Patent ID: 8125389
Filing Date: 2012-02-28
Classification: G01S

Abstract:
1. An apparatus comprising: a clock module configured to generate a clock signal; a pseudorange measurement module configured to determine a plurality of first pseudoranges based on the clock signal and a plurality of respective wireless television signals received by an apparatus, wherein each of the first pseudoranges represents a difference between a time of transmission of the respective wireless television signal from a respective transmitter and a time of reception of the respective wireless television signal at the apparatus and a time offset of the clock signal; a frequency offset measurement module configured to determine a plurality of first estimates of frequency offsets of the wireless television signals received by the apparatus based on the clock signal; an estimation module configured to determine a first estimate of a location of the apparatus based on the first pseudoranges, the first frequency offsets of the wireless television signals, and locations of the transmitters; and a receiver module configured to receive indications of times of transmission of the wireless television signals and measurements of the frequencies of the wireless television signals, wherein the measurements of the frequencies of the wireless television signals are determined at one or more monitor units receiving the wireless television signals at known locations; wherein the pseudorange measurement module is further configured to determine the plurality of first pseudoranges based on the clock signal, the plurality of respective wireless television signals received by the apparatus, and the times of transmission of the wireless television signals; wherein the frequency offset measurement module is further configured to determine the plurality of first estimates of the frequency offsets of the wireless television signals received by the apparatus based on the clock signal and the measurements of the frequencies of the wireless television signals; and wherein the estimation module comprises: a pseudorange processing module configured to determine a first interim estimate of the location of the apparatus, and a first interim estimate of the time offset of the clock signal, based on the first pseudoranges; and a Doppler processing module configured to determine a first interim estimate of the velocity of the apparatus, and a first interim estimate of the frequency offset of the clock signal, based on the first estimates of the frequency offsets of the wireless television signals.