Robust self-localization with satellite navigation

Abstract

A method for self-localization using satellite navigation is described. The method involves self-localization of at least two vehicles at a known distance (d v ) positioned GNSS receiving devices (A1, A2), wherein a first ego position (P1) of a first GNSS receiving device (A1) is determined on the basis of a satellite navigation signal received by the first GNSS receiving device (A1), and a second ego position (P2) of a second GNSS receiving device (A2) is determined on the basis of a satellite navigation signal received by the second GNSS receiving device (A2). Based on the first ego position (P1) and the second ego position (P2), an estimated distance (d s ) between the first GNSS receiving device (A1) and the second GNSS receiving device (A2). The estimated distance (d s ) is measured with the previously known distance (d v). Finally, based on a comparison result (EG), it is determined whether the self-localization of the GNSS receiving devices (A1, A2) is sufficiently precise and reliable. Furthermore, a validation device (20) is described. Finally, a vehicle (40) is described.

Description

[0001] The invention relates to a method for validating self-localization using satellite navigation. The invention further relates to a validation device. Furthermore, the invention relates to a vehicle with such a validation device.

[0002] When rail transport is to become more automated, aspects of assisted and driverless train operation are usually also discussed. Precise and robust localization of a rail vehicle within the track network is a crucial requirement for achieving such automation. For this purpose, so-called GNSS systems (GNSS stands for "Global Navigation Satellite System"), such as GPS (GPS stands for "Global Positioning System"), are used for global localization.

[0003] However, the accuracy and reliability of a GNSS system are influenced by various interference factors. Improvements to GNSS systems, such as DGPS (Differential GPS) or RTK (Real Time Kinematics, a geodesic method for precisely determining position coordinates using satellite navigation methods), can minimize atmospheric disturbances and time measurement inaccuracies in GNSS satellites, thus achieving positioning accuracy of a few centimeters, at least with a clear line of sight to the satellites.

[0004] However, local interference, such as multipath propagation or diffraction effects of GNSS signals on or through buildings, is not compensated for by the above-mentioned correction systems. Targeted attacks such as jamming or spoofing cannot be detected either. Jamming involves deliberately disrupting satellite signals so that they cannot be received. Spoofing involves simulating satellite signals in order to manipulate or influence positioning based on the satellite signals.

[0005] The task is therefore to achieve robust and precise localization of a vehicle, especially a rail vehicle, even when interference phenomena occur.

[0006] This object is achieved by a method for validating self-localization with satellite navigation according to patent claim 1, a validation device according to patent claim 12 and a vehicle according to patent claim 13.

[0007] In the method according to the invention for validating self-localization using satellite navigation, self-localization is performed by at least two GNSS receiving devices positioned at a predetermined distance from each other. As will be explained in more detail later, the GNSS receiving devices positioned at a predetermined distance are preferably arranged on a vehicle, particularly preferably on a rail vehicle, but they can also be stationary. A GNSS receiving device is understood to be a device with which GNSS signals from satellites can be received and an ego position of the GNSS receiving device can be determined.

[0008] In the method according to the invention, a first ego position of a first GNSS receiving device of the GNSS receiving devices positioned at a known distance is determined on the basis of a satellite navigation signal, and a second ego position of a second GNSS receiving device positioned at the known distance of the positioned GNSS receiving devices from the first GNSS receiving device is determined on the basis of a satellite navigation signal.

[0009] Furthermore, an estimated distance between the first GNSS receiver and the second GNSS receiver is determined based on the first ego position and the second ego position. The estimated distance is compared with the previously known distance.

[0010] During validation, the comparison results are used to determine whether the self-localization of the GNSS receivers is sufficiently precise and reliable. If the deviation between the previously known distance and the estimated distance is too large, the determined ego positions are discarded, and the measurements are preferably repeated by the GNSS receivers. It is advantageous to use only reliable and accurate measurement data for self-localization.

