EP-4740043-A1 - METHOD FOR COMPUTING AND/OR FOR MONITORING THE OPERATION OF A SATELLITE POSITIONING SYSTEM ON BOARD A VEHICLE, AND ASSOCIATED DEVICE AND COMPUTER PROGRAM PRODUCT

EP4740043A1EP 4740043 A1EP4740043 A1EP 4740043A1EP-4740043-A1

Abstract

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

Inventors

PERRIN, Jean-Cédric
RECASENS, Yan

Assignees

THALES

Dates

Publication Date: 20260513
Application Date: 20240705

Claims (15)

1. Method for calculating and/or monitoring the operation of a satellite positioning system of a main vehicle in a geographical area (Z), the operation of said positioning system including the integrity, 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 geographical area (Z); - acquisition of spatio-temporal coordinates of the satellites of a GNSS system for each observation temporal coordinate; - acquisition of characteristics and spatio-temporal coordinates representative of known positions of sources of electromagnetic disturbances of a GNSS system signal, located in or near the geographic zone (Z); - acquisition of data representative of characteristics of the satellite positioning system of the main vehicle; calculation of an impact of sources of electromagnetic disturbance on the operation of the satellite positioning system of the main vehicle for each service and each constellation of the GNSS system and for each spatial and temporal observation coordinate as a function of the spatial observation coordinate, the temporal observation coordinate corresponding to this spatial observation coordinate, the spatio-temporal coordinates of the satellites of the GNSS system at the temporal observation coordinate, the spatio-temporal coordinates representative of the known positions of the sources of electromagnetic disturbance at the temporal observation coordinate and data representative of characteristics of the satellite positioning system.
2. Calculation and/or monitoring method according to claim 1 further comprising the acquisition of characteristics and/or spatio-temporal coordinates representative of positions of at least one auxiliary vehicle, equipped with a satellite positioning system and located in or near the geographical zone (Z), and their use in said calculation of the impact of sources of electromagnetic disturbance.
3. Calculation and/or monitoring method according to any one of claims 1 and 2, characterized in that it further comprises the following steps for: at least one vehicle selected from the main vehicle and, if applicable, the at least one auxiliary vehicle: obtaining a planned trajectory (TPR) of the respective vehicle, the planned trajectory (TPR) connecting a starting position (PD) to a destination of the respective vehicle and comprising a departure date of the respective vehicle or the planned trajectory (TPR) connecting a current position (PA) of the vehicle to the destination of the respective vehicle and comprising a current date; and determining the spatial and temporal observation coordinates lying on the planned trajectory (TPR) of the respective vehicle at an estimated date from the departure date of the respective vehicle or from the current date and an estimated travel time for this spatial coordinate from the starting position of the respective vehicle or from the current position to this spatial coordinate.
4. Calculation and/or monitoring method according to claim 3, characterized in that it further comprises the following step: - division of the planned trajectory (TPR) into a plurality of sections determined according to the impact of sources of electromagnetic disturbance on the operation of the satellite positioning system at each of the spatial and temporal observation coordinates located on the respective section.
5. Calculation and/or monitoring method according to claim 4, characterized in that it further comprises the following step: warning a driver and/or a crew of the respective vehicle when the current position of the respective vehicle approaches a section with high disruption forecast (TPE), and/or in the event of loss of capacity and/or degradation of performance.
6. Calculation and/or monitoring method according to one of claims 3 to 5, characterized in that the planned trajectory (TPR) of the respective vehicle is obtained: - by calculating several possible trajectories (TPO) of the respective vehicle connecting either the starting position (PD) to the destination or the current position (PA) to the destination; - by determining spatial and temporal observation coordinates located on the several possible trajectories (TPO) of the respective vehicle at a date estimated from the departure date of the respective vehicle or from the current date and an estimated travel time for this spatial observation coordinate and this possible trajectory (TPO) from the departure position of the respective vehicle or from the current position to this observation spatial coordinate; - by acquiring the space-time coordinates of the GNSS system satellites for each observation time coordinate of each possible trajectory (TPO); by calculating, for each possible trajectory (TPO), the impact of the sources of electromagnetic disturbance on the operation of the satellite positioning system of the respective vehicle at each of the observation space and time coordinates as a function of the observation space coordinate, the observation time coordinate associated with this observation space coordinate, the space-time coordinates of the GNSS system satellites at the observation time coordinate, the space-time coordinates representative of known positions of the sources of electromagnetic disturbance, data representative of characteristics of the satellite positioning system, and where applicable, characteristics and/or space-time coordinates representative of positions of at least one other vehicle chosen from the main vehicle and the at least one auxiliary vehicle; - by determining the planned trajectory (TPR) among the possible trajectories (TPO) based on the impact of the sources of electromagnetic disturbances on the operation of the satellite positioning system of the respective vehicle at each spatial and temporal observation coordinate located on the possible trajectory (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 geographic zone (Z), the calculation of the impact of the sources of electromagnetic disturbance on the operation of the satellite positioning system includes the calculation of the distances, elevations and azimuths of each source of electromagnetic disturbance and of each satellite of the GNSS system at each of the spatial and temporal observation coordinates of the possible trajectory (TPO) and/or of the planned trajectory (TPR) and/or of the geographic 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 selected from the main vehicle and, where appropriate, the at least one auxiliary vehicle: acquisition of data representative of a category of the respective vehicle and/or a shape of the respective vehicle and/or a position of an antenna on the respective vehicle and/or movement characteristics of the respective vehicle; and in that said impact on the operation of the satellite positioning system at each of the spatial and temporal observation coordinates is calculated as a function of an antenna gain of the antenna of the respective vehicle estimated for each spatial and temporal observation coordinate, from the data representative of the category of the vehicle and/or the shape of the vehicle and/or the position of the antenna on the vehicle and/or an orientation of the vehicle at this spatial and temporal observation coordinate estimated on the basis of the data representative of the movement characteristics.
10. Calculation and/or monitoring method according to any one of the preceding claims, characterized in that it further comprises the following step for at least one vehicle chosen from the main vehicle and, where appropriate, the at least one auxiliary vehicle: acquisition of data representative of a topography and obstacles of the geographical area (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 area (Z).
11. Calculation and/or monitoring method according to any one of the preceding claims, characterized in that the acquisition of spatial coordinates representative of known positions of sources of electromagnetic disturbances is repeated at regular intervals.
12. Calculation and/or monitoring method according to any one of the preceding claims, characterized in that it further comprises the following steps: verification of proper operation of the main vehicle positioning system at regular time intervals with respect to the predictions; if the deviation from the predictions is greater than a threshold, generation of a message updating a database of spatial coordinates representative of the known positions of sources of electromagnetic disturbances in the geographic zone (Z).
13. Calculation and/or monitoring method according to any one of the preceding claims, characterized in that the geographical area (Z) is divided into a plurality of boxes constituting a grid, the grid preferably comprising a predefined resolution, the spatial and temporal observation coordinates comprising a plurality of positions each located in one of the boxes constituting the grid, preferably located in the center of the box constituting the grid, the geographical area observed for the same instant in time, the spatial and temporal observation coordinates all referring to the same instant of observation.
14. Computer program product comprising software instructions which, when executed by a computer, implement the calculation and/or monitoring method according to any one of the preceding claims.
15. Device for calculating and/or monitoring the operation of a satellite positioning system of a main vehicle in a geographical zone (Z), comprising technical means adapted to implement the calculation and/or monitoring method according to any one of claims 1 to 13.

