Location-determination method and apparatus
First Claim
1. A global positioning method comprising:
- a) using a global positioning system (“
GPS”
) receiver to receive a GPS signal;
b) computing a pseudorange for a GPS satellite without performing signal tracking on the received GPS signal; and
c) using the computed pseudorange to identify an estimated location of the GPS receiver.
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Accused Products
Abstract
Some embodiments of the invention provide a location-determination system that includes several transmitters and at least one receiver. Each transmitter transmits a signal that includes a unique periodically-repeating component, and the receiver receives a reference signal. Based on the received reference signal, the location-determination system identifies an estimated location of the receiver as follows. For each transmitter in a set of transmitters, the system computes a phase offset between the received reference signal and a replica of the transmitter'"'"'s periodically-repeating component. The system also identifies an approximate location of the receiver and an approximate receive time for the received signal. The system then uses the identified approximate location and time, and the computed phase offsets, to compute pseudoranges for the set of transmitters. Finally, the system identifies the estimated location of the receiver by using the computed pseudoranges.
61 Citations
25 Claims
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1. A global positioning method comprising:
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a) using a global positioning system (“
GPS”
) receiver to receive a GPS signal;
b) computing a pseudorange for a GPS satellite without performing signal tracking on the received GPS signal; and
c) using the computed pseudorange to identify an estimated location of the GPS receiver. - View Dependent Claims (2)
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3. A method of computing a pseudorange for a GPS receiver and a GPS satellite, wherein the GPS receiver receives a GPS signal and the GPS satellite repeatedly transmits a code, the method comprising
a) identifying a phase offset between the received GPS signal and a replica of the satellite'"'"'s code, wherein the phase offset corresponds to a particular segment of the code; -
b) identifying an approximate GPS-receiver location;
c) identifying an approximate time for the received GPS signal;
d) computing the pseudorange for the GPS satellite based on the computed phase offset, the approximate GPS-receiver location, and the approximate time. - View Dependent Claims (4, 5, 6, 7, 8)
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9. A method of computing a pseudorange for a receiver and a transmitter, wherein the receiver receives a reference signal starting at a particular time and the transmitter transmits a signal with a periodically-repeating component, the method comprising
a) identifying a phase offset between the received reference signal and a replica of the transmitter signal'"'"'s periodically-repeating component, wherein the phase offset corresponds to a particular segment of the periodically-repeating component; -
b) computing the length of the particular segment;
c) computing the length of complete periodically-repeating components that the particular satellite has transmitted by the particular time after transmitting the particular segment;
d) calculating the pseudorange based on the computed lengths. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 19, 20, 21, 22, 23, 24, 25)
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18. For a global positioning system (“
- GPS”
) that includes a plurality of GPS satellites and a GPS-receiver, a method of identifying an estimated location of a GPS receiver, wherein each particular GPS satellite transmits a signal that includes a periodically-repeating code unique to the particular GPS satellite, wherein the GPS receiver receives a signal starting at a particular time, the method comprisinga) for each particular GPS satellite in a set of the GPS satellites, 1) determining a phase offset between the received signal and a replica of the satellite'"'"'s code, wherein the phase offset corresponds to a particular segment of the particular satellite'"'"'s code;
2) computing the length of the code segment;
3) computing the length of complete codes that the particular satellite transmitted after the code segment by the particular time; and
4) calculating a pseudorange for the particular satellite based on the computed lengths; and
b) identifying the estimated location of the receiver by using the computed pseudoranges.
- GPS”
Specification