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Radars used by air-crafts have two important characteristics; First, they should have a real-time signal processing system finishing signal processing before deadline while getting and processing successive in-phase and quadrature data. Second, they can cover a lot of modes including A2A(Air to Air), A2G(Air to Gound), A2S(Air to Sea), and Ground Map(GM). So the structure of radar signal processing SWs in modern airborne radars are becoming more complicate. Also, the implementation of radar signal processing SW needs to reuse common code blocks between other modes for efficiency or change some of the code blocks into alternative algorithm blocks. These are the reason why the radar signal processing SW framework suggested in this paper is taking advantage of modular programming. This paper proposes an modular framework applicable on the airborne radar signal processing SW maintaining the real-time characteristic using the signal processing procedures for A2G/A2S as examples. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

A target-tracking method using the ground moving target indicator (GMTI) mode on active electronically scanned array (AESA) radar is proposed. The GMTI mode can operate in wide ground areas. However, the 3-dB beamwidth of the X-band radar is narrow, and a target is detected on multiple adjacent beams. To delete overlapping target plots, beam-to-beam processing considering a real-time system is proposed. In addition, a track while scan (TWS) multiple-target-tracking algorithm was constructed for the system. Through a flight test with true car mounted GPS, it was confirmed that the real-time processing ability and target-tracking performance of the GMTI algorithm were satisfactory. [ABSTRACT FROM AUTHOR]

An airborne radar echo signal includes signals returned from clutter and a target; thus, simulating the signal from the clutter may be crucial for predicting and analyzing accurate radar performance. Because it can be extremely difficult and expensive to obtain real measured signal data for various scenarios, an accurate signal generation method is required. Existing weather clutter and ground clutter simulators for an X-band airborne radar are combined to simulate the echo signal when two clutters exist simultaneously. The weather clutter effect becomes more significant with increasing frequencies, such as in the X-band. The proposed simulator can generate time-do- main signals by considering the random characteristics of the clutter signal and the Doppler effect caused by the movement of aircraft and clutter. In addition, a simple scheme is proposed for generating signals from artificial structures. Finally, the finite bandwidth of the transmitted chirp signal is calculated to improve the accuracy of the generated signal. [ABSTRACT FROM AUTHOR]

We present a ground clutter reflectivity calculation method and a signal generation model of the simulated sea/land clutters of airborne radars using real navigation and radar operation information. The navigation and radar operation information were obtained by loading airborne radar on aircraft. The real navigation information and real sea/land clutters were obtained in the sea and land regions, and sea/land clutter reflectivity values calculated using the presented method were compared with the values of sea/land clutter reflectivity models of earlier studies. We confirmed the validity of the proposed sea/land clutter generation model by comparing real and simulated sea/land clutters. [ABSTRACT FROM AUTHOR]

The modern active electronically scanned array (AESA) airborne radar features an interleaved mode, whereby situational awareness can be maximized via incorporation of the radar's electronic beam pointing capability. This interleaved mode can enable simultaneous operation of two or more modes, such as the air-to-air and sea surface-search modes, via the technique of time-sharing. One of the key requirements for successful realization of the interleaved mode is a beam scheduler design that facilitates effective control of the allocated resources for each mode. Thus, in this paper, we propose an effective beam scheduler that can control the allocated resources for each mode through the mode-switching option based on the radar's frames, bars, and beams. Furthermore, the proposed beam scheduler involves the mode-switching decision logic and calculates the processing ratio for each mode. [ABSTRACT FROM AUTHOR]

The results of the fabrication of active electronically scanned array (AESA) antennas with low-profile, low-weight, wide-scan, and thermal stability characteristics for aircraft-mounted radar are described. To reduce the size and weight of the antenna, a transmit– receive block is constructed in a quasi-tile structure in which the radio-frequency circuit-related transmit–receive module is a brick type, which is a flat structure, and the control board is a tile type, which is a stacked structure, to reduce the depth of the front of the antenna. In addition, the depth of the rear part of the antenna was reduced by manufacturing power and plate-shaped control-related modules at the rear of the antenna. The reduced antenna depth maximizes the effective isotropic radiated power (EIRP) and gain to noise temperature (G/T) by enlarging the antenna aperture. The manufactured antenna can scan a wide angle of ±70°. The cooling efficiency is improved by using a dual cooling structure that allows the cooling water to pass through the front cooling plate and then through the rear cooling plate. The EIRP of the manufactured AESA antenna is 104.04 dBmi, and G/T is 7.46 dB/K in Taylor weighting. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Some airborne radars are equipped with a mode to quickly detect and track targets that approach the front of an aircraft at a high speed from a far distance. This paper explains the use of high pulse repetition frequency(HPRF) waveforms for operating this forward high-speed-target detection mode. HPRF waveforms are not ambiguous in reference to the target velocity, but they are so in the case of the target range. Therefore, the use of HPRF waveforms requires the resolving of the range ambiguity to track targets using their range information. This paper presents a design of HPRF waveform operation, target range extraction, and signal processing for target detection in the forward high-speed-target detection mode based on active electronically scanned array(AESA) radars. A waveform operation method for target tracking is then presented. Flight test results in the forward high-speed-target detection mode are shown based on the AESA radar and proposed method. [ABSTRACT FROM AUTHOR]

Simulation of the strong clutter occurring from the airborne radar is essential in the efficient development and performance evaluation of the aircraft radar system. If the efficient simulation of the clutter can be successful, algorithms can be proved and analyzed and also the performance evaluation is possible in the laboratory environment. Therefore, development and implementation of the airborne radar system can be achieved very economically in the effective way. However, the clutter simulation procedure is very difficult and tedious since the clutter environment changes in numerous ways as it depends on the flight path, direction of antenna beam, reflectivity of the surface, etc.. Thus, in this paper, the general Doppler spectrum model is suggested for efficient simulation of the various clutter environment. Also, it is shown that the various type of clutter in time domain can be generated easily by changing and adjustment of parameters in the general Doppler spectrum model. [ABSTRACT FROM AUTHOR]

This study presents the results of the acquisitions of Doppler beam sharpening(DBS) images, obtained through flight trials of the airborne active electronically scanned array(AESA) radar. To use the AESA radar for DBS image acquisition, we designed methods for beam operation and image formation considering the beam operation peculiarities of the AESA radar. Selection methods of pulse repetition frequency(PRF) and waveforms to achieve the required azimuth resolution of the images are described, and the steps for implementation of our image formation method are presented and explained. Under the condition of mounting the AESA radar on the ramp door of cargo plane, methods for obtaining DBS images through flight trials are also explained, and the obtained images are compared with aerial ground photographs. [ABSTRACT FROM AUTHOR]