Accurate path restoration method based on directed graph highway network model

Abstract

The present invention discloses a path precision restoration method based on a directed graph highway network model, which belongs to the technical field of path precision restoration methods. Initialization: an initial billing gantry and an initial determination point are (-1, A), and the Floyd algorithm is called to calculate the distances from the two endpoints of the first billing gantry f1 to the starting point A. The calculation results are compared, and the endpoint with the smaller distance is B, then B is the next necessary point. The Floyd algorithm is called to calculate the distances from the two endpoints of the next billing gantry f2 to the starting point B. The calculation results are compared, and the endpoint with the smaller distance is C, then C is the next necessary point. Based on the directed graph highway network model, a highway network that can accurately reflect the actual road connectivity is constructed, and the precise calculation of the point-to-point minimum rate path and the point-to-point shortest path of the highway based on the actual road network connectivity is realized. In the case of omissions and erroneous transactions in the billing gantries, path restoration can be achieved based on the shortest path.

Description

Technical Field

[0001] The present invention relates to a path precision restoration method, in particular to a path precision restoration method based on a directed graph highway network model, and belongs to the technical field of path precision restoration methods. Background Art

[0002] Starting from January 1, 2020, provincial toll stations will be eliminated on national highways. By deploying gantries at key nodes on highways to obtain the actual driving path of vehicles, the traditional charging method based on the shortest distance from the entrance station to the exit station will be changed to accurate charging based on the actual driving path. ETC antennas are deployed on highway gantries. Through the ETC antennas, they can communicate with the ETC equipment on the vehicle or the CPC composite pass card (the pass card manually issued at the highway entrance) through microwave signals to obtain vehicle information and write the corresponding billing information of the gantry to the ETC equipment or CPC composite pass card. Then, the data of the vehicle's passage is generated, processed by the gantry software, and sent to the gantry server and the central server, thus completing this gantry transaction. There are two necessary conditions for accurate highway toll collection:

[0003] A toll gantry-based highway network model that can demonstrate accurate connectivity;

[0004] Accurate restoration of vehicle driving paths;

[0005] The existing highway network solutions have the following problems:

[0006] There are errors in the connectivity of the highway network;

[0007] The road network model currently used by expressways is an undirected graph model, which does not support semi-connected interchanges or U-turns in interchanges. It cannot accurately reflect the accuracy of the expressway network. A directed graph-based road network model is needed. Take the accessibility of the semi-connected interchange of Shanghai S32 Shenjiahu Expressway and G60 Shanghai-Kunming Expressway as an example, as shown in the attached manual. Figure 1 As shown in the figure, only vehicles traveling east-west on the S32 Shenjiahu Expressway can transfer to the north-south direction of the G60 Shanghai-Kunming Expressway, and only vehicles traveling north-south on the G60 Shanghai-Kunming Expressway can transfer to the west-east direction of the S32 Shenjiahu Expressway. The other directions are not connected, as shown by the green arrows in the figure. The green routes represent the paths that can be connected to the interchange, and the rest are not connected;

[0008] The accuracy of vehicle information captured by the billing gantry;

[0009] Due to system reasons, environmental reasons and other factors, the billing gantry antenna is unable to accurately capture the signals emitted by the ETC device or CPC composite pass card and complete the gantry transaction.

[0010] There is a missing billing gantry in the path restoration;

[0011] When the vehicle was driving, the antenna of the passing billing gantry did not capture the signal emitted by the vehicle's ETC device or CPC composite pass card, resulting in no vehicle passing record under the gantry on the central server side.

[0012] There is reverse billing gantry interference in path restoration;

[0013] When a vehicle is driving, the ETC device or CPC composite pass card on the vehicle will be captured and traded by the antenna of a nearby billing gantry that the vehicle has not actually passed. The billing gantry that is mistakenly traded is collectively referred to as a reverse billing gantry. Reverse billing gantries are divided into three categories: reverse billing gantry, side billing gantry, and rear billing gantry, as shown in the figure in the manual. Figure 2 Shown is a schematic diagram of a reverse gantry;

[0014] Reverse billing gantry

[0015] Reverse billing gantries refer to two billing gantries with opposite starting and ending points, such as Figure 2 As shown in the figure, the reverse billing gantry of gantry (S, A) is gantry (A, S). When a vehicle is traveling from toll station C to toll station A, the correct forward transaction gantry should be gantry (S, A), but it may be mistakenly captured by gantry (A, S). This is called reverse gantry interference.

