Design Improvement For Tn30 Tacan Signal Process And Control System

TACAN system is kind of essential radio navigation equipment being largely equipped with our military aircraft, of which performance directly effects our military operation and flight training ensuring. To make TACAN system being advanced in technology and operating stably and reliably plays an important role in our military modernization information construction. TN30 TACAN is a new generation of full solid and digital airborne equipment with functions of bearing and distance measurement at the mode of A/G (Air/Ground) and A/A, and developing by one of our military industry company, and will be equipped with our aircraft. At present, the prototype of TN30 TACAN has been manufactured. After test, some design problems have been found, such as poor strong signal anti-interference, poor bearing and distance measurement accuracy and stability, big volume of hardware circuit, more kinds of components, backward signal processing circuit (information unit) and controlling circuit (controlling unit). Then the circuits and structure of information unit and controlling unit must be re-designed.Because of the design problems existing in the prototype of TN30 TACAN, we made and enforced the improvement project. The paper is a summary on the study, engineering design and test.In this improvement project, we adopted the mature of signal coherent processing technique and Kalman filtering, selected advanced components such as A/D high speed sampling circuit, new generation of DSP(Digital Signal Processor), FPGA (Field Programmable Gate Array), etc. optimized the design of TN30 TACAN airborne equipment information unit and controlling unit through simplifying and optimizing the existing DSP processor, MCU micro controller and peripheral medium/small scale IC, put some functions of hardware into the software and combining the information unit and controlling unit into information processing unit. With the test, it was proved that: After improvement design, the anti-interference ability of video frequency signal processing, bearing and distance measurement accuracy and stability have been improved a lot. The equipment volume, weight and cost have been reduced, and its production ability and stability have been increased much.This paper, based on TACAN basic principle, studies and analyzes the system function requirement for TACAN information processing unit, outside interface requirement, the parameter of main hardware circuit and interface, requirement for software and along with analyzing on the main modules and subprogram, etc. and designs the corresponding functional circuit according to the above requirements, and further designs hardware circuit block diagram and circuit diagram of the complete information processing unit, operation flow diagram of the main software module. It introduces the performance test result on the new project prototype.