APPARATUS AND METHOD FOR USE IN GLOBAL POSITION MEASUREMENTS

• US 20100231445A1
• Filed: 08/31/2007
• Published: 09/16/2010
• Est. Priority Date: 08/31/2006
• Status: Active Grant

• Current Assignee: Sige Semiconductor Europe Ltd (Skyworks Solutions Incorporated)
• Original Assignee: Sige Semiconductors Inc (Skyworks Solutions Incorporated)
• Inventors: Tarlow, Ben
• Granted Patent: US 8,400,353 B2
• Time in Patent Office: Days
• US Class Current: 342/357.280
• 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, the receiver having circuitry configured to receive signals from at least one source providing global positioning information, the apparatus comprising:

a parameter change detector configured to detect a change in at least one parameter associated with the receiver; and

a parameter error determiner configured to determine if the change in the at least one parameter is to be treated as erroneous.

2. The apparatus as claimed in claim 1, wherein said parameter change detector is configured to detect a sudden change in said at least one parameter.

3. The apparatus as claimed in claim 1, wherein said parameter error determiner is configured to determine if the change is to be treated as erroneous based on at least one of (1) a magnitude of the change, (2) a rate of change and (3) whether or not the change is sudden.

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

5. The apparatus as claimed in claim 4, further comprising at least one of:

(1) an input coupled to said determiner for receiving said further information; and

(2) a generator configured to generate said further information.

6. The apparatus as claimed in claim 4, wherein said further information comprises any one or more of:

(1) a measurement of said parameter at a different time to the detected change;

(2) a value for said parameter;

(3) a threshold change in the value of said parameter;

(4) a measurement of a different parameter at substantially the same time as the detected change, or at a different time; and

(5) information that describes one or more aspects of the environment in an area proximate the receiver, when the apparatus is in use.

8. The apparatus as claimed in claim 6, wherein said different parameter comprises any one of:

(1) a position of said receiver determined by at least one of said apparatus and said receiver;

(2) a clock offset between the clock of the receiver and the clock of the at least one source;

(3) velocity of said receiver;

(4) acceleration of said receiver;

(5) geometric dilution of precision (GDOP);

(6) a number of sources from which the receiver receives signals;

(7) a determined pseudorange for a signal received by said receiver;

(8) the strength of a signal received by said receiver;

(9) a parameter measured by an inertial sensor;

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

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

9. The apparatus as claimed in claim 8, wherein said position comprises any one or more of altitude and lateral position.

10. The apparatus as claimed in claim 6, wherein said information that describes one or more aspects of the environment comprises any one or more of information derived from a light sensor co-located with the receiver, architectural environment information and geographical environment information.

11. The apparatus as claimed in claim 1, wherein said at least one parameter comprises one or more parameters received, detected by, or determined by at least one of said receiver and said apparatus.

12. The apparatus as claimed in claim 1, wherein said at least one parameter comprises any one of:

(1) a position of said receiver determined by at least one of said apparatus and said receiver;

(2) a clock offset between the clock of the receiver and the clock of the at least one source;

(3) velocity of said receiver;

(4) acceleration of said receiver;

(5) geometric dilution of precision (GDOP);

(6) a number of sources from which the receiver receives signals;

(7) a determined pseudorange for a signal received by said receiver;

(8) the strength of a signal received by said receiver;

(9) a parameter measured by an inertial sensor;

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

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

14. The apparatus as claimed in claim 1, wherein said parameter error determiner is adapted to determine if the change is physically possible.

15. The apparatus as claimed in claim 1, further comprising a response controller responsive to said parameter error determiner and configured to cause an action if the change in the at least one parameter is to be treated as erroneous.

16. The apparatus as claimed in claim 15, wherein the response controller is configured to cause at least one of the following actions:

(1) search for a direct line of sight signal;

(2) modify a weighting value of a signal or discard a signal from one or more sources from which the receiver receives a signal;

(3) alter a measured pseudorange;

(4) alter a measured pseudorange based on an estimated amount of multi-path;

(5) provide an indication of the presence of one or more multi-path component(s) of signal(s);

(6) one or more of predict, estimate, determine and provide an indication of the magnitude of one or more multi-path component(s) of signal(s);

(7) one or more of detect, determine and provide an indication of information on the environment local to the receiver;

(8) correct a determined position which was determined based on the at least one parameter having the change;

(9) provide an indication of a possible position inaccuracy to a user;

(10) one or more of determine and provide an indication of the magnitude of an error in one or more parameters;

(11) one or more of control and modify a strategy for one or more of acquiring and tracking signal(s) transmitted from one or more sources;

(12) stop using or searching for one or more particular sources;

(13) prompt a user for one or more of a response and an input;

(14) call upon an environment information database used to describe at least one aspect of the environment in an area proximate to the receiver;

(15) limit the use of at least one parameter during a period when the at least one parameter is outside an acceptable range, the start of the period identified by the change in the at least one parameter;

(16) modify the at least one parameter having the change; and

(17) identify the change in the at least one parameter and wait for a subsequent position determination before deciding whether the change is erroneous.

