Radar air-to-air missile semi-physical simulation system scheme

An Fengzeng, Wu Zhaoxin, Wang Haifeng, Ma Huimin, China Academy of Air-to-Air Missile Research

The development of a missile weapon system is a very complicated system project. It not only includes a number of specialized fields, but also the content of new technologies is getting higher and higher. As a result, the single-missile cost of missiles has greatly increased. If the missile guidance system's performance is fully assessed by flight tests, the development costs of missiles will be very expensive and the development progress will be very long. In addition, some boundary conditions cannot be achieved in the external field and can only be simulated in the laboratory. Simulation technology provides an effective technical means to solve these problems.

With the development of new technologies and the need of foreign countries' strategies, the simulation technology of missile weapon systems has been greatly developed. Semi-physical simulation of guided loops has played an important role in the development of missile weapon systems. At present, various European and American countries have established a variety of advanced missile weapon system simulation labs, such as the US Army Advanced Simulation Center (ASC), Raytheon, Eglin Air Force Base, BAe and Marconi of the United Kingdom. The AIM-120, the sky-lighting missile and the advanced medium-range air-to-air missile, has done a lot of work and has spent a lot of money to establish a radio frequency simulation laboratory. The establishment of these laboratories has greatly advanced the development of missile weapon systems.

The design goals of the radar missile semi-physical simulation system are as follows:

a. Meet the needs of the semi-physical simulation test of guided missile development phase guidance system, provide guidance system parameters debugging, model verification and algorithm coordination verification methods for missile development, and provide results prediction for field tests;

b. Automatic control of the simulation test process, including self-testing, missile state control, simulation start-up, and completion;

c. Real-time acquisition of simulation test data, including telemetry information of missile output, trajectory information of simulation model output, control information of simulation equipment, etc., and real-time and post-event display and analysis of simulation results;

d. Real-time monitoring of simulation test status and emergency handling of abnormal conditions.

Through the analysis of system design goals, combined with the latest development of simulation technology and computer technology, the following design ideas are adopted:

a. Take the five-axis turntable as the center, equipped with the necessary simulation equipment, constitute a radar-type missile semi-physical simulation system;

b. All simulation devices are computer controlled to automate the simulation test process;

c. According to the different functions in the system, design different subsystems to reduce the system design difficulty, save the system development funds, and accelerate the development schedule;

d. The computer network uses a real-time network to form a distributed real-time simulation system.

The purpose of the radar-based air-to-air missile simulation system is to provide a more realistic motion environment and electromagnetic environment for missiles. Therefore, radio frequency simulation laboratories generally consist of the following components:

a. Microwave anechoic chamber: Used to provide free propagation space for electromagnetic waves. Usually there is a radio frequency target simulator at one end of the dark room and a flight turntable at the other end;

b. Target Simulator: RF signal used to radiate target and background;

c. Target Signal Simulator: Used to generate target and background RF signals;

d. Turntable: used to simulate the attitude of the missile in flight;

e. Simulation computer system and software: Control for simulation equipment, solution of simulation model, management of simulation test, etc.;

f. For composite long-range guided missiles, data link simulators are also included.

4.1 Structure of the Target Simulator

Which form of target simulator is used will directly affect the composition of the simulation system. Common types of target simulators include: mechanical target simulator, array target simulator, and target simulator in the form of a compact field.

a. Mechanical target simulator: Using a set of mutually perpendicular guide rails, the motor drives the target horn movement to simulate the target position;

b. Array Target Simulator: A triad antenna array is used to control the position of the target on the antenna array by controlling the amplitude and phase of the resultant signals of each triplet antenna;

c. Target simulator in the form of a compact field: Using a collimator principle, the RF signal of the analog target is fed through a waveguide and a coaxial cable to a horn antenna located at the focal point of a cut parabolic antenna. The RF signal radiated by the horn antenna is reflected by the parabolic antenna to form a plane wave to meet the far-field conditions.

The purely mechanical target simulator has low target positioning accuracy and is currently used less frequently. The array-type target simulator has high control accuracy and can simulate multiple targets and various types of interference. Therefore, the array-type target simulator has been widely used, but it needs a spherical array consisting of a large microwave dark room and several hundred horn antennas, and the development cost is greatly reduced. increase. The target simulator in the form of a compact field has a relatively compact structure and does not require the establishment of large microwave darkroom and spherical array antennas, which also saves research costs.

Therefore, the simulation system uses a target simulator in the form of a compact field.

