船用导航雷达是船舶航行、进出港不可缺少的工具，在船用电子设备中占有重要地位。船用导航雷达中, 数字接收机是核心，对其性能指标要求越来越高，模拟接收机存在中频漂移、灵敏度、距离分辨率不足等问题，本文主要研究船用导航雷达数字接收机中的关键技术，旨在改善数字接收机的性能指标，降低中频漂移，提高接收机灵敏度，节约生产成本。 本文对船用导航雷达数字接收机的基本原理和构成进行分析。结合船用导航雷达脉冲调制的特点以及对远近距离目标的不同要求，对系统算法设计、采样率和量化位数的选取等问题进行了详细分析，完成了带通采样和数字下变频的设计，降低了模拟电路及滤波电路设计的复杂度，以较低的采样频率和数据速率实现了中频信号的数字正交解调。通过匹配滤波、FFT和旁瓣抑制模块来实现频域数字脉冲压缩的设计，抑制距离旁瓣产生的虚假信号，防止信号丢失，提高了对邻近大小目标的分辨能力；有效地解决了雷达作用距离与距离分辨率之间的矛盾，保证了雷达在一定作用距离下提高距离分辨率。 系统模块仿真结果表明，船用导航雷达数字接收机的性能指标均满足设计要求，达到了接收高质量的雷达回波图像的目的。

Marine navigation radar is an indispensable tool for a ship sailing, in and out port, and plays an important role in marine electronic equipment. Digital receiver is the core in Marine navigation radar, and its performance is required more and more higher. Intermediate frequency drift problems, lack of sensitivity and range resolution are resisting in analog receiver. The key technologies is mainly studied in order to improve the performance index, reduce the frequency drift, improve sensitivity and save the cost of production in this paper. The basic principle and composition of marine navigation radar digital receiver are analyzed. Combining with the characteristics of marine navigation radar pulse modulation and the different requirements of far and near distance target, the algorithm design to the system, sampling rate and quantization bits selection problems are analyzed in detail, the design of band-pass sampling and digital down conversion are completed, the complexity of the analog circuit and filter circuit design are reduced and digital orthogonal demodulation of the IF signal is achieved with lower sampling frequency and data rate. The frequency domain digital pulse compression is realized by matching filtering, FFT and side lobe suppression module, which can suppress false signals generated by distance side lobe to avoid the loss of signal, improve the resolution of the target near and far to effectively solve the contradiction between the radar range and range resolution and guarantee to improve resolution in a certain distance. The simulation results of system module show that the performance indexes of marine navigation radar digital receiver can meet the design requirements, and achieve the purpose of receiving high quality radar echo image.