Real Time Design and Realization of Digital Radar Pulse Compression Based on Linear Frequency Modulation (LFM) without Components around Zero Frequency Using FPGA

Abstract

Good range resolution can be achieved with a shorter pulse. But on the other hand, shorter pulses need more peak power. The shorter the pulse gets, the more should its peak power be increased so that enough energy is packed into the pulse. High Peak Power makes the design of transmitters and receivers more difficult since the components used to construct these must be able to withstand the peak power. One way to overcome the problem of high peak power is to convert the short pulse into a long one and using some form of modulation to increase the bandwidth of the long pulse so that the range resolution is not compromised. This technique is called Pulse Compression and is used widely in Radar applications where high peak power is undesirable. This paper introduces a new radar pulse compression system, using a type of Linear Frequency Modulation (LFM) signal which lacks components around zero frequency. A core structure of a pulse processor is similar to a standard matched filter, modified to suit the application. Flexibility in the design permits the use of multiple code types and lengths needed, which eliminate ambiguities, caused by high pulse repetition frequencies. The device used in this application is a field programmable gate array (FPGA) which has distinct advantages compared to other application specific integrated circuits (ASIC) for the purposes of this work. The FPGA provides flexibility, for example, full reconfiguration in milli-seconds and permits a complete single chip solution.