measuring distance using radio - Page 1
Forum section: electronics / projects

author: Greg J
author_rank: Regular Contributor
timestamp: June 14, 2017, 10:03:21 am
content: Hey folks,I have a project idea, but one of the crucial technological pieces to it is the ability to see in 3d space where the other "objects" are.If I had to measure distance using radio weaves - but we are talking cm not km, how hard is it ? Are there any open source projects or parts that have implemented it? I don't want to reinvent the wheel.Please give me your thoughts.Cheers.FYITF

author: Someone
author_rank: Super Contributor
timestamp: June 14, 2017, 11:50:06 am
content: Depends a lot on what sort of objects you want to track. Multiple angle vision is good for many passive objects, while acoustic or magnetic is good for a few active objects orienting themselves. Don't know of open source projects

author: Greg J
author_rank: Regular Contributor
timestamp: June 14, 2017, 08:13:23 pm
content: Thanks.I'm trying to imagine any types of models driving on 2D track, but there will be wheels and stuff in the way - so it has to be able to work when antennae are obstructed slightly.

author: metrologist
author_rank: Super Contributor
timestamp: June 14, 2017, 08:20:11 pm
content: One centimeter is roughly 30 GHz. I gave up on that strategy quick.

author: Vtile
author_rank: Super Contributor
timestamp: June 14, 2017, 08:31:08 pm
content: Mmm.. Laser. Oh, radio not general electromagnetic spectrum.Maser?https://en.wikipedia.org/wiki/MaserOk. poor joke, it is again that time of the night (here).

author: metrologist
author_rank: Super Contributor
timestamp: June 14, 2017, 09:36:23 pm
content: Later, I thought I'd use laser interferometry, because I was looking less than 0.01 mm resolution.Mild obstructions will be difficult to overcome. You'd have multipath issues even if you could use microwaves.

author: mubes
author_rank: Regular Contributor
timestamp: June 14, 2017, 11:01:22 pm
content: A single UWB link will give you about +/- 50mm resolution using DWM1000 modules or similar. There's the source code for a model car using this technique athttp://github.com/mubes/garonne. I'm afraid the positioning code itself is only a binary blob, but that can be fixed.DAVE

author: rfeecs
author_rank: Frequent Contributor
timestamp: June 14, 2017, 11:46:25 pm
content: Something like this?http://hackaday.com/2017/01/24/millimeter-wave-radar-tracks-gestures/These guys were using up to 26GHz for level sensing. Looks like they are moving up to 80GHz:https://www.vega.com/radar

author: hamdi.tn
author_rank: Frequent Contributor
timestamp: June 15, 2017, 12:05:45 am
content: Ti lately talking about this mmWave, i think they already have a demo board for it.http://www.ti.com/lsds/ti/sensing-products/mmwave-sensors/mmwave-overview.page

author: metrologist
author_rank: Super Contributor
timestamp: June 15, 2017, 01:25:27 am
content: that is cool... stuff! Thank you!!!

author: theatrus
author_rank: Frequent Contributor
timestamp: June 15, 2017, 02:25:07 am
content: There is a market for "Gesture control" systems now (thanks various cars that added this), if you're ok with 20cm range. Its not true tracking but gets some datahttp://www.microchip.com/design-centers/capacitive-touch-sensing/gestic-technology/overview

author: PointyOintment
author_rank: Frequent Contributor
timestamp: August 04, 2017, 11:31:54 am
content: https://hackaday.io/project/9242-subpos-ranger

author: tggzzz
author_rank: Super Contributor
timestamp: August 04, 2017, 03:05:31 pm
content: Quote from: metrologist on June 14, 2017, 08:20:11 pmBack in 1996(!) I knew people that wanted to measure that king of distance, where rotating machinery and splashing/flowing oil was present.They wanted to use 60GHz. I have confidence they understood the problems and solutions, but technology was too rare and expensive.

author: ebastler
author_rank: Super Contributor
timestamp: August 04, 2017, 03:16:25 pm
content: Quote from: Greg J on June 14, 2017, 10:03:21 amCould you provide a bit more detail please?- What is the range of distances you need to cover?- What resolution and accuracy do you need?- How fast are the objects moving?- What update rate do you need for positions?- How large are the objects? Can they be equipped with passive reflectors (optical, radio, acoustical or whatever)? Can they be equipped with active beacons (e.g. light or radio transmitters)?It would help if you actually disclose your project idea... I am confused about the basic geometry. Why do you need 3D position information, when the objects are moving on wheels in 2D?