Satellite navigation receiver and method for switching between real-time kinematic mode and precise positioning mode

• US 10,627,528 B2
• Filed: 03/18/2016
• Issued: 04/21/2020
• Est. Priority Date: 06/29/2015
• Status: Active Grant

• Current Assignee: Deere & Company
• Original Assignee: Deere & Company
• Inventors: Lie, F. Adhika Pradipta, Zeitzew, Michael A., Shao, Yunfeng, Dai, Liwen L.
• Primary Examiner(s): Nguyen, Chuong P
• Application Number:
  US15/074,183
• Publication Number:
  US 20170299731A1
• Time in Patent Office: 1,495 Days
• Field of Search: 34235727, 34235731, 34235751, 34235728, 34235724, 34235744
• CPC Class Codes: G01S 19/13 Receivers
• CPC Class Codes: G01S 19/42 Determining position
• 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 19/43 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
• CPC Class Codes: G01S 19/45 by combining measurements of signals from the satellite radio beacon positioning system with a supplementary measurement

Abstract

A system or method uses an offset vector to provide seamless switching between a real- time kinematic (RTK) mode and a precise positioning mode. A correction wireless device is adapted to receive, at the reference receiver, a precise signal encoded with precise correction data. A precise positioning estimator of the reference receiver is arranged to determine a precise position based on the measured carrier phase of the received satellite signals and the received precise correction data in a precise correction mode. At the reference receiver, an offset module can determine a base offset vector between the precise position and a reference RTK position for the reference receiver. At the reference receiver, a wireless communications device is capable of transmitting, via an RTK signal, RTK correction data.

Claims

1. A method for operating one or more satellite navigation receivers, the method comprising:

receiving, by a reference receiver, one or more satellite signals;

measuring, by the reference receiver, a carrier phase of the received satellite signals;

receiving, at the reference receiver, a precise signal encoded with precise correction data;

determining, by a precise positioning estimator of the reference receiver, a precise position based on the measured carrier phase of the received satellite signals and the received precise correction data in a precise correction mode;

determining a base offset vector between the precise position and a reference real-time kinematic (RTK) position for the reference receiver;

transmitting, via an RTK signal, RTK correction data, which comprises a representation of the base offset vector, to a mobile receiver;

receiving, by the mobile receiver, one or more satellite signals;

measuring, by the mobile receiver, a carrier phase of the received satellite signals;

receiving, at the mobile receiver, the RTK correction data comprising the base offset vector;

smoothing the base offset vector to yield a reliable smoothed base offset vector after an initialization time period;

determining, by a real-time kinematic (RTK) position estimator of the mobile receiver, a real-time kinematic position based on the measured carrier phase of the received satellite signals and the received RTK correction data in an RTK correction mode;

receiving, at the mobile receiver, a precise signal encoded with precise correction data;

determining, by a precise positioning estimator of the mobile receiver, a precise position based on the measured carrier phase of the received satellite signals and the received precise correction data in a precise correction mode; and

upon loss or interruption of the RTK signal, while reaching an end of the initialization time period with the smoothed base offset vector and while having attained convergence on the precise position in conjunction with ambiguity resolution of the measured carrier phase associated with the precise position at the mobile receiver, switching to a precise position mode, wherein a next precise position estimate is compensated by the smoothed base offset vector to avoid a jump or discontinuity in the next precise position estimate.

2. The method according to claim 1 further comprising:

determining a relative position of the mobile receiver;

upon loss, interruption or corruption of the RTK signal, while not having a smoothed base offset vector that is smoothed over a threshold duration or over the initialization time period, or not reaching an end of the initialization time period of the smoothing filter, and while not converging on the precise position at the mobile receiver, switching to a relative position mode.

3. The method according to claim 2 wherein a next precise position estimate is based on a last available RTK position prior to the loss and a relative position vector between a last available measurement time and a next measurement time.

4. The method according to claim 1 further comprising:

upon loss, interruption or corruption of the RTK signal, while not reaching the end of an initialization time period without the base offset vector determined over a threshold duration or while converging on phase ambiguities underlying the precise position for the base offset vector, switching to the precise position mode, wherein a next precise position estimate is compensated by a stored offset vector in a data storage device of the mobile receiver from a prior convergence of the precise position at the reference receiver or the mobile receiver to avoid a jump or discontinuity in the next precise position estimate.

5. The method according to claim 1 further comprising:

upon loss or interruption of the RTK signal, while reaching of the end of an initialization time period with a smoothed base offset vector and while having attained convergence on the precise position in conjunction with ambiguity resolution of the measured carrier phase associated with the precise position, switching to a precise position mode, wherein a next precise position estimate is compensated by the smoothed base offset vector and wherein the smoothed base offset vector applies to the reference receiver and the mobile receiver of the same manufacturer that does not require an additional receiver bias to avoid a jump or discontinuity in the next precise position estimate.

6. A method for operating one or more satellite navigation receivers, the method comprising:

receiving, by a reference receiver, one or more satellite signals;

measuring, by the reference receiver, a carrier phase of the received satellite signals;

receiving, at the reference receiver, a precise signal encoded with precise correction data;

determining, by a precise positioning estimator of the reference receiver, a precise position based on the measured carrier phase of the received satellite signals and the received precise correction data in a precise correction mode;

determining a base offset vector between the precise position and a reference real-time kinematic (RTK) position for the reference receiver;

transmitting, via an RTK signal, RTK correction data, which comprises a representation of the base offset vector, to a mobile receiver; and

upon loss, interruption, or corruption of the RTK signal, while not reaching the end of an initialization time period or while reaching the end of the initialization time period without the base offset vector determined over a threshold duration and while not converging on resolved phase ambiguities underlying the precise position for the base offset vector, switching to the precise position mode, wherein a next precise position estimate is compensated by a rover offset vector to avoid a jump or discontinuity in the next precise position estimate.

