The BVLOS Opportunity
Commercial aviation regulators across the world are currently grappling with how to enable commercial drones to be operated Beyond Visual Line of Sight (BVLOS), meaning outside of the direct visual range of the pilot.
In the longer term BVLOS flying is an essential requirement for the global logistics industry, which is looking to develop both autonomous passenger and air freight aircraft systems, as well as the much anticipated home delivery drone for your late night pizza. These systems will need to fly without direct visual observation and are the combination of safe BVLOS flying and autopilot autonomous control.
In the more immediate term, the combination of BVLOS drone systems and supporting regulation would bring opportunities for surveying, as well as search and rescue operations. Operating BVLOS allows drones to cover greater areas on a single mission and improve the cost and effectiveness of these information gathering airborne operations. Adding automation would allow many routine quantity surveying tasks such as stock pile measurement to become fully automated.
BVLOS and the military
Militaries have long understood the value of flying drones beyond the line of site. The second world war in particular brought us the German built V1 and V2 rockets, as well as the Japanese balloon bomb programs that flew incendiary balloons over the pacific to start fires on the US mainland. While these aircraft were deliberately designed to be operated autonomously BVLOS, it’s fair to say that in these operations they weren’t all that concerned about safety.
These primitive BVLOS drones lacked the ability to send or receive information and were not designed to be reused. It is the inclusion of sensors and communications systems to military drones that has expanded their role in modern militaries to an essential platform for Intelligence, Surveillance and Recognisance (ISR).
Smaller military drones work with sensors and direct radio links to provide enhanced situational awareness and intelligence for groups of soldiers in the field. One of the smallest examples is the 16-gram Black Hornet Nano that works with multiple camera sensors, a video streaming radio data link and GPS to allow the drone to be flown BVLOS via a set of GPS waypoints or in first person view up to 1.5km away by the operator.
The 16gram Black Hornet Nano used BVLOS in close infantry support.Larger military drones that are designed to collect intelligence and perform strike roles over much larger distances use a satellite communications link rather than direct radio communications with the operator. As the strike role for these aircraft has increased, developers have worked to increase the capability of the aircraft to penetrate contested airspace. This includes the development of Active Electronically Scanned Array (AESA) radar capability to detect other aircraft so that they can be targeted with air to air missiles. A by-product of this is that the military has created drone aircraft with the situational awareness to be flown BVLOS in congested civilian airspace.
The BVLOS civilian flying challenge
Flying drones in civilian airspace has two major safety challenges. The first of these is avoiding a forced landing or ground collision through the reliability of the aircraft and its control system; the second is avoiding an air to air collision through good situational awareness of other aircraft. Smaller drones also face a third issue in some areas stemming from intentional bird attacks on flying drones.
Operating within Visual Line of Sight (VLOS) is the primary means by which drone operators solve most of these safety challenges, and is why regulations limit operations to VLOS without specific exemptions. Visual sighting is the primary means by which operators choose safe forced landing areas, avoid ground collisions and keep separation from people, property, birds and other aircraft. Developing systems to safely fly BVLOS means developing reliable drone communications and control systems and the situational awareness to avoid other aircraft and vulnerable ground areas. Even flying within VLOS is a challenge when operating with other aircraft, and is why commercial drone operators use an aircraft radio in addition to VLOS to integrate safely with commercial airspace.
A significant hurdle for BVLOS operations is that not all aircraft use a called system called Automatic Dependence Surveillance and Broadcast (ADS-B). This system becomes compulsory for all instrument flying certified aircraft as of 2017 and uses an aircraft mounted ADS-B transponder to communicate with other transponder equipped aircraft and air traffic control in the local vicinity with altitude, speed and heading data. The system then automatically determines which aircraft climbs and descends to avoid an incident.
Despite the usefulness of ADS-B, many small recreational manned aircraft do not have the system installed. This means that equipping a drone system with ADS-B is not a cure-all that allows operation in civilian airspace without visual oversight. Use of ADS-B equipped drones is however, an important safety advance in avoiding incidents with commercial passenger aircraft.