JP4981601B2 - Own vehicle position calculation device, own vehicle position calculation method, and own vehicle position calculation program - Google Patents

Description

  The present invention relates to a host vehicle position calculation device, a host vehicle position calculation method, and a host vehicle position calculation program.

  In a vehicle position calculation device mounted on a car navigation system or the like, the vehicle position detected by GPS or the like may not necessarily indicate the position of the vehicle that is actually traveling due to radio interference or the like. At that time, map matching is known in which the vehicle position is matched with a position on a link indicating a road given in advance as map information.

  For example, as a means for calculating the position of the host vehicle, the travel distance is calculated from the vehicle speed of the host vehicle, and the host vehicle is matched to a position on the link of the map that is advanced by the travel distance. In addition, as a method of correcting the vehicle position error that occurs when passing through curved roads, the vehicle travel distance (arc length) at the time of right / left turn is calculated by the intersection of the road center line before and after the right / left turn (of the intersection) There is known a method of correcting the vehicle position at a point added from the node.

  In the own vehicle position determination method described in Patent Document 1, when the own vehicle turns right or left at an intersection or the like, first, the own vehicle is linearly moved to the intersection of the road center line before and after the right or left turn on the map. Next, the direction of the own vehicle is changed by the intersection angle of the road center line before and after the right or left turn at the intersection. Thereafter, a method for determining the position of the vehicle on the map by linearly moving the vehicle whose direction has been changed on the center line of the road after the right or left turn is disclosed.

Further, in the vehicle travel position display device described in Patent Document 2, there is a method of correcting the current position of the vehicle by comparing the current position of the vehicle with a test point (node: intersection of road centerlines before and after turning right and left). For example, when a right / left turn of a vehicle is detected, the correction amount is calculated based on the width of the road before and after the right / left turn, the bending angle of the vehicle, and the turning radius of the arcuate traveling locus, and the vehicle position The vehicle position accuracy is improved by correcting the above.
JP-A-4-67300 JP-A-8-61969

  Improve driving comfort and reliability for car navigation by displaying the correct vehicle position on the screen of the vehicle position calculation device such as car navigation and notifying the driver of the correct vehicle position. can do. Therefore, it is necessary to improve the accuracy of map matching.

  In order to perform high-precision map matching, it is necessary to select on which road the vehicle is running. If there is only one road around the vehicle, that road may be selected as it is. However, when there are a plurality of roads around the vehicle, it is necessary to select one road from the roads. The display of the road to be corrected is extremely important information for the driver for controlling the own vehicle such as a left turn at an intersection or deceleration by speed limitation.

  For example, there is a method of selecting a road existing at a position closest to the vehicle position before correction. This method is based on the premise that both the vehicle position before correction detected by GPS and the link position set on the map information are both highly accurate. If the accuracy of any information is low, the road selection accuracy is low, which is inconvenient.

  The position of the link set on the map information may not be highly accurate. For example, when the nodes constituting the map displayed in the car navigation are not arranged at the exact points (intersections of the road center line), the positions of the links having these nodes as the end points are also inaccurate. At this time, a road far from the host vehicle may be selected as a correction destination road.

  Therefore, the main object of the present invention is to solve the above-described problem and to select the road on which the vehicle is traveling with high accuracy when the measured vehicle position is map-matched on the road of the map. And

In order to solve the above problems, the present invention provides:
A vehicle position calculation device for correcting the vehicle position displayed on the navigation screen,
For a link indicating a road, a map information acquisition unit that acquires map information including the direction of the link from the storage means;
A vehicle position detection unit for detecting the vehicle position by communication means;
An uncorrected own vehicle position calculation unit that associates the own vehicle position detected by the own vehicle position detection unit with the map information acquired by the map information acquisition unit and sets the own vehicle position before correction;
By detecting the steering operation to the vehicle, and the azimuth calculation section for calculating a square position in the traveling direction of the vehicle,
For each link around the vehicle, wherein the person-position of the vehicle, a link differencing is minimized with the direction position of the link, and a correction destination road selecting unit that selects a link showing a correction destination road,
A corrected vehicle position calculation unit that determines a position on the link selected by the correction destination road selection unit as a corrected vehicle position;
The corrected vehicle position determined by the corrected vehicle position calculation unit is displayed in association with the map information acquired by the map information acquisition unit, and the corrected vehicle position from the vehicle position before correction And a vehicle position display unit that displays a warning that the vehicle is staggered when the distance to the vehicle varies .
Other means will be described later.

