite positioning system thus enables positioning, navigation, and time measurement (Positioning, Navigation, Time: PNT) and is therefore considered a PNT system.

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

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

[0006] The strategic importance of satellite positioning systems is well established. Among their advantages are the global and permanent coverage of the PNT, the security of operations, and their performance.

[0007] The weakness of these satellite positioning systems lies in their vulnerability to electromagnetic disturbances, particularly radio frequency interference, and especially in the vulnerability of the receiver to these disturbances. In the presence of such disturbances, their performance and their ability to provide a valid and intact 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.

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

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

[0010] The existence of unintentional and / or intentional sources of electromagnetic interference degrades the performance of the satellite positioning system, and may even render unavailable certain capabilities of the receivers used, such as acquisition, tracking, integrity, dual-frequency or multi-constellation processing, and the use of an augmentation system (ABAS)....

[0011] Even if vehicles participating in a mission can move safely without a satellite positioning system thanks to additional sensors, the massive increase in sources of electromagnetic interference is considered a threat because it can jeopardize the success of any mission, or at the very least, complicate mission execution and impose a greater workload on both vehicle drivers in the field and personnel at the operational command centers for these missions. The presence of these threats also necessitates the maintenance of complementary communication, navigation, and surveillance services to meet performance and success requirements.

[0012] Having to operate in an electromagnetically disturbed mission space when the integrity, capability, and / or performance of the PNT are required for mission success poses numerous problems. In particular, it is necessary to anticipate threats to the integrity, performance, and capability of the satellite positioning system, their evolution, and their impacts on the various mission systems and personnel in the field, in order to decide on the mission implementation strategy or strategies in terms of locations, dates, and resources.

[0013] A system for generating a visual representation of interference sources that disrupt the operation of a satellite positioning system is known from document WO 2015 / 065664 Al. The visual representation may include a map covered with visual indicators showing the location and magnitude of the interference.

[0014] However, the known system does not allow the impact of the sources to be determined The system does not allow for the determination of the impact of interference sources on the operation of a particular satellite receiver and on the onboard positioning system, nor does it affect the integrity, capabilities, and performance of the latter in a vehicle operating within a defined geographical area and at different altitudes. Furthermore, the system cannot determine the impact of interference sources on the operation of a satellite receiver at a specific date and time. Therefore, the system cannot predict or estimate the risk of malfunction of the onboard satellite positioning receiver when the vehicle is located at specific positions within the geographical area at a specific time.Similarly, the existing system cannot determine the impact of interference sources on the operation of a satellite positioning system installed in a vehicle that must follow a specific flight plan or route at a precise date and time. Finally, such a system cannot reduce the risk of malfunction of the onboard satellite positioning system by proposing a 4D flight plan or route that would reduce, or even minimize, the risk of electromagnetic interference.

[0015] In order to partially or totally address these various problems, one aim of the invention is to propose a calculation and / or monitoring method enabling the prediction or reduction of the risks of malfunction of the satellite positioning system used by a vehicle operating in a geographical area, and to provide a precise view of the present and future situation in terms of capacity and performance of the PNT adapted to each user, at any point in a geographical area, at various altitudes and within a given time range, or at any point of a planned 4D trajectory crossing the geographical area or even for the coordination of 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.

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

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

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

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

[0020] - acquisition of spatio-temporal characteristics and coordinates sensing of known positions of sources of electromagnetic interference to a GNSS system signal, located in or near the geographical area;

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

[0022] - calculation of the impact of electromagnetic disturbance sources on the function operation, including integrity, capabilities and performance, of the main vehicle 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 corresponding to that spatial observation coordinate, the spatio-temporal coordinates of the GNSS system satellites to the temporal observation coordinate, the spatio-temporal coordinates representing the known positions of electromagnetic disturbance sources to the temporal observation coordinate and data representative of satellite positioning system characteristics.

