Radio frequency (RF) ranging in propagation limited RF environments utilizing aerial vehicles

A method comprising:

• operating a Global Positioning System (GPS) receiver coupled with a transponder, proximate to first known coordinates;
• determining first coordinates of the GPS receiver;
• broadcasting, from a range detector, a first Radio Frequency (RF) signal at a first carrier frequency (f1);
• receiving, at the range detector, a first RF rebroadcast of the first RF signal from the transponder operating proximate to the first known coordinates, wherein the first RF rebroadcast is at a second carrier frequency (f2) that is different from f1;
• calculating a first distance from the range detector to the transponder based on the first RF signal and the first RF rebroadcast;
• operating the GPS receiver proximate to second known coordinates;
• determining second coordinates of the GPS receiver;
• broadcasting, from the range detector, a second RF signal at f1;
• receiving, at the range detector, a second RF rebroadcast at f2 of the second RF signal from the transponder operating proximate to the second known coordinates;
• calculating a second distance from the range detector to the transponder based on the second RF signal and the second RF rebroadcast;
• and
• calculating a position relative to the first known coordinates and the second known coordinates based on the first distance and the second distance, the first coordinates and the second coordinates of the GPS receiver, and the first known coordinates and the second known coordinates.

An apparatus comprising:

• a range detector configured to transmit RF signals at a first carrier frequency (f1), and to receive RF signals at a second carrier frequency (f2) that is different than f1;
• and
• a Global Positioning System (GPS) receiver coupled with a transponder, and configured to determine coordinates of the GPS receiver, wherein the transponder is configured to provide the coordinates of the GPS receiver to the range detector,
• wherein the range detector is further configured, in response to the GPS receiver operating at each of a plurality of different locations, to receive the coordinates of the GPS receiver, to broadcast an RF signal at f1, to receive an RF rebroadcast at f2 of the RF signal from the transponder, and to calculate a distance from the range detector to the transponder based on the RF signal and the RF rebroadcast,
• wherein the range detector is further configured to determine coordinates of the range detector based the distance calculated at each of the plurality of different locations.

A method comprising:

• in response to operating a Global Positioning System (GPS) receiver coupled with a transponder at each of a plurality of different locations, performing the steps of:
• receiving, by a range detector, coordinates of the GPS receiver;
• broadcasting, by the range detector, a Radio Frequency (RF) signal at a first carrier frequency (f1);
• receiving, by the range detector, a RF rebroadcast of the RF signal from the transponder, wherein the RF rebroadcast is at a second carrier frequency (f2) that is different from f1;
• and
• calculating, by the range detector, a distance from the range detector to the transponder based on the RF signal and the RF rebroadcast;
• and
• determining, by the range detector, coordinates of the range detector based the distance calculated at each of the plurality of different locations.