Method and system for navigation using GPS velocity vector
First Claim
1. A vehicle navigation device includes a computer platform comprising:
- a global positioning system (GPS) receiver operable to acquire and track a GPS signal;
a processor assembly; and
a memory, wherein the memory includes;
last recorded GPS information comprising at least one of Ephemeris information and Almanac information;
a GPS velocity vector determination module operable to output a velocity vector in the absence of current Ephemeris based upon the tracked GPS signal and the last recorded GPS information; and
a dead reckoning module operable to determine a current location of the navigation device based on the determined velocity vector and a dead reckoning startup location, comprising;
a verification logic for determining an estimated position calculated from pseudo-ranges and Doppler values using the last recorded GPS information, then comparing the estimated position against a last recorded location, and using the last recorded location as the dead reckoning position if a difference between the estimated position and the last recorded location does not exceed a predetermined value.
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0 Petitions
Accused Products
Abstract
A navigation device includes a computer platform that includes a global positioning system (GPS) receiver operable to acquire and track a GPS signal, a processor assembly, and a memory. The memory includes at least one of last recorded Ephemeris and Almanac information, and a GPS velocity vector determination module operable to generate a velocity vector output in the absence of current Ephemeris based upon the tracked GPS signal and the last recorded GPS information. A method of vehicle navigation in the absence of current Ephemeris includes acquiring and tracking a GPS signal, retrieving from a memory a last recorded location of a vehicle, setting a dead reckoning startup location equal to the last recorded location, retrieving from a memory at least one of a last recorded Ephemeris and Almanac, determining a current velocity vector and determining a current location based upon the velocity vector and the dead reckoning startup location.
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Citations
10 Claims
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1. A vehicle navigation device includes a computer platform comprising:
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a global positioning system (GPS) receiver operable to acquire and track a GPS signal; a processor assembly; and a memory, wherein the memory includes; last recorded GPS information comprising at least one of Ephemeris information and Almanac information; a GPS velocity vector determination module operable to output a velocity vector in the absence of current Ephemeris based upon the tracked GPS signal and the last recorded GPS information; and a dead reckoning module operable to determine a current location of the navigation device based on the determined velocity vector and a dead reckoning startup location, comprising; a verification logic for determining an estimated position calculated from pseudo-ranges and Doppler values using the last recorded GPS information, then comparing the estimated position against a last recorded location, and using the last recorded location as the dead reckoning position if a difference between the estimated position and the last recorded location does not exceed a predetermined value. - View Dependent Claims (2)
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3. A method of vehicle navigation in the absence of current Ephemeris, the method comprising a navigation device performing the steps of:
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acquiring and tracking a GPS signal; retrieving from a memory a last recorded location of a vehicle; retrieving from the memory at least one of a last recorded Ephemeris and Almanac; comparing the last recorded location against an estimated position calculated from the last recorded Ephemeris or Almanac; setting a dead reckoning startup location equal to the last recorded location if a difference between the estimated position and the last recorded location does not exceed a predetermined value; determining a current velocity vector based upon the GPS signal and the last recorded Ephemeris or Almanac; and determining a current position based upon the velocity vector and the dead reckoning startup location. - View Dependent Claims (4, 5, 6, 7)
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8. At least one processor configured to perform the actions of:
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acquiring and tracking a GPS signal; retrieving from a memory a last recorded location of a vehicle; retrieving from the memory at least one of a last recorded Ephemeris and Almanac; comparing the last recorded location with an estimated position calculated from the last recorded Ephemeris or Almanac; setting a dead reckoning startup location equal to the last recorded location if a difference between the estimated position and the last recorded location does not exceed a predetermined value; determining a current velocity vector based upon the GPS signal and the last recorded Ephemeris or Almanac; and determining a current location using the velocity vector and the dead reckoning startup location.
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9. A machine-readable medium comprising executable instructions stored thereon, comprising:
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a first set of instructions for acquiring and tracking a GPS signal; a second set of instructions for retrieving from a memory a last recorded location of a vehicle; a fourth set of instructions for retrieving from the memory at least one of a last recorded Ephemeris and Almanac; a fifth set of instructions for determining a current velocity vector based upon the GPS signal and the last recorded Ephemeris or Almanac; a sixth set of instructions for determining a current location using dead reckoning, based upon the velocity vector and a dead reckoning startup location; a seventh set of instructions for comparing the last recorded location against an estimated position calculated from the last recorded Ephemeris or Almanac; and a third set of instructions for setting the dead reckoning startup location equal to the last recorded location if a difference between the estimated position and the last recorded location does not exceed a predetermined value.
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10. A method of vehicle navigation in the absence of current Ephemeris, comprising:
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continuously receiving GPS signals from tracked satellites; switching to a dead reckoning mode when the last recorded Ephemeris becomes unusable, wherein switching to a dead reckoning mode includes; retrieving from a memory at least one of a last recorded Ephemeris and Almanac; comparing a last calculated GPS location against an estimated position calculated using the last recorded Ephemeris or Almanac; setting a dead reckoning startup location equal to the last calculated GPS location if a difference between the estimated position and the last calculated GPS location does not exceed a predetermined value; determining a current velocity vector based upon the GPS signal and the last recorded Ephemeris or Almanac; and determining a current location based upon the velocity vector and the dead reckoning startup location.
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Specification