基于LAS码的星群多目标测控技术研究  

On Multi-Object TT&C Technology for Formation Flying Satellites Based on LAS Code

作　　者：李飞龙[1] 李志强[1] 李广侠[1] 南海涛[2] 孙健俊 

机构地区：[1]解放军理工大学通信工程学院,南京210007 [2]西安卫星测控中心渭南站,陕西渭南714011

出　　处：《飞行器测控学报》2014年第3期188-195,共8页Journal of Spacecraft TT&C Technology

基　　金：国家自然科学基金(No.60972061);国家高技术研究发展计划("863"计划)(No.2008AA12A204)

摘　　要：针对星群多目标同时测控问题,基于星群轨道根数的时延特性和多普勒频移特性分析可得,星群多目标测控的上行链路遥控与测距信号可实现S-CDMA(Synchronous Code Division Multiple Access,同步码分多址),由于星间距离较小,下行链路遥测与测距信号满足QS-CDMA(Quasi-synchronous code division multiple access,准同步码分多址)。上行链路遥控和测距信号形式设计为PCM-BPSK-CDMA(Pulse Code Modulation-Binary Phase Shift Keying-Code Division Multiple Access,脉冲编码调制-二进制相移键控-码分多址),上行链路信号采用Gold序列扩频;下行链路遥测和测距信号形式设计为PCM-BPSK-CDMA,根据总的时延差,提出下行链路采用基于等长脉冲间隔法构造的LAS(Large Area Synchronous,大区域同步)码扩频。结果表明:比特信噪比Eb/N0为10.5dB时,遥控误码率为1×10-6;Eb/N0为9.6dB时,遥测误码率为1×10-5——与达到相同误码性能的Gold序列相比有1dB改善,因此,LAS码相比于Gold码能够获得更好的误码性能。Ground-based multi-object TT＆C （Tracking, Telemetry and Command） technology for clusters of forma tion flying satellites is analyzed. Propagation delay and Doppler frequency shift of formation flying satellites based on satellite ephemeris orbital parameters show that the uplink tracking and ranging signal is synchronous CDMA （Code Division Multiple Access） and it is designed as the form of PCM-BPSK-CDMA （Pulse Code Modulation-Binary Phase Shift Keying-Code Division Multiple Access）, which is spread by Gold sequence. The downlink telemetry and ranging signal is quasi-synchronous CDMA and is also designed as the form of PCM-BPSK-CDMA. Meanwhile, the downlink signal is spread by LAS （Large Area Synchronization） code, which is constructed by a new method of e- qual pulse interval according to downlink time delay error. When uplink Eb/No is more than 10.5 dB, the BER （Bit Error Rate） of tracking information is less than 1×10^-6. When downlink Eb/No is more than 9.6 dB, the BER of telemetry information is less than 1×10^-5, which is improved by 1 dB compared with Gold sequence. The BER per- formance applying LAS code is better than that using Gold sequence.

关 键 词：多目标测控 大区域同步(LAS)码 多用户干扰 星群 时延差 

分 类 号：V556.1[航空宇航科学与技术—人机与环境工程]