Radio Frequency Triangulation (Positioning) [closed]

Question

I'd like to know if it's possible to somehow triangulate (or otherwise) get a location of a moving object inside a defined area, let's say, 200m x 200m, by using radio waves. I've been looking at some transceivers and the range shouldn't be impossible (budget doesn't really matter). What would i need? Is there some reading material out there about this?

What i thought about was having a few "Antennas" positioned around the defined area, listening for the RF signal from the moving object - and then somehow calculate the distance from the object to the antenna, and that way get the exact location of the object by combining the data from all antennas.

Is this somehow possible, anyone care to point me in the right direction? Thanks a lot guys.

Edit: Forgot to mention that the accuracy wouldn't have to be so precise, maybe ~15cm?

Answer 1

Phased antenna arrays are used for beamforming: sending a signal in a certain direction and estimating direction of arrival.

DOA and a several antenna arrays could be used for Localization, which is what you are looking for. This source explains that 2D localization can be performed with 3 receivers using only the TDOA information.

I'm not sure if its practical or applicable to the problem you want to solve, just an avenue for investigation.

Answer 2

well, similar question was posted on this link, you can definitely give it a shot... https://electronics.stackexchange.com/questions/8690/signal-triangulation

Personally I think, if your target area is really like within 200m X 200m you can take a look at RFID based solutions. Passive RFID systems utilize something called a Received Signal Strength Indicator (RSSI) to determine how close an object is to an RFID reader. RSSI can't tell you the exact range, but you can surely find out if it is getting near or far. I have seen RFID systems being used to identify the loading of trucks in a given area roughly the same size as your requirement.

The only caution is if you are using multiple tags on an object for the directivity of target then RFID wont be so accurate as the RSSI level from different tags wont give a conclusive result.

Phased array system is highly accurate, but its a tad costly to implement.

You can find some reference documents in this article. It has good collection of RF ranging and Direction Finding manuals.

Answer 3

There's quite a lot of academic papers out there on this, e.g. scholar search and products, e.g. ekahau. The simplest to have a go with is probably trilateration with hardware that reports an RSSI, which you use to infer distance. Time difference of signal arrival is another level of accurate and tricky.

A lot of these techniques are quite sensitive to the environment: 15cm accuracy in open space, with sufficient receivers, is doable. If you add walls, furniture and people it gets harder. Then you need to survey the site for what a beacon in that location looks like; add in the variation depending on where a user with the device is (big bags of water block radio); and then interpolate between places.

You have an arduino tag on your question. I'm not sure what the significance of this is, but as above - do check what data you can get from your hardware.