Missile Guidance System Research Articles

Generic model of aircraft susceptibility to radar under conditions of electronic counter measures

This paper is only concerned with the susceptibility. Susceptibility of an aircraft is influenced by the following factors: 1) the location, number, and capabilities of the enemy air defense weapons; 2) the aircraft's basic design (e.g., geometric shape and the use of radar absorbing materials to degrade the enemy's radar detection capabilities and speed or agility to avoid any approaching enemy missiles) and onboard equipment or weapons (e.g., the use of onboard electronic attack equipment to degrade enemy missile guidance systems and antiradiation missile (ARM) to destroy the enemy air defense systems); 3) the tactics that are employed by the pilot. We can't “control” the location, number, and capabilities of the enemy weapons. Once the aircraft enters the service, its basic design cannot be changed any more. For the aircraft in service, its susceptibility can be further reduced by adding more advanced onboard equipment or weapons and employing more flexible tactics. The advanced aircraft in development (e.g., the fifth generation fighter aircraft) may exhibit a lower degree of susceptibility when they first enter the service, however, this superiority will be gradually eliminatedby proliferating threats [4]. The most advanced aircraft today also face the problem of reducing their susceptibility in the future. We present a generic model to gain insight into how electronic counter measures (ECMs) affect the susceptibility of aircraft. Our main purpose is to reduce the susceptibility of the aircraft in service, by applying airborne ECM techniques. Although some advanced stealth aircraft have been put into service in some countries, more aircraft in service are not stealthy, especially in developing countries. Compared with stealth coating and other techniques, ECMs have some advantages in reducing the susceptibility of aircraft in service. For example, the stealth coating is often sensitive to the radar frequency, and the maintenance cost of the stealth coating may be too high for some aircraft [5]. Shaping the surface of the aircraft to obtain a smaller radar cross section (RCS) value may be effective to decrease monostatic radar's returns, but this does not apply to bistatic radar [6]. Moreover, it is almost impossible to change the geometric shape of the existing aircraft.

Generic model of aircraft susceptibility to radar under conditions of electronic counter measures

This paper is only concerned with the susceptibility. Susceptibility of an aircraft is influenced by the following factors: 1) the location, number, and capabilities of the enemy air defense weapons; 2) the aircraft's basic design (e.g., geometric shape and the use of radar absorbing materials to degrade the enemy's radar detection capabilities and speed or agility to avoid any approaching enemy missiles) and onboard equipment or weapons (e.g., the use of onboard electronic attack equipment to degrade enemy missile guidance systems and antiradiation missile (ARM) to destroy the enemy air defense systems); 3) the tactics that are employed by the pilot. We can't “control” the location, number, and capabilities of the enemy weapons. Once the aircraft enters the service, its basic design cannot be changed any more. For the aircraft in service, its susceptibility can be further reduced by adding more advanced onboard equipment or weapons and employing more flexible tactics. The advanced aircraft in development (e.g., the fifth generation fighter aircraft) may exhibit a lower degree of susceptibility when they first enter the service, however, this superiority will be gradually eliminatedby proliferating threats [4]. The most advanced aircraft today also face the problem of reducing their susceptibility in the future. We present a generic model to gain insight into how electronic counter measures (ECMs) affect the susceptibility of aircraft. Our main purpose is to reduce the susceptibility of the aircraft in service, by applying airborne ECM techniques. Although some advanced stealth aircraft have been put into service in some countries, more aircraft in service are not stealthy, especially in developing countries. Compared with stealth coating and other techniques, ECMs have some advantages in reducing the susceptibility of aircraft in service. For example, the stealth coating is often sensitive to the radar frequency, and the maintenance cost of the stealth coating may be too high for some aircraft [5]. Shaping the surface of the aircraft to obtain a smaller radar cross section (RCS) value may be effective to decrease monostatic radar's returns, but this does not apply to bistatic radar [6]. Moreover, it is almost impossible to change the geometric shape of the existing aircraft.

Analysis of Nonlinear Missile Guidance Systems Through Linear Adjoint Method

In this paper, a linear simulation algorithm, the adjoint method, is modified and employed as an efficient tool for analyzing the contributions of system parameters to the miss - distance of a nonlinear time-varying missile guidance system model. As an example for the application of the linear adjoint method, the effect of missile flight time on the miss - distance is studied. Since the missile model is highly nonlinear and a time-varying linearized model is required to apply the adjoint method, a new technique that utilizes the time-reversed linearized coefficients of the missile as a replacement for the time-varying describing functions is applied and proven to be successful. It is found that, when compared with Monte Carlo generated results, simulation results of this linear adjoint technique provide acceptable accuracy and can be produced with much less effort.

