Program Control Measurement And Application Of Ship Automatic Identification System

AIS is a ship navigation aid system,which is helpful to the accuracy andsafety of ship navigation.And it is the basis of information and digital shipping.As AIS evolves,the demand for AIS shipborne system is gradually increasing.Its communication performance determines whether the entire AIS networkcan function properly,which directly affects the safety of each vessel’s navigation at sea.The measurement of transmitter performance and receiver performancearound the AIS is improved to address the shortcomings of traditional measurement methods.The performance of AIS transmitter is controlled by multiple indicators,We study the carrier frequency,carrier power,and falling edge time of the AIS signal among them.Firstly,a program-controlled measurement scheme of the AIS signal carrier frequency based on the spectrometer is proposed.Computer LAN communication with spectrometer is through the front-end ports,spectrometer input port connects with AIS transmitter RF output port,its working principle: the computer by sending SCPI command set spectrometer into signal capture work mode,after the spectrum analyzer captures the signal,if it conforms to the operating frequency band range of the AIS signal and the signal power is greater than 5d Bm,the data of AIS signal will be sent to the computer,the computer according to whether the frequency deviation is less than 500 Hz to determine whether it is a valid AIS signal.Secondly,this paper proposes a power meter-based AIS carrier power measurement scheme,where the computer sends SCPI commands to control power The AIS carrier power is measured by the AIS carrier power meter,and it is judged by whether the deviation of the carrier power is within ±1.5d B to judge the AIS ship platform to be measured the transmitting power is qualified.Finally,an oscilloscope-based programmed measurement scheme for AIS falling edge time was proposed.The oscilloscope captures the AIS falling edge signal when computer sends SCPI command to it.And the data received is qualified according to whether the falling edge time is less than 1 ms.The performance of the AIS receiver is also controlled by many indicators,as most of the metrics that affect the performance of the AIS receiver need to be calculated packet error rate,and the manual measurement of packet error rate is very inefficient.A packet error rate programmed measurement scheme of AIS based on arbitrary waveform generator was proposed.By constantly varying the transmit power of AWG,multiple sets of packet error rates and the sensitivity of the AIS receiver are measured.In addition,when co-channel rejection performance,adjacent-channel rejection performance or other performance are detected,the AIS signal and the interference signals need to co-exist,so we proposes a scheme using only one AWG to generate AIS signals and interference signals simultaneously.All in all,the program control measurement scheme proposed in this paper saves manpower,increases measurement efficiency,and makes the accuracy of measurement guaranteed.