Power cycling for a global positioning system

• US 7,256,731 B2
• Filed: 05/27/2004
• Issued: 08/14/2007
• Est. Priority Date: 05/27/2004
• Status: Active Grant

• Current Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Original Assignee: Northrop Grumman Corporation
• Inventors: Siegel, Neil G., Bixler, David
• Primary Examiner(s): PHAN, DAO LINDA
• Application Number:
  US10/855,205
• Publication Number:
  US 20050275587A1
• Time in Patent Office: 1,174 Days
• Field of Search: 342/357.06, 342/357.13, 342/374, 701/207, 701/213, 455/277.1, 455/343.1
• US Class Current: 342/357.74
• CPC Class Codes: G01S 19/258 relating to the satellite constellation, e.g. almanac, ephemeris data, lists of satellites in view
• CPC Class Codes: G01S 19/27 creating, predicting or correcting ephemeris or almanac data within the receiver
• CPC Class Codes: G01S 19/34 Power consumption
• CPC Class Codes: H04B 1/1615 Switching on; Switching off, e.g. remotely battery saving circuits associated with selective call operation H04W52/00; details of power consumption reduction in a PLL, H03L7/0802, H03L7/14, H03L2207/08, H03L2207/18; muting amplifiers by gain control see H03G3/34
• CPC Class Codes: H04W 52/0274 by switching on or off the equipment or parts thereof
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Methods and systems are presented for controlling power cycling in a global positioning system (GPS) assembly. The assembly comprises a power management component that operates to switch a GPS receiver between at least a first mode, in which the receiver is actively receiving almanac and positioning data, and a second mode, in which the receiver does not actively receive data according to a power cycling routine of the receiver. A memory stores a plurality of quanta of almanac data as associated memory blocks, each memory block having an associated status indicating the length of time for which the associated almanac data is expected to be useful. A signal processing component processes a received signal containing at least a portion of a quantum of almanac data and identifies the quantum of almanac data within the received signal. A receiver control adjusts the power cycling routine of the GPS receiver according to the associated status of a memory block associated with the identified quantum of almanac data.

Claims

1. A global positioning system (GPS) assembly, comprising:

a power management component that operates to switch a GPS receiver between at least a first mode, in which the receiver is actively receiving almanac and positioning data, and a second mode, in which the receiver does not actively recieve data according to a power cycling routine of the receiver;

a memory that stores a plurality of quanta of almanac data as associated memory blocks, each memory block having an associated status indicating the length of time for which the associated almanac data is expected to be useful;

a signal processing component that processes a received signal containing at least a portion of a quantum of almanac data and identifies the quantum of almanac data within the received signal; and

a receiver control that adjusts the power cycling routine of the GPS receiver according to the associated status of a memory block associated with the identified quantum of almanac data.

2. The system of claim 1, the power cycling routine directing the power management component to switch to the first mode at regular intervals as to maintain a desired precision in position information for the GPS assembly, such that a desiredtime-to-quick-fix can be achieved when the GPS receiver is switched to the first mode.

3. A handheld communications device comprising the GPS assembly of claim 1.

4. The communications device of claim 3, further comprising a communications module operative to communicate with at least one other handheld communications device through a mobile base station.

5. The communications device of claim 4, in which the mobile base station includes a GPS receiver that obtains at least one quantum of almanac data and a communications module that broadcasts the at least one quantum of almanac data to a plurality of handheld communications devices.

6. The assembly of claim 1, wherein the receiver control adjusts the power cycling routine to stay in the first mode until the entirety of the identified quantum of almanac data has been received.

7. The assembly of claim 1, wherein the receiver control adjusts the power cycling to switch the GPS receiver from the second mode to the first mode at a time when a desired quantum of almanac data is expected to be received, based upon the identified quantum of almanac data.

8. A method of conserving power in a handheld global positioning system (GPS) locator device comprising:

activating a GPS receiver to obtain a position fix for an associated device according to a predefined power cycling routine;

receiving a portion of a subframe of almanac data for the GPS receiver while the GPS receiver is active;

identifying at least one block of stored almanac data associated with the recieved portion of a subframe; and

adjusting the power cycling routine of the GPS receiver according to an associated status of the identified block of stored almanac data, the status indicating the length of time for which the block of almanac data is expected to be useful.

9. The method of claim 8, the predefined power cycling routine being operative to maintain current position information for the GPS locator device as to allow for a desired time-to-quick-fix when the GPS receiver is activated.

10. The method of claim 8, wherein adjusting the power cycling routine includes allowing the GPS receiver to remain active until the remainder of the portion of a subframe has been received.

11. The method of claim 8, further comprising:

determining a memory block having an associated status indicating that its associated stored almanac data is invalid; and

calculating an expected time at which a subframe associated with the memory block will be received, according to the received portion of a subframe and a known sequence of subframes.

12. The method of claim 11, wherein adjusting the power cycling routine includes adjusting the power cycle to activate the GPS receiver at the calculated time.

13. The method of claim 8, further comprising receiving updated almanac data from an associated mobile base station.

14. A handheld communications system, comprising:

a radio frequency (RF) transceiver operative to communicate with other handheld communication systems through a mobile base station;

a memory that stores a plurality of quanta of almanac data as associated memory blocks, each memory block having an associated status indicating the length of time for which the associated almanac data is expected to be useful, the mobile base station periodically providing updates to the associated memory blocks via an RF transmission; and

a power management component that operates to switch the transceiver between at least a first mode, in which the transceiver is actively receiving data, and a second mode, in which the transceiver does not actively receive data according to a power cycling routine of the transceiver.

15. The system of claim 14, further comprising:

a signal processing component that processes a received signal containing at least a portion of a quantum of almanac data and identifies the quantum of almanac data within the received signal; and

a transceiver control that adjusts the power cycling routine of the transceiver according to the associated status of a memory block associated with the identified quantum of almanac data.

16. The system of claim 14, wherein the mobile base station is operative to relay communications between a plurality of associated handheld communications systems within an associated coverage area.

17. The system of claim 14, wherein the mobile base station is operative to relay communications between the handheld communication system and at least one entity outside of an associated coverage area.

18. The system of claim 17, wherein the mobile base station provides the updated almanac information to the handheld communications system along with relayed communications.

19. A method of conserving power in a handheld communications system that comprises a global positioning system (GPS) receiver, comprising:

activating an associated receiver according to a predefined power cycling routine to receive desired data from a mobile base station;

receiving at least a portion of a quantum of almanac data along with the desired data during communication with the mobile base station;

identifying at least one block of stored almanac data associated with the received at least a portion of a quantum; and

adjusting the power cycling routine of the receiver according to an associated status of the identified block of stored almanac data, the status indicating the length of time for which the block of almanac data is expected to be useful.

20. The method of claim 19, wherein adjusting the power cycling routine includes allowing the GPS receiver to remain active after the desired data has been received until the entirety of the at least a portion of a subframe has been received.

21. The method of claim 19, the desired data including situational update information related to at least one other handheld communication system.

22. The method of claim 19, the method further comprising determining a location associated with the handheld communication device and reporting that location to the base station.