New technique for direct satellite connections at extremely low transmit power
Traditional satellites in geostationary orbit (GEO satellites) are located around 36,000 kilometers from the Earth. To overcome this distance and reach the satellites by radio normally requires high-power transmitters with very large antennas.
Our new transmission technique, by contrast, enables smaller transmitters and antennas to transmit small amounts of data, such as sensor data, directly from the ground to a GEO satellite. The technique uses a waveform that has been specially optimized for low data rates, which ensures successful transmission even at extremely low transmit power. For optimum use of the technique, we have also developed a C-band antenna that measures only approximately seven centimeters in diameter.
The new technique reduces transmit power sufficiently to allow the waveform to be operated below the threshold at which re- gulatory restrictions for the C-band apply. As a result, the technique can be used with antennas that require no alignment and will still not interfere with other satellite systems. Another advantage of the solution is that it can be operated using small, cost- effective transmitter and receiver terminals that have long battery lives.
This transmission technique is a special development for Internet of Things applications via satellite (Satellite IoT). Such IoT connections via satellite are always a helpful solution in situations where small amounts of data have to be transmitted but there is no mobile communications or terrestrial IoT network infrastructure available. They enable applications such as temperature and humidity monitoring in agriculture, and condition monitoring for oil and gas infrastructure for maintenance purposes and to detect leaks early on.
A technology demonstration has shown that the technique works in practice. This involved several portable transmitters equip- ped with the C-band antenna acting as IoT sensor nodes and transmitting their GPS positioning data via a GEO satellite.