Method for operating a GNSS-based navigation module during a start phase

Abstract

A method for operating a GNSS-based navigation module (1) in a vehicle (2) during a start phase of the vehicle (2), the method comprising the steps of: a) querying initial GNSS navigation data (3) from an external data source (4) providing data at a data rate greater than a data supply rate of a regular data source of the GNSS system for the GNSS navigation data (3) and receiving the initial GNSS navigation data (3) from the external data source (4); b) querying initial GNSS correction data (5) from an external data source (6) providing data at a data rate greater than a data supply rate of a regular data source of the GNSS system for the GNSS correction data (5) and receiving the initial GNSS correction data (5) from the external data source (6); and c) determining at least one initial output parameter based on the initial GNSS navigation data (3) and the initial GNSS correction data (5).

Description

Technical Field

[0001] The present invention relates to a method for operating a GNSS-based navigation module during a start-up phase and a navigation module configured to execute the method. The present invention can be particularly applied to autonomous driving.

Background Art

[0002] Background Art In order to improve the performance of GNSS-based systems for positioning, often an external data source or other regular data source that sends information for positioning via a data channel different from the satellites of the GNSS system is used. This is particularly relevant because such data sources can usually only continuously transmit the data required for positioning at a very low bit rate, and transmission in the form of data packets with a lot of information is not possible within one or very short time intervals.

[0003] Such an approach is used in particular for a quick start of GNSS-based systems after an operation interruption and is also referred to as A-GPS (A = assisted). The navigation information required at the start of the system is usually received via GNSS satellites only at a very slow data rate.

[0004] The data or navigation information required by the navigation module for positioning can be divided into GNSS navigation data and GNSS correction data. In this case, the GNSS navigation data is the data directly received from the satellites to perform signal propagation time measurement and then enable position estimation based on this. In this case, this is in particular the coded phase information transmitted from the satellites in terms of time. The GNSS correction data is here, for example, data to enable the errors in positioning to be corrected by the propagation time measurement since the signal propagation times can be affected by different conditions respectively. Examples of such obstacles are, for example, ionospheric disturbances or tropospheric disturbances, deviations in the satellite orbits, etc. The corresponding GNSS correction data is also referred to as, for example, ionospheric data, tropospheric data or orbit data.

[0005] The use of GNSS correction data is common and essential for high-precision GNSS-based positioning.

[0006] GNSS correction data can be calculated in various forms. A frequently used method for calculating GNSS correction data is the calculation of the error from the reference measurement, from which appropriate GNSS correction data for correcting the observed error can be determined. Another frequently used method for calculating GNSS correction data is the calculation using a model. This can be, for example, an ionospheric model, a tropospheric model or a satellite orbit model.

[0007] GNSS correction data can basically be provided in various formats. The prominent ones are the OSR format (OSR = Observation State Representation) and the SSR format (SSR = State Space Representation). In the OSR format, correction data for each individual satellite is transmitted. In the SSR format, correction data for each individual physical effect on the signal transmission from the satellite to the receiver is transmitted. In particular, in the OSR format, the total amount of GNSS correction data required for accurate positioning becomes quite large. In the normal operation of the GNSS system, a relatively long period is required to transmit such a total amount of data. The data in the SSR format is not user-specific. A two-way communication for transmitting user-specific information from the user to the data provider so as to enable the use of user-specific data is unnecessary in the case of data in the SSR format. The unidirectional communication channel that normally provides SSR data is, for example, a communication channel based on the L-band communication signal that can be used by the GNSS satellite for data transmission to the GNSS receiver. The bandwidth available for data provision via the L-band is narrow. Summary of the Invention Problems to be Solved by the Invention

[0008] Disclosure of the Invention Starting from these points, a particularly advantageous method for operating a GNSS-based navigation module capable of rapid and accurate positioning in the start phase will be described. Means for Solving the Problems

[0009] Here, a method for operating a GNSS-based navigation module in a vehicle during the start phase of the vehicle, a) Querying an external data source that supplies data at a data rate greater than the data supply rate of the normal data source of the GNSS system for GNSS navigation data for initial GNSS navigation data, and receiving the initial GNSS navigation data from the external data source; b) Querying an external data source that supplies data at a data rate greater than the data supply rate of the normal data source of the GNSS system for GNSS correction data for initial GNSS correction data, and receiving the initial GNSS correction data from the external data source; c) Determining at least one initial output parameter based on the initial GNSS navigation data and the initial GNSS correction data; A method including the above is described.

