Thanks for helping. I'm looking for a system that will help me find exact distance between a transmitter and receiver at a frequency of milli seconds, in distance accuracy of milli meters.

I want to avoid environmental factors, reflections or line of sight issues. My initial idea is to have a transmitter pulsating at 30 msec. Use the time taken between signals received to calculate the exact distance. Initially I am looking for a range of 20 m. But in future I would like to explore the idea of upto 1000m.

I think GPS wouldn't work, I am open to any modulation techniques. Are there any pre existing modules?


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  • \$\begingroup\$ Pre-existing technique is called "radar". Most recently, look into laser rangefinder. Did you research these techniques? \$\endgroup\$ – Ale..chenski Nov 30 '18 at 1:31
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    \$\begingroup\$ BTW one transmitter repeating signals at some interval is not going to give you a range of any kind unless you have some kind of TOF clock synchronization between the two devices. At millimeter resolution scales clock drift can become a problem. \$\endgroup\$ – isdi Nov 30 '18 at 1:41
  • \$\begingroup\$ Are you allowed to use a corner reflector? NASA had the lunar lander astronauts leave a panel of such optically-square mirrors on the moon, for improved distance measuring. \$\endgroup\$ – analogsystemsrf Nov 30 '18 at 3:26
  • \$\begingroup\$ I'm new to all this and these are excellent head ways for me to go research more. Thanks! \$\endgroup\$ – Dj Sbouy Nov 30 '18 at 9:28
  • \$\begingroup\$ Why are syncho tx rx system are hard to design? When we can have miniature remote controlled robotics. \$\endgroup\$ – Dj Sbouy Nov 30 '18 at 9:42

Gosh, so does every other RTLS system. (/humor)

Research UWB (ultra wideband) ranging if you want off the shelf modules. That's probably going to be your best bet for millimeter grade accuracy.

There are of course other systems such as laser TOF/interforemetry, however they are line of sight (unless you use mirrors) and don't go through most objects.

Using RF triangulation techniques can be done, however multipath issues are problematic (hence the UWB push).

It all depends on your environment (which you say very little about).

  • \$\begingroup\$ Why are syncho tx rx system are hard to design? When we can have miniature remote controlled robotics. \$\endgroup\$ – Dj Sbouy Nov 30 '18 at 9:42
  • \$\begingroup\$ Is there a way I can chat or message to you? I believe this site doesn't have that option. \$\endgroup\$ – Dj Sbouy Nov 30 '18 at 22:35
  • \$\begingroup\$ There is chat facility, but you have to have a reputation of 20+ to to be able to write in one, yet viewing public conversations is no problem (yes, it's frustrating, but it's not really SE's primary goal). The downsides to chat is that it can be hours between responses (for example I'll be unavailable most of tomorrow). \$\endgroup\$ – isdi Nov 30 '18 at 23:04

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