[0023] The method according to the invention thus makes it possible, for a defined path in space and time, to precisely determine the impact of electromagnetic interference sources on the operation, in particular on the integrity, capabilities, and performance, of the receiver and satellite positioning system of a vehicle operating in the geographical area. Therefore, the method according to the invention makes it possible to predict or reduce the risks of malfunction of the satellite positioning system receiver accurately as the vehicle follows the path and, potentially, the consequences of such a malfunction on the entirety of a mission in which the vehicle participates.

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

[0025] - a step of acquiring spatio-temporal characteristics and / or 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 electromagnetic disturbance sources;

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

[0027] i) obtaining a planned trajectory of the respective vehicle, the planned trajectory linking a starting position to a destination of the respective vehicle and including a departure date of the respective vehicle, or the planned trajectory linking a position current vehicle details at the respective vehicle's destination and including a current date;

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

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

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

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

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

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

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

[0035] d) by calculating, for each possible trajectory, the impact of electromagnetic interference sources 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 spatiotemporal coordinates of the GNSS system satellites at the temporal observation coordinate, the spatiotemporal coordinates representing known positions of the electromagnetic interference sources, data representing characteristics of the satellite positioning system, and, where applicable, the characteristics and / or spatiotemporal coordinates representing positions of at least one other vehicle chosen from among the main vehicle and the other minus one auxiliary vehicle;

[0036] e) by determining the planned trajectory among the possible trajectories as a function of 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;

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

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

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

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

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

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

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

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

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

[0046] The invention will become clearer upon reading the following description, given solely by way of non-limiting example, and made with reference to the drawings in which:

[0047] [Fig-1] [Fig.1] is a schematic representation of a computing and / or monitoring the operation of a vehicle's satellite positioning system in a geographical area as per this application;

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

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

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

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

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

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

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

[0055] [Fig.7] [Fig.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 geographical area at a given time t and altitude;

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

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

[0058] [Fig. 10] [Fig. 10] is a representation of the power after antenna received from the source of electromagnetic disturbances along the 4D trajectory crossing the geographical area;

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

[0060] Fig. 1 illustrates a calculation and / or monitoring device 10 of the operation of a satellite positioning system of a vehicle in a geographical area Z.

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

[0062] By operation of the vehicle's 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 or recover this signal, as well as its performance when it is able to at least acquire a signal, particularly in terms of the accuracy of the PNT and the speed of the measurement chain, this speed depending in particular on the time to acquire a satellite signal as well as the response time of the system to an acquired signal.

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

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

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

[0066] Alternatively, when the method is implemented 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 further capable of being stored on a computer-readable medium (not shown). The computer-readable medium is, for example, a medium capable of storing electronic instructions and being connected to a bus of a computer system. By way of example, the readable medium is an optical disc, a magneto-optical disc, ROM, RAM, any type of non-volatile memory (e.g., FLASH or NVRAM), or a magnetic card. A computer program comprising software instructions is then stored on the readable medium.

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

[0068] The geographical area Z can be a fixed, expandable, or mobile geographical area. It can also be a corridor around a flight plan or trajectory. In the following, when we refer to "near geographical area Z," we mean an expanded geographical area including geographical area Z. This expanded geographical area can, for example, be defined by a boundary located a predetermined distance from the boundary delimiting geographical area Z.

[0069] The geographical area Z can be divided into a plurality of cells forming a grid. The grid may have a predefined resolution. When the process performs A step is performed for each point in the geographic area; for each cell, the step can be performed on a point located within the cell, preferably at the center of the cell. The geographic area can thus be rasterized.

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

[0071] The receiver allows the determination of its position and / or speed of movement, i.e., also the position of the vehicle and / or the speed of the vehicle, based on GNSS signals that it receives from navigation satellites. Each receiver may have its own characteristics and use one or more GNSS services.

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

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

[0074] The vehicle is one of the members of a group of vehicles dedicated to carrying out a mission and is referred to hereafter as the "main" vehicle to distinguish it in the description from the other vehicles in the group, which are referred to as "auxiliary" vehicles. It should be noted that the distinction between main and auxiliary vehicles is used solely for the purpose of clarity in the description and does not imply any notion of hierarchy or priority.