[0011] The validation device according to the invention has an input interface for receiving position data from at least two GNSS receiving devices positioned at a predetermined distance from one another and configured to perform self-localization. The GNSS receiving devices are configured to determine a first ego position of a first GNSS receiving device of the two receiving devices based on a satellite navigation signal and to determine a second ego position of a second GNSS receiving device of the two receiving devices based on a satellite navigation signal. The validation device is preferably arranged on a vehicle, particularly preferably a rail vehicle.

[0012] Part of the validation device according to the invention is also a distance determination unit for determining an estimated distance between the first GNSS receiving device and the second GNSS receiving device on the basis of the first ego position and the second ego position received from the input interface.

[0013] The validation device according to the invention further comprises a comparison unit for comparing the estimated distance with the previously known distance.

[0014] In addition, the validation device according to the invention comprises a validation unit for determining, based on the result of the comparison, whether the self-localization of the GNSS receiving devices is sufficiently precise and reliable. During validation, additional uncertainties in the individual measurements and the calibration of the GNSS receiving devices can be taken into account. These uncertainties can be determined using a static and statistical test. Such a test is therefore preferably carried out at rest at a previously known position. A large number of ego position determinations are carried out, and statistical data of these position values ​​are generated. Based on the statistical data, a plausibility level can be defined at which the measurements can still be trusted. Such a plausibility level can have one or more threshold values ​​that are used during validation orthe comparison should not be exceeded if the position data is to be released.

[0015] The uncertainties of the individual GNSS receiving devices are preferably determined using a statistical method, and plausibility levels are defined on this basis. Such statistical methods preferably include a comparison with a threshold value determined by a χ2 distribution.

[0016] If two measurements are available that have a known relationship to each other, the measurement points can be converted into each other using the known transformations that characterize the relationship. This also applies to the measurement uncertainties. These can then be determined using the Mahalanobis distance. The Mahalanobis distance D is given by: D(x,y)=(x−y)T∑−1(x−y).

[0017] The measurement points x and y correspond to the same transformed measurement points, Σ corresponds to the transformed covariance matrix of the two measurements.

[0018] The χ2 function can be used to determine the volume or the probability with which the measurement points correspond to the joint measurement uncertainty. Based on this, a threshold is determined, e.g., 3 * Σ -> 99.73%, against which the Mahalanobis distance can be compared. The probability indicates how often this threshold choice is correct.

[0019] Details on the application of the Mahalanobis distance are described on the Wikipedia page "Mahalanobis distance" at https: / / en.wikipedia.org / wiki / Mahalanobis_distance. Further in-depth information on this topic can be found in P.C. Mahalanobis: On the generalized distance in statistics. In: Proceedings of the National Institute of Science of India. Volume 2, No. 1, 1936, pp. 49-55.

[0020] To further determine the lower thresholds, variable attenuators can be used in the receiver. "Lower thresholds" are defined here as the lowest signal-to-noise ratio at which position determination is still possible.

[0021] Typical reception strengths of signals from individual satellites can also be determined statistically. Amplitude deviations can be identified by comparing the reception strengths with reference values. Such deviations indicate interference, particularly spoofing.

[0022] Advantageously, the accuracy of positioning can be maintained even in the event of local interference, such as multipath propagation or diffraction of GNSS signals on and through buildings, or the position measurement can be restricted to GNSS receiving devices that are not affected by the local interference. If all receiving devices are affected by the interference, positioning can still be performed using older, previously validated position data. Targeted attacks, such as jamming or spoofing, can also be detected, as these generally lead to implausible position data.

[0023] The vehicle according to the invention, preferably a rail vehicle, has GNSS receiving devices, a validation device according to the invention for generating validated position data of the vehicle, and a control device for assisted or automated control of a vehicle's journey based on the generated position data of the vehicle. The vehicle according to the invention shares the advantages of the validation device according to the invention.

[0024] Some of the aforementioned components of the validation device according to the invention can be implemented entirely or partially in the form of software modules in a processor of a corresponding computer system. A largely software-based implementation has the advantage that even computer systems already used in vehicle control and monitoring can be easily upgraded to operate in the manner according to the invention via a software update.