[0010] In this regard, GNSS means a global navigation satellite system, such as GPS (Global Positioning System) or Galileo. The order presented for steps a), b), and c) is illustrative, and thus can be set as the normal operation flow of the method, or can be operated at least once in the presented order. Further, steps a), b), and c), particularly steps a) and b), can also be executed at least partially in parallel or simultaneously. In particular, steps a), b), and c) can be executed using the navigation module described in this specification. The vehicle is preferably an automobile, such as a passenger car, and is particularly preferably configured for autonomous (driving) operation or self-driving operation.

[0011] The start phase, in particular here, means the phase immediately after starting or restarting the vehicle when the vehicle has been pre-stopped for a predetermined time interval. Depending on the length of the time interval (for example, whether it was more than 30 minutes or more than several hours, or whether it was over several days), the data for position determination (GNSS correction data or GNSS navigation data) received during the last start of the vehicle is no longer suitable for high-precision position determination. In particular, GNSS correction data must be updated extremely regularly in order to be usable for accurate position determination.

[0012] The vehicle described in this specification is in particular a passenger car. However, it can also be any other vehicle, such as a truck, ship or aircraft.

[0013] At least one output parameter determined in step c) is in particular a position. In this case, the position as the output parameter can preferably also be directly used in step b) to initiate a query according to GNSS correction data dependent on the position. Also, the output parameter can be any other possible position parameter, such as a position change or a moving speed, etc. Preferably, at least one position is determined as the output parameter in step c), and in some cases further output parameters are also determined.

[0014] According to the method described in this specification, at the time of starting the GNSS-based navigation module, a rapid start of high-precision position determination becomes possible. This is achieved because in the start phase both GNSS navigation data and GNSS correction data are supplied to the GNSS from an external data source, where these data are received by the navigation module at a significantly higher data rate and thus in a significantly shorter time than is possible in the normal operation of the GNSS-based navigation module. Therefore, high-precision position determination can be performed extremely quickly.

[0015] Particularly preferably, in step b), at least one first query for initial GNSS correction data that is independent of the position of the vehicle is made.

[0016] Furthermore, before step b), a first initial position is determined using the initial navigation data received in step a), and in step b), second queries for initial GNSS correction data that are each different depending on the position of the vehicle are made, where it is advantageous for the queries to include information regarding the first initial position.

[0017] For the query to the GNSS correction data, it is particularly advantageous if the navigation module regards its own position as at least approximately known. This, of course, also applies particularly to GNSS correction data that is position-dependent. If there is no such information regarding the self-position, it is necessary to wait at least somewhat for the position-dependent correction data. For such reasons, it can be meaningful to perform the determination of the first initial position already without the correction data according to the present invention and then use the first initial position as a query parameter for the query of the initial GNSS correction data. Optionally, such a first initial position can also be read from a memory in which the first initial position at the last stop of such a vehicle was stored.

[0018] Then, as soon as the initial correction data is received as a response to the corresponding query, the determination of the second initial position can be performed. In this case, the initial GNSS navigation data and the initial GNSS correction data are already taken into account at this point, whereby a high accuracy is already achieved during the positioning.

[0019] The improvement achieved by the method described herein is, in particular, the ability to already achieve a high position accuracy in the start phase. This is because, during the positioning, it is possible to operate using (temporally) up-to-date GNSS correction data that cannot be used in the start phase without the method described herein.

[0020] Also, it is advantageous if the GNSS correction data queried and received in step b) includes integrity information that defines the integrity of the GNSS correction data. Preferably, the GNSS navigation data received in step a) also includes integrity information that defines the integrity of the GNSS navigation data.

[0021] Such integrity information is used to calculate the integrity of the determined output parameters, in particular the integrity of the determined position, when determining the output parameters (especially in positioning). The integrity of the determined position is, in particular, partial information that is a component of the position determined in step c). The integrity of the determined position can be further processed together with the position by other components in the vehicle. In step c), as part of the initial output parameters, in particular, the integrity of the initial output parameters is also determined. Integrity information is extremely important especially when the determined output parameters are used as parameters for the purposes of autonomous driving and driver assistance systems. This is particularly true when at least one of the initial output parameters is the (initial) position.

[0022] A further facilitation when performing high-precision positioning in the start phase is that steps a) and b) are performed in parallel, only GNSS correction data that is independent of the position is queried and received in step b), and in step c), access is made only to the GNSS correction data that is independent of the position in order to determine the initial position based on the initial GNSS navigation data and the initial GNSS correction data. In order to execute steps a) and b) simultaneously, it is important that these steps do not overlap with each other.

