GNSS surveying using RTK engine verification

• US 10,281,588 B2
• Filed: 07/17/2015
• Issued: 05/07/2019
• Est. Priority Date: 07/17/2014
• Status: Active Grant

• Current Assignee: Javad GNSS, Inc.
• Original Assignee: Javad GNSS, Inc.
• Inventors: Ashjaee, Javad
• Primary Examiner(s): Akonai, Olumide Ajibade
• Assistant Examiner(s): Malley, Sr., Daniel P
• Application Number:
  US14/802,895
• Publication Number:
  US 20160018530A1
• Time in Patent Office: 1,390 Days
• CPC Class Codes: G01S 19/396 Determining accuracy or reliability of position or pseudorange measurements
• CPC Class Codes: G01S 19/426 by combining or switching between position solutions or signals derived from different modes of operation in a single system
• CPC Class Codes: G01S 19/428 using multipath or indirect path propagation signals in position determination
• CPC Class Codes: G01S 19/43 using carrier phase measurements, e.g. kinematic positioning; using long or short baseline interferometry
• CPC Class Codes: G01S 19/44 Carrier phase ambiguity resolution; Floating ambiguity; LAMBDA [Least-squares AMBiguity Decorrelation Adjustment] method

Abstract

Systems and methods for performing land surveying using real-time kinematic (RTK) engine verification are provided. In one example, a first set of positions of a GNSS receiver may be determined using each of a plurality of RTK engines. If a number of the plurality of RTK engines that produce a fixed solution is greater than or equal to a threshold value, a position of the GNSS receiver may be determined based on at least a portion of the first set of positions. The determined position may then be stored. This process may be repeated any number of times to produce a desired number of stored positions. In response to the number of stored positions being equal to a minimum value, a final position of the GNSS device may be determined based on the stored positions.

Claims

1. A method for determining a position of a GNSS receiver, the method comprising:

determining whether a plurality of position measurements from a plurality of real-time kinematic (RTK) engines are within a first threshold distance from previously determined positions, from the plurality of RTK engines;

in accordance with a determination that the plurality of position measurements are not within the first threshold distance;

resetting one or more of the plurality of RTK engines;

after resetting one or more of the plurality of RTK engines, determining a plurality of additional position measurements using the plurality of RTK engines;

determining the position of the GNSS receiver based on the plurality of additional position measurements and the previously determined positions; and

in accordance with a determination that the plurality of position measurements are within the first threshold distance;

determining the position of the GNSS receiver based on the plurality of position measurements and the plurality of previously determined positions.

2. The method of claim 1, wherein determining the plurality of position measurements comprises:

(a) receiving position signals from a plurality of GNSS satellites and at least one base station;

(b) determining a set of positions of the GNSS receiver using the plurality of RTK engines based on the received position signals; and

(c) determining whether the set of positions is within the first threshold distance from previously determined positions, wherein in response to determining that the set of positions is within the first threshold distance from the previously determined positions;

storing at least a portion of the set of positions as a position measurement;

determining a plurality of weights associated with the position measurement based on a number of RTK engines among the plurality of RTK engines producing a fixed solution that did not produce a fixed solution in a previous measurement or that produced a fixed solution after being reset;

determining whether a sum of the plurality of weights is greater than a threshold weight, wherein determining the plurality of additional position measurements using the plurality of RTK engines is performed in response to determining that the sum of the plurality of weights is greater than the threshold weight, and wherein in response to determining that the sum of the plurality of weights is not greater than the threshold weight, resetting the plurality of RTK engines and repeating steps (a)-(c).

3. The method of claim 2, wherein determining whether the set of positions is within the first threshold distance from previously determined positions further comprises:

in response to determining that the set of positions is not within the first threshold distance from the previously determined positions;

resetting the sum of the plurality of weights; and

resetting the plurality of RTK engines.

4. The method of claim 3, wherein the at least a portion of the set of positions comprises outputs from the RTK engines of the plurality of RTK engines that produce a fixed solution.

5. The method of claim 1, wherein determining the plurality of additional position measurements comprises:

(d) receiving position signals from a plurality of GNSS satellites and at least one base station;

(e) determining a set of positions of the GNSS receiver using the plurality of RTK engines based on the received position signals; and

(f) determining whether the set of positions is within the threshold distance from previously determined positions, wherein in response to determining that the set of positions is within the threshold distance from the previously determined positions;

storing at least a portion of the set of positions as a position measurement; and

determining a plurality of weights associated with the position measurement based on a number of RTK engines among the plurality of RTK engines producing a fixed solution that did not produce a fixed solution in a previous measurement or that produced a fixed solution after being reset.