[0025] In this respect, the object is also achieved by a corresponding computer program product with a computer program which can be loaded directly into a computing system, with program sections for carrying out the steps of the method according to the invention for validating self-localization with satellite navigation, in particular the sub-steps for determining an estimated distance between the first GNSS receiving device and the second GNSS receiving device on the basis of the first ego position and the second ego position, for comparing the estimated distance with the previously known distance and for carrying out a validation of the GNSS receiving devices on the basis of a result of the comparison which provides information as to whether the self-localization of the GNSS receiving devices is sufficiently precise and reliable, when the program is executed in the computing system.Advantageously, such a computer program product may, in addition to the computer program, comprise additional components, such as documentation, and / or additional components, including hardware components, such as hardware keys (dongles, etc.) for using the software.

[0026] A computer-readable medium, e.g., a memory stick, a hard disk, or another portable or permanently installed data storage device, on which the program sections of the computer program that can be read and executed by a computer system are stored, can be used for transport to the computer system and / or for storage on or in the computer system. For this purpose, the computer system can, for example, have one or more cooperating microprocessors or the like.

[0027] The dependent claims and the following description each contain particularly advantageous embodiments and developments of the invention. In particular, the claims of one claim category can also be developed analogously to the dependent claims of another claim category and their description sections. Furthermore, within the scope of the invention, the various features of different embodiments and claims can also be combined to form new embodiments.

[0028] In a preferred embodiment of the method according to the invention for validating self-localization with satellite navigation, the validation step comprises the steps of, in the event that the result of the comparison exceeds a deviation between the previously known distance and the estimated distance by more than a predetermined maximum deviation: - the determined ego positions are discarded, - a message is displayed stating that the GNSS receivers whose distance was determined are not reliable.

[0029] Subsequently, after a predetermined time interval, the measurements are repeated by the GNSS receiving devices to determine whether the GNSS receiving devices may be valid or still invalid at a later time.

[0030] Advantageously, only reliable position data is used for geolocation of the GNSS receiving devices. Furthermore, the user is alerted when one or more GNSS receiving devices are disrupted. Furthermore, the validation is continuously updated, allowing dynamic disruption phenomena to be tracked and, thanks to the updates, ensuring the maximum number of GNSS receiving devices can be utilized.

[0031] In a variant of the inventive method for validating self-localization using satellite navigation, more than two GNSS receiving devices are used in the self-localization step, and individual GNSS receiving devices whose GNSS signals are disrupted are identified based on several previously known distances between the GNSS receiving devices. Advantageously, individual GNSS receiving devices can be located and identified based on several distances between different GNSS receiving devices, since the distance of the respective GNSS receiving device to each of the other GNSS receiving devices is also corrupted by a corrupted signal. If the signals from the other GNSS receiving devices are correct, their distances from one another are determined correctly.

[0032] If more than two GNSS receivers are used for self-localization, individual GNSS receivers are identified as unreliable based on the results, preferably using a process of elimination, and only their determined ego positions are discarded. This advantageously allows individual GNSS receivers that are experiencing interference to be identified, allowing the maximum possible number of GNSS receivers to be used for self-localization.

[0033] Alternatively, an inclusion procedure can be used for validation, which determines which GNSS receivers belong to a group of reliable GNSS receivers. Methods such as RANSAC (RANSAC stands for "Random Sample Consensus") or Prediction by Partial Matching are suitable for implementing an inclusion procedure. The application of the RANSAC procedure is explained, for example, in Martin A. Fischler and Robert C. Bolles: Random Sample Consensus: A Paradigm for Model Fitting with Applications to Image Analysis and Automated Cartography. March 1980. Prediction by Partial Matching is a family of adaptive statistical data compression algorithms based on context models and forecasts.