Formation of gold-plated electroformed copper structures

Gold-plated electroformed copper structures are used to protect sensors from stray radiation and improve the image quality in infrared cameras, imaging systems, missile guidance systems and several other devices. These multilayer electroformed objects have tight dimensional and weight tolerances. Furthermore, their internal and external surfaces often exhibit low and high emissivity, respectively. Reflectivity at the outer surface was achieved by gold electrodeposition. Moreover, inner copper layer was converted to copper oxides to obtain high absorption. Characterisation of the coatings were done in terms of microstructure, roughness, infrared specular reflectivity of layers, texture and stress formation by SEM, profilometer, FTIR, parallel beam XRD and deposit stress analyzer, respectively.

Study of Proportional Guidance Trajectory based on Guiding Principle

In missile guidance systems, classical proportional navigation law has been used most widely. But with the increasing of the maneuverability of the targets, the classical proportional navigation guidance law has been unable to meet the requirements of people on the ballistic parameters. So this paper will further study the algorithm error of guidance law. Based on the previous theoretical results and the working principle of aircraft in the homing guidance system, this paper studies a guidance trajectory guidance principle which based on the ratio, and has carried on the analysis and the simulation theory. And simulation accuracy analysis has been carried on with practical examples. The results show that the method is put forward to effectively reduce the guided ballistic calculation method of error.

Back-stepping active disturbance rejection control design for integrated missile guidance and control system via reduced-order ESO

This paper proposes a novel composite integrated guidance and control (IGC) law for missile intercepting against unknown maneuvering target with multiple uncertainties and control constraint. First, by using back-stepping technique, the proposed IGC law design is separated into guidance loop and control loop. The unknown target maneuvers and variations of aerodynamics parameters in guidance and control loop are viewed as uncertainties, which are estimated and compensated by designed model-assisted reduced-order extended state observer (ESO). Second, based on the principle of active disturbance rejection control (ADRC), enhanced feedback linearization (FL) based control law is implemented for the IGC model using the estimates generated by reduced-order ESO. In addition, performance analysis and comparisons between ESO and reduced-order ESO are examined. Nonlinear tracking differentiator is employed to construct the derivative of virtual control command in the control loop. Third, the closed-loop stability for the considered system is established. Finally, the effectiveness of the proposed IGC law in enhanced interception performance such as smooth interception course, improved robustness against multiple uncertainties as well as reduced control consumption during initial phase are demonstrated through simulations.

Intelligent Missile using Artificial Neural Networks

Missile guidance systems using the Proportional Navigation (PN) guidance law is limited in performance in supporting wide class of engagement scenarios with varying mission and target parameters. For surpassing this limitation, an Artificial Neural Network (ANN) to substitute the PN guidance is proposed by the authors. The ANN based system enables learning, adaptation, and faster throughput and thus equips the guidance system with capability akin to intelligent biological organisms. This improvement could remove the barrier of limitations with allowable mission scope. In this paper, a Multi-Layer Perceptron (MLP) has been selected to implement the ANN based approach for replacing PN guidance. Attempts to replace PN guidance using MLP are limited in the literature and warrant greater attention due to significant theoretical development with the MLP field in recent times. It is shown in this paper, that the MLP based guidance law can effectively substitute PN for a wide range of engagement scenarios with variations in initial conditions. A foundational argument to justify using an MLP for substituting PN is provided. Besides this, the design, training and simulation based testing approach for an MLP to replace PN has been devised and described. The potential for faster throughput is possible as the MLP nodes process information in parallel when generating PN like guidance commands. The results clearly demonstrate the potential of MLP in future applications to effectively replace and thus upgrade a wide spectrum of modern missile guidance laws.

The Static Unbalance Analysis and Its Measurement System For Gimbals Axes of an Inertial Stabilization Platform

Abstract To reduce the influence of the static unbalance on an infrared missile guidance system, a new static unbalance measure system for the gimbals axes has been developed. Considering the coupling effects caused by a mass eccentricity, the static balance condition and measure sequence for each gimbal axis are obtained. A novel static unbalance test approach is proposed after analyzing the dynamic model of the measured gimbal axis. This approach is to drive the measured gimbal axis to do sinusoidal reciprocating motion in a small angle and collect its drive currents in real time. Then the static unbalance of the measured gimbal axis can be obtained by the current multi-cycle integration. Also a measuring system using the proposed approach has been developed. A balanced simulator is used to verify the proposed approach by the load and repeatability tests. The results show the proposed approach enhances the efficiency of the static unbalance measurement, and the developed measuring system is able to achieve a high precision with a greater stability.

