关键词: 罗盘, 软件无线电, 频差检测, 中频数字化

Abstract: A fast carrier frequency offset detection algorithm is proposed for the compass navigation signal，which is implemented by DSP.After the IF signal digital down conversion and decimation，it gets the information of carrier frequency offset with small data quantity and improves computing speed of DSP by fitting arctangent in the numerical method.Computer simulation and actual comparison test show that this algorithm can detect the navigation signal’s carrier frequency offset quickly and precisely，and makes the azimuth information of software radio compass calculation more effective.Compared with the traditional frequency offset detection achieved by simulating the frequency discriminator in radio compass，the proposed method has the advantages of high accuracy，flexible programmability and low cost，and it has some potential for application in the future.

Key words: compass, software radio, frequency offset detection, Intermediate Frequency（IF） digitization