摘要
针对低轨卫星 DSSS通信中的信号载频提取难点 ,对载频 -码元的时频联合二维搜索的快速算法进行了改进。利用 FFT在频域处理循环相关 ,有效地降低了搜索的运算量 ,在 6ms内同时捕获扩频信号的载频和码起点。以 ADSP BF5 3 3构建其手持终端的硬件平台 ,体积、功耗小 ,抗干扰能力强 ,在 -2 1 d B的低信噪比下仍能够稳定工作。最后给出了试验数据并进行了分析。
According to the carrier-frequency capture of low earth orbit (LEO)′s direct sequence spread spectrum (DSSS) communication,a method of the carrier-frequency and code start-point planar search is improved. Using the method both code start-point and carrier-frequency are get at the same time. Through FFT,the calculation of the cycle-correlation is decreased,and one planar search only needs 6 ms. The palmtop device is set up with ADSP BF533,which is small and power-down. Furthermore,the anti-jamming capability of the system is good,and it can steadily work in the low-SNR environment below -21 dB. Finally,experimental data are analyzed.
出处
《数据采集与处理》
CSCD
2004年第2期174-179,共6页
Journal of Data Acquisition and Processing
关键词
扩频通信
载频提取
DSP
信噪比
信号检测
卫星通信
communication
low earth orbit
low-SNR
DSSS
Doppler frequency shifting
carrier-frequency capture
two-dimensional search
