If you have ever experienced a natural disaster (hurricane, tornado, earthquake, wildfire, etc.), you are well aware of the importance of communications during this time. A functioning communication network is essential to coordinating emergency and recovery operations, rebuilding infrastructure as well as allowing the public to contact rescue services, family and friends.
Following a disaster, disruption to the communications network is all too often a problem, usually due to damage to cables and cell towers as well as the loss (or shut down) of electrical power. Yet, the ability to provide an “on-demand” communications infrastructure is critical to the needs of first responders and public safety personnel.
Recently, mobile operators have been developing the use of unmanned aerial vehicles (UAVs) or “drones” equipped with telecommunications equipment to provide cellular service to areas following disasters. These ultra-portable “flying cell sites” can be deployed quickly and conveniently for temporary coverage, until more permanent solutions are deployed.
UAVs come in a variety of configurations. These include free-flying medium- and high-altitude UAVs as well as tethered low-altitude UAVs. Free-flying high-altitude UAVs may be launched outside the immediate disaster area and navigated to perform a holding pattern in the area where they are needed, but they are generally unable to hover at a precise location. Free-flying high-altitude UAVs rely on an on-board power source for equipment operation and propulsion which can limit their mission duration. Although high-altitude UAVs have a large field of view providing a wider area of coverage, they are prone to high latency for communications traffic as well as limits to traffic density.
Tethered low-altitude UAVs use a physical tether between the UAV and the ground. The tether can be used to send power to the UAV allowing long-term operations to take place at a single location. In addition, data can be sent up and down the tether in a point-to-point fashion. These types of UAVs operate from a physical site at the base of their tether and are limited to an altitude of typically 400 feet or less. Equipped with small cells and antennas, these devices can be easily transported, deployed and moved quickly to accommodate rapidly changing conditions in an emergency scenario. Compared to conventional mobile cell sites the use of tethered UAVs allows antennas to be placed higher to avoid ground clutter and improve coverage.
The goal of any communications recovery operation is to provide temporary solutions for communications services until normal permanent infrastructure is repaired or rebuilt. The use of UAVs may be particularly relevant during the early phases of a recovery operation, until conventional fixed infrastructure is up and running. And with advanced planning, the use of UAVs can significantly improve the speed and quality of disaster recovery operations.