  According to the present invention, when the measured vehicle position is map-matched on a road on a map, the road on which the vehicle is traveling can be selected with high accuracy.

  Embodiments relating to the present invention will be described below with reference to the drawings.

  FIG. 1 is a configuration diagram of a host vehicle position calculation device showing an embodiment of the present invention. The own vehicle position calculation device 1 is installed in an automobile and is incorporated in a computer such as a car navigation device. In addition, the own vehicle position calculation device 1 is configured as a computer including at least a memory serving as storage means used when performing calculation processing and a calculation processing device that performs the calculation processing. The memory is constituted by a RAM (Random Access Memory) or the like. Arithmetic processing is realized by an arithmetic processing unit configured by a CPU (Central Processing Unit) executing a program on a memory.

  The vehicle position calculation device 1 includes a vehicle position calculation unit 10, a vehicle position correction unit 20, and a vehicle position display unit 30. The own vehicle position calculation unit 10 calculates the uncorrected own vehicle position. The own vehicle position calculation unit 10 includes a map information acquisition unit 11, an own vehicle position detection unit 12, an uncorrected own vehicle position calculation unit 13, a parameter detection unit 14, and an own vehicle information acquisition unit 15.

  The map information acquisition unit 11 acquires map information from the storage means. The own vehicle position detection unit 12 detects own vehicle position information. The uncorrected own vehicle position calculation unit 13 arranges the own vehicle position detected by the own vehicle position detection unit 12 on the map acquired by the map information acquisition unit 11, and sets it as the uncorrected own vehicle position. The parameter detection unit 14 detects a parameter related to travel information of the host vehicle based on outputs from various sensors. The own vehicle information acquisition unit 15 acquires the catalog specification of the own vehicle information from the storage means.

  The own vehicle position correcting unit 20 corrects the uncorrected own vehicle position calculated by the own vehicle position calculating unit 10 and calculates the corrected own vehicle position. The own vehicle position correction unit 20 includes a traveling direction calculation unit 21, a correction destination road selection unit 22, and a corrected own vehicle position calculation unit 23. The traveling direction calculation unit 21 includes at least one calculation unit among the azimuth calculation unit 21a and the gradient calculation unit 21b.

  The traveling direction calculation unit 21 uses the map information acquired by the map information acquisition unit 11, the travel information detected by the parameter detection unit 14, and the own vehicle information acquired by the own vehicle information acquisition unit 15. Calculate the direction vector. The direction calculation unit 21a sets the direction vector (for example, north is 0 degrees, east is 90 degrees, south is 180 degrees, and west is 270 degrees. Of the traveling direction vectors of the own vehicle, it is also called a direction. It is changed by turning right). The gradient calculation unit 21b calculates a gradient vector (indicating the up and down of the road on which the vehicle is traveling, also referred to as an inclination) among the traveling direction vectors of the vehicle.

  The correction destination road selection unit 22 corrects based on the traveling direction vector of the own vehicle calculated by the traveling direction calculation unit 21 from a plurality of roads existing in the vicinity of the own vehicle in the map information acquired by the map information acquisition unit 11. Select the destination road. The corrected vehicle position calculation unit 23 corrects the vehicle position before correction on the correction destination road selected by the correction destination road selection unit 22 to obtain the corrected vehicle position.

  The own vehicle position display unit 30 is a position on the map indicated by the map information, including the uncorrected own vehicle position calculated by the own vehicle position calculation unit 10 and the corrected own vehicle position calculated by the own vehicle position correction unit 20. To display.

