SkyDemon Traffic Display and Collision Avoidance

SkyDemon can display other aircraft on the main map and in a dedicated traffic display instrument, and it can also warn you when you are going to get too close to another aircraft. It can only do this when connected to a traffic receiver device. There are various technologies for the broadcast of aircraft position and trajectory (known as electronic conspicuity) and various products designed to receive it.

Electronic Conspicuity Technologies

There are three main technologies in use today for broadcasting information about your aircraft, which other aircraft may receive and use for collision avoidance.


An international standard. Broadcast from your transponder or a standalone device. Emitted by most large aircraft and received by the widest number of receivers. Transmissions occur in a protected band of the radio spectrum.


A proprietary technology designed originally for gliders, but with many powered aircraft using it too. Devices can be portable or built in to the aircraft. Transmissions occur on a consumer band of the radio spectrum.


A proprietary and open standard for broadcasting aircraft positions. Currently only broadcast and received by the PilotAware product. Transmissions occur on a consumer band of the radio spectrum.

All three technologies perform the same basic function of transmitting your aircraft position and trajectory.

Broadcasting Your Position

The most important part of electronic conspicuity is broadcasting your position. It may be tempting to think about receiving first, but looking at the bigger picture it makes a more significant difference to safety if your own aircraft is visible to everybody else.

There are many different products on the market which can receive various combinations of the technologies listed above. However, almost every product can receive ADS-B transmissions. Therefore, it is our recommendation that whatever product(s) you use, you ensure your aircraft is broadcasting its position using ADS-B. So, how can you broadcast ADS-B?

Using Your Transponder

Most transponders can be upgraded so that they broadcast your position as part of their return. To do this, they typically need to be connected to a source of GPS information. Some of the receivers below can act as this source. Your avionics engineer can advise on this.

Using a Standalone Device

The CAP 1391 document published by the UK CAA sets out how portable devices can emit ADS-B without having to be part of a transponder. So far only one manufacturer, uAvionix, has marketed products fulfilling these criteria.

Receiving Other Aircraft

Once you are broadcasting your own position you will almost certainly wish to receive information on other aircraft, so you can use SkyDemon to help you avoid an aircraft you may not have seen with your eyes.

There are many different products you can use to receive information on other aircraft. All the products broadcast with one of the technologies above but also receive at least one of them.

Product Price
Broadcast Technology Receive Technology
uAvionix SkyEcho £443 Yes No No Yes Yes (1) No
Air Avionics AT-1 Traffic System £1800 Source (3) Yes No Yes Yes No
PilotAware £325 Source (3) No Yes Yes Ground (2) Yes
  1. The receiver can detect aircraft transmitting FLARM when the customer has licensed FLARM decoding functionality in SkyDemon.
  2. The receiver cannot detect FLARM transmissions itself, air-to-air. However if within range of a ground station (run by volunteers) then FLARM traffic may be rebroadcast by the ground station and the device will receive it.
  3. The device cannot broadcast your position with ADS-B itself, but it can be connected to a compatible transponder by a qualified person to enable that transponder to broadcast your position with ADS-B.

Mode S/C Reception

Some products support receiving basic aircraft data over traditional Mode S/C transponder returns. These do not include any position information, and therefore SkyDemon cannot display them on your map or in the traffic instrument; we also cannot use the information for collision avoidance.