A complete electronic conspicuity device will give Voice Alerts similar to that given by an Air Traffic Service. Voice alerts allow the 'pilot in command', to maintain the primary visual scan whilst being given detailed information on local aircraft that are being received by PilotAware.
A typical voice alert for a target which is transmitting its GPS co-ordinates and can therefore be accurately located in space and time is reproduced below.
This is in the format given by an air traffic controller.
PilotAware incorporates fixed zones around your aircraft at all times during operation.
(i) 'Outer Zone' 10Km and 2000ft.
(ii) "Middle Zone" 5km and 1000ft.
(iii) "Inner Zone" 3Km and 500ft.
These are fixed and are not changeable, however the distance that you want to hear the first alert is selectable using the zones in the configuration page of PiloAware.
When another aircraft transmitting GPS coordinates enters a zone, an alert will sound. i.e. "Traffic, 11 O'clock, 800 feet above, 10 kilometres". This means a target is 30 degrees to your left and 800 ft above. This type of voice alert will be given for detected PilotAware, FLARM, ADS-B and Mode-S/3D transmissions that deliver a 3D position.
If the target transits through to the next zone then another alert will be given.
Unlike modern transmitters that includes a GPS position, standard Mode-C/S transmissions do not transmit a 3D location. Consequently, voice alerts have to be in a different format.
Based upon the signal strength from the Mode C/S 1090MHz transmission and using the inverse square law, the distance of the target can be estimated in relation to the users chosen configuration.
(iv) Ultra short.
Vertical separation is calculated from the height transmitted from the Mode C/S target. A barometer on the PilotAware Bridge records local barometric pressure to ensure correct separation.