[0075] The vehicle group may include one or more land vehicles and / or one or more naval vehicles and / or one or more aircraft, these vehicles being autonomous or piloted by a human being.

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

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

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

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

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

[0081] The spatial and temporal observation coordinates comprise a spatial observation coordinate defining a point in the geographic area and a temporal observation coordinate associated with the spatial observation coordinate defining a point in time. Preferably, the spatial observation coordinates are three-dimensional coordinates. The first temporal observation coordinate and the last temporal observation coordinate can define a temporal observation range. The spatial observation coordinate can correspond to a position of the vehicle predicted for a point in time corresponding to the temporal observation coordinate associated with that spatial observation coordinate.

[0082] Alternatively, the observation time range can be defined by the user by entering a time mark at the beginning of the observation time range and a time mark at the end of the observation time range.

[0083] 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.

[0084] The calculation and / or monitoring method includes a step of acquiring the spatiotemporal coordinates of the GNSS system satellites for each observation time coordinate. The spatiotemporal coordinates of the satellites can be acquired by retrieving them from a GNSS database (BDGNSS) where they have been previously stored. The spatiotemporal 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 stored.

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

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

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

[0088] By determining the position of visible satellites and, where applicable, measurements taken that can serve as calibration, the method can implement a step of calculating the distance and received power from each visible satellite at any point in the geographic area Z and over the entire defined observation time range using propagation models. In particular, the method can implement a step of calculating the distance and received power 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 GNSS signal propagation due to the presence of a free space between the receiver and the satellite and / or ionospheric propagation phenomena and / or masking by terrain and / or masking by buildings.

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

[0090] By source of electromagnetic interference, we mean any natural or artificial source of electromagnetic signal emitting an electromagnetic signal capable of interfering with the operation of the satellite positioning system itself or with the GNSS signal to be received by that satellite positioning system. By way of example, it could be a GNSS signal jamming device, in particular a device operating by interference in the radio frequency domain, or a spoofing device, or a destructive system that compromises the integrity of the system.

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

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

[0093] The calculation and / or monitoring method may further include a step of acquiring the spectrum (center 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 been previously deposited, such as the RFI BDRFI database.

[0094] The database of electromagnetic interference sources, in particular the RFI BDRFI database, can be populated by a system for detecting, locating, cataloging, and characterizing electromagnetic interference sources. This system can be capable of collecting data from multiple observations (ground, air, space) by various means such as radar, flight recordings (commercial, cargo), and vessels, preferably located near or within geographical zone Z, including the main vehicle itself or auxiliary vehicles. This system could, for example, be managed by an international organization (e.g., the European Civil Aviation Equipment Organisation: EUROCAE, CNS, NATO, etc.).This system can analyze and consolidate data from multiple observations deposited on a network, particularly a secure network, using artificial intelligence processing based on data from known sources of electromagnetic interference stored in the database and / or information reported by the computing and / or monitoring device 10 in order to continuously generate / update the database. This database of sources of electromagnetic interference can... The electromagnetic interference sources may be global or limited to a region and are directly exploited by the computing and / or monitoring device. The sources of electromagnetic interference may be stationary and / or emit the electromagnetic signal continuously. They may also be mobile and / or emit the disruptive electromagnetic signal intermittently and / or consist of different types of modulation and other dynamic characteristics. In this case, the method may include a step of acquiring data representative of the expected movements of the electromagnetic interference sources and / or data representative of the emission characteristics of the electromagnetic interference sources, such as an expected emission timing of the electromagnetic signal, modulation of the electromagnetic signal, and / or other dynamic characteristics.Data representing expected movements of electromagnetic disturbance sources and / or data representing the emission characteristics of electromagnetic disturbance sources can be acquired by retrieving them from a database where they have been previously deposited, such as the electromagnetic disturbance source database, in particular the RFI BDRFI database.

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

[0096] The calculation and / or monitoring process may further include 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 probable scenario, for example. The desired result in terms of probability may, for example, be obtained by user input via the user interface (UI) or by retrieving it from a database where it has been previously stored.

