Design And Realization Of Signal Simulator For Platform Inertial Navigational System

Modern armament develops rapidly. High reliability, stability, precision for armament is demanded. It is necessary how to simulate battlefield environment and provide more real ,overall external environment and check the equipment entirely and repeatedly during development, test, medium maintenance periods.With the Navy armament developing continuously, its technical performance improving continuously and demand for higher and higher precision , it requires an inertial navigation system to provide very reliable position, velocity, bearing, posture etc. to make sure that ships is safe and weapon system's precision is more reliable. So it is necessary to develop correlative inertial navigation signal simulating equipment and understand precisely working conditions, conveniently check, test an inertial equipment.According to technical requirements and function of a submarine real bearing measurement system for inertial navigation signal simulators, the development technology and way for inertial navigation signal simulators are introduced overall in this paper .The simulator has friendly man-machine interface. Navigation information can be displayed dynamically in graphic and instrumentation and underwater posture for submarines can be displayed in three-dimensional cartoons.The mathematical model for simulation module of platform inertial navigation system simulator is first set up. The operational status , mode and operational principle while simulating for the system is provided. Simulator's control and communication is achieved by self -development PCI I/O card; The simulation for inertial output signal is realized by axis angle conversion circuit board. Multi-channel inertial navigation digits and simulation signals are transmitted simultaneously though RS232,RS422 and Ethernet through rough & fine channels. Signal simulators transmit navigation, posture information and condition signals in digital mode to be convenient for the system's development, test, acceptance, maintenance.Outputting the bearing of static ,dynamic (in all voyage conditions and sea states) horizontal posture information and its condition signals for inertial navigation systems are simulated. Analogue quantity is transmitted to the combined centre in multipolar resolver mode and the digital quantity of the above information can be transmitted through RS422 serial port and Ethernet. Binding the information of bearing, pitch, rolling, longitude, latitude, time, altitude(height) etc. are simulated in the equipment and transmitted to users by serial port and Ethernet. Meanwhile bearing, pitch, rolling information are transmitted outside in analogue quantity solid-state synchronizer mode. Moreover all kinds of error models can be added into the simulated output information which is convenient for the system's development and test.All kinds of information demonstrate a good man-machine interactive interface.Faults are detected, displayed, output and warned for signal simulators.Software for master controllers is made up of 5 functional modules. System management module is software main circulating module which accomplishes initialization, drives of all kinds of interfaces, set up of all control parameters and controls of other software modules. Simulating operation module generates moving trajectory of simulated objects based on the given parameters(initial position, end position, route etc.), then samples the trajectory according to the set velocity of the object and synchronous periods , calculates the moving status of each trajectory point ,forms each moving parameter. Signal generating module generates output signal amplitude adjustment information and signal to noise ratio adjustment data on the basis of the set parameters relative positions of trajectory points and the precision of the simulating system to control the amplitude of signals and signal to noise ratio to make simulating results is nearly to the real situation. All sorts of signals are arranged in each output signal of inertial navigation and make the output meet the demands for the interfaces of inertial navigation signals. Communication control module accomplishes the control of transmission of network cards, 422, conversion module communication signals. At first the status of 422 communication interface serial port, parallel port is checked. Information is begun to be transmitted when the subsystem is ready for communication. Information is transmitted in time sequences. Information are received in circulating access lining to protect loss and unentirety. A storage area is set up for each information. Information is received at the back console and put directly in the buffer area for the system processing. Dynamic effect generating module mainly drives three-dimensional images moving to make simulated effects more real ,including images moving control, light effects, foreground contraction and enlargement etc.Development process and soft structure for the simulator is described in design of software program and the specific software achievement in VC++6.0 conditions; The submarine model is established with 3D Studio MAX. Three-dimensional display of underwater submarine's moving posture with OpenGL and real-time display of moving trajectory of submerged submarines can be achieved .With these technology ,an inertial navigation signal simulator is successfully developed and the problems of maintenance ,test and checkout for real bearing measurement systems are solved.