Patent ID: 8634504

Claim:
A correlation calculating method of correlating a received code signal with a replica code signal by a calculation circuit, the received code signal being obtained by demodulating a received signal, which is a signal obtained by receiving a positioning satellite signal, comprising: sampling the received code signal at ½ chip interval to obtain sampling values; dividing the sampling values into first sampling code and second sampling code, the first sampling code being odd-degree sampling values and the second sampling values being even-degree sampling values; obtaining first correlation result by correlating the first sampling code and a replica code; obtaining second correlation result by correlating the second sampling code and a first delayed replica code, the first delayed replica code being obtained by delaying the replica code by ½ chip; synthesizing the first correlation result and the second correlation result to obtain first synthesis result at ½ chip interval; obtaining third correlation result by correlating the first sampling code and a second delayed replica code, the second delayed replica code being obtained by delaying the first delayed replica code by ½ chip; and synthesizing the second correlation result and the third correlation result to obtain a second synthesis result at ½ chip interval.