Positioning by computing pseudo-speeds in a satellite navigation system

• US 6,181,275 B1
• Filed: 05/27/1999
• Issued: 01/30/2001
• Est. Priority Date: 05/28/1998
• Status: Expired due to Term

• Current Assignee: WSOU Investments, LLC (WSOU Holdings, LLC)
• Original Assignee: Alcatel SA (Nokia Corporation)
• Inventors: Journo, Stephane, Lobert, Bruno, Chenebault, Jean
• Primary Examiner(s): Tarcza, Thomas H.
• Assistant Examiner(s): PHAN, DAO LINDA
• Application Number:
  US09/320,656
• Time in Patent Office: 614 Days
• Field of Search: 342/357.01, 342/357.05, 342/357.16
• US Class Current: 342/357.25
• CPC Class Codes: G01S 19/42 Determining position
• CPC Class Codes: G01S 19/52 Determining velocity
• CPC Class Codes: G01S 5/12 by co-ordinating position lines of different shape, e.g. hyperbolic, circular, elliptical or radial

Abstract

A method of locating a receiver in a navigation system comprising a constellation of satellites transmitting signals, includes the steps of:

measuring pseudo-distances between the receiver and the satellites from the signals received from the satellites,

measuring pseudo-speeds between the receiver and the satellites from signals received from the satellites, and

computing the position of the receiver from the combination of measured pseudo-distances and pseudo-speeds.

The position of the receiver is computed by minimizing the matrix of covariance of the measured pseudo-distances and pseudo-speeds. This provides an accurate position of the receiver in a simple manner, in particular for a constellation of satellites in low Earth orbit.

Claims

1. A receiver for a navigation system comprising a constellation of satellites transmitting signals, the receiver comprising:

means for measuring pseudo-distances between the receiver and the satellites from signals received from the satellites;

means for measuring pseudo-speeds between the receiver and the satellites from signals received from the satellites; and

means for computing an instantaneous position of the receiver from the combination of measured pseudo-distances and pseudo-speeds, wherein the computing of the instantaneous position assumes that a radial speed of the receiver can be neglected, and wherein the constellation of satellites is in low Earth orbit.

2. A receiver according to claim 1, wherein the pseudo-speed measuring means measure the pseudo-speeds from the Doppler shift of the signals received from the satellites.

3. A system according to claim 1, further comprising means for computing the speed of the receiver from the measured pseudo-speeds.

4. A receiver according to claim 1, wherein the computing means compute the position or the speed of the receiver by a least squares method.

6. A receiver according to claim 1, wherein the computing means further comprise means for predicting the position of the receiver, for example using Kalman filters.

5. A receiver for a navigation system that includes a constellation of satellites transmitting signals, comprising:

means for measuring pseudo-distances between the receiver and the satellites from signals received from the satellites;

means for measuring pseudo-speeds between the receiver and the satellites from signals received from the satellites; and

means for computing the instantaneous position of the receiver from the combination of measured pseudo-distances and pseudo-speeds, wherein the means for computing compute the position or the speed of the receiver by minimizing the matrix of covariance of the measured pseudo-distances and pseudo-speeds.

7. A method of locating a receiver in a navigation system comprising a constellation of satellites transmitting signals, comprising the steps of:

measuring pseudo-distances between the receiver and the satellites from received ones of the signals from the satellites,

measuring pseudo-speeds between the receiver and the satellites from the signals received from the satellites, and

computing an instantaneous position of the receiver from a combination of the measured pseudo-distances and the pseudo-speeds, wherein the computing of the instantaneous position assumes that a radial speed of the receiver can be neglected, and wherein the constellation of satellites is in low Earth orbit.

8. A method according to claim 7, wherein the step of measuring the pseudo-speeds comprises measuring the Doppler shift of the signals received from the satellites and computing the pseudo-speeds from the measured shift.

9. A method according to claim 7, wherein the step of computing the position of the receiver also includes a step of computing the speed of the receiver from the measured pseudo-distances and pseudo-speeds.

10. A method according to claim 7, wherein the computation step comprises computing the position or speed of the receiver by a least squares method.

12. A method according to claim 7, wherein the computing step comprises a step of predicting the position of the receiver, for example using Kalman filters.

11. A method of locating a receiver in a navigation system having a constellation of satellites transmitting signals, comprising the steps of:

measuring pseudo-distances between the receiver and the satellites from the signals received from the satellites;

measuring pseudo-speeds between the receiver and the satellites from signals received from the satellites; and

computing the position of the receiver from a combination of measured pseudo-distances and pseudo-speeds, wherein the computing step comprises computing the position or speed of the receiver by minimizing the matrix of covariance of the measured pseudo-distances and pseudo-speeds.