[0034] Particularly preferably, several groups of GNSS receiving devices with directional properties are used for self-localization, and an angle of the satellites relative to a respective group of GNSS receiving devices is measured and compared with an angle of the satellites relative to the respective group of GNSS receiving devices, which angle is determined on the basis of a predicted position of the satellites calculated on the basis of ephemerides.

[0035] Angles of satellite signals can be captured using so-called "digital beamforming" methods, which involve signal measurement with a software-defined phase shift. Ephemerides are defined here as predicted, time-dependent satellite positions stored in a data storage device, particularly a database. Advantageously, the angle from which a satellite signal arrives at the GNSS receiving device can be verified. If, for example, a deviation is detected, it can be concluded that either a satellite signal is being reflected off objects, particularly walls, or that some other interference, particularly spoofing, is occurring.

[0036] Preferably, each of the groups of GNSS receiving devices can be configured such that each direction is covered by at least one GNSS receiving device in each of the groups. If a signal from a specific directional segment is detected as invalid, only those GNSS receiving devices or their received signals whose reception range overlaps with the directional segment can be discarded in each of the groups of GNSS receiving devices.

[0037] The inventive method for validating self-localization using satellite navigation can be implemented particularly easily if the known distance between the GNSS receiving devices is constant. The distance is constant if the GNSS receiving devices are permanently installed on a base. The base itself can be stationary or mobile. In particular, the base can be formed by a vehicle, preferably a rail vehicle. Advantageously, the known distance can be determined particularly precisely because it does not change.

[0038] The distance between the GNSS receiving devices can also be non-constant, but temporarily static and can be determined using a suitable model, preferably a vehicle model, particularly preferably a rail vehicle model, preferably as a function of a route, particularly preferably as a function of a rail line. For example, a track layout based on map data can be incorporated into the distance calculation. While a rail vehicle, which comprises several carriages, is traveling straight ahead, a static positional relationship between GNSS receiving devices arranged on different carriages of the rail vehicle can be assumed. In this situation, a distance between the GNSS receiving devices can advantageously be determined precisely and as static.

[0039] If at least two GNSS receiving devices are arranged on a rail vehicle and only one potentially valid GNSS receiving device is temporarily available for self-localization because the other GNSS receiving devices are currently classified as invalid, one of the following estimated values ​​is preferably used as a comparison value in the method according to the invention for validating self-localization with satellite navigation: - a speed of the possibly valid GNSS receiving device, - an orientation of the possibly valid GNSS receiving device, - an orientation of a GNSS receiving device or a group of GNSS receiving devices.

[0040] The estimated size is preferably compared with one of the following prior information: - a position and / or an orientation of a currently used track, - an elevation profile of the track being used, - a position and / or orientation of a GNSS receiving device during previous measurements.

[0041] If only one potentially valid GNSS receiving device is available, the distance to one of the other GNSS receiving devices currently classified as unreliable cannot be reliably determined. If the reliability of this one GNSS receiving device is to be tested, data based on satellite signals received by this GNSS receiving device can be compared with reference data, preferably based on map data. Although their accuracy may be lower than the accuracy of the known distance between the GNSS receiving devices, such a substitute comparison may still be reliable enough to detect interference effects that impair the reception of a satellite signal.

[0042] In the event that only one potentially valid GNSS receiver is available, one of the following comparison values ​​is preferably used to verify the satellite data: - Position data based on DRL, - a position of a mobile radio cell in which the potentially valid GNSS receiving device is currently located, - a reference time, - an estimated orientation based on the Earth's magnetic field or on earth movement data.

[0043] “DRL” is an abbreviation for “Dynamic Radar Localization” and is described in WO 2022 / 228 738 A1.

[0044] Advantageously, these data can be used as alternative comparison data to determine whether a satellite signal received by a GNSS receiving device is reliable when all other GNSS receiving devices have been classified as currently unreliable. The reference time can be recorded as internet time or from a synchronized, long-term stable clock, particularly an atomic clock, and can be used in particular to predict ephemerides when incorporating angles from which satellite signals are detected.