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

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

[0099] The characteristics of the main vehicle's antenna may include an antenna diagram showing the gain for each azimuth / elevation. It is recommended that this antenna diagram be representative of the antenna's pattern after installation on the main vehicle (for example, taking into account masking, attenuation due to the vehicle (e.g., fenders) and the ground plane).

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

[0101] The characteristics of the satellite positioning system on board the vehicle may include in particular the performance and accuracy of each additional sensor, their participation in the development of the vehicle's PNT and their accuracy in particular when certain GNSS receiver capabilities are lost (e.g. switching to Inertial or RadioNav mode when the position from the GNSS receiver is inaccurate and / or incomplete and / or invalid).

[0102] Representative data of the characteristics of the main vehicle's satellite positioning system can be acquired by retrieving them from a database where they have been previously stored, such as a known receiver database (BDRC) and / or a known antenna database (BDAC). Representative data of the receiver and / or antenna characteristics can also be acquired by retrieving them from a receiver memory.

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

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

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

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

[0107] Part or all of these coordinates can be calculated before the mission or in real time using an appropriate computerized device that equips the control center.

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

[0109] Data representing the characteristics of an auxiliary vehicle may be mission-related. In particular, it may be a vehicle category, or a priority order of the respective auxiliary vehicle in relation to other auxiliary and / or main vehicles.

[0110] The calculation of the impact of each source of electromagnetic disturbances 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 area Z, preferably of all the auxiliary vehicles located in or near the geographical area Z.

[0111] It is understood in particular that if the operation of the main vehicle's satellite positioning system is degraded due to a source of electromagnetic interference emitting an electromagnetic signal in a frequency band data, if an auxiliary vehicle or the control center is able to communicate with the main vehicle during 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 various auxiliary vehicles, can help to limit the degradation caused by the source of electromagnetic disturbances.The step of calculating the impact of each source of electromagnetic interference on the operation of the main vehicle's satellite positioning system may include calculating distances, elevations, and / or azimuths in order to determine the power received from each source of electromagnetic interference for each spatial and temporal observation coordinate, i.e., either at each position on the route determined for the estimated date on which the main vehicle is located at that position, or at any point in the geographical area Z and over the entire defined observation time range, using propagation models that take into account a loss during the propagation of the electromagnetic signal from this source of electromagnetic interference, considering, where appropriate, the wavelength(s) of the electromagnetic signal and / or the weather forecast for the geographical area Z and / or terrain masking.

[0112] The step of calculating the impact of each source of electromagnetic interference on the operation of the main vehicle's satellite positioning system can be carried out according to 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 the impact of each source of electromagnetic interference on the operation of the satellite positioning system can be based on the maximum power of the electromagnetic signal emitted by the respective source of electromagnetic interference, for example.When the desired outcome in terms of probability corresponds to the best-case scenario, the step of calculating the impact of each source of electromagnetic interference on the operation of the satellite positioning system can be based on the minimum power of the electromagnetic signal emitted by the respective source of electromagnetic interference, for example. When the desired outcome in terms of probability corresponds to the average and / or most probable scenario, the step of calculating the impact of each source of electromagnetic interference on the operation of the satellite positioning system can be based on the average and / or most probable power of the electromagnetic signal emitted by the respective source of electromagnetic interference, for example.

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

[0114] The spatial coordinates defining the starting position PD, the current position PA of the main vehicle, and / or the destination can, for example, be acquired by user input via the user interface (UI). These spatial coordinates can also be acquired by retrieving them from a database where they have been previously stored. For example, these spatial coordinates can 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 main vehicle's receiver.

[0115] The planned trajectory (TPR) can, for example, correspond to a predefined or calculated path of the main vehicle. The planned trajectory (TPR) can, for example, be obtained through user input via the user interface (UI), received from the flight control center, or retrieved from a database where it has been previously stored. The planned trajectory (TPR) can be limited to a flight plan or be a precise trajectory linked to the capabilities of the aircraft, generated by a trajectory computer or a Flight Management System (FMS).