[0016] Lateral billing gantry

[0017] Lateral billing gantries refer to two billing gantries with a common vertex and a lateral direction, such as Figure 2 As shown in the figure, the lateral gantry of gantry (S,B) is (S,C). When a vehicle is traveling from toll station D to toll station B, the correct gantry for the transaction should be gantry (S,B). However, at the S interchange, gantry (S,C) may have captured the vehicle first, causing it to be mistakenly traded. This is called lateral gantry interference.

[0018] Rear billing gantry

[0019] Backward charging gantries refer to two gantries with a common vertex and directions opposite to each other, such as Figure 2 As shown in the figure, the rearward billing gantry of gantry (S,A) is (S,C). When a vehicle passes through interchange S from toll station D to toll station A, the correct forward transaction gantry should be gantry (S,A). However, at interchange S, gantry (S,C) may have captured the vehicle first, leading to the incorrect transaction. This is known as rearward gantry interference.

[0020] The legality of the billing gantry itself

[0021] The current industry solution is to store a list of gantries with a reverse relationship on the gantry. During a transaction, a check is performed to determine whether the previous transaction gantry, as recorded on the ETC device or CPC composite pass card, is the reverse gantry. If not, the transaction proceeds with the current gantry. However, if the previous transaction gantry, as recorded on the ETC device or CPC composite pass card, is missing, the legitimacy of the current gantry cannot be determined.

[0022] Therefore, a path accurate restoration method based on a directed graph highway network model is designed to solve the above problems. Summary of the Invention

[0023] The main purpose of the present invention is to provide a method for accurately restoring paths based on a directed graph highway network model. The present invention designs a highway network model based on a directed graph, constructs a highway network that can accurately reflect the actual road connectivity, and realizes the accurate calculation of point-to-point minimum rate paths and point-to-point shortest paths based on the actual network connectivity of the highway.

[0024] The present invention proposes an accurate highway path restoration algorithm based on a directed highway network model. In the case of omissions and erroneous transactions in the billing gantries, path restoration can be achieved based on the shortest path.

[0025] The purpose of the present invention can be achieved by adopting the following technical solutions:

[0026] The accurate path restoration method based on the directed graph highway network model includes the following steps:

[0027] Step 1: Initialization, the initial billing gantry and the initial determination point are (-1, A);

[0028] Step 2: Use the Floyd algorithm to calculate the distances between the two endpoints of the first billing gantry f1 and the starting point A. Compare the calculated results. If the endpoint with the smaller distance is B, then B is the next required point.

[0029] Step 3: Use the Floyd algorithm to calculate the distances from the two endpoints of the next billing gantry f2 to the starting point B. Compare the calculated results. If the endpoint with the smaller distance is C, then C is the next required point.

[0030] Step 4: For the next gantry, the judgment method in step 3 is used repeatedly to compare the distances between the two end points of this gantry and the necessary point C calculated in step 3, and the next gantry pi is determined until all billing gantries are processed;

[0031] Step 5: Return to the restored billing gantry path p1, p2,…, pm.

[0032] Preferably, the previous billing gantry in step 2 can be determined as the gantry p1 represented by (A, B).

[0033] Preferably, if (A, B) contains multiple gantries, the Floyd shortest path algorithm will return the path of multiple billing gantries contained in (A, B), which is (-1, A)->(p1, B).

[0034] Preferably, in step three, the previous billing gantry can be determined as the gantry p2 represented by (B, C).

[0035] Preferably, if (B, C) contains multiple gantries, the Floyd shortest path algorithm will return the path of multiple billing gantries contained in (B, C), which is (-1, A)->(p1, B)->(p2, C).

[0036] Preferably, in step 1, A is the starting point.

[0037] Beneficial technical effects of the present invention:

[0038] The present invention provides a method for accurately restoring paths based on a directed graph highway network model. The present invention designs a highway network model based on a directed graph, constructs a highway network that can accurately reflect the actual road connectivity, and realizes the accurate calculation of point-to-point minimum rate paths and point-to-point shortest paths based on the actual network connectivity of the highway.