  Hereinafter, with respect to the embodiment in which the vehicle position calculation device 1 in FIG. 1 calculates the corrected vehicle position, the first embodiment using the azimuth calculation unit 21 a as the traveling direction calculation unit 21 and the gradient calculation as the traveling direction calculation unit 21. The second embodiment using the unit 21b will be described in order. These 1st Embodiment and 2nd Embodiment can be used together by the same own vehicle position calculating apparatus 1. FIG.

  FIG. 2 is a flowchart showing the operation of the host vehicle position calculation apparatus 1 in the first embodiment. This flowchart is repeatedly executed at a predetermined cycle because the position of the vehicle fluctuates without endurance as the vehicle travels. This flowchart may be executed not only when the host vehicle is turning a curve but also while traveling on a straight road, and it is possible to reduce the position error accumulated due to minute fluctuations during traveling. .

  First, the host vehicle position calculation unit 10 (map information acquisition unit 11, parameter detection unit 14, host vehicle information acquisition unit 15) acquires data necessary for calculation of the host vehicle position (S11). Hereinafter, necessary data will be specifically described for each processing unit of the vehicle position calculation unit 10.

  In S11, the map information acquisition part 11 acquires map information from a memory | storage means or a communication means. Examples of the storage means include a computer-readable CD-ROM, DVD-ROM, and hard disk. The communication means is used for acquiring map information from a predetermined information center, for example. In addition, since map information generally has a large amount of data, processing efficiency is better when it is acquired by narrowing down to the vicinity of the vehicle position.

Map information includes nodes that indicate major points (intersections, etc.) of roads, links that make up roads, information on topography and stores displayed in car navigation, and positions of objects around roads (latitude / longitude / altitude / road positions) Relationship).
N _n (x _n , y _n ) indicates a node. The subscript n of N _n indicates the nth node. x _n represents the longitude, _{y n} indicates the latitude.
L _n (r _L , θ _L , W _L ) indicates a link. The subscript _n of Ln indicates the nth link. r _L represents the length of the road (link length), θ _L represents the azimuth (link angle in the azimuth) of the road such as east, west, south, and north, and W _L represents the width of the lane on the road. One link corresponds to two nodes (link start and end points), and the position of the link on the map is determined. In addition, you may include the curvature radius of a road as information of links other than above-described, for example.

In S <b> 11, the parameter detection unit 14 detects a parameter related to the travel information of the own vehicle based on outputs from various sensors. The parameters to be detected are exemplified in Table 1.
The input torque T _n is obtained by a calculation formula “pump capacity coefficient × (engine speed) ² ” based on a value related to the engine. The engine speed is a catalog specification value or a measured value. The pump capacity coefficient is a catalog specification value.
Of the parameters exemplified in Table 1, the parameters that the azimuth calculation unit 21a mainly uses for calculating the azimuth vector are the vehicle speed VSP, the driver's steering operation amount α, and the vehicle yaw rate γ. In addition to the parameters, the driver's accelerator operation amount, brake operation amount, and the like may be detected.

In S11, the own vehicle information acquisition unit 15 acquires the catalog specification of the own vehicle information from the storage unit. Examples of the catalog specification parameter include a vehicle weight W and a tire radius _RT . Note that the vehicle weight W varies depending on the number of personnel, luggage, etc., so it is desirable to correct the weight by installing a weigh scale in the vehicle (measuring the displacement of the suspension).

  Next, the vehicle position calculation unit 10 calculates the vehicle position before correction (S12). Specifically, first, the own vehicle position detection unit 12 automatically communicates with a GPS (Global Positioning System) or communication from infrastructure around the own vehicle (road-to-vehicle communication or inter-vehicle communication). Detects vehicle position information (latitude, longitude, altitude, etc.). The own vehicle position is a position where the center of gravity of the own vehicle is present. Next, the vehicle position calculation unit 13 before correction arranges the vehicle position detected by the vehicle position detection unit 12 on the map acquired by the map information acquisition unit 11 and sets it as the vehicle position before correction.

  And the advancing direction calculating part 21 (azimuth | direction calculating part 21a) calculates the advancing direction vector (azimuth | direction vector) of the own vehicle (S13). Hereinafter, the details of S13 will be described from S13a to S13d.

