Optimized differential evolution for radio frequency trilateration in complex environments
A system, device and method for wireless device localization using a differential evolution algorithm in a continuous trilateration process.
1. A device localization method comprising:
(a) obtaining by a plurality of sensor distances between a wireless device and a vehicle;
(b) generating by trilateration of the distances a first population of a plurality of coordinate sets, each set describing a possible location in 3-D space of the device;
(c) computing fitness levels of each of the plurality of the coordinate sets by employing a fitness function based on ranging results obtained from a plurality of anchors having known positions;
(d) saving coordinates sets from the first population having a fitness level above a threshold fitness level;
(e) computing a vector offset to the saved coordinate sets based on updated ranging results from the plurality of anchors;
(f) applying the vector offset based on historical data to the saved coordinate sets to obtain a shifted population;
(g) generating a second population of a plurality of coordinate sets, each set describing a possible location in 3-D space of the device;
(h) combining the shifted population with the second population to form a combined population; and
(i) computing fitness levels of the coordinate sets in the combined population by employing the fitness function.
2. The device localization method of claim 1 further comprising:
saving the coordinate sets from the combined population having a fitness level above the threshold fitness level;
repeating operations (e) through (i) as they pertain to the combined population and to further updated ranging results from the plurality of anchors of and further repeating operations (e) through (i) on each additional combined population formed and on further updated ranging results from the plurality of anchors until the coordinate sets converge to within a defined area or a threshold number of iterations has been reached.
3. The device localization method 1 further comprising:
locating the plurality of anchors to minimize region of interest size.
4. The device localization method of claim 1 wherein the device is a wireless key and the anchors are located on a vehicle.
5. The device localization method of claim 3 further comprising:
locating the at least two of the plurality of anchors on an exterior portion of the vehicle.
6. The device localization method of claim 5 wherein at least two of the plurality of anchors are located on the same side of the vehicle as one another.
7. The device localization method of claim 5 wherein one or more of the plurality of anchors are located on an exterior portion of the vehicles and one or more of the plurality of anchors are located in the interior of the vehicle.
8. A system for localization of a wireless device comprising:
one or more processors operatively coupled to one or more non-transitory storage devices on which is stored executable computer code, which when executed by the one or more processors causes the system to perform the method of:
(a) obtaining by a plurality of sensors distances between a wireless device and a vehicle;
(b) generating by trilateration of the distances a first population of a plurality of coordinate sets, each set describing a possible location in 3-D space of the device;
(c) computing fitness levels of each of the plurality of the coordinate sets by employing a fitness function based on ranging results obtained from a plurality of anchors having known positions;
(d) saving coordinates sets from the first population having a fitness level above a threshold fitness level;
(e) computing a vector offset to the saved coordinate sets based on updated ranging results from the plurality of anchors;
(f) applying the vector offset based on historical data to the saved coordinate sets to obtain a shifted population;
(g) generating a second population of a plurality of coordinate sets, each set describing a possible location in 3-D space of the device;
(h) combining the shifted population with the second population to form a combined population; and
(i) computing fitness levels of the coordinate sets in the combined population by employing the fitness function.
9. The system for localization of a wireless device of claim 8 further comprising:
saving the coordinate sets from the combined population having a fitness level above the threshold fitness level;
repeating method operations (e) through (i) as they pertain to the combined population and to further updated ranging results from the plurality of anchors and further repeating operations (e) through (i) on each additional combined population formed and on further updated ranging results from the plurality of anchors until the coordinate sets converge to within a defined area or a threshold number of iterations has been reached.
10. The system for localization of a wireless device of claim 8 further comprising:
locating the plurality of anchors to minimize region of interest size.
11. The system for localization of a wireless device of claim 8 wherein the device is a wireless key and the anchors are located on a vehicle.
12. The system for localization of a wireless device of claim 11 further comprising:
locating the at least two of the plurality of anchors on an exterior portion of the vehicle.
13. The system for localization of a wireless device of claim 11 wherein at least two of the plurality of anchors are located on the same side of the vehicle as one another.
14. The system for localization of a wireless device of claim 11 wherein one or more of the plurality of anchors are located on an exterior portion of the vehicles and one or more of the plurality of anchors are located in the interior of the vehicle.