Receiving device, receiving method, computer program, and portable terminal

A receiving method comprising:

• receiving a signal from a satellite in a global positioning system;
• converting a frequency of the received signal into a predetermined intermediate frequency;
• carrying out synchronization acquisition for detecting a phase of a spread code of a signal of the converted intermediate frequency, and detecting a carrier frequency of the signal of the intermediate frequency;
• by using a synchronization holding unit for generating a spreading code synchronized with the spread code and referring to a counter operating with a clock oscillated from a temperature-compensated oscillator oscillating at a predetermined frequency, assigning and setting, per satellite, the detected phase of the spread code and the detected carrier frequency to each of a plurality of channels independently provided in a corresponding manner to a plurality of the satellites, synchronously holding the spread code and a carrier by using the set phase of the spread code and the set carrier frequency, and also demodulating a message included in the intermediate frequency;
• executing operation control including a positioning calculation using the demodulated message;
• and
• in a sleep period in which a positioning operation is not carried out, the synchronization holding unit causing only the spreading code generation unit to operate, and also the counter that the synchronization holding unit refers to operating.

A computer program for causing a computer to execute:

• receiving a signal from a satellite in a global positioning system;
• converting a frequency of the received signal into a predetermined intermediate frequency;
• carrying out synchronization acquisition for detecting a phase of a spread code of a signal of the converted intermediate frequency, and detecting a carrier frequency of the signal of the intermediate frequency;
• by using a synchronization holding unit for generating a spreading code synchronized with the spread code and referring to a counter operating with a clock oscillated from a temperature-compensated oscillator oscillating at a predetermined frequency, assigning and setting, per satellite, the detected phase of the spread code and the detected carrier frequency to each of a plurality of channels independently provided in a corresponding manner to a plurality of the satellites, synchronously holding the spread code and a carrier by using the set phase of the spread code and the set carrier frequency, and also demodulating a message included in the intermediate frequency;
• executing operation control including a positioning calculation using the demodulated message;
• and
• in a sleep period in which a positioning operation is not carried out, the synchronization holding unit causing only the spreading code generation unit to operate, and also the counter that the synchronization holding unit refers to operating.