Direction finding. What I can do?   - Page 1
Forum section: electronics / rf-microwave

author: MikeP
author_rank: Regular Contributor
timestamp: October 14, 2017, 11:07:38 am
content: Hello.I have no experience with RF devices therefore I ask for help. It is necessary to create system of tracking or direction finding. The range of action is up to 30 meters. The object is equipped with a beacon. It can be not RF – system but not infrared. Distance between antennas on receiver – up to a one meter.What principles or finished devices I can apply?I will be very grateful for the help.Thanks.Mike.

author: tggzzz
author_rank: Super Contributor
timestamp: October 14, 2017, 11:41:22 am
content: You should be aware that it is not just the transmitter and receiver that matter, but also the radio channel between them. The latter depends strongly on many factors, including frequency plus any and all radio reflectors nearby.Hence, before you get a usable answer, you will also need to define the environment in which it will be used and the resolution and repeatability required.

author: Ian.M
author_rank: Super Contributor
timestamp: October 14, 2017, 12:27:23 pm
content: If its outdoors with a clear sky view, differential GPS with your own local fixed basestation may be an option. Seehttp://grauonline.de/wordpress/?page_id=1468to get some ideas.GPS is unusable for precise positioning inside most buildings, underneath thick forest canopies (especially when wet) or in dense urban area locations where most of the sky is obscured by high-rise buildings, and multi-path reflections off metal clad building faces or energy efficient glazing are common.

author: MikeP
author_rank: Regular Contributor
timestamp: October 15, 2017, 11:51:36 am
content: Many thanks.Firstly, it is necessary to determine the position in two axes: X & Y. Axis Z - beyond the real.Second - the system should not depend on external factors. System operation is possible both indoors and outdoors. The GPS is not applicable.Third, the resolution should be no more than 2-3 degree or better.I am inclined to think that this problem can be solved in the ultrasonic range. But maybe there are technologies about which I do not know anything.Thanks again.M.

author: NivagSwerdna
author_rank: Super Contributor
timestamp: October 15, 2017, 12:01:39 pm
content: I find my tortoise using one of these...https://loc8tor.co.uk/features/Has some of the characteristics you are after. Direction become more accurate the closer you are... which is fine for my application.

author: voltz
author_rank: Frequent Contributor
timestamp: October 15, 2017, 12:26:43 pm
content: Cannot use RF. [edit: i read this wrong, yes he can]Cannot use external systems.Indoors / outdoors operation.Must be within 2-3 degrees accuracy.up to 30m operation.tricky.Ultrasonics are possible but i doubt the resolution will be good enough, not without some serious noise cancelling / modelling software.Laser guided. Possibly using a scanning laser and reflectors at the targets. Are the targets line of sight?Using camera technology to 'see' the targets and software to recognise them. Again, are the targets line of sight.High intensity magnetic pulses from the targets. Not RF, purely magnetic field with a very sensitive receiver (X-Y coils)any good?

author: PA0PBZ
author_rank: Super Contributor
timestamp: October 15, 2017, 12:31:58 pm
content: Quote from: voltz on October 15, 2017, 12:26:43 pm"It can be not RF – system" - I read that as it can be something else than RF, but I had to read it 3 times. Maybe op wants to clarify?

author: voltz
author_rank: Frequent Contributor
timestamp: October 15, 2017, 12:39:56 pm
content: Quote from: PA0PBZ on October 15, 2017, 12:31:58 pmYes quite. Could read that two ways..

author: fcb
author_rank: Super Contributor
timestamp: October 15, 2017, 01:38:49 pm
content: There was an episode of The Amp Hour or Embedded that interviewed an engineer that did something similar for Valve or Oculus or someone. They used IR and some sort of rotating optics.Probably also look at how motion capture for inspiration.

author: MikeP
author_rank: Regular Contributor
timestamp: October 16, 2017, 07:47:20 am
content: Quote from: voltz on October 15, 2017, 12:26:43 pmWhy can not I use the RF system ?! I think this is the best solution.My problem is the lack of experience with RF and GHz components. There should be ready-made modules of receivers and transmitters.

author: Nusa
author_rank: Super Contributor
timestamp: October 16, 2017, 08:00:49 am
content: If you make the beacon a recurring noise in the audible range, then every human with functioning ears is equipped to track it.For ultrasonic noises, you could use dogs to track that. Or for the lower end of the scale, teenagers.Or are biological solutions cheating?

author: voltz
author_rank: Frequent Contributor
timestamp: October 16, 2017, 08:39:09 am
content: MikeP , this is my mistake, i had read your post as Cannot use RF - you clearly CAN use RF if you want. And is a good way to go now we know that option is available.. Sorry for the confusion.