[0045] Preferably, the at least two GNSS receiving devices are designed and aligned to cover every possible orientation. Satellite signals can advantageously be acquired from all directions and checked for validity. The GNSS receiving devices are preferably aligned to cover two independent advantageous areas. When using the GNSS receiving devices on a rail vehicle, these areas can cover the area to the left and right of the rail vehicle.

[0046] In a variant of the method according to the invention for validating self-localization with satellite navigation, the reliability of the self-localization of the at least two GNSS receiving devices is determined by determining a plurality of ego position measurements of a measurement sequence over time and applying a clustering algorithm, in particular a "prediction by partial matching" or a RANSAC algorithm, to the estimated values ​​of the ego position measurements.

[0047] The invention is explained in more detail below with reference to exemplary embodiments in the accompanying figures. They show: Fig. 1 is a flowchart illustrating a method for validating self-localization with satellite navigation according to an embodiment of the invention, Fig. 2 is a schematic diagram illustrating an arrangement for validated self-localization with a validation device according to an embodiment of the invention, Fig. 3 is a flowchart illustrating a method for validating self-localization with satellite navigation according to an alternative embodiment of the invention, Fig. 4 a schematic representation of a rail vehicle according to an embodiment of the invention.

[0048] In Fig. 1 shows a flowchart 100 illustrating a method for validating self-localization using satellite navigation.

[0049] In step 1.I, a self-localization of two GNSS receiving devices A1, A2 positioned at a known distance from each other is performed. A first ego position P1 of a first GNSS receiving device A1 is determined based on a satellite navigation signal received by the first GNSS receiving device A1, and a second ego position P2 of a second GNSS receiving device A2 is determined based on a satellite navigation signal received by the second GNSS receiving device A2. The constellation of the two GNSS receiving devices A1, A2 is known in advance, so that, in particular, a distance d v between the GNSS receiving devices A1, A2 is previously known.

[0050] In step 1.II, an estimated distance d sbetween the first GNSS receiving device A1 and the second GNSS receiving device A2 on the basis of the determined first ego position P1 and the determined second ego position P2.

[0051] In step 1.III, the estimated distance d s then with the previously known distance d v compared, whereby a comparison result EC is achieved.

[0052] Subsequently, in step 1.IV, based on the comparison result EG, it is determined whether the self-localization of the GNSS receiving devices A1, A2 is sufficiently precise and reliable. If the result EG indicates that the self-localization is sufficiently precise, i.e., a deviation does not exceed the threshold value SW, which is Fig. 1 is marked with “n”, the system proceeds to step 1.V. In the event that it has been determined that the self-localization is not sufficiently precise, which is Fig. 1 is marked with “y”, the process returns to step 1.I and the determined position data P1, P2 are discarded.

[0053] In step 1.V, the determined position data P1, P2 are released if it was determined in step 1.IV that the self-localization is sufficiently precise.

[0054] In Fig. 2 illustrates an arrangement 2 for validated self-localization with a validation device 20 according to an embodiment of the invention.

[0055] The arrangement 2 comprises two mutually at a previously known distance d vpositioned GNSS receiving devices A1, A2, a first GNSS receiving device A1 and a second GNSS receiving device A2. The first GNSS receiving device A1 is configured to determine a first ego position P1 of the first GNSS receiving device A1 based on a satellite navigation signal S1, and the second GNSS receiving device A2 is configured to determine a second ego position P2 of the second GNSS receiving device A2 based on a satellite navigation signal S2.

[0056] The validation device 20 according to an embodiment of the invention comprises an input interface 21 which is configured to receive the position data P1, P2 generated by the GNSS receiving devices A1, A2.

[0057] Part of the validation device 20 according to the invention is a distance determination unit 22 for determining an estimated distance d sbetween the first GNSS receiving device A1 and the second GNSS receiving device A2 based on the first ego position P1 and the second ego position P2.

[0058] The validation device 20 according to the invention also has a comparison unit 23 for comparing the estimated distance d s with the previously known distance d v on.

