Is it possible to measure a buried object’s depth based on the signal received from a tag applied to that item?
It is not possible to measure the depth of a buried object based on the signal from an RFID tag affixed to it. While passive ultrahigh-frequency (UHF) RFID readers do have the capability of measuring a tag’s received signal strength, this can be influenced by differences in soil composition and the amount of moisture in that soil, which makes calculating depth very difficult. If you know the depth when you bury the object, however, you could write that data to the tag and then attain that information when you later read the tag.
—Mark Roberti, Founder and Editor, RFID Journal
Which Consumer Goods Retailers Have Deployed RFID? »