Automatic road charging system based only on satellite navigation with guaranteed performance and method for its analysis and design

• US 7,865,391 B2
• Filed: 01/18/2007
• Issued: 01/04/2011
• Est. Priority Date: 01/18/2006
• Status: Active Grant

• Current Assignee: GMV SA
• Original Assignee: GMV SA
• Inventors: Martinez-Olagüe, Miguel Angel, Cosmen-Schortmann, Joaquin
• Primary Examiner(s): Jabr; Fadey S
• Application Number:
  US11/655,047
• Publication Number:
  US 20070216364A1
• Time in Patent Office: 1,447 Days
• Field of Search: 705/13, 701/13, 235/384
• US Class Current: 705/13
• CPC Class Codes: G07B 15/063 using wireless information transmission between the vehicle and a fixed station identification of vehicles G08G
• CPC Class Codes: G08G 1/20 Monitoring the location of vehicles belonging to a group, e.g. fleet of vehicles, countable or determined number of vehicles

Abstract

An automatic charging system for charging a vehicle for using an infrastructure delimited by a boundary during a charging period Tc based on Global Navigation Satellite Systems (GNSS) location with guaranteed performance. The system includes an onboard receiver with integrity guarantee which, in addition to providing position information, provides additional information relating to the error that can be expected in the position consisting of a health flag (denoting a Healthy/Unhealthy status), and a Radial Protection Level (RPL) relating to the amount limiting the horizontal position error according to one direction and with a probability equal to a known value I_Rx.

Claims

1. A method implemented on a computer having a processor and a memory coupled to said processor for analysis and design of a perimetral charging system for charging a vehicle (i) for usage of an infrastructure delimited by a boundary during a charging period Tc, comprising the following steps:

obtaining a Global Navigation Satellite System (GNSS) performance map (D_RX, I_RX, RPL), determining for each point within the boundary and for each sampling moment a probability of having a position tagged as healthy by an onboard receiver (D_Rx=D_Rx({right arrow over (Rr)}_i(t^I_j),t^I_j), as well as expected Radial Protection Level (RPL) values associated with its position measurements for a certain given value of integrity I_RX, according to the performance of the GNSS onboard receiver and GNSS visibility conditions;

obtaining using said processor a charging availability map associated with each point within the boundary and sampling moment (p_j), calculating for each point within the boundary and sampling moment the probability that a vehicle located at said point at that moment generates a healthy position sample and is detected by a system detection module which determines that a vehicle is within the boundary at a moment when all demarcated points of a region comprised by a circle of radius RPL centered on said position are within the boundary, so that the GNSS performance map is used together with the following expression of r on each point within the boundary;

p_j=D_Rxj·

r_j

wherein;

D_Rxj=D_Rx({right arrow over (Rr)}_i(t^I_j), t^I_j) is the GNSS position availability (D_RX) at a given point and moment, as obtained in the previous step; and

r_j=r_j(z_rj);

is the probability that a circle of radius RPL_ij centered on {right arrow over (R_mi^H)}(t_j) is within the boundary, this being a function only of the distance from the point to the boundary (z_rj) and of the expected RPL value at the point;

creating a universe of possible trajectories (Tr_i) according to available real traffic data for the road, each trajectory being defined by a sequence of horizontal position vectors that the vehicle defines on said road and by the frequency of occurrence data thereof (fr_i);

determining using said processor the charging availability for each trajectory (Pd_i), determining the charging availability for each trajectory Tr_i using a formulation that is a function only of the number of points K that a system charging module requires, of the charging availability at each point of the trajectory, of a decorrelation time of the error of the positions obtained by the GNSS receiver, of GNSS availability, of the length of the trajectory that is within the perimeter, and of the speed of the vehicle throughout the trajectory;

determining using said processor the average charging availability from Pd_i and the frequency of occurrence of each trajectory fri as;

Charging availability(Average)=Σ

Pd_i·

fr_i

determining the probability of mischarging as;

2. The method of analysis and design of a perimetral charging system according to claim 1, further comprising the steps of delimiting the boundary of the perimetral charging system by the points of all entrance roads to the charging area and then notifying a user of a vehicle that the vehicle is subject to charge.

3. The method of analysis and design of a perimetral charging system according to claim 1, wherein the charging module determines that the vehicle has used the infrastructure during said charging period Tc when there is a predefined number K of positions for which the detection module has determined that the vehicle is within the boundary, such that for K positions, a region comprised by a circle of radius RPL centered on them being within the boundary during Tc is used,

and wherein the value of K is chosen so as to assure that the probability of mischarging, in which the vehicle carrying the onboard receiver that has not been within the boundary during the charging period is charged, is delimited, the relationship between K and said probability of mischarging being given by the following expression:

4. The method of analysis and design of a perimetral charging system according to claim 1, wherein in order to charge, the direction of the road on which the vehicle has traveled must be determined by checking that at least two positions are available, the sequence of these positions over time defining the circulation direction, and the regions defined by a circle of radius RPL centered thereon do not intersect.

5. A method implemented on a computer having a processor and a memory coupled to said processor for analysis and design of a road charging system for charging a vehicle (i) for usage of an infrastructure delimited by a boundary during a charging period Tc, and which allows, for a given road section characterized by its geometry, particularly a length L and a distance d between an edge of the road and the boundary, and the geometry of its surroundings, analyzing system performance in terms of charging availability and probability of mischarging as a function of a number of positions K required by a charging module, said method comprising:

calculating using said processor the charging availability using a conservative approximation based on conclusions comprising (1) the vehicle is always on the road on which vehicles circulate and at the outer edge of the road, (2) the distance of the outer edge of the road to the boundary is d characteristic of the infrastructure and considered constant in the section, and (3) position errors for probabilities of an order of magnitude of the availability can be conservatively limited by a zero-mean Gaussian distribution with a standard deviation calculated as RPL/F, where RPL is a Radial Protection Level as provided by an onboard receiver, and F is a factor associated with a probability I_RX of the Gaussian distribution,

where said calculating step includes;

determining upper allowable limits of a probability (Pmd) of mischarging for a vehicle not using the road from a number

(Np) of vehicles that stay off the road and from a desired requirement for the probability of mischarging of MD or more vehicles during a charging period Tc (PMD), resolving the following expression by iteration;

6. The method of analysis and design of a road charging system for roads according to claim 5, comprising applying the method to identify the road sections complying with certain specified charging availability and probability of mischarging requirements.

7. The method of analysis and design of a road charging system for roads according to claim 5, further comprising the steps of further modeling the RPL value as a known function of I_RX according to features of the onboard receiver, and determining, for a given road section characterized by its geometry, particularly the length L and distance d between the edge of the road and the boundary, and the geometry of its surroundings, and given certain charging availability and probability of mischarging requirements, I_RX of the receiver complying with said requirements.

8. The method of analysis and design of a road charging system for roads according to claim 5, wherein the charging module determines that the vehicle has used the infrastructure during said charging period Tc when there is a predefined number K of positions for which the detection module has determined that the vehicle is within the boundary, such that for K positions, a region comprised by a circle of radius RPL centered on them being within the boundary during Tc is used,

and wherein the value of K is chosen so as to assure that the probability of mischarging, in which the vehicle carrying the onboard receiver that has not been within the boundary during the charging period is charged, is delimited, the relationship between K and said probability of mischarging being given by the following expression:

9. The method of analysis and design of a road charging system for roads according to claim 5, wherein in order to charge, the direction of the road on which the vehicle has traveled must be determined by checking that at least two positions are available, the sequence of these positions over time defining the circulation direction, and the regions defined by a circle of radius RPL centered thereon do not intersect.