System and method for improving GPS signal processing in a mobile phone by using MEMS

• US 7,595,750 B2
• Filed: 11/18/2005
• Issued: 09/29/2009
• Est. Priority Date: 12/31/2004
• Status: Active Grant

• Current Assignee: Alcatel-Lucent SA (Nokia Corporation)
• Original Assignee: Alcatel-Lucent SA (Nokia Corporation)
• Inventors: Monnerat, Michel, Lobert, Bruno
• Primary Examiner(s): Tarcza, Thomas H
• Assistant Examiner(s): LIU, HARRY K
• Application Number:
  US11/813,194
• Publication Number:
  US 20080143596A1
• Time in Patent Office: 1,411 Days
• Field of Search: 342/357.06, 342/457
• US Class Current: 342/357.35
• CPC Class Codes: G01S 19/26 involving a sensor measurement for aiding acquisition or tracking
• CPC Class Codes: G01S 19/28 Satellite selection
• CPC Class Codes: G01S 19/29 carrier including Doppler, related G01S19/246 takes precedence
• CPC Class Codes: G01S 19/52 Determining velocity

Abstract

A receiver (R) for use in a user mobile terminal (U) in a satellite positioning system having a constellation of satellites (S) in which the receiver (R) acquires data from a satellite related to the position of the mobile terminal (U). A MEMS device (M) is incorporated in the receiver (R) and is adapted for detecting the absolute value ({circumflex over (V)}_u) of the speed of the mobile terminal (U) and subsequently providing said value to the receiver (U). Means are provided for computing, by or for the receiver (R), the value corresponding to the vector components (V_ux, V_uy, V_uz) of the speed of the mobile terminal which in turn make possible the Doppler effect related to the users speed is obtained.

Claims

1. A receiver (R) for use in a user mobile terminal (U) in a satellite positioning system having a constellation of satellites (S), said receiver (R) adapted for acquiring data from a satellite related to the position of the mobile terminal (U), characterized in that the receiver is provided with means for computing a speed of the mobile terminal based on information obtained from acquiring at least two satellites, wherein the means for computing a speed of the mobile terminal comprise a MEMS device (M), adapted for detecting an absolute value ({circumflex over (V)}_u) of a speed of the mobile terminal (U) and for providing said value to the receiver (R);

and in that the receiver is provided with means for computing, by or for the receiver (R), a corresponding value for vector components (V_ux, V_uy, V_uz) of the speed of the mobile terminal.

2. A receiver according to claim 1 comprising means for deducing a user Doppler information related to other satellites of the constellation based on said speed of user mobile terminal (U) so as to enable acquisition of signals from said other satellites using said Doppler information.

3. A receiver according to claim 1, wherein the information on the vector components (V_ux, V_uy, V_uz) of the speed of the mobile terminal is used in order to obtain a Doppler effect value related to said mobile terminal (U).

4. A receiver according to claim 1, wherein the information on the vector components (V_ux, V_uy, V_uz) of the speed of the mobile terminal is obtained from the following system of equations:

5. A method for acquiring a satellite signal in a user mobile terminal (U) in a satellite positioning system having a constellation of satellites (S) comprising the steps of:

acquisition of at least two satellites (S);

obtaining an absolute value ({circumflex over (V)}_u) of the speed of the mobile terminal (U), by means of a MEMS device (M), based on the information retrieved with the two said satellites signals;

deduction of a user Doppler information related to other satellites of the constellation using said speed of said user mobile terminal (U); and

acquisition of signal of other satellites in the constellation using said user Doppler information.

6. The method of claim 5 wherein the absolute value of the speed of the user mobile terminal is used for obtaining corresponding values for vector components (V_ux, V_uy, V_uz) of the speed of the user mobile terminal (U).

7. The method of claim 6, comprising the step of using the information on the vector components (V_ux, V_uy, V_uz) of the speed of the mobile terminal for obtaining a Doppler effect value related to said mobile terminal (U).

8. The method of claim 7, wherein the information on the vector components (V_ux, V_uy, V_uz) of the speed of the mobile terminal is obtained from the following system of equations:

9. The method of claim 5 wherein before the step of acquiring at least two satellites, the following steps are performed:

obtaining an elevation angle of the satellites (S) in a visibility with respect to the mobile terminal

sorting the satellites (S) according to their elevation angle

starting the acquisition process with the satellite having the highest elevation value.