[0039] The present invention proposes an accurate highway path restoration algorithm based on a directed highway network model. In the case of omissions and erroneous transactions in the billing gantries, path restoration can be achieved based on the shortest path. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a semi-connected schematic diagram of an interchange of a highway network model in the prior art;

[0041] Figure 2 This is a schematic diagram of a reverse gantry in the prior art;

[0042] Figure 3 A schematic diagram of vertices and edges of a highway network according to a preferred embodiment of a method for accurately restoring a path based on a directed graph highway network model of the present invention;

[0043] Figure 4 A schematic diagram of vertices and edges of a highway network according to a preferred embodiment of a method for accurately restoring a path based on a directed graph highway network model of the present invention;

[0044] Figure 5This is a schematic diagram of path restoration based on a billing gantry and the shortest path according to a preferred embodiment of the method for accurate path restoration based on a directed graph highway network model of the present invention. DETAILED DESCRIPTION

[0045] In order to make the technical solution of the present invention more clear and specific to those skilled in the art, the present invention is further described in detail below with reference to embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0046] like Figure 5 As shown, the method for accurately restoring a path based on a directed graph highway network model provided in this embodiment includes the following steps:

[0047] Step 1: Initialization, the initial billing gantry and the initial determination point are (-1, A);

[0048] Step 2: Use the Floyd algorithm to calculate the distances between the two endpoints of the first billing gantry f1 and the starting point A. Compare the calculated results. If the endpoint with the smaller distance is B, then B is the next required point.

[0049] Step 3: Use the Floyd algorithm to calculate the distances from the two endpoints of the next billing gantry f2 to the starting point B. Compare the calculated results. If the endpoint with the smaller distance is C, then C is the next required point.

[0050] Step 4: For the next gantry, the judgment method in step 3 is used repeatedly to compare the distances between the two end points of this gantry and the necessary point C calculated in step 3, and the next gantry pi is determined until all billing gantries are processed;

[0051] Step 5: Return to the restored billing gantry path p1, p2,…, pm.

[0052] The present invention designs a highway network model based on a directed graph, constructs a highway network that can accurately reflect the actual road connectivity, and realizes the precise calculation of the point-to-point minimum rate path and the point-to-point shortest path of the highway based on the actual road network connectivity.

[0053] The present invention proposes an accurate highway path restoration algorithm based on a directed highway network model. In the case of omissions and erroneous transactions in the billing gantries, path restoration can be achieved based on the shortest path.

[0054] In this embodiment, the previous billing gantry in step 2 can be determined as the gantry p1 represented by (A, B).

[0055] In this embodiment, if (A, B) includes multiple gantries, the Floyd shortest path algorithm will return the path of multiple billing gantries included in (A, B), which is (-1, A)->(p1, B).

[0056] In this embodiment, in step three, the previous billing gantry can be determined as the gantry p2 represented by (B, C).

[0057] In this embodiment, if (B, C) contains multiple gantries, the Floyd shortest path algorithm will return the path of multiple billing gantries contained in (B, C), which is (-1, A)->(p1, B)->(p2, C).

[0058] In this embodiment, A is the starting point in step 1.

[0059] Example 2

[0060] like Figure 3 As shown in the figure, toll station A, interchange B, and toll station C are three consecutive nodes on the highway network. Vehicles can travel from toll station A to toll station C via interchange B, but vehicles traveling in the opposite direction from toll station C cannot travel through interchange B to toll station A. In this diagram, the toll units (A, B) between toll station A and interchange B and the toll units (B, C) between interchange B and toll station C are connected. According to the above definitions of vertices and edges, toll units (A, B) and (B, C) are vertex V1 and vertex V2, respectively, and the connectivity between vertex V1 and vertex V2 is edge E1. Toll unit (C, B) in the opposite direction cannot connect to toll unit (B, A), so there is no connectivity between these two vertices, that is, no edge exists.

[0061] Example 3

[0062] Taking Shanghai's expressways as an example, there are 298 toll collection units within the network, with 866 connections between them. Therefore, the network model G(V,E) constructed in this paper corresponds to a vertex set V consisting of 298 vertices and an edge set E consisting of 866 edges, with edge weights representing the distance between toll collection units or the toll amount. Based on this, the classic Floyd algorithm can be applied to generate point-to-point shortest paths or minimum-rate paths, including the shortest paths and minimum rates from toll station to toll station, toll station to billing gantry, billing gantry to billing gantry, and billing gantry to toll station within the expressway network.

[0063] A gantry-based vehicle path includes the entrance toll station, the exit toll station, and all gantries between the entrance and exit. An accurate path requires supplementing missed gantries and eliminating those with erroneous transactions. The core concept of the path restoration algorithm is to restore the vehicle's path between entrance station A and exit station Z based on the gantries with transactions (including those with erroneous transactions). If a transaction is made to gantry f(E, F), then either E or F must be a required point for the vehicle. This method uses the Floyd algorithm to calculate the shortest path to determine whether E or F is the required point. Ambiguous gantries and interchanges are skipped. The shortest path is the shortest distance based on the gantry implemented in the directed highway network model G(V, E).

