UAVs (unmanned aerial vehicles) and other unmanned systems utilise radios and other forms of communications for a variety of reasons, including authorization for public safety, the transmission of telemetry , sensor, image and video data, as well as long-range communication for Beyond Visual Line of Sight (BVLOS) applications. Several technologies are in use.
Wireless communication, based on the IEEE 802.11 Ethernet standard, is popular due to the flexibility and robustness of the technology. Ethernet technology is ubiquitous and so hardware such as wireless modems and specialised integrated circuits are widely available at low cost, and standard networking applications and protocols can be integrated into an unmanned vehicle quickly and easily with few changes.
Cellular communication over 3G or 4G networks has several advantages, such as ease of use and the fact that the required infrastructure has already been provided by the mobile operator. However, the user therefore has no control over the network. Coverage and quality of service are also dependent on geographical location and may be non-existent in particularly remote areas.
Analogue radio, using frequency modulation (FM) technology and radio frequency (RF) signals, can be used for control of an unmanned vehicle as well as for streaming of images and PAL or NTSC video. The analogue signals are susceptible to noise and do not deliver as clear image quality as other methods, but have the advantage of low latency, as well as gradual signal degradation as opposed to a sudden unannounced cutoff.
Digital radios usually operate over IP networks, giving them the security and flexibility of IP communications. The technology requires large amounts of processing power, which can make SWaP (size, weight and power) issues a challenge for UAVs and other space-constrained unmanned systems. Range and visibility can be affected by obstacles such as tall buildings and trees, which is an especially problematic for ground-based systems such as UGVs (unmanned ground vehicles).
MIMO (Multiple Input Multiple Output) technology-based radios can overcome some of the limitations of operating in urban terrain. MANET (Mobile Ad Hoc Network) and swarm technologies can also be utilised with digital radios to set up networks of unmanned vehicles, extending the range of communications as well as providing self-healing and advanced routing facilities.