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CDMA作为一种抗噪声强、带宽分配灵活,保密性强的传输接入方式被广泛的应用于民用、军用低轨卫星通信系统中。而信号的捕获和同步分析对于设计一个可实现的低轨卫星CDMA接收机是至关重要的。在低轨卫星信道上的CDMA传输必须着重考虑以下两点:低轨卫星信道上的衰落以及相对较大的多普勒频移。本文针对低轨卫星信道特征,着重分析了在此信道上的信号检测(Signal Detection),初始的码捕获(Code Acquisition),载波捕获(CarrierAcquisition)方法以及性能,并给出了基于FPGA实现的方案。
CDMA is widely used in civil and military LEO satellite communication systems as a transmission access method with strong anti-noise, flexible bandwidth allocation and high confidentiality. Signal capture and synchronization analysis is crucial to designing a realizable LEO satellite CDMA receiver. CDMA transmission over low orbit satellite channels must focus on the following two points: the fading on the LEO satellite channel and the relatively large Doppler shift. In this paper, we focus on the characteristics of low-orbit satellite channels, and focus on the Signal Detection, Code Acquisition, Carrier Acquisition methods and performance on this channel, and give a scheme based on FPGA .