[0064] Example 4

[0065] by Figure 5 To illustrate the implementation steps of the present invention, assume that a vehicle travels from A to E and has transaction records at four billing gantries. The transaction time sequence is f1->f3->f2->f4, where f3 is the incorrect transaction gantry. The calculation process for path restoration is as follows:

[0066] Step 1: Initialization, the initial gantry and initial determination point are (-1, A);

[0067] Step 2: Compare the distances from the two endpoints of gantry f1 to A, determine that A is the necessary point and f1 is the first gantry;

[0068] Step 3: The two endpoints B and D of the billing gantry f3 are calculated using the Floyd algorithm to calculate the shortest paths from the two endpoints B and D of the gantry to the endpoint A. After comparison, the shortest path distance between AB is less than the distance between AD, so B is determined to be the must-pass point and the previous gantry is determined to be f1.

[0069] (-1,A)->(f1,B)

[0070] Step 4: Use the Floyd algorithm to calculate the shortest path between the two endpoints B and C of the billing gantry f2 and the necessary point B calculated in Step 3. After comparison, B is the necessary point, and the previous gantry can be determined to be f1.

[0071] Step 5: The two endpoints C and E of the billing gantry f4 are compared using the Floyd algorithm to compare the distances from the two endpoints of the billing gantry f4 to the necessary point B calculated in Step 4. After comparison, the shortest path distance between BC is less than the distance between BE, so the previous point C can be determined as the fixed point, and the previous billing gantry is f2.

[0072] (-1,A)->(f1,B)->(f2,C)

[0073] Step 6: The other endpoint E of the billing gantry f4 is the exit, so f4 is the last gantry.

[0074] (-1,A)->(f1,B)->(f2,C)->(f4,E)

[0075] Based on the above six steps, the correct path for the vehicle can be calculated as f1->f2->f4. Billing gantry f3 is an incorrect transaction gantry and has been removed.

[0076] The above are only further embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes based on the technical solutions and concepts of the present invention within the scope disclosed by the present invention, which fall within the scope of protection of the present invention.

Claims

1. A method for accurately restoring paths based on a directed graph highway network model, characterized by: The steps include: Vehicles from A to E have transaction records at four billing gantries. The transaction time sequence is f1->f3->f2->f4, where f3 is the incorrect transaction gantry. Initialization, the initial gantry and initial determination point are (-1, A); Compare the distances from the two endpoints of gantry f1 to A, determine that A is the necessary point and f1 is the first gantry; The two endpoints B and D of the billing gantry f3 are calculated using the Floyd algorithm to calculate the shortest paths from the two endpoints B and D to the endpoint A. After comparison, the shortest path distance between AB is less than the distance between AD, so B is determined to be the necessary point, and the previous gantry is determined to be f1; The two endpoints B and C of the billing gantry f2 are calculated using the Floyd algorithm to calculate the shortest path from the two endpoints B and C of the gantry to the necessary point B calculated in Step 3. After comparison, B is the necessary point, and it can be determined that the previous gantry is still f1; The two endpoints C and E of the billing gantry f4 are compared using the Floyd algorithm to compare the distances from the two endpoints of the billing gantry f4 to the necessary point B calculated in Step 4. After comparison, the shortest path distance between BC is less than the distance between BE. Therefore, the previous point C can be determined as the fixed point, and the previous billing gantry is f2. The other endpoint E of the billing gantry f4 is the exit, so f4 is the last gantry; Based on the above 6 steps, it can be inferred that the correct path of the vehicle is f1->f2->f4; the billing gantry f3 is an erroneous transaction gantry and has been eliminated.

2. The method for accurately restoring a path based on a directed graph highway network model according to claim 1, characterized in that: Determine the portal p1 represented by (A,B).

3. The method for accurately restoring a path based on a directed graph highway network model according to claim 2, characterized in that: If (A,B) contains multiple gantries, the Floyd shortest path algorithm will return the path of multiple billing gantries contained in (A,B), which is (-1,A)->(p1,B).

4. The method for accurately restoring a path based on a directed graph highway network model according to claim 3 is characterized by: Determine the portal p2 represented by (B, C).

5. The method for accurately restoring a path based on a directed graph highway network model according to claim 4 is characterized in that: If (B, C) contains multiple gantries, the Floyd shortest path algorithm will return the path of multiple billing gantries contained in (B, C), which is (-1, A) -> (p1, B) -> (p2, C).

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