Continuous second-order sliding mode based impact angle guidance law

In this paper, a new continuous robust impact angle constraint guidance law with finite-time convergence is proposed for intercepting maneuvering targets with unknown acceleration bounds. The presented guidance law is based on nonsingular terminal sliding mode (NTSM), smooth second-order sliding mode and finite-time convergence disturbance observer (FTDOB). In light of the introduced FTDOB, which is used to estimate and compensate the lumped uncertainty in missile guidance system, no prior knowledge of target maneuver is required. Thus, the proposed guidance law is capable of real implementation. Differently from the widely used boundary layer technique, chattering is eliminated effectively under the proposed guidance law without any performance sacrifice. Using finite-time bounded function approach and Lyapunov stability criteria, rigorous finite-time stability proof in both reaching and sliding phases is given. Theoretical analysis and numerical simulations show that the proposed guidance law can achieve more accurate interception with a wide range of intercept angles and superior overall performance than traditional NTSM algorithm.

Analysis of Nonlinear Missile Guidance Systems Through Linear Adjoint Method

In this paper, a linear simulation algorithm, the adjoint method, is modified and employed as an efficient tool for analyzing the contributions of system parameters to the miss—distance of a nonlinear time-varying missile guidance system model. As an example for the application of the linear adjoint method, the effect of missile flight time on the miss—distance is studied. Since the missile model is highly nonlinear and a time-varying linearized model is required to apply the adjoint method, a new technique that utilizes the time-reversed linearized coefficients of the missile as a replacement for the time-varying describing functions is applied and proven to be successful. It is found that, when compared with Monte Carlo generated results, simulation results of this linear adjoint technique provide acceptable accuracy and can be produced with much less effort.

English

Ring Laser Gyroscope (RLG) which uses the principle of Sagnac effect is a sensor to sense angular information very precisely. In order to get excellent performance from Ring Laser Gyroscope, Intensity of laser beams, Cavity Path length and also Dithering mechanism needs to be ultra-stable and maintained consistently. Hence control algorithms and hardware is implemented in RLG’s for these three controls. Most of the algorithms implemented are linear and simple in nature. It is felt to use non-linear algorithms based on the dynamics [1] of the RLG to improve performance of an RLG. So in this paper it is proposed to study the principals involved in an RLG control and simulate the dynamics for understanding the non-linarites and finally design new control algorithms for controlling the RLG. MATLAB/Lab VIEW are proposed to be used for realizing these algorithms and finally implement them in DSP. And also this signal processing is emulated in Lab VIEW software and finally implemented on FPGA. This system is used in Missile guidance and control systems, Robotics and Space crafts for tracking, balancing and controlling the motion

Design of BP Neural Network Controller for Infrared Seeker Servo System Based on Stribeck Friction Model

The high precision of the seeker is the key to reduce the Miss-Distance and improve precision in the guidance system of missile, and the seeker stabilized platform servo system is safeguard of the overall performance of seeker. So based on the Stribeck friction model, this paper studies and compares the precision of position and velocity that controlled by PID control and BP neural network when the seeker platform working at low speed. Finally, according to the MATLAB simulation results, applying modern control theory as controller based on Stribeck friction model can improve precision and the problem of flat and dead zone at low speed.

Design and Research of Hardware-in-the Loop Platform of Infrared Seeker Based on Lab-VIEW

With the development of infrared missile guidance system fleetly, the simulation plays more and more important role in the integrated testing of infrared missile guidance system, because it is a key technology to shorten manufacture period and to advance efficiency-cost ratio. This paper designs hardware-in-the-loop simulation platform of infrared guidance system, including: the simulation modeling of kinematics equation of characteristics, the generation technology of target background and antagonistic, the key technology design of hardware and software are researched thoroughly about signal resting, their constructions are discussed in detail.

Nonlinear Finite-Horizon Regulation and Tracking for Systems with Incomplete State Information Using Differential State Dependent Riccati Equation

This paper presents an efficient online technique used for finite-horizon, nonlinear, stochastic, regulator, and tracking problems. This can be accomplished by the integration of the differential SDRE filter algorithm and the finite-horizon state dependent Riccati equation (SDRE) technique. Unlike the previous methods which deal with the linearized system, this technique provides finite-horizon estimation and control of the nonlinear stochastic systems. Further, the proposed technique is effective for a wide range of operating points. Simulation results of a missile guidance system are presented to illustrate the effectiveness of the proposed technique.

Interception of an aerodynamically stable weaving re-entry vehicle

Traditional missile guidance laws are designed against fighter aircraft, with a much lower velocity (600–800 m/s) than ballistic missiles. To see whether intercepting a theatre ballistic missile inside the atmosphere is difficult in terms of missile guidance, trajectories of two different re-entry vehicles and the terminal phase of their interception, while the interceptor is guided by its own sensors, are simulated using MATLAB/Simulink. The interception is always successful if the inherent delay of the missile guidance system is small (below 0.5 seconds). The re-entry vehicles follow weaving trajectories, but the amplitude of the weave is small and does not pose problems for the interceptor. Neither does the high velocity of the missile (2,600 m/s), provided that the interceptor is near the inverse trajectory at the start of the terminal phase. Consequently, current missile guidance technology seems to be sufficient against aerodynamically stable missiles, but early detection and tracking are essential for success.