[0023] Another further acceleration when performing high-precision positioning can be achieved when the initial position, initial GNSS navigation data and / or initial GNSS correction data in step c) are at least partially read from memory. According to the method described herein, access to memory here is in any case supplemented by access to an external data source. This is especially true when the information stored in memory is old (whichever it is of the initial position or GNSS navigation data or initial GNSS correction data). In some cases, the determination of the initial position in step c) is made as a result of the weighted migration of data obtained and stored in memory during the last driving of the vehicle, and also in the GNSS correction data and GNSS navigation data received from an external data source in steps a) and b), or at the initial position determined based on these data.

[0024] In particular, with regard to GNSS correction data, there is a problem that they become old over time. For this reason, GNSS correction data collected, recorded and stored in memory during the previous operation phase of the vehicle can no longer be used for normal positioning if the vehicle has been stopped for a long time or placed in a non-activated state after the previous operation phase.

[0025] Also preferably for the method, in step b), the initial GNSS correction data is received as a data packet that enables the initialization of at least one correction algorithm in the navigation module.

[0026] Preferably, such data packets include GNSS correction data, particularly in the SSR format. Such data preferably has a location-independent validity, which may be global in extreme cases. Location-independent validity here also includes cases where the data is location-independent in a locally limited area / region. For example, data packets of GNSS correction data may exist for all of Europe or all of Germany or similar regions. For the query of such data packets of GNSS correction data in step b), preferably, information regarding each region is fixedly stored, or a flag regarding for which region data packets of GNSS correction data are received is passed during the query. That is, a complete set of such GNSS correction data is received from an external data source in step b). Thereafter, the navigation module can be configured using the set of such GNSS correction data. Such SSR correction data arrives only slowly or only in a distributed state over a relatively long period during the normal operation of the navigation module. By directly supplying such correction data as data packets for the start of operation of the navigation module, a very rapid and accurate determination of output parameters (particularly location) can be performed.

[0027] In connection with the described method, it is particularly advantageous if the external data source used in step a) and / or step b) is external to the stationary part of the satellite navigation system's orbit.

[0028] It is particularly preferred if the external data source used in step a) and / or step b) is ground-controlled.

[0029] Also, it is advantageous if the external data source used in step a) and / or step b) is a mobile radio data source.

[0030] Through such an external data source, GNSS correction data and / or GNSS navigation data can be received extremely quickly in the start phase. This is because such a data source becomes available extremely quickly especially after startup.

[0031] As already explained, the method is configured for the start phase of the operation of the navigation module. Preferably, following steps a) to c), a normal operating mode is switched to in which GNSS navigation data and / or GNSS correction data are received from the satellites of the satellite navigation system.

[0032] GNSS navigation data are received in normal operation constantly or preferably completely or exclusively via the satellites of the satellite navigation system. In contrast, GNSS correction data can also be received partly in normal operation from other data sources via the satellites, for example via a correction data service that continuously provides a data stream of correction data.

[0033] Also preferably, during steps a) to c), it is monitored whether GNSS navigation data can be received via the satellites of the satellite navigation system with a quality exceeding a threshold quality, and if they can be received, the GNSS navigation data received via the satellites are used for positioning.

[0034] Even more preferably, during steps a) to c), it is monitored whether GNSS correction data can be received via the satellites of the satellite navigation system with a set quality exceeding a threshold quality, and if they can be received, the GNSS correction data received via the satellites are used for positioning.

[0035] The handling of the method relates in particular to SSR data as GNSS correction data or as initial GNSS correction data received in step b). Preferably, the threshold quality is a set quality selected such that a higher quality than the quality of the initial GNSS correction data (usually) received in step b) is obtained. The GNSS navigation module then switches the correction data used from the initial GNSS correction data to GNSS correction data received via the satellite. In yet other alternative embodiments of the described method, the GNSS navigation data and / or GNSS correction data received from an external data source in steps a) and b) are compared with the data later received from a regular data source (in particular a satellite) in (the normal operating mode). Thereby, preferably, a verification of the data quality, in particular of the data transmission quality of the GNSS navigation data and / or GNSS correction data, is performed.

[0036] According to a further aspect, it is also possible to provide a computer program for carrying out the method described herein. This relates, in other words, in particular to a computer program (product) comprising instructions for causing a computer to carry out the method described herein when the program is executed. Furthermore, it is also possible to provide a machine-readable storage medium storing the computer program. Generally, the machine-readable storage medium is a computer-readable data carrier.

