Description
The objective is to develop, embark and carry out an in-orbit experiment to investigate the performance of specific air interfaces over very low frequencies (in the 24 to 72 MHz range) for very low data rate (Internet of Things (IoT), emergency paging etc) from satellite to ground and vice versa. This experiment will include the channel characterisation (including space weather effects) and communication performance assessment in outdoor and indoor urban and maritime environments.Targeted Improvements: Enabling very lowdata range communication systems not existing today in ESA Member States which could lead to new types of messaging services in outdoor and indoor environmentsDescription: The use of very low frequencies (below 100MHz) has not been explored in depth for satellite communications. Propagation experiments in the terrestrial world (e.g. those using Weak Signal Propagation Reporter) suggest thatspecific waveforms could be used at these very low frequencies (24-72 MHz) for very low data rate satellite communications (1 to 30bits per second) over very large distances. Initial experiments are underway outside Europe which could lead to new services such ascommunicating via satellite in the maritime or aeronautical HF bands or offer IoT services to ground nodes in outdoor and indoor environments.This activity will develop ground and space terminals that will be able to support in a flexible manner experimentation with various waveforms using Software Defined Radios (SDR) and flexible frontends. Ground terminals will be used in various geographical regions to experiment with the specific propagation effects at these frequencies. The experiment will serve to derive reliable link budget calculations as regular link budget calculations for these low frequencies are not very reliable due to the variable propagation characteristic. The space terminal will require the development of an innovative antenna solution for these very low frequencies in order to be able to carry out experiments over the complete frequency range. Communication experiments will be carried out inout-door and in in-door challenging environments including high- and low-density urban environments, environments with and withoutmultipath, low- and high rising buildings presenting a large range of signal attenuation and industrial buildings with complex noise environments. Critical performances shall be measured such as waveform performance including acquisition time, bit error rate, data rate, drop-out. The activity includes an experimental phase of at least 12 months and will be implemented by a dedicated or hostedsatellite mission.