Method for Selecting a Satellite Combination for a Position Determination

Abstract

A method for selecting a combination of GNSS satellites to carry out a position determination from a plurality of visible GNSS satellites in a GNSS receiver taking account of the variance of the satellite signals of the respective GNSS satellites includes: a) sorting the visible GNSS satellites using at least two different sorting algorithms according to predefined criteria catalogues which take account of the variance of the satellite signals, and determining at least two satellite presortings which determine GNSS satellites of which the satellite signals have a low variance according to the relevant predefined criteria catalogue; b) selecting a weighting function for weighting the satellite presortings ; c) creating a final satellite sorting by a weighting of the satellite presortings according to the relevant weighting function, so that a weighted final satellite sorting is produced; and d) carrying out a satellite combination selection on the basis of the final satellite sorting.

Claims

1. A method of selecting a combination of global satellite navigation systems (GNSS) satellites to carry out a position determination from a plurality of visible GNSS satellites in a GNSS receiver taking into account variance of the satellite signals of the respective GNSS satellites, comprising: sorting the visible GNSS satellites using at least two different sorting algorithms according to predefined sets of criteria which take into account the variance of the satellite signals and determining at least two satellite presortings with which GNSS satellites are determined, the satellite signals of which have a low variance according to the respective predefined set of criteria; selecting for each of the satellite presortings a respective weighting function for weighting the associated satellite presortings; creating a final satellite sorting by weighting the satellite presortings according to the respective weighting function to obtain a weighted final satellite sorting ; and carrying out a satellite combination selection on the basis of the final satellite sorting.

2. The method according to claim 1, wherein sorting the visible GNSS satellites comprises: at least one sorting according to an angle-based sorting algorithm, in which a weighting is carried out using angular parameters of the respective GNSS satellites .

3. The method according to claim 1, wherein sorting the visible GNSS satellites comprises: at least one sorting according to a geometry-based sorting algorithm, in which a weighting is carried out using geometric parameters of a respective orbit of the respective GNSS satellites.

4. The method according to claim 1, wherein selecting for each of the satellite presortings a respective weighting function comprises: selecting a first weighting function when a complicated environment, in which view vectors from the GNSS receiver to GNSS satellites can be interrupted, is present.

5. The method according to claim 4, wherein the first weighting function takes into account a satellite presorting determined according to a geometry-based sorting algorithm with a reduced weighting factor.

6. The method according to claim 1, wherein selecting for each of the satellite presortings a respective weighting function comprises: selecting a second weighting function when open sky conditions are present, and view vectors from the GNSS receiver to GNSS satellites are free.

7. The method according to claim 6, wherein the second weighting function takes into account a satellite presorting determined according to an angle-based sorting algorithm with a reduced weighting factor.

8. A global satellite navigation systems (GNSS) receiver configured to carry out the method according to claim 1.

9. A computer program product configured to carry out the method according to claim 1.

10. An electronic storage medium on which a computer program product according to claim 9 is stored.

Description

[0046] The figures discussed in the following explain the described method further, whereby the disclosure is not limited to the illustration in the figures; the figures rather merely show a preferred design example. The figures show:

[0047] FIG. 1: a GNSS receiver; and

[0048] FIG. 2: a diagram of an implementation of the described method;

[0049] FIG. 1 shows a GNSS receiver 8, which can carry out position determinations with the help of GNSS satellites 6. Satellite signals 5 from the GNSS satellites 6 are received by a navigation filter module 1. The navigation filter module 1 transmits the GNSS signals to the signal tracker module 2, which is configured to carry out the here-described method and selects or combines GNSS satellites 6 for position determination. To do this, the signal tracker module also accesses data provided by the SV data module 4. This includes correction data to take into account the ionosphere or the troposphere, for example.

[0050] The determined combination of GNSS satellites 6 for position determination is passed to the position determination module 3. The position determination module 3 then determines the respective position based on this combination of GNSS satellites 6 and carries out a provision of position data 7 to further control devices 9. Such control devices 9 can be part of further systems in a motor vehicle, for example.

[0051] FIG. 2 shows a detailed diagram for carrying out the described method. The modules and algorithms shown in FIG. 2 are preferably implemented in the signal tracker module 2.

[0052] First, the satellite signals 5 are determined and processed using various sorting algorithms 11,12, 13. This corresponds to step a). In an angle-based sorting algorithm 11, weighting and sorting is carried out using angle parameters of the respective GNSS satellites 6. In a geometry-based sorting algorithm, weighting and sorting is carried out using parameters of the orbit of the respective GNSS satellite 6. In a measurement error-based sorting algorithm, weighting and sorting is carried out using stored and estimated variance data.

[0053] Each sorting algorithm preferably comprises a set of criteria 15, which is sorted according to a ranking order 14 and which is processed in sequence to determine the satellite presorting 10. Cost parameters 16, which indicate the manner in which the respective criterion of the set of criteria affects the satellite presorting 10, are preferably stored for each criterion in the set of criteria 15.

[0054] Thus, three different satellite presortings 10 are created, each of which is then weighted according to a weighting function 17, 18 to determine a final satellite sorting 20. This corresponds to step c) of the described method. The position of the individual GNSS satellite in the final satellite sorting 20 can shift compared to the satellite presorting 10. There is preferably a first weighting function 17, which is selected when a complicated environment, in which view vectors from the GNSS receiver to GNSS satellites can in principle be interrupted, is present. There is preferably a second weighting function 18, which is selected when a free field of view is present and view vectors from the GNSS receiver to GNSS satellites should in principle be free. The appropriate weighting function 17, 18 is selected with the help of a selection module 22, which in particular also takes into account the (suspected) current position in order to select the correct weighting function 17, 18. This corresponds to step b) of the described method.

[0055] A satellite combination selection 21 is then carried out on the basis of the final satellite sorting 20. This corresponds to step d) of the described method.