Patent ID: 9651647
Date: 2017-05-16
CPC Classifications: G01S

Claim:
1. A method comprising: receiving signals, in a receiver from a transmitter, along a traveled path, wherein the traveled path is a path actually traveled by the receiver; storing, in a memory, a first estimated track, wherein the first estimated track includes an estimate of the traveled path of the receiver, recording, in a memory, signal power levels of the received signals, wherein the signal power levels include a first measured signal power level measured at a first time and a second measured signal power level measured at a second time, wherein the first time is before the second time; associating, in the memory, the first measured signal level power with the first time and associating the second measured signal power level with the second time; identifying, by a processor, an extracted change between the first measured signal power level associated with the first time and the second measured signal power level associated with the second time, associating, in the memory, a first location on the first estimated track with the extracted change; storing, in the memory, a model including a model of an obstruction and a model of the transmitter; simulating, by the processor and based on the model, modeled signals from the model of the transmitter to points along the first estimated track to generate expected signal power levels of the modeled signals; identifying, by the processor, an expected change of the expected signal power levels, wherein the expected change is caused by a modeled propagation path transitioning from a modeled obstructed propagation path to a modeled unobstructed propagation path, storing, in the memory, an association between a second location on the first estimated track with the expected change; identifying, by the processor, the expected change as corresponding to the extracted change; generating a second estimated track, wherein the second estimated track is an estimate of the traveled path, based on the first location on the first estimated track associated with the extracted change and the second location of the first estimated track associated with the expected change; and storing the second estimated track in the memory, wherein the second estimated track includes smaller positional errors than the first estimated track relative to the traveled path.