GPS receiver and GPS position measurement method

• US 20010020913A1
• Filed: 03/01/2001
• Published: 09/13/2001
• Est. Priority Date: 03/02/2000
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Hasegawa, Koji
• Granted Patent: US 6,480,145 B2
• Time in Patent Office: Days
• US Class Current: 342/357.06
• CPC Class Codes: G01S 19/235 Calibration of receiver components
• CPC Class Codes: G01S 19/34 Power consumption

Abstract

A GPS receiver is disclosed wherein GPS position measurement can be performed stably and rapidly without the necessity to wait for periodical time information from a GPS satellite and power consumption is minimized also with a minimized position measurement time through the selection of an optimum time interval between intermittent receptions of GPS signals. The GPS receiver includes a GPS block for performing position measurement based on a signal transmitted from a GPS satellite to update a navigation message and repeating standby and startup thereof, an external clock block for holding frequency information and time information of a high accuracy and outputting a start signal to the GPS block, which is in a standby state, based on the frequency information and the time information held therein, and a frequency measurement block for measuring a frequency offset which is a displacement of a frequency oscillator of the GPS block with reference to the frequency information held in the external clock block and outputting information of the measured frequency offset to the external clock block.

Claims

1. A GPS receiver, comprising:

a GPS block for performing position measurement based on a signal transmitted from a GPS satellite to update a navigation message and repeating standby and startup thereof; and

an external clock block for holding frequency information and time information of a high accuracy and outputting a start signal to said GPS block, which is in a standby state, based on the frequency information and the time information held therein.

2. A GPS receiver according to

claim 1

, further comprising a frequency measurement block for measuring a frequency offset which is a displacement of a frequency oscillator of said GPS block with reference to the frequency information held in said external clock block and outputting the measured frequency offset to said external clock block.

3. A GPS receiver according to

claim 2

, wherein said external clock block controls standby and startup of said GPS block based on the frequency offset outputted from said frequency measurement block.

4. A GPS receiver, comprising:

position measurement execution means including a frequency oscillator for performing position measurement based on a signal transmitted from a GPS satellite;

radio wave clock reception means for receiving a carrier from a radio wave clock broadcasting station; and

frequency measurement means for measuring an error of said frequency oscillator of said position measurement execution means based on a frequency of the carrier received by said radio wave clock reception means.

5. A GPS receiver according to

claim 4

, wherein said frequency measurement means outputs the measured error of said frequency oscillator to said radio wave clock reception means, and said radio wave clock reception means controls startup/standby of said position measurement execution means based on the error of said frequency oscillator outputted from said frequency measurement means.

6. A GPS position measurement method for a GPS receiver, comprising the steps of:

receiving a hierarchical navigation message from each of a plurality of GPS satellites;

storing the received navigation messages into a memory;

storing frequency information and time information of a high accuracy into an external clock which normally is in an operating state; and

repeating startup and standby of said GPS receiver within a predetermined time determined using the frequency information and the time information held in said external clock to perform position measurement of said GPS receiver from said GPS satellites to update the navigation messages stored in said memory.

7. A GPS position measurement method according to

claim 6

, wherein an interval of time between startup and standby of said GPS receiver is varied based on a degree of accuracy of the frequency information or the time information held by said external clock.