This paper investigates the coded high PRF radar which is capable of measuring the distance and velocity of moving target in wide range directly and simultaneously. The system uses radar waveform in which carrier wave of each pulse is modulated using bi-phase code of successive random sequences independent in each other. By this method, the system can expand measuring distance to the extend of sequence period having long time interval, and can measure high velocity corresponding to short sampling interval of transmitted pulses.
The system has a unique feature of the measuring distance capability under residued noise and clutter condition in contrast to conventional high PRF system using multi PRF ranging, and additionally has supression capability equal to the signal processing gain against unwanted incoming signal uncorrelated with radar signal. On the contrary, time sidelobe noise generated in the process of sequence correlation influences signal detection performance in case of receiving strong clutter. From a study on application to C-band surveillance radar operating in SEA STATE 4 clutter environment, it is found that the designed system can measure distance up to 150km (resolution 30m) and velocity up to 800m/s for moving target (radar crossection 5m²) under detection probability 0.5 and false alarm rate 10^-8