Automated observatory in Antarctica: real-time data transfer on constrained networks in practice

Abstract

Abstract. In 2013 the scientists from the geophysical centre at Dourbes started a project to install a fully automated magnetic observatory in Antarctica. This isolated place comes with specific requirements: unmanned station during six months, low temperatures with extreme values up to –50°, minimize power consumption, satellite bandwidth limited to 56 Kbit/sec. The ultimate aim is to collect real-time magnetic data every second in Belgium: vector data from a lemi-25, absolute F measurements from a gems proton magnetometer and absolute magnetic inclination and declination measurements (approximately 5 times a day) with an automated DI-flux. To achieve real-time data transfer with traditional file transfer protocols (for instance sftp, mail, rsync), you fight against their limitations in terms of real-time. After evaluation of pro and cons of the on that moment available real-time internet of things (IoT) protocols and seismic software solutions known to UGCS, we chose to use message queuing telemetry transport (MQTT) and receive the one second data with a negligible latency cost and no loss of data. Each individual instrument sends his data towards Belgium immediately after capturing it and arrives at approximately 300 milliseconds after sending which corresponds with the normal satellite latency.