The direction calculation unit 21a determines whether or not the host vehicle is traveling straight (S13a). Therefore, the steering angle θ _S is obtained by the calculation formula “θ _S = α / G” (α is the steering operation amount, G is the steering ratio). Next, when the straight traveling determination formula “| θ _S | ≦ θ _th ” (θ _th is a threshold for determination) is satisfied for a predetermined time, it is determined that the host vehicle is traveling straight (S13a, Yes), and processing To S13b. On the other hand, if the straight traveling determination formula is not satisfied even once during the predetermined time, it is determined that the vehicle is turning a curve (S13a, No), and the process proceeds to S13c.

The azimuth calculation unit 21a calculates the reference posture parameter θ _st by the calculation formula “θ _st = (θ _S + θ _sz × integral coefficient) / N” based on the steering angle θ _sz calculated one cycle before ( S13b). Note that θ _sz is the steering angle θ _S calculated one cycle before the calculation cycle, N is the number of repetitions for each calculation cycle in which θ _st is calculated, and the integral coefficient is a value determined according to the calculation cycle.

Azimuth calculation unit 21a, a link angle theta _L of closest to the straight path of the vehicle, as a reference attitude parameters θ _st (S13c).

The azimuth calculating unit 21a uses the steering angle θ _S calculated in S13a and the reference attitude parameter θ _st calculated in S13b or S13c to calculate the azimuth vector θ _P using the calculation formula “θ _P = θ s−θ _st ”. Calculate (S13d). Instead of theta _P, the distance ratio tan .theta _P having moved the vehicle may be as a direction vector.

As described above, S13a to S13d have been described as the calculation method of the orientation vector in S13. As another realization method of S13, using the front camera attached to the front part of the vehicle or the rear camera attached to the rear part of the vehicle, the white line of the road on which the vehicle travels is recognized to calculate from the lateral vehicle motion. May be. Furthermore, by utilizing the yaw rate γ and lateral acceleration Gy of the vehicle may be calculated azimuth vector theta _P and the reference attitude parameters theta _st. Or, from the speed or acceleration of the yaw axis gyro sensor to calculate, may be obtained azimuth vector theta _P. However, the calculated orientation vector theta _P was as described above, are matched to at least order, including measurement error in the range of at least ± 1 to 5 m around the corrected vehicle position P _{3 (described} in detail later) The

Here, the correction destination road selection unit 22 selects a correction destination road from a plurality of roads existing in the vicinity of the pre-correction own vehicle position obtained in S12 based on the calculated traveling direction vector of the own vehicle ( S14). Specifically, the vector difference between the link angle θ _{L of} each of the plurality of roads and the azimuth vector θ _P calculated in S13 is calculated by the calculation formula “| θ _P −θ _L |”, and the difference is minimized. Select the link as the road to be corrected.

  As another method for selecting the correction destination road (S14), there is a comparative example in which the road closest to the vehicle position before correction is selected as the correction destination road. However, compared to the comparative example using low-accuracy position information, the method using a high-precision traveling direction vector can suppress erroneous selection of a road on which the vehicle position is not actually traveling.

  The corrected vehicle position calculation unit 23 corrects the vehicle position before correction on the correction destination road selected in S14 to obtain the corrected vehicle position (S15).

  FIG. 3 is an explanatory diagram showing the vehicle position before correction and the vehicle position after correction. FIG. 3A is a diagram showing that the host vehicle proceeds from a straight road toward a curved road. FIG. 3B is an enlarged view of a part of FIG.

Nodes N _n , N _{n + 1} , N _{n + 2} , and N _{n + 3} in FIG. 3A exist on the links L _n−1 , L _n , L _{n + 1} , and L _{n + 2} . And the own vehicle is traveling toward each traveling direction (direction vector θ _P ) at each uncorrected own vehicle position P ₁ . Vehicle position calculating apparatus 1 includes a pre-correction vehicle position P _1, with reference to the orientation vector theta _P, obtain corrected vehicle position P ₃ on the link.

  The calculation of the corrected vehicle position (S15) in FIG. 2 can be realized by, for example, either (1) the shortest distance method or (2) the travel distance method.

