SYSTEM AND METHOD FOR DETERMINING THE POSITION OF A CONTROL AREA

摘要

The invention relates to a method for determining the position and shape of a control area on a road on which a vehicle is travelling, and to which a usage charge applies. According to the invention, a segment of the road is divided into segment sections and the perimeter of geographical coordinates of the control area associated with each segment section is calculated. At at least two different moments, a GNSS receiver calculates the position of the vehicle, said calculated positions being inside the control area; a control area being provided that is defined by a perimeter of geographical coordinates, fulfilling the requirements in terms of charging availability being above a pre-determined threshold value and the probability of a charging error being below a threshold value.

主权项

1. A method for determining the position and shape of closed control areas on a segment of road to which a usage charge is applicable, defining a probability pmd of failure to generate usage charges for a segment user and a probability pfa generating usage charges for a vehicle travelling along a road other than the segment of road to which the usage charge applies: characterised in that the method comprises the following steps:
a. Division of the segment of road selected into “N” segment sections, with each segment section having an associated closed control area; b. Characterisation of the length of the N segment sections and the road half-width a, in the N segment sections; c. Characterisation of the topology of the segments of road outside the N segment sections of road; d. Characterisation of the GNSS errors inside of and around the N segment sections depending on the level of protection PLi(x) defining a curve of maximum GNSS error margins depending on the probability that a curve of margins is lower than the maximum margin curve; e. Identification of the probability (pfa)i of detecting a vehicle assuming that these are all equal and the probability (pmd)i of failure to detect a vehicle also assuming that these are all equal and their values can be derived from probabilities pmd and pfa according to a distribution of the binomial type:pfa=∑j=1m-1(m-1j)(1-pfai)jpfaim-1-jpmd=∑j=mn(nj)(1-pmdi)jpmdin-j f. Definition of a minimum closed control area length positioned in the centre of the segment section to guarantee that, under nominal conditions, there are at least two positions inside the control area, with the length greater than 2V/f, where V is the speed at which the vehicle travels and f is the frequency of refreshing the position calculation by means of a GNSS receiver; g. Estimation of a minimum distance ui between the perimeter edge of the closed control area and any road outside that control area on which a vehicle can travel to ensure that the probability (pfa)i is lower than or equal to the maximum probability threshold value (pfa)i for detecting a vehicle travelling along a segment of a road other than the segment of road to which a usage charge is applicable; where the distance ui corresponds to the value of the PLi(x) curve for a probability equal to 1−(pfa)i; h. Estimation of a minimum distance di between the potential positions of the user inside the control area and the edges of the same area to ensure that the probability of failure to detect a vehicle travelling on the segment is less than or equal to (pmd)i; where the distance di corresponds to the value of the PLi(x) curve for a probability value equal to 1−(pmd)i; i. Definition of the shape of the closed control area that complies with:
length greater than 2V/f;distance di less than or equal to the shortest distance from the point furthest from the edge of the two points guaranteed to be inside the area under the previous condition;the Minkowski sum of the control area and a circle of radius ui which does not intersect with the zone covering the possible places through which a vehicle can travel outside the segment of road to which a usage charge is applicable; j. Selection of “M” possible closed control areas which fulfil the inequations in absence of intersections between control areas; where N≧M≧n; k. Supply of a subset “n” of closed control areas for the M possible control areas.