4.2 Computer Control Methods

With the development of computer technology, air-to-air missiles are becoming increasingly intelligent. At present, the missile's own control algorithm is completed by the computer. In addition, due to the complexity of the hardware-in-the-loop simulation system, various simulation equipments in the system are controlled by computers, so as to realize the automatic control of the equipment itself and the information of the missile. Hinge.

Usually, the control method of the computer system can be divided into centralized control and distributed control. Centralized control is generally suitable for more compact systems, and distributed control is suitable for systems with more decentralized functions. In the radar-based air-to-air missile semi-physical simulation system, not only a large number of mathematical calculations, but also a lot of simulation equipment, requires a lot of I / O, if the centralized control method, the computer's requirements are very high, the cost increases a lot. In addition, due to the strong correlation between computers and simulation equipment in the hardware-in-the-loop simulation system, each device is far away from each other and its functions are relatively dispersed, so it is more suitable for distributed control methods. Domestic and foreign RF simulation laboratories, such as Boeing Aerospace, the US Army Advanced Simulation Center, Raytheon’s Patriot Missile Simulation Laboratory, have adopted distributed control solutions.

4.3 Real-time network solution

Because the simulation system adopts a distributed scheme, the interconnection between computers becomes the key to the development of the hardware-in-the-loop simulation system. The data update rate of the missile semi-physical simulation system is required to be less than 1 ms. Each sub-system completes a large number of calculations in such a short time, and completes the data transmission within the system. Any time the speed is reduced, it will become a bottleneck to realize the real-time performance of the system. Increased the difficulty of interconnecting computers. Therefore, high-speed real-time performance is the primary indicator of the semi-physical simulation computer network.

Since the main purpose of the local area network is resource sharing, the network response time is very long and difficult to predict, so it is not suitable for the missile semi-physical simulation system. In the early days, communication between external hardware-in-the-loop simulation computers generally used special interface equipment, which was very large and expensive. Later, with the large number of applications of VME bus products in the field of real-time control in foreign countries, there have been computer interconnection technologies such as VME bus repeaters, multi-master module repeaters, DMA data transfer, and shared memory interfaces. These technologies have been adopted. Satisfy the missile real-time simulation and other fields. However, since these technologies are not networks in the true sense, the system's ability to expand is limited, and management and maintenance of the system are also inconvenient.

In recent years, real-time interconnection technology has made great breakthroughs. Based on the shared memory interface, various ring-type and star-type topology real-time networks have been developed, which can meet the needs of missile real-time simulation and have excellent expansion capabilities. In this solution, VMIC's reflective memory network is selected. It adopts a ring topology and can be expanded to 256 independent nodes. The data transmission is software-transparent and has no I/O overhead. Therefore, it has extremely low network response time. The physical delay of the node is less than 1μs, and has a very high transmission rate, which can fully meet the requirements of the update rate of 1 ms required for radar-based air-to-air missile simulation.

4.4 Simulation System Composition

According to the form of the target simulator selected in the system plan, the control method of the computer, and the real-time network solution, the new RF simulation system is configured with a 5-axis turntable and a missile guidance control system as the center. The detailed composition is as follows:

a. Five-axis turntable: It is composed of a three-axis turntable that simulates the missile's attitude movement and a two-axis turntable that simulates the movement of the target. Its function is to receive information about the yaw, pitch, and roll channels of the missile sent by the simulation computer, and to reproduce the space of the missile. Attitude movement, receiving the target azimuth and altitude information sent by the simulation computer, and reproducing the change of the missile-target line of sight;

b. Target Signal Simulator: The simulated target echo signal generated by the RF source can simulate the Doppler shift of the target, the attenuation law of the target reflected power with distance, the distance delay of the target signal and various interferences;

c. Data Link Simulator: It is mainly used to simulate the data link signal of the carrier to correct the trajectory;

d. Simulation Computer: It is mainly used to solve the models of carrier, missile and target kinematics, missile target relative kinematics, carrier aircraft relative kinematics, and missile dynamics;

e. Simulation console: Mainly used for the simulation of the system's working status management and simulation test timing detection and control;

f. Real-time network: It is mainly used for the real-time communication between the internal computer of the simulation system, and transmits the control information and simulation results of the simulation equipment.

Radar air-to-air missile semi-physical simulation system block diagram is shown in Figure 1.

Fig.1 Block diagram of a semi-physical simulation system for radar-based air-to-air missiles

The semi-physical simulation system uses a target simulator in the form of a compact field and is equipped with other simulation equipment. It can provide a more realistic motion environment and electromagnetic environment for active radar missiles. It can meet the missile guidance and control system parameters optimization, model verification and flight The need for prediction of test results.

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