Indian Journal of Science and Technology

Abstract

In modern radars waveform design plays a vital role. In the design of rBackground/Objectives: adars the most significant parameter is the range resolution. With the help of the signal processing tools like auto correlation and ambiguity function various waveform designs can be achieved. Methods/Statistical Analysis: In the proposed paper the discrete frequency coding method of random NLFM (Non Linear Frequency Modulation) signal is described which results in a random like frequency evolution. Random NLFM enables to achieve the thumbtack ambiguity function while minimizing the crosstalk between frequencies. Findings: Random NLFM signals for different lengths are generated which are used in radars and sonars and also their ambiguity plots are obtained. The PSLR (Peak Side Lobe Ratio) and ISLR (Integrated Side Lobe Ratio) for these signals are evaluated and a comparison is made among these signals to identify best NLFM waveform. Application/ Improvements: Non Linear Frequency Modulation waveforms using algebraic random number generators that are quite robust to electronic counter measures and have long duration for long range applications. In future applications of NLFM especially in RADAR/SONAR applications, this idea may result into new methodology.

Keywords: Ambiguity Function, Discrete Frequency Coding, ISLR, NLFM, PSLR, Pulse Compression, Radar