[0116] The calculation and / or monitoring method includes a step of calculating an estimated arrival time for the planned trajectory TPR. The estimated arrival time can be obtained by adding an estimated travel time to the departure time. The estimated travel time can be derived from previous travel times following the same 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 retrieving it from the 4D trajectory.

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

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

[0119] The calculation and / or monitoring method may include 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 on the planned trajectory can thus each constitute one of the spatial and temporal coordinates for observation. The estimated date on which the main vehicle is located at the respective position can be estimated from the travel times of previous journeys along the same or a similar route taken by other vehicles, or from a computer that takes into account, among other things, the properties of the main vehicle.

[0120] Positions located on the planned trajectory (TPR) can be spaced equidistant from each other. The number of positions selected allows for defining a desired resolution. 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 separated by 10 seconds or 0.2 nautical miles, for example.

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

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

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

[0124] In cases where the impact calculation takes into account the characteristics and spatiotemporal coordinates representative of the 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 within the context of the mission, taking into account the different vehicles to be coordinated. Advantageously, at least one planned TPR trajectory is obtained – mutatis mutandis – for at least one auxiliary vehicle, preferably for all the auxiliary vehicles located in or near the geographical area Z.

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

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

[0127] In this case, the method may include determining groups of possible trajectories (GTPOs). Each GTPO group includes one possible trajectory (TPO) for each of the main and auxiliary vehicles, the different possible TPOs within a given GTPO group being compatible with each other and with the mission requirements. The method may further include ranking the different GTPO groups according to the overall impact of electromagnetic interference sources on the group of vehicles. In this way, the control center can determine the optimal GTPO group of possible trajectories not from the perspective of a single vehicle, but from the perspective of all the main and auxiliary vehicles dedicated to the mission.

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

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

[0130] In a particular embodiment, all trajectory calculations are performed on computing resources equipping the control center, then movement instructions are generated based on these trajectories and in particular on the possible trajectory groups (GTPO). The movement instructions are then transmitted to the various vehicles concerned.

[0131] In an alternative embodiment, the calculation of the recommended trajectory for a predetermined time interval is performed by the respective vehicle's computing means, based on data transmitted by the control center for the entire group of vehicles at the beginning of the time interval. Local adjustment of the main vehicle's trajectory by its driver may be permitted. Then, 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 for the following time interval.

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

[0133] According to one possibility, the recommended trajectory as TPR may correspond to the possible trajectory TPO having the least impact on the operation of the satellite positioning system of the respective vehicle. According to an alternative, the recommended trajectory 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, accurate to within < 0.1nm at 95%) and having a minimum travel time for the respective vehicle and / or minimum vehicle fuel consumption.

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

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

[0136] Data representing the vehicle category and / or the vehicle shape and / or the antenna position on the vehicle and / or the vehicle's motion characteristics can be acquired by retrieving them from a database where they have been previously stored, such as a vehicle database, and / or from a flight simulator and / or trajectory computer. "Vehicle category" refers to the type of vehicle selected, for example, land vehicle, airplane, helicopter, drone, etc.

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

[0138] Representative topographic data for geographic area Z can be acquired from a database known as a DEM (Digital Elevation Model) database. This representative topographic data for geographic area Z may include representative data for obstacles such as buildings and data from a digital terrain model (DTM). The representative topographic data allows for the evaluation of masking and propagation losses of useful and harmful signals, such as GNSS signals or interfering signals like interference signals emitted by interference sources. These databases are particularly useful for drone or naval applications, i.e., when the vehicle is a drone or a boat. They are also useful in terrestrial and low-altitude flight applications.

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

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

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

[0142] The method may further include a step of dividing the planned trajectory TPR and / or the different trajectories TPO into a plurality of segments, and a step of determining, for each segment, 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 segment, whether the segment is a segment with a high disturbance prediction TPE or a segment with a low disturbance prediction TPF or, where appropriate, a segment with a medium disturbance prediction TPM.

