Abstract：This paper studies the accurate tracking problem under the condition of unknown or changing turning rate, an adaptive coordinated turning tracking algorithm based on UKF is proposed. The algorithm makes full use of the dimensionality extension technology and the adaptive fading factor technology, continuously estimates the turning rate in real time and adjusts the process noise and its corresponding gain based on the fading factor. At the same time, adaptively adjusts the sampling range of the unscented Kalman filter algorithm to make the sampling points closer to the real state of the target. Simulation results show that the algorithm achieves good tracking performance when the turning rate changes, and effectively improves the accuracy and stability of tracking maneuvering target.

Abstract：With the continuous development of military science and technology, the storage system for storing key and sensitive data is becoming more and more important in the military field. As an important data signal working band, L-band has been widely used in satellite navigation, warning radar, communication reconnaissance and other fields. This paper introduces a high-speed serial bus technology based on JESD204B, an ultra-low jitter clock scheme and the latest high-speed ADC to realize L-band RF direct acquisition. The sampling rate can reach 6 GS/s, and the measured SFDR can reach more than 67 dBFS,the direct acquisition data is digitally down converted through FPGA and sent to the storage unit for data storage.

Abstract：Aiming at the cooperative detection task in spatial perception, using the detection channel capacity as the optimization target, the bee colony algorithm is improved and the joint optimization of the swarm trajectory and power is realized. Firstly, a multi-transmit and multi-receive cooperative detection model is constructed. Based on the perspective of information theory, the channel capacity of the detection model is deduced and used as the objective function for optimizing the power and radiation power of unmanned clusters. The factors that affect and constrain the objective function are analyzed and sort out one by one, so as to clarify the optimization objectives and constraints. Then, aiming at the shortcomings of the bee colony algorithm, its search strategy and parameter optimization method are improved. Furthermore, a dynamic optimization process of collaborative detection based on the modified bee colony algorithm is constructed. Finally, through simulation verification and algorithm comparison, it shows that the algorithm in this paper can improve the perception ability of UAV swarm cooperative detection.

Abstract：For wideband active phased array radar, channel mismatch could affect array processing performance, which can be compensated by channel equalization technology. Most of the existing studies are based on simulation models, supported by few measured data, and the equalization evaluation method is too single. In this paper, a comprehensive evaluation system combining residual mismatch characteristics, pulse compression and beam forming antenna pattern is constructed, which can evaluate the equalization effect more comprehensively. In addition, taking an airborne active phased array radar as a platform, the frequency domain equalization algorithm of 150 MHz wideband signal is tested in engineering, and the rectangular window weighted equalization algorithm is proposed. The simulation and measured data both show that the algorithm improves the equalization effect.

Abstract：The k value of OS-CFAR detector has the defect of uncertain value taking method. Considering the target echo signal in practical engineering application, after passing through the pulse compression matched filter, the output is the shape of SA function bell envelope. Therefore, when the k value is selected, the background clutter estimation may be taken into the energy unit of the interfering target, which makes the clutter estimation too large and leads to missed detection of the target. In this paper, a modified k-value method is proposed. When the OS-CFAR detector selects k-value, the target echo is considered as an extended target, so that the value of k is more accurate. Through detailed simulation experiments, it is found that the performance of OS-CFAR detector changes with k value under the two conditions of whether there are interfering targets in the reference sliding window, and it is proved that the OS-CFAR detector with modified k value has better performance in multi-target environment.

Abstract：In order to optimize and upgrade radar display technology, a radar A-display circuit based on FPGA is designed and implemented in this paper. The FPGA integrated radar display IP core is used to realize the sampling, processing and displaying of radar front-end signals. The design takes advantage of the huge programmable logic unit of the FPGA chip. The rich mature IP cores realize the functions of receiving, sampling, transforming and displaying the radar input signal of the single-chip logic chip. It simplified the hardware structure of the previous radar display system, reduced the display delay of the signal, and improved the radar display performance. At the same time, the design can realize other radar display methods by further modifying the internal IP core, so that it has the versatility and scalability of hardware devices.

Abstract：Aiming at solving the problem that the traditional electrical direction finding technology cannot meet the requirements of future electronic reconnaissance systems, a microwave photonic direction finding compact system based on phase interferometer principle is proposed and studied by simulation in this paper, using the double parallel Mach-Zehnder(DP-MZM) modulator to realize direction finding with ultra-wide band and high accuracy. The simulation and experiment results show that the proposed system can achieve the phase difference measurement from -90° to 90° in the frequency range of 5~40 GHz, and the measuring error is within ±2°.

Abstract：The noise and interference are usually described by Gaussian distribution in the traditional track association model, while the massive use of electronic equipment makes the battlefield electromagnetic environment more and more complex. To address this problem, this paper proposes a multi-target trajectory association model based on uncertainty distribution, by introducing uncertainty distribution function to describe the noise and interference in the trajectory association process, so that the model is more in line with the real situation on the battlefield, constructs a multi-target trajectory association process in the case of dual sensors, and uses classical algorithms to simulate and verify different numbers of targets. The results show that the model proposed in this paper outperforms the traditional model under the same conditions and can bring improvement in the association accuracy.

Abstract：Small size, low power consumption and low probability of intercept are the characteristics of frequency modulation continuous wave(FMCW) radar. It is widely used in vehicle navigation radar, low probability of intercept radar and so on. In this paper, the system draws on the design of the MIT coffee can radar, a small S-BAND FMCW radar system is developed which draws on the design of the MIT coffee can radar and uses the modularized integrated microwave device. The system designs simple array antenna to increase the echo intensity, adjusts electronic circuit boards to enhance system stability, improves audio interface to make the system more widely used and uses Range Doppler(RD) algorithm to measure target velocity. Furthermore, a modified RD imaging algorithm was implemented to the original stop-and-go static model to compensate for the effect of Doppler stretching on synthetic aperture radar(SAR) imaging during motion. The simulation and experiment results show that the system is reasonable and reliable.

Abstract：In the process of radar to sea detection, the near-range sea clutter echo power is high, which seriously affects the radar receiver work and subsequent signal processing. In order to balance the gain and sensitivity of radar receiver, a reasonable design of sensitivity time control (STC) curve is needed. This paper introduces four STC design curve methods using GARCH model, polynomial function, radar distance equation and exponential function, and compares and analyzes the near-range sea clutter suppression performance of the four STC curves by using the measured data under high and low sea conditions. The experimental results show that the STC curves in the form of radar distance equation have significant performance in suppressing sea clutter in both high and low sea states; the STC curves modeled by GARCH model are suitable for low sea states; the STC curves in the form of polynomial and exponential are close to each other in different sea states.