Patent ID: 8149163

Claim:
A GPS compound device having a configuration including a GPS receiver, comprising: an integration processor for outputting a position, a velocity, and an azimuth of a moving body; an error estimator for estimating at least a velocity error and an azimuth error of the outputs from the integration processor based on at least an output from the GPS receiver and the outputs from the integration processor; and a GPS abnormality detector for detecting an abnormality of the output from the GPS receiver based on a difference between at least one of a pseudorange measurement and a Doppler frequency measurement of the output from the GPS receiver and an estimated value of the measurement, wherein, when the abnormality is detected by the GPS abnormality detector, an abnormal period is counted, and based on comparison of the count value with a predetermined threshold, the output from the GPS receiver is determined whether to be treated as abnormal or normal.