Radar Seeker Research Articles

Multi-Group of Dual-Frequency Pulse Waveform Design for Anti-Range Eclipse of High PRF PD Guidance Radar

Range eclipse is a serious problem in high pulse repetition frequency (PRF) pulse doppler (PD) terminal guidance radar. In this paper, we propose a new scheme, which exploits multi-group of dual-frequency pulse waveform, for anti-range eclipse. Each group contains two pulse waveforms with different PRF, which has its own range region of anti-range eclipse and anti-range ambiguity simultaneously. In the scheme, only one pulse group works at a moment, which can avoid range eclipse and effectively measure target distance. According to the changing of target distance, radar switches the pulse group to other group to guarantee target in the range region of no eclipse in the tracking term. Simulation results show that this method can effectively prevent high PRF PD radar seeker from range eclipse.

A Novel Decoupled LOS Rate Estimator for Terminal Guidance

An novel decoupled estimation algorithm based on kalman filter is presented to solve the line-of-sight (LOS) rate estimation problem in terminal guidance of air-to-air combat. The measurements of target azimuth and elevation are obtained by missile-borne active radar seeker which use a monopulse doppler radar. As it cant be directly measured by this kind of radar, the LOS rate which is needed as the input of guidance law should be estimated from these angle measurements. The close-loop simulation of LOS rate estimation in typical terminal guidance scenario that an air-to-air missile seeks a military fighter validates the presented algorithm.

A Novel Decoupled LOS Rate Estimator for Terminal Guidance

An novel decoupled estimation algorithm based on kalman filter is presented to solve the line-of-sight (LOS) rate estimation problem in terminal guidance of air-to-air combat. The measurements of target azimuth and elevation are obtained by missile-borne active radar seeker which use a monopulse doppler radar. As it cant be directly measured by this kind of radar, the LOS rate which is needed as the input of guidance law should be estimated from these angle measurements. The close-loop simulation of LOS rate estimation in typical terminal guidance scenario that an air-to-air missile seeks a military fighter validates the presented algorithm.

Modelling and simulation of spatial‐temporal correlated K distributed clutter for coherent radar seeker

Modelling the clutter with accurate spatialtemporal correlation, amplitude statistical characteristic and coherence is significant to the evaluation of constant false alarm rate (CFAR) detection performance for coherent radar seeker in clutter. In this study, the authors propose a modelling method for spatialtemporal correlated coherent K distributed clutter. At first, with the assumption that clutter shape parameter is known, the authors estimate the scale parameter of K distributed clutter by calculating the clutter power of the range reference cell of CFAR detection according to the radar seeker operating circumstance. Then, they model the temporal correlated coherent K distributed clutter and spatial correlated coherent K distributed modulation component, respectively, by employing exogenous modelling method. The authors propose to modulate the temporal clutter with spatial modulation sequence to obtain spatialtemporal correlated coherent K distributed clutter for multiple range reference cells of CFAR detection. Finally, they show the validity of the proposed modelling method by simulation.

A novel pulsed Doppler radar seeker modeling method used for closed loop trajectory simulation

A novel pulsed Doppler radar seeker modeling method used for closed loop trajectory simulation

A novel SINR and mutual information based radar jamming technique

The improvements of anti-jamming performance of modern radar seeker are great threats to military targets. To protect the target from detection and estimation, the novel signal-to-interference-plus-noise ratio (SINR)-based and mutual information (MI)-based jamming design techniques were proposed. To interfere with the target detection, the jamming was designed to minimize the SINR of the radar seeker. To impair the estimation performance, the mutual information between the radar echo and the random target impulse response was used as the criterion. The spectral of optimal jamming under the two criteria were achieved with the power constraints. Simulation results show the effectiveness of the jamming techniques. SINR and MI of the SINR-based jamming, the MI-based jamming as well as the predefined jamming under the same power constraints were compared. Furthermore, the probability of detection and minimum mean-square error (MMSE) were also utilized to validate the jamming performance. Under the jamming power constraint of 1 W, the relative decrease of the probability of detection using SINR-based optimal jamming is about 47%, and the relative increase of MMSE using MI-based optimal jamming is about 8%. Besides, two useful jamming design principles are concluded which can be used in limited jamming power situations.