7. The method according to claim 6 further comprising:

receiving, by the mobile receiver, one or more satellite signals;

measuring, by the mobile receiver, a carrier phase of the received satellite signals;

receiving, at the mobile receiver, the RTK correction data comprising the base offset vector;

at the mobile receiver, determining, by a real-time kinematic (RTK) position estimator of the mobile receiver, a real-time kinematic position based on the measured carrier phase of the received satellite signals and the received RTK correction data in an RTK correction mode;

receiving, at the mobile receiver, a precise signal encoded with precise correction data;

determining, by a precise positioning estimator of the mobile receiver, a precise position based on the measured carrier phase of the received satellite signals and the received precise correction data in a precise correction mode;

determining a rover offset vector between the precise position and the RTK position for the same measurement time or epoch.

8. The method according to claim 6 further comprising:

determining a relative position of the mobile receiver;

upon loss, interruption or corruption of the RTK signal, while not having a smoothed base offset vector that is smoothed over a threshold duration or over the initialization time period, or not reaching an end of the initialization time period of the smoothing filter, and while not converging on the precise position at the mobile receiver, switching to a relative position mode.

9. The method according to claim 8 wherein a next precise position estimate is based on a last available RTK position prior to the loss and a relative position vector between a last available measurement time and a next measurement time.

10. A system for operating one or more satellite navigation receivers, comprising:

at a reference receiver, a measurement module for measuring a carrier phase of the received satellite signals;

a correction wireless device for receiving, at the reference receiver, a precise signal encoded with precise correction data;

a precise positioning estimator of the reference receiver for determining a precise position based on the measured carrier phase of the received satellite signals and the received precise correction data in a precise correction mode;

at the reference receiver, an offset module for determining a base offset vector between the precise position and a reference RTK position for the reference receiver;

at the reference receiver, a wireless communications device for transmitting, via an RTK signal, RTK correction data, which comprises a representation of the base offset vector, to a mobile receiver;

at the mobile receiver, an offset module for determining a mobile offset vector between the precise position and the RTK position for the same measurement time or epoch;

upon loss, interruption or corruption, of the RTK signal, while attaining the smoothed base offset vector and while not having converged on resolved phase ambiguities underlying the precise position for the base offset vector, a mode controller adapted to switch to the precise position mode, wherein a next precise position estimate is compensated by the mobile offset vector to avoid a lump or discontinuity in the next precise position estimate.

11. The system according to claim 10 further comprising:

at the mobile receiver, a measurement module for measuring a carrier phase of the received satellite signals;

a wireless communications device for receiving, at the mobile receiver, the RTK correction data comprising the base offset vector;

at the mobile receiver, a smoothing filter for smoothing the received base offset vector to yield a smoothed base offset vector after an initialization period; and

a real-time kinematic (RTK) position estimator of the mobile receiver for determining a real-time kinematic position based on the measured carrier phase of the received satellite signals and the received RTK correction data in an RTK correction mode.

12. The system according to claim 11 further comprising:

the mode controller authorizing the compensation by the smoothed base offset vector if the smoothing filter has reached an end of the initialization time period to yield the smoothed base offset vector, and if the precise position estimator of the mobile receiver has converged upon the precise position in conjunction with ambiguity resolution of the measured carrier phase associated with the precise position.

13. The system according to claim 10 further comprising:

upon loss, interruption or corruption of the RTK signal, while not reaching the end of the initialization time period and while not converging on the precise position for the base offset vector, a mode controller adapted to switch to the precise position mode, wherein a next precise position estimate is compensated by the stored offset vector in a data storage device of the mobile receiver associated with a prior convergence of the precise position at the reference receiver or the mobile receiver to avoid a jump or discontinuity in the next precise position estimate.

14. The system according to claim 10 further comprising:

at the mobile receiver, a measurement module for measuring a carrier phase of the received satellite signals;

a wireless communications device for receiving, at the mobile receiver, the RTK data correction data;

a real-time kinematic (RTK) position estimator of the mobile receiver for determining a real-time kinematic position based on the measured carrier phase of the received satellite signals and the received RTK correction data in an RTK correction mode;

a correction wireless device for receiving, at the mobile receiver, a precise signal encoded with precise correction data;

a precise positioning estimator of the mobile receiver for determining a precise position based on the measured carrier phase of the received satellite signals and the received precise correction data in a precise correction mode;

at the mobile receiver, an offset module for determining a mobile offset vector between the precise position and the RTK position for the same measurement time or epoch; and

upon loss, interruption or corruption of the RTK signal, a mode controller adapted to switch to a precise position mode, wherein a next precise position estimate is compensated by the mobile offset vector to avoid a jump or discontinuity in the next precise position estimate.

15. The system according to claim 10 further comprising:

a relative positioning estimator for determining a relative position of the mobile receiver;

upon loss of the RTK signal and while not converging on the precise position, a mode controller adapted to switch to a relative position mode.

16. The system according to claim 15 wherein a next precise position estimate is based on a last available RTK position prior to the loss and the determined relative position from the time of the loss to the next time.

17. The system according to claim 10 further comprising:

upon loss or interruption of the RTK signal while reaching of the end of the initialization time period without a smoothed base offset vector and while attaining convergence on the precise position in conjunction with ambiguity resolution of the measured carrier phase associated with the precise position, a navigation positioning estimator is adapted to switch to a precise position mode, wherein a next precise position estimate is compensated by the smoothed base offset vector and wherein the smoothed base offset vector applies to the reference receiver and the mobile receiver of the same manufacturer that does not require an additional receiver bias to avoid a jump or discontinuity in the next precise position estimate.