Location by triangulation


The GPS 1PPS signal is (should be) connected to the baseband chip in the gateway and that gives a sub micro-second accuracy of the timing.
This means you need a special gateways and all gateways need to do this in the same way. In theory this is possible but not on TheThingsNetwork.


How about the development of a smart antenna which estimates the angle of the incoming signal, that way updating the gateways with these antennas would allow localization ?


And how would this solve the multipath problem exactly? The signal might be striking the antenna on a totally different angle and direction of where the gateway is.

This technology (beam forming) exists, it's what those fancy 802.11ac routers with their three antenna's do, but it only works under LOS or minimal multipath (e.g. high carrier frequency) conditions.


I recently attended a meetup in Zurich. One of the topics was iot geolocation of nodes (without gps chip in the nodes). The technology is based on the time of arrival of the same message in 3 to 4 gateways with a gps chip. The problem is to determine the exact time of arrival of messages which may take up to almost 2 seconds to arrive (e.g. sent with SF12). This is a very complex problem and the algorithms to determine the TOA are owned by Semtech.
A document from the CSEM website https://www.csem.ch/ has some more detailsDoc.pdf (567.6 KB)
Just realised that the CSEM solution was mentioned earlier in the Application development thread



February 1 - The Things Conference

(Arjan) #110

However, using fixed SF11 or SF12 is not allowed.