Radio telemetry signal quality enhancement system to improve Earth remote sensing using unmanned aerial vehicles efficiency in real-time kinematics mode

When conducting remote sensing of the Earth using unmanned aerial vehicles, the problem of connection disruption between the operator’s base station and the unmanned aerial vehicle controller often arises due to natural obstacles to radio signal propagation (relief, vegetation, etc.) as well as a large range of the vehicle. The loss of connection is especially critical when surveying is carried out using a real-time kinematics technology, which ensures the transmission of correction amendments from the base station to the unmanned aerial vehicle controller to ensure high-precision spatial referencing of the obtained data. The objective of the work was to create a signal retransmission system with the possibility to install it on a light-class unmanned aerial vehicle capable of hovering in the air for more than three hours, for transmitting a radio signal from the base to the unmanned aerial vehicle via a third-party device beyond natural terrain obstacles and over long distances. Having compared various methods of signal transmission via a third-party device, the authors determined the most suitable configuration that meets the requirements for signal transmission quality and design simplicity for performing work in hard-to-reach regions. To create the repeater, RFD radio modems of various series were used and various operating frequencies were tested due to their availability and wide customization capabilities. The work resulted in obtaining a repeater pair of radio modems that make it possible to redirect the radio signal from the base station to the unmanned aerial vehicle without any loss of data quality and transfer rate for performing remote sensing of the Earth using the real-time kinematics technology. A secondary feature of the repeater is the possibility to use it as a search system in case of unmanned aerial vehicles emergency landing if the search beacon is unavailable.