Apparatus and method for use in global position measurements

• US 8,400,353 B2
• Filed: 08/31/2007
• Issued: 03/19/2013
• Est. Priority Date: 08/31/2006
• Status: Active Grant

• Current Assignee: Sige Semiconductor Europe Ltd (Skyworks Solutions Incorporated)
• Original Assignee: Sige Semiconductor Europe Ltd (Skyworks Solutions Incorporated)
• Inventors: Tarlow, Ben
• Primary Examiner(s): Issing, Gregory C
• Application Number:
  US12/310,551
• Publication Number:
  US 20100231445A1
• Time in Patent Office: 2,027 Days
• Field of Search: 342/357.58, 342/357.59
• US Class Current: 342/357.58
• CPC Class Codes: G01S 19/13 Receivers
• CPC Class Codes: G01S 19/21 Interference related issues ; Issues related to cross-correlation, spoofing or other methods of denial of service
• CPC Class Codes: G01S 19/22 Multipath-related issues

Abstract

Apparatus and methods are provided for use in a receiver that receives global positioning data from one or more satellites above the Earth'"'"'s surface. The apparatus and methods involve detecting a change in at least one parameter associated with the receiver and determining if the change in the at least one parameter is to be treated as erroneous. As a result of determining if the change in the at least one parameter is to be treated as erroneous, a further action may be performed. Determining if the change is to be treated as erroneous may include, for example, detecting changes in more than one parameter and determining if the changes are coincident. Detecting a change in at least one parameter may also enable the receiver to predict the presence and magnitude of multipath components of signals, predict changes in an environment local to the receiver, predict large errors in position estimates determined by the receiver and modify an acquisition and tracking strategy used by the receiver.

Claims

1. An apparatus for a receiver configured to determine position based at least in part on global positioning information, the apparatus comprising:

receiver circuitry associated with a receiver and configured to receive a signal from at least one source providing global positioning information;

a parameter change detector configured to detect changes in a determined position of the receiver and a clock offset between a clock associated with the receiver and a clock associated with the at least one source; and

a parameter error determiner configured to determine if the change in the determined position is to be treated as erroneous when the changes in the determined position and the clock offset are sudden and coincident.

2. The apparatus of claim 1 wherein said parameter change detector is further configured to detect sudden changes.

3. The apparatus of claim 1 wherein said parameter error determiner is further configured to determine if the change in the determined position is to be treated as erroneous based on at least one of a magnitude of each change and each rate of change.

4. The apparatus of claim 1 wherein said parameter error determiner is further configured to determine if the change in the determined position is to be treated as erroneous based on further information.

5. The apparatus of claim 4 further comprising at least one of an input coupled to said parameter error determiner for receiving said further information and a generator configured to generate said further information.

6. The apparatus of claim 4 wherein said further information includes at least one of:

a measurement of at least one of the determined position and the clock offset at a different time to the detected change;

a value for at least one of the determined position and the clock offset;

a threshold change in the value of at least one of the determined position and the clock offset;

a measurement of a different parameter at substantially the coincident time as the detected changes, or at a different time; and

information indicative of one or more aspects of an environment in an area proximate the receiver, when the apparatus is in use.

7. The apparatus of claim 6 wherein said different parameter includes anyone of:

velocity of said receiver;

acceleration of said receiver;

geometric dilution of precision (GDOP);

a number of sources from which the receiver receives signals;

a determined pseudorange for the signal received by said receiver;

strength of the signal received by said receiver;

a parameter measured by an inertial sensor;

a parameter indicative of the presence or absence of a multi-path component of the signal received by said receiver; and

information indicative of the one or more aspects of the environment in the area proximate the receiver.

8. The apparatus of claim 1 wherein said determined position includes at least one of altitude and lateral position.

9. The apparatus of claim 6 wherein said information indicative of the one or more aspects of the environment includes at least one of information derived from a light sensor co-located with the receiver, architectural environment information, and geographical environment information.

10. The apparatus of claim 1 wherein said parameter change detector is further configured to detect a change in at least one of:

velocity of said receiver;

acceleration of said receiver;

geometric dilution of precision (GDOP);

a number of sources from which the receiver receives signals;

a determined pseudorange for the signal received by said receiver;

strength of the signal received by said receiver;

a parameter measured by an inertial sensor;

a parameter indicative of a presence or an absence of a multi-path component of the signal received by said receiver; and

a parameter indicative of an aspect of an environment in an area proximate the receiver.

11. The apparatus of claim 1 wherein said parameter error determiner is configured to determine if the change in the determined position is physically possible.

12. The apparatus of claim 1 further comprising a response controller responsive to said parameter error determiner and configured to cause an action if the change in the determined position is to be treated as erroneous.

