Direction finding with RSSI

RE: Direction finding with RSSI

iforce2d — Mon, 25 Aug 2014 07:00:48 GMT

I think you are both right :) I should have mentioned that this will be an open air, always in line-of-sight application with no obstructions, so RSSI should be reliable enough. Also, it does not need to be super-accurate - just good enough to keep the transmitter in the camera frame most of the time.

RE: Direction finding with RSSI

Nikita — Mon, 25 Aug 2014 06:50:44 GMT

I was talking about having on pilot side (on the ground) omnidirectional antenna and on plane side is directional antenna that can mechanically rotate. Plane antenna direction can be automatically adjust to the maximum RSSI position. So first plane can scan all 360°and determine the maximum RSSI direction and after this keep traking this direction deviations. And it can periodically rescan all 360° to determine if it's still the maximum RSSI direction. But better way is to have continiously rotating antenna and scan all the 360° all the time.

RE: Direction finding with RSSI

iforce2d — Mon, 25 Aug 2014 06:10:08 GMT

Thanks for the replies. Yes you have a good point, the FPV pilots are not interested in aiming the antenna at the plane itself. Eventually I'm hoping that my 'vehicle' will be a quadcopter, so multipath issues should not be a major concern. I think I will give this a try anyway, since it's fairly cheap and easy, and see how it goes :)

RE: Direction finding with RSSI

Janek Mann — Sun, 24 Aug 2014 10:50:50 GMT

Yes, I'm just trying to manage her/his expectations; in a real, non-freespace environment, the direction found will not point the camera directly at the transmitter.

RE: Direction finding with RSSI

Nikita — Sun, 24 Aug 2014 06:31:18 GMT

He can manage to determine the direction of transmitter with a mechanically rotatable directional antenna.

RE: Direction finding with RSSI

Janek Mann — Sat, 23 Aug 2014 20:23:05 GMT

The example of the antenna tracker you link to is different from your case for two reasons:

Their goal is to aim an antenna in such a way as to optimise the RSSI, not physically pointing at the receiver
The receiver is high in the air and as such is in near free space

In your case this is unlikely to work as RSSI is not strictly directional in the general case (affected by multi path, antenna pattern, etc etc).

Other than that, yes you could have the nrf51822 modules listen to the signal from the NRF24l01+, the modules won't interfere with the link much though the antennas could if placed in close proximity.