Abstract: In a baseband process circuit unit, a demodulation unit demodulates a received satellite signal which carries a navigation message to obtain a demodulated data. Further, an error bit detection unit detects an error bit from among the demodulated data using a parity code included in the demodulated data. An inconsistent bit detection unit detects an inconsistent bit by comparing the demodulated data with prescribed comparison data. An adoption determination unit determines whether or not to adopt the demodulated data, based on a difference between the error bit and the inconsistent bit. In addition, a correction unit corrects the demodulated data, in a case where the demodulated data is determined to be adopted by the adoption determination unit.

Abstract: A method of determining adequacy of acquisition includes: attempting to acquire a satellite signal from a satellite and decoding first satellite orbit data; and determining the adequacy of acquisition of the satellite signal by using the first satellite orbit data and second satellite orbit data that has been acquired from the satellite.

Abstract: A cross correlation determination method includes: executing a first decoding of decoding a navigation message included in a received satellite signal using a first replica code and a second decoding of decoding the navigation message using a second replica code; and determining the occurrence of a cross correlation using the result of the first decoding and the result of the second decoding.