Research on Missile System with Strapdown Guidance Technology

This paper presents a project of missile guidance system based on the strapdown guidance technology. The project is composed of strapdown seeker and inertial measurement unit. The integrated guidance and control technology have been adopted. The project raise accuracy of missiles on the premise that the low cost should be guaranteed. According to simulation experiment, this paper proves the feasiblity of the scheme, and it has good ballistic missile.

Proportional Navigation With Delayed Line-of-Sight Rate

This brief discusses the convergence analysis of proportional navigation (PN) guidance law in the presence of delayed line-of-sight (LOS) rate information. The delay in the LOS rate is introduced by the missile guidance system that uses a low cost sensor to obtain LOS rate information by image processing techniques. A Lyapunov-like function is used to analyze the convergence of the delay differential equation (DDE) governing the evolution of the LOS rate. The time-to-go until which decreasing behaviour of the Lyapunov-like function can be guaranteed is obtained. Conditions on the delay for finite time convergence of the LOS rate are presented for the linearized engagement equation. It is observed that in the presence of line-of-sight rate delay, increasing the effective navigation constant of the PN guidance law deteriorates its performance. Numerical simulations are presented to validate the results.

Jamming effect analysis of infrared reticle seeker for directed infrared countermeasures

In directed infrared countermeasures (DIRCM), the purpose of jamming toward missiles is making missiles miss the target (aircraft of our forces) in the field of view. Since the DIRCM system directly emits the pulsing flashes of infrared (IR) energy to missiles, it is more effective than present flare method emitting IR source to omni-direction. In this paper, we implemented a reticle seeker simulation tool using MATLAB-SIMULINK, in order to analyze jamming effect of spin-scan and con-scan reticle missile seeker used widely in the world, though it was developed early. Because the jammer signal has influence on the missile guidance system using its variable frequency, it is very important technique among military defense systems protecting our forces from missiles of enemy. Simulation results show that jamming effect is greatly influenced according to frequency, phase and intensity of jammer signal. Especially, jammer frequency has the largest influence on jamming effect. Through our reticle seeker simulation tool, we can confirm that jamming effect toward missiles is significantly increased when jammer frequency is similar to reticle frequency. Finally, we evaluated jamming effect according to jammer frequencies, by using correlation coefficient as an evaluation criterion of jamming performance in two reticle missile seekers.

Bloodhound on my Trail: Building the Ferranti Argus Process Control Computer

Digital computers for process control were developed at the end of the 1950s. They had different design objectives from computers for scientific or commercial use. The Ferranti Argus was among the first computers worldwide used for direct digital control. The Argus was invented at Ferranti’s Wythenshawe Automation Division, Manchester, by Maurice Gribble. The starting point was a prototype digital computer developed for the Blue Envoy guided missile using low power hearing aid transistors. Announced by Ferranti as the ‘process control transistor computer’ in November 1958, Argus came into civilian and military use in 1962. It was used for process control at a soda ash plant for ICI and as part of a Cold War missile guidance system for the Bloodhound Mark 2 surface-to-air missile deployed by the Royal Air Force. While a small team of engineers within Ferranti used Argus to develop digital techniques for guided missile control, another technically powerful group of civilian users led development of the Argus for direct digital control of an ICI chemical plant at Fleetwood, Lancashire. The paper shows how the computer was invented, how it was developed in military and civilian contexts by small communities of practice and how these groups coalesced, grew and dispersed. As projects shifted towards software development, teams became smaller and women programmers were given considerable responsibility. These events highlight a key transition from analogue to digital control in manufacturing industry and defence during the early 1960s. Use of direct digital control by ICI followed commercial logic. The military were forced to switch to digital computation because technical advances in radar meant analogue calculations would not be accurate enough for Bloodhound Mark 2.

Intelligent Control Method of Ground to Air Missile Based on FCMAC

Intelligent control methods of missile guidance and control system (GACS) are studied in this paper. Secondly, the component and principle of GACS is introduced. Based on the fuzzy neural network, this paper constructs a basic structure of the intelligent control method of missile. Meanwhile, a new intelligent control method of rolling channel of missile based on Fuzzy Cerebella Model Articulation Controller (FCMAC) is designed. Under complicated environmental conditions, the missile can be accurately controlled with this method. Finally, the application value is illustrated. It’s very meaningful to improve the combat capability.