Signal processing method of a novel polarized array radar seeker

This paper proposes a novel polarized radar seeker based on the polarized antenna array. A fully polarized signal processing method for the proposed radar seeker is studied under the environments with electromagnetic interferences. A dual polarized antenna array is employed to transmit and receive the radar signals. The instantaneous polarization signal processing technique is used to detect and recognize the targets. The direction of arrival(DOA) of the target is measured through the spatial spectrum with high resolution for the polarized array radar seeker system. The fully polarized signal model of the polarized array radar seeker is formulated and a specific signal processing algorithm is expounded. The theoretical research and numerical simulation results demonstrate that the proposed radar seeker has good performances in target detection and electronic warfare. The research results can provide an effective technical approach to develop and research the new generation radar seeker.

Single-Pulse System of Radar Anti-Aimeds Jamming Performance

In modern warfare, electronic jamming air defense missile weapon system is the greatest threat to the seeker for terminal guidance radar interference is an important aspect of electronic interference. Successful interference allows the weapon system hit rate to reduce or even out of control. Therefore, analysis of the impact of interference on radar seeker to intercept and track the performance of meaningful analysis and modeling, this paper mainly targeting blanket jamming interference and interference conditions of the monopulse system radar seeker performance were analyzed.

Detection of chaff centroid jamming aided by GPS/INS

Chaff centroid jamming released by vessel makes the target indicated azimuth angle of radar seeker of anti-ship missile bias off the target. The failure to detect the presence of chaff centroid jamming is catastrophic to target tracking for the radar seeker. In this study, the authors take the azimuthal in-phase monopulse ratio of radar seeker as test statistic and detect the presence of chaff centroid jamming with the aid of GPS/INS. Probability density functions of the azimuthal in-phase monopulse ratio when jamming is absent and present are derived at first. Then the authors propose a method using the measured information of both GPS/INS and radar seeker to estimate the target off-boresight azimuth angle which is vital for detection threshold setting. Finally, the authors show the performance of the chaff centroid jamming detection by simulations and analyse the effects of some key jamming parameters on detection performance.

Line-of-Sight Angle Rate Reconstruction for Phased Array Strapdown Seeker

The phased array strapdown radar seeker’s detecting information is coupled with missile attitude information. Hence, the measurement information can not be used for proportional navigation directly. The method of reconstructing inertial line of sight (LOS) rate in phased array strapdown seeker is presented using the missile-target relative motion geometric and filtering algorithm. Considering measurement noise and nonlinearity of the phased array strapdown radar guidance systems, the principle of unscented kalman filter (UKF) is introduced to estimate LOS rate. The simulation results show that the reconstruction method is correct and the extraction of LOS rate is effective.

A hybrid STAP approach to target detection for heterogeneous scenarios in radar seekers

Adaptive detection of moving targets on the sea is important for radar seekers. Recently, more attention has been paid to the deleterious effect of clutter heterogeneity on space-time adaptive processing (STAP) for pulse Doppler radar. Since secondary samples are no longer statistically independent and identically distributed (IID) in heterogeneous environments, this is subjected to a great challenge to target detection for radar seekers. Due to the fact that chaff jamming severely affects the performance degradation of target detection, the hybrid detection algorithm is proposed to suppress the sea clutter and chaff jamming. Firstly, the range cells can be classified into two regions according to the power, namely clutter region and hybrid region. Then we propose different algorithms to process two regions. The fixed point (FP) estimator is used to estimate the clutter covariance matrix in clutter region. While the power selected training (PST) algorithm is used to select the homogeneous secondary samples, and an algorithm based on two-step subspace projection for hybrid interference suppression is presented in hybrid region. Finally, the proposed Pareto-based generalized likelihood ratio test (PBGLRT) detector can detect the slowly moving targets in heterogeneous interference. Simulation results show that the PBGLRT detector outperforms both the low rank normalized adaptive match filter (LRNAMF) and normalized adaptive match filter (NAMF) detectors against interference heterogeneity.

Simulation of Digital Beam Forming for Radar Seeker

A scheme for simulation of DBF used in radar seeker by Simulink is proposed in this paper. Considering the feature of digital devices, an optimized modular simulation model is built up. Experiments show that the model parameters are flexible and results are reliable, which can be used in hardware design for reference.

A Review of Synthetic Aperture Radar Seeker Related Technology Research

Synthetic aperture radar seeker (SARS) is the extension in the field of the synthetic aperture technology, and now has become a hot spot in the research and development of radar seeker. In this paper we summarized the research of the SARS related system and imaging guidance related technology. We analyzed the way of long range ballistic missile using matched guidance at the front stage of ballistic trajectory and using target search guidance at the end of ballistic trajectory. Finally we prospect the direction of SARS development.

