Research On Key Technologies Of Marine Navigation Radar Digital Receiver

Marine navigation radar is an indispensable tool for a ship sailing, in and out port, andplays an important role in marine electronic equipment. Digital receiver is the core in Marinenavigation radar, and its performance is required more and more higher. Intermediatefrequency drift problems, lack of sensitivity and range resolution are resisting in analogreceiver. 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 areanalyzed. Combining with the characteristics of marine navigation radar pulse modulation andthe 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 ofband-pass sampling and digital down conversion are completed, the complexity of the analogcircuit and filter circuit design are reduced and digital orthogonal demodulation of the IFsignal is achieved with lower sampling frequency and data rate. The frequency domain digitalpulse 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 betweenthe 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 marinenavigation radar digital receiver can meet the design requirements, and achieve the purpose ofreceiving high quality radar echo image.