[0143] The low TPF disturbance prediction may correspond to a high probability of proper functioning of the satellite positioning system and / or a high probability of GNSS signal integrity, for example. The disturbance prediction A high TPE (Total Perceived Exposure) may correspond to a high probability of malfunction of the satellite positioning system and / or a high probability of loss of the GNSS PNT (Personal Navigation Satellite System), for example. A medium TPM (Total Perceived Exposure) forecast may correspond to a high probability of performance degradation of the satellite positioning system and / or a high probability of loss of GNSS signal integrity, for example.

[0144] The method may further include a warning step for a driver (or pilot) of the main vehicle and / or a crew of the main vehicle when the vehicle's current position approaches a segment with a high disturbance prediction (TPE) or, where applicable, a segment with a medium disturbance prediction (TPM). The driver warning step may include a warning of a loss of integrity, capability, and / or performance of the vehicle's satellite positioning system.When the vehicle is an aircraft, the warning stage may include an alert to notify the pilot, as the aircraft operator, and / or the aircraft crew of an imminent exceedance of the Required Navigation Performance (RNP), an imminent loss of receiver capability (e.g., 2 minutes before the loss of acquisition capability), and / or an imminent transition to a navigation mode without using the satellite positioning system (coasting). This allows for anticipating and managing the imminent loss of GNSS availability with complete peace of mind and improves flight safety. A receiver failure is likely to cause stress among the pilot and / or crew.Therefore, 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 crew of the main vehicle.

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

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

[0147] Thus, the method monitors and compares measurements and interference risks in real time and provides feedback to keep the database of electromagnetic interference sources up to date. The disappearance of a predicted interference allows for the extrapolation of the disappearance or attenuation of one of the known interference sources. The presence of an unpredicted interference allows for the extrapolation of the emergence of a new electromagnetic interference source or an amplification of one of the known interference sources. This information can then be transmitted so that a monitoring center can update the database of electromagnetic interference sources after cross-referencing the various pieces of information received.

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

[0149] According to one possibility, the plurality of cells constituting the grid can be arranged in three dimensions. The grid can, for example, include a background layer at ground level and at least one top layer corresponding to a defined altitude, such as the cruising altitude of a commercial airliner. The defined altitude can, for example, be user-defined. The user can enter the desired defined altitude in the user interface.

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

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

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

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

[0154] The antenna gain determination step can be performed for all acquired spatial and temporal observation coordinates, that is, either for any position in the geographic area Z and / or over the entire observation time range, or for all positions on the possible trajectories TPO and / or on the planned trajectory TPR and for all dates corresponding to these positions. The method may further include a step of displaying the antenna gain for a given position in the geographic area during the defined observation period and / or during the trajectory tracking. Such a graphical representation is given in [Fig 6B] and Figure 1 IB as an example.

[0155] The method may further include a step of determining the signal level of the GNSS system satellites received after the antenna. Determining the received signal level after the antenna may take into account the characteristics of the vehicle's installed antenna and / or the position of the vehicle's antenna and / or the shape of the vehicle, for example, to account for possible antenna masking by the vehicle. This determination step may also take into account the vehicle's motion characteristics, such as the vehicle's maximum attitudes, for example, when the vehicle is an aircraft.The step of determining the after-antenna signal level received from the GNSS system satellites can be performed for all acquired observation time coordinates, that is, either for any position in the geographic area Z and / or over the entire observation time range, or for all positions on the possible TPO trajectories and / or on the planned TPR trajectory and for all dates corresponding to these positions. The method may further include a step of displaying the after-antenna signal level of the GNSS system satellites received for a given position in the geographic area during the defined observation period and / or during trajectory tracking. Such a graphical representation is given in [Fig 6C] and Figure 1 IC as an example.

[0156] Similarly, the method may further include a step of determining the level of received electromagnetic signals for each known source of electromagnetic interference. The step of determining the level of received interference signals may be performed for all acquired observation time coordinates, that is, either for any position in the geographical area Z and / or over the entire observation time range or for all positions on the possible trajectories TPO and / or on the planned trajectory TPR and for all dates corresponding to these positions.The method may further include 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 period and / or during trajectory tracking. Such a graphical representation is given in [Fig. 3] (for zone Z) and [Fig. 9] (along the trajectory) by way of example.

