Research On The Mechanism Of AIS Receiver Radio Frequency Interference Test

Nowadays,in automatic identification system,there are more and more users.A great deal of data exchange is eagerly required;the operation of digital communication service is largely increasing.So that radio frequency interference problem in AIS is seriously arising.Anti-interference performance of AIS terminal unit directly affects the communication quality of automatic identification system.And it is going strong that the performance of AIS station meets the requirements of revelant international stardards.Therefore,research AIS equipment anti-interference mechanism and automation testing platform system,reduce testing complexity based on meeting testing requirements and evaluate performance of AIS terminal equipment rapidly and efficiently have great significance for the current marketization of AIS equipment testing.Firstly,this paper embarks from receiving circuit structure of the receiver,combining with the radio frequency interference principles,based on IEC 62320-2,IEC 62320-1,IEC 61993-2 and other AIS station test standards,designs AIS receiver RF interference test plan.In order to improve the accuracy and efficiency of sensitivity measurement,this paper innovatively put forward the AIS receiver sensitivity measurement evaluation model.For fully test receiver anti-interference performance,this paper also increases the test items by using control interference variables method,and mainly designs the frequency sweeping method,specific test frequencies and additional tests.The optimum number of transmit packets is concluded by measuring error analysis in order to enhance the reliability of measurement results.Moreover,this paper develops the AIS receiver RF interference testing platform system.The modular system design method is conducted,and hardware and software are designed and developed in view of the test index.System hardware part includes the test host,measuring instruments and AIS receiver equipment under test,the test host control measuring instruments for AIS receiver automation measurement and data collection through the LAN link,and analyses AIS receiver data messages through a serial port.System software part based on Qt development platform in Windows system,uses VISA to transfer SCPI command,and then realizes instrument automation test and test results display.Take advantage of AIS receiver radio frequency interference testing platform system and AIS receiver performance test plan,this paper systematically tests AIS receiver sensitivity,error behaviour at high input levels,co-channel rejection,adjacent channel selectivity,spurious response rejection,intermodulation response rejection and blocking.The test results indicate that the sensitivity measurement evaluation model can measure receiver sensitivity more rapid and accurate as well as reflect receiving performance of the receiver in a certain range,quickly measure and calculate basal noise as well as dynamic range.Further more,via the platform system can rapidly analysing receiving characteristics change features in variant RF interference,and then giving the advice in circuit design and improvement of the existing test standard.