Use RF Transceiver to "home-in" on an object?

I have developed a device that uses gps to send it's location. Now I'm looking to add something that is a little more definite in terms of locating it. For instance, the gps will get me to within 100 meters of the object. From that point I need to "home in" on it to withing 20 feet or so. I was thinking about using some sort of RF transceiver that, when I got close, I could get "pings" from and it would increase in strength the closer I got. This would be a sort of treasure hunt.

Can anyone direct me towards a through-hole mounted rf transceiver or has anyone ever attempted something like this already?? So far, I can only find SMD RF Transceivers.

For that matter, is this even possible or am I barking up the wrong tree with the RF transceiver thing as a homing device??

The best you could do without some fairly extensive processing and RF work would be to use a receiver with RSSI (received signal strength indicator), and that’s probably not as accurate as the GPS.

Rocket and high altitude balloon folks use the GPS to get within 20 feet, then count on beepers and bright colors to get to the rocket/payload.


Thanks for the info. I'll look into the RSSI. This may be what I need. I'm thinking that the noise and color wont work for what I need. I'm looking to hide and object and have people try and track it down as part of a challenge or game. If its in bushes somewhere and beeping and flashing, then any old yahoo could pick it up. The object is a phone, that has GPS built in and the accuracy isnt reliably 20 feet. You've definitely pointed me in a good direction thought with the RSSI.

Thanks again.

The thing with GPS is that its slightly inaccurate but the inaccuracy should be consistent.

Two identical GPS units next to each other should be showing nearly identical position. Your probably looking at under a meter precision.

Amateur Radio operators (hams) call this radio direction finding (RDF or just DF); googling on those terms may turn up some info. There are lots of methods and techniques.