Hi Matthew, Check out the NanoLoc (http://www.nanotron.com/EN/PR_nl_TRX.php). They can do localization using time of flight. Jennic also has a chip that does a similar thing, and there are a bunch of others on the way. But for now, you are stuck with RSSI. You can't do time of flight measurements using the hardware currently supported by TinyOS.
Cheers, - Thomas On Wed, Jun 15, 2011 at 7:51 AM, Matthew Jacques <[email protected]> wrote: > Thanks for all of the suggestions so far. > We have been experimenting and researching for the last few days but we have > been unable to come up with any sort of solution to our problem. We need to > have a network of randomly placed nodes that can localize themselves in > relation to each other. We would prefer to not use any static nodes but at > this point we are willing to try anything. Even when we used static nodes, > the static nodes still could not reliably measure the distance (because > there is so much multipathing/interference i guess?) > Is this just impossible to do? Is there any way to relativity reliably > localize nodes that are 1-3 meters from each other? > Thanks so much, > Matthew Jacques > On Tue, Jun 14, 2011 at 6:05 PM, Michael Schippling <[email protected]> > wrote: >> >> search for "rssi location" and various other combinations. >> there has been a lot of work done on this, and none of it >> is very accurate. >> >> MS >> >> Matthew Jacques wrote: >>> >>> Hello, >>> >>> I am currently trying to build a WSN using MicaZ motes and I need to >>> know, to a fair degree of accuracy, how far apart one node is from another. >>> I was reading up on how it is possible in some cases to use RSSI and LQI to >>> achieve this. I tried taking measurements of average RSSI when the nodes >>> were 1.5, 2 and 2.5 meters apart but the results were very erratic. While I >>> did notice that the RSSI tended to be higher when the nodes were further >>> away from each other, the results were not accurate enough to place the node >>> within even 4 meters of its actual location. >>> Is RSSI not an accurate enough way to get the precision I need? If not >>> is there any other method I can use to get the distance between nodes? >>> >>> I was also thinking of maybe using the system time of the nodes to time >>> how long a signal took to travel between them but I figured that with the >>> time to send and the turnaround time of the message in the other node this >>> would be a pretty inaccurate way to do it. Is that even worth trying? >>> >>> Thanks, >>> >>> Matthew Jacques >>> >>> >>> ------------------------------------------------------------------------ >>> >>> _______________________________________________ >>> Tinyos-help mailing list >>> [email protected] >>> https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help > > > _______________________________________________ > Tinyos-help mailing list > [email protected] > https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help > _______________________________________________ Tinyos-help mailing list [email protected] https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
