Design And Implementation Of Doppler Omnidirectional Beacon Monitoring System

China’s civil aviation industry is in the growth period for a long time.Navigation systems such as instrument landing system,Doppler omni-directional beacon and range finder play an important role in ensuring the safe flight and take-off and landing of aircraft.Doppler omni-directional beacon is the key equipment of subgrade navigation system module.Once these equipment in the aircraft navigation or take-off and landing process failure,can only rely on the experience of the captain,through the visual conditions as a reference for aircraft control,which will greatly increase the probability of aircraft danger.Therefore,it is very important to study the working mechanism of Doppler omni-directional beacon,improve its performance and ensure the normal operation of Doppler omni-directional beacon for the safe navigation of civil aircraft.In order to ensure that the Doppler omni-directional beacon(Dvor)is in normal state at all times,this paper studies the Dvor performance monitoring system.The electromagnetic wave combination signal radiated by Dvor to space is obtained by monitoring antenna,and the received signal is filtered and demodulated,and then compared with the preset reference value(angle,modulation,level,etc.),so as to judge whether the system works normally and provide accurate navigation signal.The monitoring system shall collect 9960hz level,30Hz FM signal level,identification code and other signals in real time according to the requirements,and demodulate the signals.When the signal is abnormal,the monitoring system will automatically switch to another set of Dvor,turn off the fault Dvor and give an alarm.The successful design of the monitoring system completely ended the past history of manual monitoring of Dvor,and realized the automatic monitoring of Dvor operation.The monitoring system described in this paper consists of monitoring hardware(monitor)and remote monitoring software.The monitor mainly monitors the signal processing unit and selection controller unit,monitors the transmitted signal of Dvor,detects the possible harmful error or fault,and generates early warning or alarm.In terms of hardware,the on-off logic,coaxial relay control,battery monitoring,DME interface and test controller are designed;the modem,DC converter,antenna system and equipment panel are optimized.The monitoring software transmits the data collected by the monitor through the computer network to remotely monitor and control the performance of Dvor and store the running status of Dvor.Through MATLAB simulation and field test,the Dvor performance monitoring system is designed and manufactured.After practical application,the indicators of the monitoring system have achieved the desired results,and the automation of Dvor performance monitoring has been realized.