13. The apparatus of claim 12 wherein the action includes at least one of:

searching for a direct line of sight signal;

modifying a weighting value of a signal or discarding a signal from one or more sources from which the receiver receives a signal;

altering a measured pseudorange;

altering the measured pseudorange based on an estimated amount of multi-path;

providing an indication of a presence of one or more multi-path components of signals;

one or more of predicting, estimating, determining and providing an indication of a magnitude of the one or more multi-path components of signals;

one or more of detecting, determining and providing an indication of information on an environment local to the receiver;

correcting the determined position;

providing an indication of a possible position inaccuracy to a user;

one or more of determining and providing an indication of a magnitude of an error in one or more parameters;

one or more of controlling and modifying a strategy for one or more of acquiring and tracking signals transmitted from one or more sources;

stopping using or searching for one or more particular sources;

prompting the user for one or more of a response and an input;

calling upon an environment information database used to describe at least one aspect of an environment in an area proximate to the receiver;

limiting the use of at least one of the determined position and the clock offset during a period when the at least one of the changes of the determined position and the clock offset is outside an acceptable range;

modifying the at least one of the determined position and clock offset; and

identifying the change in at least one of the determined position and the clock offset and waiting for a subsequent position determination before deciding whether the changes are erroneous.

14. The apparatus of claim 12 wherein the action is performed to mitigate error resulting from the change in the determined position.

15. The apparatus of claim 1 wherein said determined position includes altitude, said parameter error determiner being further configured to determine if a change in altitude is to be treated as erroneous based on a detected change in clock offset.

16. A receiver including the apparatus as claimed in claim 1.

17. The apparatus of claim 3 wherein said parameter error determiner is further configured to determine if the change in the determined position is to be treated as erroneous based on at least one of comparing the magnitude of each change to a magnitude threshold, and comparing each rate of change to a rate threshold.

18. A method for use in a receiver configured to determine position based at least in part on global positioning information, the method comprising:

receiving a signal from at least one source providing global positioning information;

detecting changes in a determined position of a receiver and a clock offset between a clock associated with the receiver and a clock associated with the at least one source; and

determining if the change in the determined position is to be treated as erroneous when the changes in the determined position and the clock offset are sudden and coincident.

19. The method of claim 18 wherein detecting changes includes detecting sudden changes.

20. The method of claim 18 wherein determining if the change in the determined position is to be treated as erroneous is based on at least one of a magnitude of each change and a rate of each change.

21. The method of claim 18 further comprising detecting a change in at least one of:

velocity of said receiver;

acceleration of said receiver;

geometric dilution of precision (GDOP);

a number of sources from which the receiver receives signals;

a determined pseudorange for the signal received by said receiver;

strength of the signal received by said receiver;

a parameter measured by an inertial sensor;

a parameter indicative of a presence or an absence of a multi-path component of the signal received by said receiver; and

a parameter indicative of an aspect of an environment in an area proximate the receiver.

22. The method of claim 18 wherein said determined position includes at least one of altitude and lateral position.

23. The method of claim 18 wherein determining if the change in the determined position is to be treated as erroneous includes determining if the change in the determined position is physically possible.

24. The method of claim 18 further comprising performing an action if the change in the at determined position is to be treated as erroneous.

25. The method of claim 24 wherein the action includes at least one of:

searching for a direct line of sight signal;

modifying a weighting value of a signal or discarding a signal from one or more sources from which the receiver receives a signal;

altering a measured pseudorange;

altering the measured pseudorange based on an estimated amount of multi-path;

providing an indication of a presence of one or more multi-path components of signals;

one or more of predicting, estimating, determining and providing an indication of a magnitude of the one or more multi-path components of signals;

one or more of detecting, determining and providing an indication of information on an environment local to the receiver;

correcting the determined position;

providing an indication of a possible position inaccuracy to a user;

one or more of determining and providing an indication of a magnitude of an error in one or more parameters;

one or more of controlling and modifying a strategy for one or more of acquiring and tracking signals transmitted from one or more sources;

stopping using or searching for one or more particular sources;

prompting the user for one or more of a response and an input;

calling upon an environment information database used to describe at least one aspect of an environment in an area proximate to the receiver;

limiting use of at least one of the determined parameter and the clock offset during a period when the at least one of the changes of the determined position and the clock offset is outside an acceptable range;

modifying at least one of the determined position and the clock offset; and

identifying the change in at least one of the determined position and the clock offset and waiting for a subsequent position determination before deciding whether the changes are erroneous.

26. The method of claim 18 further comprising, if the changes in the determined position and the clock offset are coincident in time, treating at least one of the determined position and the clock offset as erroneous or another parameter as erroneous.