[0059] Furthermore, the validation device 20 according to the invention comprises a validation unit 24. The validation unit 24 is designed to compare the comparison result EG with a threshold value SW (see Fig. 1) to determine, based on the comparison result EG, whether the self-localization of the GNSS receiving devices A1, A2 is sufficiently precise and reliable. The validation unit 24 outputs a validation result VE, which is used as a criterion in the evaluation of the measured ego positions to determine whether these data should be discarded or may be reused.

[0060] In Fig. 3 shows a flowchart 300 illustrating a method for validating self-localization with satellite navigation according to an alternative embodiment of the invention.

[0061] In step 3.I, a self-localization of a plurality of N (N is an integer greater than 2) GNSS receiver groups AG1, AG2, AG NA first ego position P1 of a first GNSS receiver group AG1 and an angle W 1s , from which a satellite signal from a satellite is received by the first GNSS receiving device group AG1, is determined based on the satellite navigation signal. Furthermore, a second ego position P2 of a second GNSS receiving device group AG2 and a second angle W are determined. 2s , from which a satellite signal from a satellite is received by the second GNSS receiving device group AG2, is determined based on the satellite navigation signal. Analogously, an Nth ego position P N an Nth GNSS receiving facility group AG N and an angle W Ns , from which a satellite signal from a satellite of the Nth GNSS receiving facility group AG N is received, based on the satellite navigation signal.

[0062] In step 3.II, an estimated distance d s12 , d s13 , ..., d sN-1N between the receiving facility groups AG1, AG2, ..., AG N based on the ego positions P1, P2, ..., P determined in step 3.I N determined.

[0063] In step 3.III, in addition to a comparison of the estimated distances d s12 , d s13 , ..., d sN-1N with the previously known distances dv 12 , dv 13 , ..., dv N-1N the reception facility groups AG1, AG2, AG N also a comparison of the measured angles W 1s , W 2s , ..., W NS the satellites to the receiving device groups AG1, AG2, ..., AG N with pre-calculated or predicted angle values ​​W 1v , W 2v , ..., W Nv These pre-calculated angle values ​​W 1v , W 2v , ..., W Nvare determined based on satellite ephemeris. This allows for the identification of erroneous satellite signals.

[0064] In step 3.IV, the individual results EG1, EG2, ..., EG m+N (m = 0.5 N * (N-1)) of the comparison performed in step 3.III with suitable threshold values ​​SW1, SW2, ..., SW m+N compared. In case results EG1, EG2, ..., EG m+N , i.e. deviations greater than assigned threshold values ​​SW1, SW2, ..., SW m+N are what in Fig. 3 is marked with “y”, the assigned determined ego positions P1, P2, ..., P N of the relevant reception facility groups AG1, AG2, ..., AG N discarded and, if necessary, a return to step 3.I is made and a new validation is carried out after a predetermined time interval.

[0065] In case that in step 3.IV results EG1, EG2, ..., EG m+N, i.e. deviations less than or equal to assigned threshold values ​​SW1, SW2, ..., SW m+N are what in Fig. 3 is marked with “n”, the process continues to step 3.V and the assigned determined ego positions P1, P2, ..., P N of the relevant reception facility groups AG1, AG2, ..., AG N as validated position data P1, P2, ..., P N released. In addition to a verification of the satellite-based determined distance between individual receiving device groups AG1, AG2, ..., AG N is therefore carried out in the Fig. 3, a check of measured angles of satellites relative to the individual receiving device groups AG1, AG2, ..., AG N . Only position data P1, P2, ..., P N to reception facility groups AG1, AG2, ..., AG N , which also include the angles W 1s , W 2s , ..., W Nsof the satellites relative to the receiving device groups AG1, AG2, ..., AG N were correctly determined will be released.

[0066] In Fig. Figure 4 shows a schematic representation of a rail vehicle 40 according to an exemplary embodiment of the invention. The rail vehicle 40 comprises a plurality of GNSS receiving devices A1, A2, which receive satellite navigation signals S1, S2 and transmit them to a validation device 20, which is also part of the rail vehicle 40. A validation result VE generated by the validation device 20 is transmitted to a control device 41 included in the rail vehicle 40. The control device 41 is configured to generate control commands based on ego position data from the GNSS receiving devices A1, A2 for controlling the rail vehicle 40.

