measuring distance
At those distances RF distance sensing is virtually useless, you'll get no useful precision out of it, the distance are just too small. Ultrasonic pinging would work pretty well. Depending on how fast your micro controller is you can get a pretty good degree of precision out of it, centimeter or inches maybe. You can throw all the 'air speed velocity' stuff right out the window and calibrate the sensor's at known distances. Simply set up the transmitter to send a pulse as strong as possible that's as short as possible that can sitll be detected. The shorter the pulse the more likley you'll be to detect echo's. Make sure the signal isn't repeated so fast that you'll get harmonic interaction if there are object that cause echo's nearby. Start at 8 feet, find the delay value, move 1 foot away find the delay value etc.. etc.. Mind you if the pulse is short enough and the dimensions and objects of a room are known exact position can actually be determined based on the echo's if you really want to study it.