The waveform operation and signal processing design in sea surveillance radar, which radiates radar pulse signals while rotating at fixed revolutions per minute (RPM), for detecting targets is shown. The radar described in this paper has multiple receiving channels to concurrently detect both low and high speed targets such as ships and aircrafts. In pulse repetition frequency (PRF) operations, both low and medium PRF waveforms for low and high speed targets are concurrently applied, respectively. This paper describes an incomplete PRF set design that is capable of resolving range ambiguity, but cannot resolve velocity ambiguity in totality owing to RPM and Doppler resolution conditions for the high-speed target detection. Nevertheless, a method to resolve the velocity ambiguity in the incomplete PRF set and a signal processing design are proposed. The proposed method was implemented and tested on a real radar thereby verifying its functionality and performance using actual data obtained from a real radar.

Some airborne radars provide the raid assessment mode, which enables the operator to separate closely spaced airborne targets, allowing the operator confirm the number of planes in a dense squadron. This paper presents a design of waveform operation, target extraction, and signal processing method for implementation of the raid assessment mode based on an AESA (active electronically scanned array) radar. The function and performance using our proposed method were confirmed through simulations and a flight test in which the raid assessment mode was conducted with the AESA radar mounted on a cargo aircraft.

Linear frequency modulation(LFM) waveforms in pulsed radars are extensively used owing to their excellent Doppler tolerance and low side-lobe level characteristics after pulse compressions. On the contrary, it is difficult to determine target Doppler velocity from single-pulse LFM waveforms because of their excellent Doppler tolerance. If it is possible to detect the range and velocity of targets with only single-pulse transmission and reception, multi-function radars can gain advantages in terms of resource management. In this paper, we propose a method of estimating target velocity using single-pulse LFM waveforms. The proposed method uses range-Doppler coupling and signal to noise ratio loss effects due to Doppler frequency inconsistency between the matched filter and signal during pulse compressions. The proposed method can estimate the target velocity from a few computations through two additional matched filtering processes after the target range detection, and its function and performance are verified via simulations.

Herein, we implement a software-in-loop simulation (SILS) system for fighter radar systems. The implemented SILS system simulates fighter radar environments and hardware by mathematical modeling, generates radar-simulated digital signals, and stores/analyzes simulation results. It includes a personal computer (PC)-based virtual radar processing unit, which can be used to develop radar control and process algorithms and codes and can also examine the functions and performance of the software and code of actual radar processing equipment by connecting actual equipment. Because antenna and transceiver models are included, the performance of the initial hardware designs at the system level can be examined in the simulation environment, thereby increasing the hardware design and development speed. We demonstrate the validity and usefulness of the SILS system, implemented using the radar environment and hardware mathematical models obtained from the development of fighter radars for numerous years, through SILS-based test results.

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