GPS RECEIVER WITH IMPROVED IMMUNITY TO BURST TRANSMISSIONS
First Claim
1. A method of operating a radio receiver, the method comprising:
- coupling a signal identifying a received signal overload condition into an automatic gain control (AGC) component;
controlling a gain value of the AGC component based on the signal identifying the received signal overload condition;
when a signal overload condition is identified;
capturing a given value of the gain value that occurred at a point in time prior to the received signal overload condition being identified;
during the signal overload condition;
instead of using the AGC component to control the gain applied to a received radio signal, coupling a locally generated bit pattern into a radio receiver back-end in response to a presence of the signal identifying the received signal overload condition, the locally generated bit pattern selected such that when processed causes less noise to accumulate in the radio receiver back-end than if a bit-stream derived from the received radio signal were processed directly using the gain of the AGC component;
after the received signal overload condition is identified to have ended;
setting the gain value of the AGC component to the given value and processing the received radio signal using the gain of the AGC component.
1 Assignment
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Accused Products
Abstract
GPS signals are typically weak and thus easily interfered with by other radio transmissions in the same or adjacent frequency bands. Interference can be especially problematic when the GPS receiver is co-located with a communications device that includes a radio transmitter, such as a cellular telephone. The transmitted signal from the co-located communication device can overload (or saturate) the GPS receiver front-end designed to receive weak GPS signals. In such a situation no useful information can be extracted from the received GPS signals originating from the GPS satellites. Described herein is a novel apparatus and method that can be used to minimize the effect of co-located interference on a GPS receiver.
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Citations
20 Claims
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1. A method of operating a radio receiver, the method comprising:
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coupling a signal identifying a received signal overload condition into an automatic gain control (AGC) component; controlling a gain value of the AGC component based on the signal identifying the received signal overload condition; when a signal overload condition is identified; capturing a given value of the gain value that occurred at a point in time prior to the received signal overload condition being identified; during the signal overload condition; instead of using the AGC component to control the gain applied to a received radio signal, coupling a locally generated bit pattern into a radio receiver back-end in response to a presence of the signal identifying the received signal overload condition, the locally generated bit pattern selected such that when processed causes less noise to accumulate in the radio receiver back-end than if a bit-stream derived from the received radio signal were processed directly using the gain of the AGC component; after the received signal overload condition is identified to have ended; setting the gain value of the AGC component to the given value and processing the received radio signal using the gain of the AGC component. - View Dependent Claims (3, 4, 5, 6, 7)
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2. (canceled)
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8. A radio receiver for receiving radio signals, the radio receiver comprising:
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an automatic gain control (AGC) component adapted to control a gain value of the automatic gain control component based on a signal identifying a received signal overload condition; a converter for deriving a bit-stream of digital data from a received radio signal; and a data modifier for substituting the bit-stream of digital data with a locally generated bit pattern in response to a signal identifying the received signal overload condition, the locally generated bit pattern being selected such that when processed it causes less noise to accumulate in the radio receiver back-end than if the bit-stream of digital data were processed using the gain of the AGC component; wherein when a signal overload condition is identified the AGC is configured to; capture a given value of the gain value that occurred at a point in time prior to the received signal overload condition being identified; wherein during the signal overload condition; instead of using the AGC component to control the gain applied to a received radio signal, the data modifier couples the locally generated bit pattern into the radio receiver back-end; wherein after the received signal overload condition is identified to have ended the AGC is configured to; set the gain value of the AGC component to the given value and process the received radio signal using the gain of the AGC component. - View Dependent Claims (9, 10, 11, 12, 13, 14, 18, 20)
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15. A method of limiting the effect of interfering transmission on a GPS receiver, the method comprising:
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controlling a gain value of an AGC component based on a signal identifying a received signal overload condition provided by a transmitter local to the GPS receiver; wherein the step of controlling a gain value comprises; when a signal overload condition is identified; capturing a given value of the gain value that occurred at a point in time prior to the received signal overload condition being identified; during the signal overload condition; instead of using the AGC component to control the gain applied to a received radio signal, coupling a locally generated bit pattern into a radio receiver back-end in response to a presence of the signal identifying the received signal overload condition, the locally generated bit pattern selected such that when processed causes less noise to accumulate in the radio receiver back-end than if a bit-stream derived from the received radio signal were processed using the gain of the AGC component; after the received signal overload condition is identified to have ended; setting the gain value of the AGC component to the given value and processing the received radio signal using the gain of the AGC component. - View Dependent Claims (19)
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16. (canceled)
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17. (canceled)
Specification