[0157] The method may further include a step of determining the antenna gain of the respective vehicle antenna with respect to each of the sources of electromagnetic interference. 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, to account for potential antenna masking by the vehicle. When the antenna is an adaptive antenna capable of eliminating a limited number of electromagnetic interference sources, the determination of the antenna gain applied to each electromagnetic signal from an electromagnetic interference source can also take this into account, and the new antenna pattern can be applied to the received GNSS satellite signals. This determination step can further consider the vehicle's motion characteristics, such as maximum vehicle attitudes, for example, when the vehicle is an aircraft. Alternatively or additionally, this determination step can also consider the estimated vehicle attitudes at each position observed during the TPR and / or TPO trajectory tracking.In particular, when the aircraft is in a horizontal attitude, the fuselage partially masks electromagnetic signals emitted by sources of electromagnetic interference originating from a position below the aircraft.

[0158] The step of determining the antenna gain applied to electromagnetic disturbances can be performed for all acquired spatial and temporal observation coordinates, that is, either for any position in the geographic area Z and / or over the entire observation time range, or for all positions on the possible trajectories TPO and / or on the planned trajectory TPR and for all dates corresponding to these positions. The method may further include a step of displaying the antenna gain and / or antenna pattern for a given position in the geographic area during the defined observation period and / or during trajectory tracking.

[0159] The method may further include a step of determining the level of the received post-antenna electromagnetic signals for each known source of electromagnetic interference. The determination of the received post-antenna electromagnetic signal level 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.

[0160] When the antenna is an adaptive antenna capable of eliminating a limited number of electromagnetic interference sources, the determination of the level of the received electromagnetic signals after the antenna can also take this into account. This determination step can further consider the vehicle's motion characteristics, such as a maximum vehicle attitude, for example, when the vehicle is an aircraft.

[0161] The step of determining the level of the electromagnetic signals received after the antenna for each source of electromagnetic disturbance can be carried out for All acquired observation time coordinates, that is, either for any position in the geographic area Z and / or over the entire observation time range, or for all positions on the possible trajectories TPO and / or on the planned trajectory TPR, and for all dates corresponding to these positions. The method may further include a step of displaying the level of received post-antenna electromagnetic signals for a known source of electromagnetic disturbance, in which a graphical representation of the received post-antenna electromagnetic signal level is displayed to the user. Such a graphical representation is given in [Fig. 4] (for area Z) and [Fig. 10] (along the trajectory) by way of example.

[0162] The determined levels of the received electromagnetic signals 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.

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

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

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

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

[0167] By way of example, [Fig. 5] shows a table visualizing the residual power – after antenna and receiver processing – of the various interfering electromagnetic signals received in the geographical area potentially affecting three services of a satellite positioning system (L1 C / A, L1 P(Y), L2 P(Y)). The left-hand column of the table represents the level of the interfering electromagnetic signals received after antenna at any point in the geographical area Z, each row in this column corresponding to a known source of electromagnetic interference. The three columns on the right-hand side of the table each concern a level of the residual interfering electromagnetic signal after antenna and after a signal filtering step, anti-interference processing, and correlation of the interference signal with the respective GNSS service for each of the three services.The first of these three columns concerns the L1 C / A service, the second of these three columns concerns the L1 P(Y) service, and the third column, that is, the last column on the right, concerns the L2 P(Y) service. For each of the three right-hand columns of the table, the first row relates to a first known electromagnetic interference, the second row to a second known electromagnetic interference, and the third row to a third known electromagnetic interference. For example, the cell in the upper right of the table represents the residual power of the received signal from the first source of electromagnetic interference after antenna, filtering, anti-interference processing, and correlation for the L2 P(Y) service. The bottom row represents the sum of the different residual interfering electromagnetic signals for each of the services.For example, the box to the left of the last line represents the sum of the residual powers of the 3 interfering electromagnetic signals after antenna, after filtering, after anti-interference processing and after correlation for the L1C / A service.

