Patent ID: 8665149

Claim:
A navigation signal processing apparatus for processing a navigation signal received from a navigation satellite to thereby facilitate navigation signal acquisition of a receiving terminal, the navigation signal processing apparatus comprising: a database; a receiving unit configured to receive the navigation signal from the navigation satellite, including to receive first navigation data and to subsequently receive second navigation data after a time interval synchronized with a code period of the navigation signal; a processing unit configured to detect a frequency offset and a code offset from the navigation signal, including to respectively detect first and second code offsets, and to respectively detect first and second frequency offsets, from the received first and second navigation data; and an operation unit configured to compute a clock offset of the navigation signal that is a difference between the second frequency offset and a Doppler frequency shift, including when navigation satellite information associated with the navigation satellite is not stored in the database, to calculate the Doppler frequency shift using a difference between the first and second code offsets, the time interval, and a carrier frequency and a code frequency set in accordance with the navigation signal, and when the navigation satellite information is stored in the database, to calculate the Doppler frequency shift using a location and a speed of the navigation satellite, a location and a speed of the receiving terminal, and the carrier frequency; wherein the processing unit performs the navigation signal acquisition using the computed clock offset and a search range that is determined by the second frequency offset and the second code offset, but not by the computed clock offset.