MODELING OF ADS-B DATA TRANSMISSION VIA SATELLITE

For modelling transmission of ADS-B messages via low-orbit satellite constellation Iridium, the original model of a communication channel "Aircraft-to-Satellite-to-Ground Station" was built using MATLAB Simulink. The model comprises "Aircraft Uplink Transmitter" (Bernoulli Random Binary Generator, Convolutional Encoder, BPSK Baseband Modulator, High Power Amplifier with a memoryless nonlinearity, Transmitter Dish Antenna Gain), "Uplink Path" (Free Space Path Loss, Phase/Frequency Offset), "Satellite Transponder" (Receiver Dish Antenna Gain, Satellite Receiver System Temperature, Complex Baseband Amplifier, Phase Noise, Transmitter Dish Antenna Gain), "Downlink Path" (Free Space Path Loss, Phase/Frequency Offset), "Ground Station Downlink Receiver" (Receiver Dish Antenna Gain, Ground Receiver System Temperature, Viterbi Decoder), "Error Rate Calculation" block and "Display". The modelling was realized without and with convolutional coding (r = 3/4, K = 7) at different noise temperatures and free space losses. Dependencies of a Bit Error Rate on free space path losses, antenna's diameter, phase/frequency offsets, satellite transponder linear gain, aircraft and satellite transponder high power amplifier back-off level, and phase noise were received and analysed.