17. The apparatus as claimed in claim 1, wherein said at least one parameter comprises altitude, and said apparatus further comprises a detector for detecting changes in clock offset between the clock of the receiver and the clock of the at least one source, and said parameter error determiner is adapted to determine if a change in altitude is to be treated as erroneous based on a detected change in clock offset.

18. A receiver having circuitry configured to receive signals from at least one source providing global positioning information including an apparatus as claimed in claim 1.

51. The apparatus of claim 3 wherein said parameter error determiner is configured to determine if the change is to be treated as erroneous based on at least one of:

(1) determining the magnitude of the change and comparing it to a threshold; and

(2) determining the rate of change and comparing it to a threshold.

52. The apparatus of claim 15 wherein at least one action that the response controller is configured to perform, if the change in the at least one parameter is to be treated as erroneous, is performed to mitigate error resulting from the change.

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19. A method for use in a receiver, the receiver having circuitry configured to receive signals from at least one source providing global positioning information, the method comprising:

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.

20. The method as claimed in claim 19, wherein detecting a change in at least one parameter associated with the receiver comprises detecting a sudden change in said at least one parameter.

21. The method as claimed in claim 19, wherein determining if the change in the at least one parameter is to be treated as erroneous comprises determining if the change is to be treated as erroneous based on at least one of:

(1) a magnitude of the change;

(2) a rate of change; and

(3) whether or not the change is sudden.

29. The method as claimed in claim 19, wherein said at least one parameter comprises one or more parameters received, detected by, or determined by said receiver.

30. The method as claimed in claim 19, wherein said at least one parameter comprises any one of:

(1) a position of said receiver determined by at least one of said apparatus and said receiver;

(2) a clock offset between the clock of the receiver and the clock of the at least one source;

(3) velocity of said receiver;

(4) acceleration of said receiver;

(5) geometric dilution of precision (GDOP);

(6) a number of sources from which the receiver receives signals;

(7) a determined pseudorange for a signal received by said receiver;

(8) the strength of a signal received by said receiver;

(9) a parameter measured by an inertial sensor;

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

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

31. The method as claimed in claim 30, wherein said position comprises any one or more of altitude and lateral position.

32. The method as claimed in claim 19, wherein determining if the change in the at least one parameter is to be treated as erroneous comprises determining if the change is physically possible.

33. The method as claimed in claim 19, further comprising:

in a manner responsive to determining if the change in the at least one parameter is to be treated as erroneous, performing an action if the change in the at least one parameter is to be treated as erroneous.

34. The method as claimed in claim 33, wherein performing an action comprises at least one of the following actions:

(1) searching for a direct line of sight signal;

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

(3) altering a measured pseudorange;

(4) altering a measured pseudorange based on an estimated amount of multi-path;

(5) providing an indication of the presence of one or more multi-path component(s) of signal(s);

(6) one or more of predicting, estimating, determining and providing an indication of the magnitude of one or more multi-path component(s) of signal(s);

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

(8) correcting a determined position which was determined based on the at least one parameter having the change;

(9) providing an indication of a possible position inaccuracy to a user;

(10) one or more of determining and providing an indication of the magnitude of an error in one or more parameters;

(11) one or more of controlling and modifying a strategy for one or more of acquiring and tracking signal(s) transmitted from one or more sources;

(12) stopping using or searching for one or more particular sources;

(13) prompting a user for one or more of a response and an input;

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

(15) limiting the use of at least one parameter during a period when the at least one parameter is outside an acceptable range, the start of the period identified by the change in the at least one parameter;

(16) modifying the at least one parameter having the change; and

(17) identifying the change in the at least one parameter and waiting for a subsequent position determination before deciding whether the change is erroneous.

35. The method as claimed in claim 19, wherein detecting a change in at least one parameter associated with the receiver comprises detecting a change in two or more parameters;

and

determining if the change in the at least one parameter is to be treated as erroneous comprises determining if the change in at least two of the two or more parameters is coincident in time; and

if the change in the at least two parameters is coincident in time, treating the at least two parameters as erroneous or another parameter as erroneous.

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