Performance Measurement of SDR based AIS Transmitter

As the largest maritime country, Indonesia needs a maritime monitoring system. It encourages the Indonesian Research Center for Satellite Technology to develop a satellite carrying a satellite-based Automatic Identification System (AIS) receiver. Following the successes of the previous satellite, the currently developed satellite, which is scheduled to be launched in the next few years, will also carry a satellite-based AIS receiver. In developing a satellite-based AIS receiver, an AIS transmitter with adequate flexibility is needed to carry out various testing. This paper aims to investigate the performance of the SDR-based AIS Transmitter. Two kinds of SDR for comparison are LimeSDR Mini and HackRF One. The output RF power, operating frequency, occupied bandwidth, and harmonic signals were measured. The result shows that the output RF power is around 7 dBm for HackRF One and 14 dBm for LimeSDR Mini with direct transmission. However, with the amplifier implemented, the total RF output power for both SDRs is around 33 dBm ±0.2 dBm, which complies with the carrier power error standard. The frequency operation also meets the requirement with less than 150 Hz drift. Likewise, the occupied bandwidth matches the requirement with less than 11 kHz. Finally, the harmonics for LimeSDR Mini and HackRF One would meet the standard, with the suggestion in implementing additional filter.