GPS receiver and GPS position measurement method

• US 6,480,145 B2
• Filed: 03/01/2001
• Issued: 11/12/2002
• Est. Priority Date: 03/02/2000
• Status: Expired due to Term

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Hasegawa, Koji
• Primary Examiner(s): Issing, Gregory C.
• Application Number:
  US09/797,025
• Publication Number:
  US 20010020913A1
• Time in Patent Office: 621 Days
• Field of Search: 342/357.12, 342/357.15, 342/357.06, 342/385, 342/386, 713/324, 713/330, 713/322
• US Class Current: 342/357.62
• 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;

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; and

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

2. 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, 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.

3. A GPS position measurement method for a GPS receiver, comprising the step 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, 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.

4. A GPS receiver, comprising:

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

an external clock block for storing frequency information and time information of a high accuracy;

said external clock block outputting a standby signal and a start signal, which are to be transmitted to said GPS block, at predetermined time intervals based on a setting signal transmitted from said GPS block and the frequency of information and the time information stored in said external clock block.

5. A GPS receiver according to claim 4, further comprising a frequency measurement block for measuring the difference of the frequency of a frequency oscillator of said GPS block from the frequency information stored in said external clock block as a frequency offset, the frequency offset being outputted from said frequency measurement block to said external clock block.

6. A GPS receiver according to claim 4, wherein said external clock block outputs the standby signal and the start signal, which are to be transmitted to said GPS block, at predetermined time intervals based on the accuracy of the frequency information and the time information stored in said external clock block.

7. A GPS receiver, comprising:

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

a radio wave clock block for holding time information of a high frequency and frequency information of a high accuracy obtained through reception of a signal transmitted from a radio wave clock broadcasting station;

said radio wave clock block outputting a standby signal and a start signal, which are to be transmitted to said GPS block, at predetermined time intervals based on a setting signal transmitted from said GPS block and the time information and the frequency information stored in said radio wave clock block.

8. A GPS receiver according to claim 7, wherein said radio wave clock block outputs the standby signal and the start signal, which are to be transmitted to said GPS block, at predetermined time intervals based on the accuracy of the time information and the frequency information stored in the said radio wave clock block.

9. 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 built in said GPS receiver;

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

repeating a startup state and a standby state of said GPS receiver within a predetermined time in response to a standby signal and a startup signal outputted from said external clock based on a setting signal transmitted from said GPS receiver to said external clock and the frequency information and the time information stored 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.

10. A GPS position measurement method according to claim 9, 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 stored by said external clock.