RF Tracking Application

[nornrich]

I am looking for an RF chipset that provides directional capability. I am looking to detect when an item breaks a barrier and at what location, using only a base recieving station and a remote transmitter. I have been looking at the development kit from Freescale using Zigbee technology. They have an accelerometer attached to the one board, but this only give orientation of the boardset. I need something that is going to give tracking capability.

Regards,

Rich.....

Richard Nornhold, PE
ampdesign@earthlink.net

 

[itsmoked]

Many of these projects would greatly benifit from GPS. Then you have your global X and Y cordinates handed to you on a platter.

 

[VEBill]

As Mr. Smoked posted, the only 'chipset' solution is probably GPS-based. With GPS it becomes a matter of scale. If your barrier is only 3cm from the base station, then GPS is not practical over such small distances.

You should post your numbers: distance, accuracy.

If you can't use GPS, then you have a range and bearing problem (single base station).

Range is simply timing (and has been discussed before). It is dangerously close to trivial with only a few gotyas. Search the forums for 'range'.

Bearing - look up Doppler Arrays where there are four whip antennas in a circle. The receiver electrically 'spins' the four antennas to induce an FM Doppler tone. The receiver extracts the phase of the induced tone to calculate bearing. Usually good to several degrees.

Once you have range and bearing, then you know where it is.

Other solutions might use two base stations and triangulation (two bearings only).

DGPS is certainly the simplest approach, assuming that the scale matches the GPS scale.

This isn't really a 'chipset' problem. It is bigger than that. It is an entire system.

 

[itsmoked]

More info from nornrich would sure help. Is this a linear border? Circular? Is it humans or robots or protozoa? Can other methods do the job? IR or laser? Line of site?