GPS receiver apparatus and receiving method

• US 6,907,346 B2
• Filed: 02/21/2003
• Issued: 06/14/2005
• Est. Priority Date: 02/25/2002
• Status: Expired due to Term

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Hori, Katsuya, Tanaka, Katsuyuki, Teranishi, Koichiro
• Primary Examiner(s): Jeanglaude, Gertrude A.
• Application Number:
  US10/475,740
• Publication Number:
  US 20040138811A1
• Time in Patent Office: 844 Days
• Field of Search: 701/207, 701/213, 701/214, 701/215, 701/300, 342/357.01, 342/357.06, 342/357.08, 342/357.09, 342/357.12, 375/149
• US Class Current: 701/213
• CPC Class Codes: G01S 19/29 carrier including Doppler, related G01S19/246 takes precedence
• CPC Class Codes: G01S 19/30 code related G01S19/246 takes precedence
• CPC Class Codes: G01S 19/34 Power consumption
• CPC Class Codes: H04B 2201/70709 with discontinuous detection

Abstract

A GPS receiver can periodically obtain range data without degrading the performance such as positioning sensitivity and positioning speed and conserve energy consumption. Supplied with IF data from a frequency conversion section 4, a synchronization hold section (6) acquires synchronization of a carrier frequency and phase synchronization of a C/A code, holds the acquired state, and obtains necessary information such as range data. When range data is obtained, a switch (23) is turned off to stop supplying the power to the synchronization hold section (6). A control section (7) executes a positioning operation using the obtained range data and the like, finds and outputs positioning information indicative of a current position. Thereafter, the switch (23) is turned on to restart the synchronization hold section (6). In this manner, control is provided to repeatedly start and stop the synchronization hold section (6).

Claims

1. A GPS receiver comprising:

a frequency conversion means for converting a high-frequency GPS signal into an intermediate frequency GPS signal, wherein the high-frequency GPS signal is transmitted as transmission data from an artificial satellite by modulating a carrier wave through a signal spectrum-spread by a spread code;

a synchronization hold means for obtaining the transmission data by receiving the intermediate frequency GPS signal supplied from the frequency conversion means and acquiring and holding synchronization of the carrier wave and phase synchronization of the spread code;

a control means for controlling repetition of an intermittent operation which operates the synchronization hold means to obtain the transmission data, then stops operating the synchronization hold means, and again operates the synchronization hold means after lapse of a specified time by using, as initial values, a carrier wave frequency and a spread code phase valid for the most recent stop condition; and

a positioning operation means for performing a positioning operation by using the transmission data obtained through the synchronization hold means and finding and outputting positioning information indicative of a current position.

2. The GPS receiver according to claim 1,

wherein the control means is configured to be able to change an operating time of the synchronization hold means in accordance with an output cycle of the positioning information.

3. The GPS receiver according to claim 1 comprising:

an initial value estimation means for estimating the carrier wave frequency and the spread code phase used as the initial values based on the already obtained transmission data,

wherein the control means can control the synchronization hold means by using the carrier wave frequency and the spread code phase as the initial values estimated in the initial value estimation means.

4. The GPS receiver according to claim 2 comprising:

an initial value estimation means for estimating the carrier wave frequency and the spread code phase used as the initial values in accordance with an output cycle of the positioning information by using the already obtained transmission data; and

an operating time estimation means for estimating an operating time for the synchronization hold means in accordance with an output cycle of the positioning information,

wherein the control means controls the synchronization hold means based on the carrier wave frequency and the spread code phase estimated in the initial value estimation means and based on the estimated operating time estimated in the operating time estimation means.

5. The GPS receiver according to claim 1,

wherein the control means controls start and stop conditions of the frequency conversion means in synchronization with stop conditions of the synchronization hold means.

6. The GPS receiver according to claim 1,

wherein the synchronization hold means comprises a Costas loop section to acquire and hold synchronization of the carrier wave and a delay lock loop section to acquire and hold phase synchronization of the spread code.

7. The GPS receiver according to claim 1 having:

a synchronization acquisition means for fast acquiring synchronization of the carrier wave and phase synchronization of the spread code and outputting the acquired carrier wave frequency and spread code phase,

wherein the control means provides control so as to operate the synchronization hold means at least after a power-on sequence by using, as the initial values, the carrier wave frequency and the spread code phase from the synchronization acquisition means, operate the synchronization hold means, and then repeatedly start and stop the synchronization acquisition means at a cycle longer than or equal to that for the synchronization hold means.

8. A GPS signal reception method comprising the steps of:

sequentially converting frequencies of a high-frequency GPS signal transmitted as transmission data from an artificial satellite by modulating a carrier wave through a signal spectrum-spread by a spread code to form an intermediate frequency GPS signal;

obtaining the transmission data by performing a synchronization hold process for the intermediate frequency GPS signal so as to acquire and hold synchronization of the carrier wave and phase synchronization of the spread code;

using, as initial values, a carrier wave frequency and a spread code phase valid for the most recent stop condition of the synchronization hold process to repeat an intermittent operation which temporarily stops the synchronization hold process after obtaining the transmission data and restarts the synchronization hold process after lapse of a specified time; and

using the obtained transmission data to perform a positioning operation and finding and outputting positioning information indicative of a current position.

9. The GPS signal reception method according to claim 8, further comprising the steps of:

change an operating time of the synchronization hold process in accordance with an output cycle of the positioning information.

10. The GPS signal reception method according to claim 8, further comprising the steps of:

estimating the carrier wave frequency and the spread code phase used as the initial values based on the already obtained transmission data; and

using the estimated carrier wave frequency and spread code phase as the initial values to restart the temporarily stopped synchronization hold process.

11. The GPS signal reception method according to claim 9, further comprising the steps of:

estimating the carrier wave frequency and the spread code phase used as the initial values in accordance with an output cycle of the positioning information by using the already obtained transmission data;

estimating an operating time for the synchronization hold process in accordance with an output cycle of the positioning information; and

using the estimated carrier wave frequency and spread code phase as the initial values and the estimated operating time to restart the temporarily stopped synchronization hold process.

12. The GPS signal reception method according to claim 8, further comprising the steps of:

controlling start and stop conditions of the frequency conversion process in synchronization with start and stop conditions of the synchronization hold process.

13. The GPS signal reception method according to claim 8,

wherein the synchronization hold process concurrently holds synchronization of the carrier wave using a Costas loop section and holds phase synchronization of the spread code using a delay lock loop section.

14. The GPS signal reception method according to claim 8, further comprising the steps of:

performing a synchronization acquisition process to fast acquire synchronization of the carrier wave and phase synchronization of the spread code and to output the acquired carrier wave frequency and spread code phase, and

executing the synchronization hold process at least after a power-on sequence by using, as the initial values, the carrier wave frequency and the spread code phase obtained by executing the synchronization acquisition process and, after execution of the synchronization hold process, repeatedly starting and stopping the synchronization acquisition process at a cycle longer than or equal to that for the synchronization hold process.