A method and apparatus for determining a location of a transmitter includes taking a Received Signal Strength (RSSI) measurement at a plurality of locations. Next, a known transmit power is subtracted from each of the RSSI measurements to produce a Propagation Loss Vector (PLV) for each location of the plurality of locations. A model is developed from the PLVs, the model including a plurality of grid points. A candidate Transmit Power Vector (TPV) is produced by subtracting the PLV for a candidate location from the RSSI measurement. Each of the RSSI measurements are matched against each TPV of the model. Once all the grid points have been evaluated, the grid point having a best match is selected as a location of the transmitter.