基于调制域增强副载波剥离的 GPS M码授权码流提取方法

针对 GPS M码授权码流获取问题,提出 1种新的基于调制域增强副载波剥离的方法。该方法利用 GPS C/A码和 M码码片起始位的相关性,在调制域上利用 BOC调制短码信息对 GPS M码信号进行累加增强,获取授权码流。首先,利用公开的 GPS C/A码辅助获取 GPS信号载波相位和 C/A码码相位；然后,分别利用获得的 GPS信号载波相位和 C/A码码相位,完成 GPS C/A码与交调量的剥离以及 M码授权码的初始相位对准；进一步,利用 BOC调制短码信息在调制域上实现累加增强,完成副载波剥离,获得 GPS M码授权码流；最后,利用实际采集信号对所提方法有效性进行了验证,并与现有方法进行了对比。结果表明,所提方法能够克服带宽内 P(Y)信号旁瓣能量对 M码授权码提 取的影响,可带来 3.5 dB左右的性能改善。

Extraction Method of GPS M Code Authorized Code Stream Based on Modulation Domain Enhanced Subcarrier Stripping

A new method based on modulation domain enhanced subcarrier stripping is proposed to solve the problem ofGPS M code authorization stream acquisition. The proposed method utilizes the start chip correlation between the GPS C/Acode and M code, and uses BOC modulation short code information to accumulate and enhance the GPS M code signal in themodulation domain to obtain the authorized code stream. First, the disclosed GPS C/A code is used to assist in obtaining thecarrier phase and C/A code phase of the GPS signal. Then, the GPS signal carrier phase and the C/A code phase are used toseparate the GPS C/A code from the intermodulation and complete the initial phase alignment of the M code authorizationcode, respectively. Furthermore, the BOC modulation short code information is used to realize the accumulation enhance.ment in the modulation domain, complete the subcarrier stripping, and obtain the GPS M code authorization code stream. Fi.nally, the effectiveness of the proposed method is verified by the actual collected signals, and compared with the existingmethods. The results show that the proposed method can overcome the influence of P(Y) signal sidelobe energy on M codeauthorization code extraction in the bandwidth, and bring a performance improvement of about 3.5 dB.