[0067] Finally, it is pointed out once again that the methods and devices described above are merely preferred embodiments of the invention and that the invention can be varied by a person skilled in the art without departing from the scope of the invention, insofar as it is defined by the claims. For the sake of completeness, it is also pointed out that the use of the indefinite articles “a” or “an” does not exclude the possibility that the features in question may be present in multiple units. Likewise, the term “unit” does not exclude the possibility that it consists of several components, which may also be spatially distributed. Regardless of the grammatical gender of a particular term, this includes persons with male, female or other gender identities. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] WO 2022 / 228 738 A1

[0043] Cited non-patent literature

[0000] PC Mahalanobis: On the generalized distance in statistics. In: Proceedings of the National Institute of Science of India. Volume 2, No. 1, 1936, pp. 49-55

[0019] Martin A. Fischler and Robert C. Bolles: Random Sample Consensus: A Paradigm for Model Fitting with Applications to Image Analysis and Automated Cartography. March 1980. Prediction by Partial Matching (in German: Prognose durch partiales Matching

[0033] Dynamic Radar Localization” (in German: “dynamic radar localization

[0043]

Claims

[1] Method for validating self-localisation using satellite navigation, comprising the steps: - Performing a self-localization of at least two of each other at a previously known distance (d v ) positioned GNSS receiving devices (A1, A2), wherein a first ego position (P1) of a first GNSS receiving device (A1) is determined on the basis of a satellite navigation signal (S1) received by the first GNSS receiving device (A1), and a second ego position (P2) of a second GNSS receiving device (A2) is determined on the basis of a satellite navigation signal (S2) received by the second GNSS receiving device (A2), - Determine an estimated distance (d s ) between the first GNSS receiving device (A1) and the second GNSS receiving device (A2) on the basis of the first ego position (P1) and the second ego position (P2), - Compare the estimated distance (d s ) with the previously known distance (d v ) as a comparison value, - Carrying out a validation of the GNSS receiving devices (A1, A2), whereby it is determined on the basis of a result (EG) of the comparison whether the self-localisation of the GNSS receiving devices (A1, A2) is sufficiently precise and reliable. [2] The method according to claim 1, wherein - the validation step in case the result (EG) shows a deviation between the previously known distance (d v ) and the estimated distance (d s ) which exceeds a predetermined maximum deviation, comprising the steps of: - the determined ego positions (P1, P2) are discarded, - a message is issued that the GNSS reception equipment (A1, A2) is not reliable, - after a predetermined time interval, the measurements are repeated by the GNSS receiving devices (A1, A2) in order to determine whether the GNSS receiving devices (A1, A2) may be valid at a later time. [3] Method according to one of the preceding claims, wherein - in the self-localization step, more than two GNSS receivers (A1, A2, ..., A N ) and - in the step of determining distances, several distances (ds 12 , ds 13 , ..., ds N-1N ) between the GNSS receiving devices (A1, A2, ..., A N ) and - in the step of validation based on previously known distances (dv 12 , dv 13 , ..., dv N-1N ) of the GNSS receiving devices (A1, A2, ..., A N ) and the distances determined during self-localization (ds 12 , ds 13 , ..., ds N-1N) individual GNSS receiving devices whose GNSS signal is disturbed are identified using a process of elimination. [4] Method according to claim 3, wherein in the validation step, individual GNSS receiving devices (A1, A2) are determined to be unreliable on the basis of the result (EG) by means of an exclusion process and only their determined ego positions (P1, P2) are discarded. [5] Method according to one of the preceding claims, wherein several groups (AG1, AG2, ..., AG N ) of GNSS receivers with directional properties for self-localization and an angle (W 1s , W 2s , ..., W Ns ) of satellites from which a satellite navigation signal is received, relative to a respective group of GNSS receiving devices (AG1, AG2, ..., AG N ) and with an angle (W 1v , W 2v , ..., W Nv) of satellites from which a satellite navigation signal is received, relative to the respective group (AG1, AG2, ..., AG N ) of GNSS receiving devices (AG1, AG2, ..., AG N ), which was determined on the basis of a predicted position of the satellites, which was calculated on the basis of ephemerides. [6] Method according to one of the preceding claims, wherein the previously known distance (d v ) between the GNSS receiving devices (A1, A2) is constant. [7] Method according to one of the preceding claims, wherein the at least two GNSS receiving devices (A1, A2) are arranged on a vehicle. [8] Method according to one of the preceding claims, wherein the at least two GNSS receiving devices (A1, A2) are arranged on a rail vehicle and, in the event that only one possibly valid GNSS receiving device (A1) is available, for validating the one GNSS receiving device (A1) - one of the following estimated values ​​is used as a comparison value: - an ego position (P1) of the GNSS receiving device, - a speed of a GNSS receiving device (A1, A2), - an orientation of a GNSS receiving device (A1, A2) or a group (AG1, AG2) of GNSS receiving devices, - and the estimated size is compared with one of the following prior information: - a position and / or an orientation of a currently used track, - an elevation profile of the track being used, - a position and / or an orientation of a GNSS receiving device (A1) and / or a group (AG1, AG2) of GNSS receiving devices during previous measurements. [9] Method according to one of the preceding claims, wherein, in the event that only one potentially valid GNSS receiving device (A1) is available, one of the following variables is used as a comparison variable: - a position determined by Dynamic Radar Localization, - a position of a mobile radio cell in which the potentially valid GNSS receiving device (A1) is currently located, - a reference time, - an estimated orientation based on the Earth's magnetic field or on the Earth's movement. [10] Method according to one of the preceding claims, wherein the at least two GNSS receiving devices (A1, A2) are designed and aligned such that every possible alignment is covered. [11] Method according to one of the preceding claims, wherein the validation of the self-localization of the at least two GNSS receiving devices (A1, A2) is carried out on the basis of a determination of a plurality of ego position measurements in a measurement sequence over time and an application of a clustering algorithm or a RANSAC algorithm to the estimated values ​​of the ego position measurements. [12] Validation device (20), comprising: - a receiving interface (21) for receiving position data (P1, P2) from at least two objects located at a previously known distance (d v) positioned GNSS receiving devices (A1, A2) for performing a self-localization, comprising a first ego position (P1) of a first GNSS receiving device (A1) of the at least two GNSS receiving devices (A1, A2), which was determined on the basis of a satellite navigation signal (S1), and a second ego position (P2) of a second GNSS receiving device (A2) of the at least two GNSS receiving devices (A1, A2), which was determined on the basis of a satellite navigation signal (S2), - a distance determination unit (22) for determining an estimated distance (d s ) between the first GNSS receiving device (A1) and the second GNSS receiving device (A2) on the basis of the first ego position (P1) and the second ego position (P2), - a comparison unit (23) for comparing the estimated distance (d s ) with the previously known distance (d v ), - a validation unit (24) for determining, on the basis of a result (EG) of the comparison, whether the self-localization of the GNSS receiving devices (A1, A2) is sufficiently precise and reliable. [13] Vehicle (40), preferably rail vehicle, comprising: - a validation device (20) according to claim 12 for validating position data (P1, P2) of the vehicle (40), - a control device (41) for assisted or automated control of a journey of the vehicle (40) on the basis of the generated position data (P1, P2) of the vehicle (40). [14] Computer program product comprising a computer program which can be loaded directly into a memory unit of a computer system, with program sections for carrying out a method according to one of claims 1 to 11 when the computer program is executed in the computer system. [15] Computer-readable medium on which program sections executable by a computer unit are stored in order to carry out a method according to one of claims 1 to 11 when the program sections are executed by the computer unit.

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