GPS access system and method
AssigneeThe Boeing Company
InventorsDavid A. Whelan, Gregory M. Gutt, Barton G. Ferrell, Clark Cohen
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Abstract
This invention describes a means for acquiring GPS P/Y code under jamming conditions. It improves jam resistance by augmenting a component of the GPS signal with one from a different satellite system, such as a low earth orbiting (LEO) satellite. The preferred embodiment of this invention employs the Iridium LEO satellite constellation broadcasting in a 10 MHz wide band about 1,621 MHz. A low-cost, integrated Iridium receiver coupled to the GPS receiver employs a single antenna that is capable of receiving both the GPS and Iridium signals together.
Claims33
A method for acquiring a first signal transmitted from a first satellite, comprising:
- acquiring a second signal transmitted from a second satellite;
- and
- searching for the first signal within an expected offset range from the acquired second signal until the first signal is acquired.
A device for acquiring a first signal transmitted from a first satellite, comprising:
- a first receiver configured to acquire the first signal;
- and
- a second receiver coupled to the first receiver, the second receiver configured to acquire a second signal transmitted from a second satellite and to send to the first receiver an estimate of an offset between the first signal and the second signal;
- whereby the first receiver can acquire the first signal by searching for the first signal within an expected offset range from the acquired second signal until the first signal is acquired.
A device for acquiring a first signal transmitted from a first satellite, comprising:
- a means for acquiring the first signal;
- a means for acquiring a second signal transmitted from a second satellite;
- and
- a means for estimating an offset between the first signal and the second signal;
- whereby the means for acquiring the first signal searches for the first signal within an expected offset range from the acquired second signal until the first signal is acquired.
The method of claim 27, wherein the expected offset range is a function of propagation delay and a likely clock error between the first signal from the GPS satellite and the second signal from the Iridium satellite.
Dependencies are inferred from the claim text.