[0037] This specification also describes a navigation module configured to execute the described method. The navigation module is particularly a navigation module for a vehicle, and can be particularly arranged inside or in contact with the vehicle, and / or can be connected to an electronic control device of the vehicle. For example, the above-described storage medium is a component of the navigation module or can be connected to the navigation module. Preferably, the navigation module is a GNSS sensor. More preferably, the navigation module is provided and configured for autonomous driving of the vehicle. Further, the navigation module may be a combination device of a motion sensor and a position sensor. Such a combination device is particularly advantageous for an autonomous vehicle. The navigation module or the calculation unit (processor) of the navigation module can access the computer program described in this specification, for example, to execute the method described in this specification.

[0038] The details, features, and advantageous configurations mentioned in relation to the method are correspondingly also obtained in the computer program and / or storage medium and / or navigation module presented in this specification, and vice versa. In this regard, the corresponding embodiments for characterizing the features in more detail are fully incorporated by reference.

[0039] The method, navigation module, and technical environment will be described in detail below with reference to the drawings. The drawings show specific examples, but the present disclosure is not limited to these examples.

Brief Description of the Drawings

[0040]

Figure 1

Embodiments for Carrying Out the Invention

[0041] In FIG. 1, a vehicle 2 (e.g., a passenger car) equipped with a navigation module 1 configured to calculate the position of the vehicle 2 based on signals from GNSS satellites 7 of a satellite navigation system 8 can be seen. In the start phase, the positioning module 1 receives initial GNSS navigation data 3 from a first external data source 4 and initial GNSS correction data 5 from a second external data source 6, and does not receive them from the satellites 7 of the satellite navigation system 8. This is done according to steps a) and b) of the method. Then, in step c), positioning is performed based on these data. After the end of the start phase (in normal operation), the initial GNSS navigation data 3 and the initial GNSS correction data 5 are replaced by regularly received (preferably received via satellites) GNSS navigation data 3 and GNSS correction data 5.

Claims

1. A method for operating a GNSS-based navigation module (1) in a vehicle (2) during a start phase of the vehicle (2), comprising: a) querying an external data source (4) that supplies data at a data rate greater than the data supply rate of the normal data source of the GNSS system for normal GNSS navigation data, which is data received directly from a satellite (7) and enables position estimation based on signal propagation time measurement, and receiving the initial GNSS navigation data (3) from the external data source (4); b) querying an external data source (6) that supplies data at a data rate greater than the data supply rate of the normal data source of the GNSS system for normal GNSS correction data, which is data received directly from a satellite (7) and enables error in positioning to be corrected by signal propagation time measurement, and receiving the initial GNSS correction data (5) from the external data source (6); c) determining at least one initial output parameter based on the initial GNSS navigation data (3) and the initial GNSS correction data (5); including subsequent to steps a) to c), switching to a normal operating mode in which normal GNSS navigation data and / or normal GNSS correction data are received from a satellite (7) of a satellite navigation system (8), during steps a) to c), monitoring whether normal GNSS navigation data and / or normal GNSS correction data can be received via a satellite (7) of a satellite navigation system (8) with a quality exceeding a threshold quality, and if so, using the normal GNSS navigation data and / or the normal GNSS correction data received via the satellite (7) for positioning.

2. The method according to claim 1, wherein in step b), at least one first query is made for initial GNSS correction data (5) that is independent of the position of the vehicle (2).

3. Before the step b), a first provisional position is determined using the initial GNSS navigation data (3) received in the step a), and in the step b), a second query is made for initial GNSS correction data (5) that are different depending on the position of the vehicle (2), the query including information at a first initial position, the method according to claim 2.

4. The initial GNSS correction data (5) queried and received in the step b) includes integrity information defining the integrity of the GNSS correction data, the method according to claim 1.

5. In the step b), the initial GNSS correction data (5) is received as a data packet, the method according to claim 1.

6. The external data sources (4, 6) used in the step a) and / or the step b) are external to a stationary part of the satellite navigation system (8) in orbit, the method according to claim 1.

7. The external data sources (4, 6) used in the step a) and / or the step b) are ground-controlled, the method according to claim 6.

8. The external data sources (4, 6) used in the step a) and / or the step b) are mobile radio data sources, the method according to claim 6.

9. A navigation module (1) configured to implement the method according to claim 1.

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