System and method to estimate carrier signal in global positioning systems (GPS)
AssigneeRockwell Collins, Inc.
InventorsSteven D. Deines, Paul D. Linhart
Life of this patent
Estimating the term…
Abstract
A method of estimating the carrier phase difference between two antennas under low signal conditions (typically called state 3) of a global positioning system (GPS) carrier signal transmitted from one of a constellation of satellites in the GPS for use in attitude determination systems is proposed. The method involves the use of multiple antennas tracking the same satellite signal and utilizing a code tracking loop filter to aid in maintaining track of the GPS waveform when the effects of doppler (i.e., the distance from a GPS satellite to the antenna is changing with time) are present.
Claims20
system for estimating the waveform of a global positioning system (GPS) carrier signal transmitted from at least one of a constellation of satellites in the GPS, the system comprising:
- a receiver, the receiver including an antenna, the antenna capable of receiving GPS signals, the receiver using a second order code tracking loop to provide an estimated measurement of a velocity of the receiver at the antenna to estimate how fast the distance from a GPS satellite to the antenna is changing.
A system for estimating the waveform of a global positioning system (GPS) carrier signal transmitted from one of a constellation of satellites in the GPS, the system comprising:
- means for receiving GPS signals;
- means for generating a code sequence for comparison with the received GPS signals;
- means for regulating the rate of the means for generating a code sequence;
- means for regulating the rate by which a locally-generated signal is mixed with the received GPS signal;
- means for measuring code phase error in the GPS signal mixed with the locally-generated signal;
- and
- means for determining the rate of change required of the regulating means, wherein the rate of change required of the regulating means corresponds to how fast the distance from the GPS satellite to the antenna is changing.
A method of estimating the waveform of a global positioning system (GPS) carrier signal transmitted from one of a constellation of satellites in the GPS, the method comprising:
- receiving a GPS signal into a receiving unit;
- using a second order code tracking loop to provide an estimated measurement of a velocity of the receiving unit at an antenna to estimate how fast the distance from a GPS satellite to the antenna is changing.
Dependencies are inferred from the claim text.