Description

TITLE: Method for calculating and/or monitoring the operation of a satellite positioning system on board a vehicle, and associated device and computer program product The present invention relates to a method for calculating and/or monitoring the operation of a positioning system using a satellite positioning receiver on board a vehicle which must operate in a geographical area and within a time range. The present invention also relates to a computer program product and a calculation and/or monitoring device associated with this method. Vehicles of all types, in particular aerial, land or naval vehicles, are equipped with a so-called satellite positioning system because it is generally based on a satellite positioning receiver and an antenna. This system can also be equipped with other additional positioning assistance sensors such as inertial units, Doppler sensors, radio navigation in the event of loss of integrity, capacity or performance of the satellite positioning receiver. The satellite positioning system is a set of components based on a constellation of satellites making it possible to provide a user, via the sensors constituting it, with their 3D position, 3D speed and time. The satellite positioning system thus allows positioning, navigation and time measurement (Positioning, Navigation, Time: PNT) and thus constitutes a so-called PNT system. 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 the piloting of missions. Similarly, drones that can participate in these missions also make extensive use of the satellite positioning system. The strategic nature of satellite positioning systems is no longer in doubt. Their advantages include global and permanent coverage of the PNT, operational safety, and their performance. The weakness of these satellite positioning systems lies in their vulnerability to electromagnetic disturbances, particularly radiofrequency interference, and in particular the vulnerability of the receiver to these disturbances. In the presence of such disturbances, their performance and their ability to provide a valid and 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 disturbing signals received, the waveforms and frequencies of the electromagnetic disturbances, the positioning of the sources of these disturbances and the 4D trajectory of the vehicle. To prohibit the use of such an operational asset, and to contest space sovereignty, numerous jamming systems are used, these systems ranging from simple interference systems to very sophisticated jammers. Sources of interference are therefore particularly numerous in and near conflict zones or areas requiring humanitarian intervention. The existence of sources of involuntary and/or intentional electromagnetic disturbances has the effect of degrading the performance of the satellite positioning system, or even making certain capacities of the receivers used unavailable, such as acquisition, tracking, integrity, dual-frequency or multi-constellation processing, use of an augmentation system (ABAS).... Even though vehicles participating in a mission can move safely without satellite positioning systems thanks to additional sensors, the massive increase in sources of electromagnetic disturbances is considered a threat because it can harm the success of any mission, or at least complicates the execution of missions, and imposes a greater workload on both the pilots of the vehicles on the ground and the personnel in the operational control centers of these missions. The presence of these threats also requires the maintenance of additional communication, navigation and surveillance services to meet performance and success requirements. Having to operate in an electromagnetically disturbed mission space while the integrity, capacity and/or performance of the PNT are required for the success of the mission poses many issues. In particular, it is necessary to anticipate threats to the integrity, performance and capacity of the satellite positioning system, their evolution, their impacts on the various systems and actors of the mission on the ground, in order to decide on the strategy(ies) for implementing the mission in terms of locations, dates and resources. Document WO 2015/065664 A1 discloses a system for generating a visual representation of interference sources that are detrimental to the operation of a satellite positioning system. The visual representation may comprise a map covered with visual indicators indicating location and magnitude of interference. However, the known system does not allow to determine the impact of interference sources on the operation of a particular sa