GPS时分二进制偏移载波调制信号的高精度无偏抗多径算法

Unbiased multipath mitigation technique for GPS time-multiplex binary offset carrier signal

二进制偏移载波调制信号将在卫星导航系统中得到广泛应用。全球定位系统的L1C信号导频分量采用了时分二进制偏移载波调制,对此信号直接采用码参考波形算法消除多径时的鉴别曲线收敛点存在偏差,从而影响测距偏差。因此,提出一种时分二进制偏移载波调制信号的高精度无偏抗多径算法。通过时分的方式分别生成针对BOC(1,1)和BOC(6,1)分量的本地闸波,以保证鉴相函数在码相位无偏差时等于0。由于更好地利用了BOC(6,1)信号分量,该技术在实现无偏跟踪的同时,还能提高跟踪精度。

B 0C ( binary offset carrier) modulation w ill be widely used in satellite navigation systems. The data and pilot channel of GPS L1C signal was modulated with the BOC ( 1 , 1 ) and the TMBOC ( time-multiplex binary offset carrier) modulation. The discrimination curve of TMBOC modulated signal was characterized with bias when using CCRW ( code correlation reference wave) technique. In order to eliminate the tracking bias, an unbiased multipath mitigation technique was proposed. The novel technique generated two categories of local wave for the BOC ( 1 , 1 ) and BOC ( 6 ,1 ) modulated component respectively, and its discrimination output was zero when there was no code phase bias. The technique can obtain unbiased tracking and a better accuracy because of the better utilization of BOC (6 , 1) signal component.