CAA have specified that the Beacons will broadcast 978MHz UAT ADS-B messages with an Emitter Category of ‘Point Obstacle’. The location broadcast by the Beacon will be based on the geographical position of the Beacon as reported by the Beacon’s built-in GNSS position source. The altitude broadcast will be a fixed altitude in feet above mean sea level (AMSL) defined based on the operating procedures for the site, e.g. as defined in the AIP (rounded to the nearest 25ft as per the UAT standard). Placement of the Beacon will be the responsibility of the site operator.
The Beacons, presenting electronically at a fixed point in space, will be there to provide pilots and other airspace users with situational awareness of the risk of collision with aerial activities at the site in the vicinity of that fixed point in space. ‘In the vicinity’ can mean above, below and in the area around that fixed point in space. For example, for glider winch launch sites the altitude AMSL of the Beacon broadcast will be the maximum altitude of the winch launch cable, though gliders usually hope to climb higher than this after release from the cable. Model aircraft flights will typically remain within the site boundaries. Hang gliders and paraglider flights may remain in the vicinity of the site or may choose to fly further afield. So the Beacons will be there to offer helpful real-time situational awareness of live activities but do not depict the full volume of airspace occupied by those flying activities.