New method for passive radar seeker to antagonize non-coherent radar decoy

Using super resolution direction of arrival (DOA) estimation algorithm to reduce the resolution angle is an effective method for passive radar seeker (PRS) to antagonize non-coherent radar decoy. Considering the power and correlation property between radar and non-coherent decoy, an improved subspace DOA estimation method based on traditional subspace algorithm is proposed. Because this new method uses the invariance property of noise subspace, compared with traditional MUSIC algorithm, it shows not only better resolution in condition of closely spaced sources, but also superior performance in case of different power or partially correlated sources. Using this new method, PRS can distinguish radar and non-coherent decoy with good performance. Both the simulation result and the experimental data confirm the performance of the method.

Anti-tank guided missiles of western Europe, Israel and India

Anti-tank guided missiles are designed to hit and destroy heavily armored tanks and other armored fighting vehicles. This review offers a historical and technical overview (development of missiles throughout generations and basic data about combat and operational actions) of this type of weapons in Western Europe, Israel and India. The review also offers prices of some missiles and tendencies of development in this branch. Anti-tank guided missiles are primarily designed to destroy armoured tanks as well as other armoured vehicles. Anti-tank guided systems differ in size, from small ones (shoulder-launched missile weapons carried by a single person) to complex weapon systems (crewserved, vehicle-mounted and airborne systems). The first generation of anti-tank guided missiles is a manually guided MCLOS (Manual Command to Line of Sight) projectile requiring an operator to guide and steer it to a target by a joystick. Vickers vigilant is a British anti-tank wire-guided missile, produced in 1956. The Bantam (Bofors Anti-Tank Missile) or Robot 53 (RB 53) is a Swedish anti-tank wire-guided missile, produced in 1963. Cobra is a German - Swiss product which entered the operational use in 1956. It was replaced by Cobra 2000 and Mamaba systems, which are anti-tank guided missiles of the first generation, but with improved guidance and electronics. ENTAC (Engin téléguidé anti-char) or MGM Petronor-32A is a French anti-tank wire-guided missile, widely spread and still in the operational use in many countries, France included. It is one of the best missiles of its generation. SS.10 preceded the ENTAC system. Its country of origin is the same (France), and it has been in the operational use since 1950. The SS.11 is a modification of the SS.10 system, used for launching from helicopters. The second generation of anti-tank guided missiles is designated by the abbreviation SACLOS (Semi-Automatic Command to Line of Sight) and represents a semiautomatic guidance of missiles in line. Generally, there are two SACLOS operating principles: - Wire and Radio guided SACLOS - Beam -Riding SACLOS ERYX is a short-range portable SACLOS produced by France and Canada. HOT, existing in three variations (HOT1, HOT 2, HOT 3), is one of the best projectiles of this generation, created as a product of cooperation of Germany and France. Milan (Missile d'Infanterie Léger Antichar) is a European leader escadrille SACLOS missile system. PBS 56 BILL 1 (Bofors, Infantry, Light and Lethal) is an anti-tank guided missile of the Swedish Army. BILL 2 is the heir of the BILL 1 system. LAHAT (Laser Homing Attack or Laser Homing Anti-Tank) is an anti-tank guided missile of low gravity, developed in 1992. Its country of origin is Israel. MAPTS (Man Portable Anti-Tank System) is an anti-tank guided missile with Beam-Riding SACLOS guidance. The country of origin is also Israel. NIMROD is a long-range anti-tank guided missile, created as a project of the Israel Aerospace Industries. Most technologically advanced and the last generation of antitank guided missiles is the third generation. These are the best technological and operational missiles currently available on the world market. This generations fully relies on lasers, electro-optical imagers or W-band radar seekers in the nose of the missile. MTBLAW is the third generation of anti-tank guided missiles developed by Sweden and Great Britain. The warhead and a part of the missile guidance system are based on BILL 2. PARS 3 LR, known also as TRIGAT-LR, is along-range anti-tank guided missile from Germany, still under development. British BRIMESTONE is designed according to a RAF request for a long-range anti-tank guided missile which allows strike aircraft to attack armoured vehicles. Spike, a 'fire and forget' missile, is intended for infantry use and is vehicle-mountable. Its country of origin is Israel. Nag is considered to be a cutting-edge antitank guided missile. It is the third generation of fire and forget systems. The system can operate in all weather conditions with a range from 4 to 7 km. The country of origin is India.