6. The method of claim 5, wherein determining whether the set of positions is within the threshold distance from previously determined positions further comprises:

in response to determining that the set of positions is not within the threshold distance from the previously determined positions, resetting the plurality of RTK engines and repeating steps (d)-(f).

7. The method of claim 6, wherein the at least a portion of the set of positions comprises outputs from the RTK engines of the plurality of RTK engines that produce a fixed solution.

8. The method of claim 1, wherein each of the plurality of RTK engines comprises a different set of parameters.

9. A non-transitory computer-readable storage medium encoded with computer executable instructions for:

determining whether a plurality of position measurements from a plurality of real-time kinematic (RTK) engines are within a first threshold distance from previously determined positions, from the plurality of RTK engines;

in accordance with a determination that the plurality of position measurements are not within the first threshold distance;

resetting one or more of the plurality of RTK engines;

after resetting one or more of the plurality of RTK engines, determining a plurality of additional position measurements using the plurality of RTK engines;

determining the position of the GNSS receiver based on the plurality of additional position measurements and the previously determined positions; and

in accordance with a determination that the plurality of position measurements are within the first threshold distance;

determining the position of the GNSS receiver based on the plurality of position measurements and the plurality of previously determined positions.

10. The non-transitory computer-readable storage medium of claim 9, wherein instructions for determining the plurality of position measurements comprises instructions for:

(a) receiving position signals from a plurality of GNSS satellites and at least one base station;

(b) determining a set of positions of the GNSS receiver using the plurality of RTK engines based on the received position signals;

(c) determining a number of fixed RTK engines based on the number of RTK engines that produce a fixed solution; and

(d) determining whether the set of positions is within the first threshold distance from previously determined positions, wherein in response to determining that the set of positions is within the first threshold distance from the previously determined positions;

storing at least a portion of the set of positions as a position measurement;

determining a plurality of weights associated with the position measurement based on a number of RTK engines among the plurality of RTK engines producing a fixed solution that did not produce a fixed solution in a previous measurement or that produced a fixed solution after being reset;

determining whether a sum of the plurality of weights is greater than a threshold weight, wherein determining the plurality of additional position measurements using the plurality of RTK engines is performed in response to determining that the sum of the plurality of weights is greater than the threshold weight, and wherein in response to determining that the sum of the plurality of weights is not greater than the threshold weight, resetting the plurality of RTK engines and repeating steps (a)-(c).

11. The non-transitory computer-readable storage medium of claim 10, wherein instructions for determining whether the set of positions is within the first threshold distance from previously determined positions further comprises instructions for:

in response to determining that the set of positions is not within the first threshold distance from the previously determined positions;

resetting the sum of the plurality of weights; and

resetting the plurality of RTK engines.

12. The non-transitory computer-readable storage medium of claim 11, wherein the at least a portion of the set of positions comprises outputs from the RTK engines of the plurality of RTK engines that produce a fixed solution.

13. The non-transitory computer-readable storage medium of claim 12, wherein the instructions for determining the plurality of additional position measurements comprises instructions for:

(d) receiving position signals from a plurality of GNSS satellites and at least one base station;

(e) determining a set of positions of the GNSS receiver using the plurality of RTK engines based on the received position signals; and

(f) determining whether the set of positions is within the threshold distance from previously determined positions, wherein in response to determining that the set of positions is within the threshold distance from the previously determined positions;

storing at least a portion of the set of positions as a position measurement; and

determining a plurality of weights associated with the position measurement based on a number of RTK engines among the plurality of RTK engines producing a fixed solution that did not produce a fixed solution in a previous measurement or that produced a fixed solution after being reset.

14. The non-transitory computer-readable storage medium of claim 13, wherein instructions for determining whether the set of positions is within the second threshold distance from previously determined positions further comprises instructions for:

in response to determining that the set of positions is not within the threshold distance from the previously determined positions, resetting the plurality of RTK engines and repeating steps (d)-(f).

15. The non-transitory computer-readable storage medium of claim 14, wherein the at least a portion of the set of positions comprises outputs from the RTK engines of the plurality of RTK engines that produce a fixed solution.

16. The non-transitory computer-readable storage medium of claim 9, wherein each of the plurality of RTK engines comprises a different set of parameters.