Range finder for formation flights
Hi,
Let's consider formation flighting. Not in an ICAO-defined formations, but of much closer, like that on aerobatic shows. That's very dangerous business so a proximity sensor of some kind is highly desired to facilitate collision avoidance in a manual or (more useful) automated way. I wonder what kind of range finding device will be more suitable for such applications.
Traditional technologies such as RADAR, DME/TACAN does not work well when the range is small. The speed of light is high so it's technically difficult (and by no mean cheap and precise) to measure a nanoseconds time of arrival interval that corresponds to a small distance. Moreover, a radar uses microwaves that has poor penetration capability so the risk of antenna shadowing in certain aircraft attitudes. So the need for multiple antennas that will complicate the setup further. The same is applicable to a lidar. And the whole interrogator-responder method (like in DME) usually provides the benefit only to the interrogator as the responder side remains not aware of the distance to the interrogator (let's keep TACAN aside). Also not good in that case.
And again, all that stuff is very complex. What is required is a device that combines the simplicity of ultrasound range finder and the advantages of RF carrier. I think there must be something because the radio navigation is not a new field and the major breakthroughs were made when the luxury of GHz computing power was not yet available so the only way was to apply a clever physics rather than a brute force. Seen a patents, research papers, DIY projects, but noting in a stores. Why?