[0168] The method may further include a step of calculating the ratio between the level of each GNSS system satellite signal received after antenna and the residual sum of the levels of interfering electromagnetic signals received after antenna, after filtering, after anti-interference processing and after correlation from each of the known sources of electromagnetic interference. This ratio can be called the signal-to-noise ratio. This step can be calculated for all acquired spatiotemporal observation coordinates, that is, either for any point in the geographical area Z and over the entire observed 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.

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

[0170] The method may, following the step of determining the signal / noise ratio, further include a step of determining a prediction of proper functioning of the receiver for each of the services of the GNSS system for all the spatio-temporal observation coordinates acquired, that is to say either for any point of the geographical area Z and over the entire observed 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.

[0171] The method may further include a step for displaying the proper functioning of the satellite positioning system, in particular its integrity and its capabilities and performance 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 proper functioning may have multiple layers. By way of example, for each of the services used, a first layer among the multiple layers may represent the receiver tracking capability, a second layer among the multiple layers may represent the receiver tracking capability with integrity, a third layer among the multiple layers may represent the re-acquisition capability, and 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 Z zone. Other layers can be added, such as the representation of dual-frequency tracking capability, dual-constellation tracking capability, and the representation of estimated position and velocity accuracy. The graphical representation of proper operation can include various cursors, for example, an altitude level and a date / time. The graphical representation of the receiver's operation, including its capabilities and performance, can be displayed to the user on a map background.

[0172] When the proper functioning step 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 step may include the display of proper functioning Operation along a 4D trajectory corresponding to a possible TPO trajectory and / or the planned TPR trajectory. The capabilities and performance along the 4D trajectory can be displayed to the user on a map background, in a horizontal view, a vertical view, or a timeline. This display step allows the user to see the receiver's capacity and performance along and / or near the 4D trajectory. An example of displaying a receiver's capabilities for a given service along such a 4D trajectory on a map background is shown in [Fig. 8].

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

[0174] When the vehicle is an aircraft, the method may further include a step of displaying a representation of the operation, in particular the capabilities and / or performance, 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, failure...).

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

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

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

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

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

[0180] - a downstream entity that will take into account the characteristics of the bearer, that is to say of the vehicle, and its on-board system (antenna, receiver, carrier, positioning system...) and translate these universal data into user data in the sense of capacity and performance.

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

[0182] The calculation and / or monitoring device 10 and the calculation and / or monitoring method make it possible to provide an accurate 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 area Z and corresponding to the system / carrier used.

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

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

[0185] The complete system thus enables multiple applications as previously described and constitutes an asset for the success of a mission, the improvement of security, preventive information and decision / planning support.

Claims

Claims

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

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

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

4. Calculation and / or monitoring method according to claim 3, characterized in that it further comprises the following step: - division of the planned trajectory (TPR) into a plurality of sections determined 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.

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

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 coordinates observation point located on the several possible trajectories (TPO) of the respective vehicle at a date estimated from the departure date of the respective vehicle or from the current date and an estimated travel time for this observation spatial coordinate and this possible trajectory (TPO) from the departure position of the respective vehicle or from the current position to this observation spatial coordinate; - by acquiring the spatio-temporal coordinates of the GNSS system satellites for each observation time coordinate of each possible trajectory (TPO); - by calculating, for each possible trajectory (TPO), the impact of the sources of electromagnetic disturbance on the operation of the satellite positioning system of the respective vehicle at each of the spatial and temporal observation coordinates as a function of the spatial observation coordinate, the temporal observation coordinate associated with this spatial observation coordinate, the 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 spatio-temporal coordinates representative of positions of at least one other vehicle chosen from the main vehicle and at least one auxiliary vehicle; - by determining the planned trajectory (TPR) among the possible trajectories (TPO) based on the impact of the sources of electromagnetic disturbance 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 antenna of the respective vehicle estimated for each spatial coordinate and temporal observation, 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 proper operation of the main 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 sources of electromagnetic disturbance in the geographical zone (Z).

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

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

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

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