Patent ID: 8942172
Filing Date: 2015-01-27
Classification: G01S,G06N,H04W

Abstract:
1. A method for positioning a mobile device in a wireless wide area network, wherein the method is executed by the mobile device or a server and the method comprise: estimating distances from the mobile device to three base stations by measuring signals between the mobile device and the three base stations; determining three measurement circles by respectively using the coordinates of three base stations as centers of the three measurement circles and the estimated distances as the radiuses of the three measurement circles; determining an object function, wherein the object function is expressed with a first variable, a second variable, a third variable, and a fourth variable, wherein the first variable, the second variable, and the third variable are respectively related to a specific value of a measured distance and a actual distance from the mobile device to the three base stations, and the fourth variable is a coefficient of the object function; respectively determining a first variable coding range, a second variable coding range and a third variable coding range according to the radiuses of the three measurement circles and the distances between the three base stations; determining a fourth variable coding range; coding the first variable coding range, the second variable coding range, the third variable coding range, and the fourth variable coding range; selecting a plurality of combinations of the first variable, the second variable, the third variable, and the fourth variable respectively within the first variable coding range, the second variable coding range, the third variable coding range, and the fourth variable coding range as a parent population of the object function; performing iterations of a genetic algorithm by using the parent population as a basis to derive a best solution of the first variable, the second variable, the third variable, and the fourth variable for the object function; and converting the best solution of the first variable, the second variable and the third variable into a position of the mobile device according to the coordinates of three base stations to position the mobile device in the wireless wide area network, wherein steps of determining the object function comprise: determining a function f(v) according to the radiuses of the three measurement circles, coordinates of three interception points of the three measurement circles and the coordinates of three base stations; and determining a constraint g(v) according to the radiuses of the three measurement circles and the distances between the three base stations; wherein the first variable, the second variable, the third variable, and the fourth variable are respectively expressed with α, β, γ, and λ, while the object function is F(α,β,γ,λ)=ƒ(v)+λ×g(v), and v=[α β γ]T.