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联合战术信息分发系统(JTIDS)是Link-16数据链系统的通信终端。当Link-16采用双脉冲结构进行传输时,JTIDS是一种序贯分集为二的直接序列/快速跳频混合扩频系统。为了最小化脉冲噪声干扰(PNI)带来的影响,本文设想在JTIDS接收机内设计一个采用噪声归一化合并方法(NNC)的MSK相干解调器。本文研究了在PNI条件下,对双脉冲结构JTIDS波形采用噪声归一化合并方法进行相干检测的误符号率(SER)性能。为便于分析,假定可以实现跳频解跳、序列同步、码片同步、32位码片序列去扰。此外,假设采用最大似然码片检测,而不是最大似然码片序列检测,因为前一种方法对于JTIDS信号来说更为实际。本文对采用NNC、不采用NNC以及已知完整边带信息的结果进行了比较,结果表明对双脉冲结构JTIDS波形进行相干检测时,采用NNC可以有效地减轻PNI带来的系统性能损失。
The Joint Tactical Information Distribution System (JTIDS) is a communication terminal for the Link-16 data link system. JTIDS is a direct sequence / fast-hop hybrid spread-spectrum system with sequential diversity of two when the Link-16 is transmitting in a two-pulse architecture. In order to minimize the impact of impulsive noise interference (PNI), this paper envisions designing a MSK coherent demodulator in the JTIDS receiver using a noise normalized combining method (NNC). In this paper, we investigate the symbol error rate (SER) performance of the coherent detection of the JTIDS waveform with PNI under the condition of PNI. For ease of analysis, it is assumed that hopping, hopping, sequence synchronization, chip synchronization, descrambling of a 32-bit chip sequence can be achieved. In addition, it is assumed that maximum likelihood chip detection is used instead of maximum likelihood chip sequence detection because the former method is more practical for JTIDS signals. In this paper, the results of using NNC, not using NNC and known complete sideband information are compared. The results show that NNC can effectively reduce the system performance loss caused by PNI when coherent detection of JTIDS waveform of double-pulse structure.