Patent Document ID: 20150348409
Application ID: 14726654
Patent Flag: 0

Claim One:
1. A method for assessing passages by a vehicle through a tolling object utilizing a GNSS system comprising an OBU in every vehicle to be surveyed by the system, said OBU receiving signals from satellites to consistently and frequently estimate position coordinates for the vehicles, comprising the steps of: (A) obtaining an initial vehicle position including a degree of uncertainty ( 50 ), (B) assigning ( 51 ) a pre-determined number of particles for each vehicle, in a meaning understood by the mathematical method referred to as the Sequential Monte Carlo Method, comprising a process model, a measurement model and a probability distribution, (C) assigning to each particle: (i) a common initial probability, and (ii) an initial state comprising at least three dimensional spatial position, (D) defining epochs in time within each of which the following procedure is conducted: (i) in a prediction step ( 52 ), using said process model to predict with uncertainty the state of each particle in the next epoch, generally represented as x t =φ t (x t-1 )+η t , wherein x t is a state vector, φ t (x t-1 ) is a function used to predict the state x t in one epoch from information of the state in the previous epoch, and η t is a process noise term, the predictions of all particles within each epoch thereby representing the probability distribution of the state vector x t given all previous measurements z t , (ii) in an updating step ( 53 ), updating the probability of the particles according to how well each particle's state from the prediction step agrees with GNSS pseudo range measurements, according to the equation z t =h t (x t )+ε t , wherein z t is a measurement vector, h t (x t ) is a possibly time-varying function of the state, and ε t is measurement noise, thereby updating the probability distribution, (iii) assessing passage or non-passage ( 54 ) by mathematically comparing the spatial definition of the tolling objects in question with the updated particle information from the prediction step ( 52 ) while applying a defined confidence level, (iv) recursively repeating steps (D)(i) through (D)(iii) at a predetermined rate.