Importance

Loading Importance Indicators...

Abstract

A demodulator circuit in which N satellite signals included in N radio waves transferred from N satellites are detected by removing noise codes and carrier waves modulated by the satellite signals and the noise codes from the radio waves to measure a position of a movable body is disclosed. N pseudo-noise code signals indicating pseudo-noise codes corresponding to noise codes peculiar to the satellites are generated in N pseudo-noise code generators, and N correlation signals indicating degrees of correlation between the radio waves and the N pseudo-noise code signals are generated in N correlation units. Therefore, the noise codes are removed from the radio waves. Also, M carrier oscillating signals corresponding to each of the carrier waves of the radio waves are generated in (N.times.M) carrier local oscillators, and the N correlation signals are frequency-converted into (N.times.M) base signals with the (N.times.M) carrier oscillating signals in (N.times.M) orthogonal frequency converters. Therefore, the carrier waves are removed from the radio waves. Thereafter, the satellite signals of the satellites are detected by time-integrating N base signals relating to N carrier oscillating signals of which frequencies agree with those of the carrier waves.

Loading the Abstract Image...

First Claim