Data Preprocessing Circuit Designs and Analyses for Subsonic Cruise Missile Infrared Image Seeker

In this literature, a data pre-processing circuit designs and analyses for an infrared image seeker of a subsonic cruise missile are proposed. The flight speed of the missile is 250m/s. Therefore, automatic contrast control and automatic brightness control are usually needed to keep wanted contrast and brightness for best image properties in target recogni- tion and tracking; especially for the missile at the terminal approaching phase to prevent signal saturation. Signal satura- tion implies target lost. The major parameters of imaging systems for contrast and brightness controls include average, maximum and minimum of gray level of the whole picture in the sampling interval. Therefore, the overall system is a compli- cated nonlinear sampled-data control system. It is difficult to describe, analyze and design the system. In this literature, the over- all system is first decomposed into two linearized sampled-data control systems to get needed loop compensations, and verified by a special range-dependent testing signal to the overall system secondly. The controlled system is further verified by a thermal plate and real flight testing. Testing results give the proposed method can provide effective way to analyze and design the consid- ered system. INTRODUCTIONS Multiple sensors for ECCM are generally expected for missile homing systems. The first dual seeker application of the world for subsonic antiship missile is the HF-2 devel- oped in Taiwan. It includes a Radar seeker and an IR image seeker with data fusing algorithm. This application prompts the capability for ECCM from chaff jamming to RF seeker and thermal jamming to IR Image seeker. The problem for IR image seeker for the missile application is the thermal energy to the charge-coupled device (CCD) (1-3) is the fourth power of the reciprocal the distance between image seeker and thermal source; i.e.; missile and target. It needs faster automatic gain control (AGC) for contrast and auto- matic pedestal control (APC) for brightness (4-7) to keep best imaging properties for target recognition and tracking; especially for the missile at terminal approaching phase. Slower response for coping with thermal energy increasing will make the signal output be saturated; i.e., all white of full frame and will lost tracking centre point for missile guidance. It this literature, models for contrast, brightness and dy- namic signals are proposed to analyses and designs of the AGC and APC circuit loops. The AGC and APC are the pre- processing systems of the video signal. The block diagram considered is shown in Fig. (1). It includes thermal sensors, analog circuits, and microprocessor. The output of the proc- essed signal satisfies RS-170 video standard. The sensor elements for thermal imaging is 256�256 focal plane CCD(1-3), the gray level of each element is digitalized to be 256 states with 8bit A/D converter. Fig. (2) shows typical minimal and maximal gray level of a thermal picture. Analog circuit gives faster signal amplification in forward-loop. It needs 256� 256� 60�10Hz at least for 60Hz picture

Model for simulating the flight control system of a antiship missile

The paper analyzes a program for simulating the flight control of an antiship missile with the radar seeker. The paper analyzes a mathematic missile model an autopilot model and a target model. Thus obtained results enable a more realistic process of flight tracking of a particular antiship missile as the missile guidance along the whole trajectory provides many advantages over unguided projectiles, primarily because of the possibility to fire at moving targets. The flight control simulation model enables further study of this missile class.

Advances in Active Radar Seeker Technology

Active radar seekers have gained wide applications in the terminal phase of missile guidance to provide hit-to-kill capability. Till recently, coherent monopulse tracker configurations were being used extensively for air-to-air missile seekers as well as surface-to-air missile seekers, while special real-beam technique-based seekers have been employed in antiship and land-attack systems. In this paper, features of active radar seekers have been described against different targets and background conditions to bring out the fact that the seeker design is highly applicationspecific in nature. The emerging trends in radar seeker technology have been identified wrt ever-changing threat scenario coupled with newer electronic countermeasure techniques, including the latest developments in components, subsystems, as well as implementation aspects.

Experimental determination of accuracy of automatic tracking of low targets by a radar coordinator with monoconical method of direction finding

The paper contains results of experimental determination of accuracy of automatic tracking of low-altitude flying objects by a radar seeker with monoconical method of direction finding.

Trajectory Optimization for Air-to-Surface Missiles with Imaging Radars

The use of trajectory optimization techniques is presented for the terminal guidance of an air-to-surface missile using a Doppler beam sharpening (DBS) radar seeker. The terminal guidance problem is characterized by a stealthy terrain-following phase that is followed by a climb and dive onto the target (a bunt trajectory). The imaging properties of DBS radars impose additional azimuth plane constraints on the trajectory that have to be incorporated into the optimization process. The various mission phases are interrelated, and the performance objectives come into conflict with the hardware constraints. The trajectory optimizer is used to generate offline open-loop controls that satisfy the various mission requirements. Numerical examples are used to illustrate the method and its efficacy.