(1) The shortest distance method will be described. In this method, a point P ₃ (x ₃ , y ₃ ) on the correction destination road located at the shortest distance from the uncorrected host vehicle position P ₁ (x ₁ , y ₁ ) is set as the corrected host vehicle position. That is, the intersection of the perpendicular drawn from the uncorrected vehicle position P ₁ (x ₁ , y ₁ ) toward the correction destination road and the correction destination road is set as the corrected vehicle position.

C (r _C , θ _C ) represents the vehicle position correction amount from the vehicle position before correction to the vehicle position after correction.

r _C represents the distance from the vehicle position before correction to the vehicle position after correction. theta _P <when the theta _L determined by _{"r C = D C sin (θ} L -θ P) ", theta _P> when the theta _L obtained by _{"r C = D C sin (θ} P -θ L) ". D _C is the travel distance of the vehicle has a base point node N _n passing through just before, determined by the integral value of the vehicle speed of the straight line path. θ _L indicates the link angle of the road to be corrected.
Δr _C is the amount of change in _{r C,} which is the difference between _{r C} that was previously calculated, and this calculated _{r C.} When Δr _C varies, it is determined that the vehicle in the lane fluctuates.

θ _C represents an angle from the vehicle position before correction toward the vehicle position after correction. When θ _P <θ _L , it is obtained as “θ _C = π / 2 + θ _L ”, and when θ _P > θ _L , it is obtained as “θ _C = π / 2−θ _L ”.

P ₃ (x ₃ , y ₃ ) is the corrected vehicle position, and is calculated between the uncorrected vehicle position P ₁ (x ₁ , y ₁ ) and the vehicle position correction amount C (r _C , θ _C ). Obtained by vector sum. x ₁ and x ₃ are longitudes, and y ₁ and y ₃ are latitudes.

(2) The travel distance method will be described. This method is passed just before reaching the pre-correction vehicle position _{P 1 (x 1, y 1} ), from the node N _n in the correction target roads, a position traced by the travel distance D _C content, the corrected self The vehicle position is P ₂ (X ₂ , Y ₂ ).

Examples of (1) the shortest distance method and (2) the travel distance method described above will be described with reference to FIG. 3 (b) is from uncorrected vehicle position P _1, indicating that is corrected to the corrected vehicle position P ₂ or the corrected vehicle position P _3.

(2) the running distance mode, the vehicle position P ₂ after the correction, the traveling distance component which the vehicle has traveled to the uncorrected vehicle position P _1, by tracing on the link L _n, is computed. Thus, the uncorrected vehicle position P ₂ after correction without starting from the vehicle position P ₁ is obtained, by a radio wave shielding, such as urban canyons, uncorrected for the vehicle position P ₁ is difficult time acquisition also It is possible to output the vehicle position.

(1) In the shortest distance method, the vehicle position P ₃ after correction the uncorrected determined vehicle position correction amount C that starting from the vehicle position P _1, the uncorrected vehicle position P _1, the vehicle position correction Calculated by vector sum with quantity C. Thus, the vehicle position P ₃ after the correction is not affected by the travel distance of the vehicle, meandering driving or, even operating at slightly different route as the position of the link L, such as will flow outwardly when the curve It is possible to output the vehicle position with high accuracy.
For example, when the outer extra travel distance that the vehicle has traveled the curve had occurred, although the vehicle position P ₂ after correction is gone ahead by that extra mileage partial vehicle position after correction since P ₃ is located the shortest distance from the uncorrected vehicle position P _1, not influenced by the extra travel distance.
In other words, when the link L is placed at the center of the road on the map data on the curve, if the vehicle is traveling outside the center of the road, the travel distance is longer than when traveling on the center of the road. vehicle position P ₂ after the correction than the vehicle position P ₃ precedes later. On the other hand, the vehicle is so short running distance than when traveling the road center when traveling inside from the center of the road, the vehicle position P ₂ after the correction than the correction after the vehicle position P ₃ is retracted.

  The own vehicle position display unit 30 displays the calculated own vehicle position on the map (S16). In addition to the car navigation display screen, the display screen may be a speedometer display screen on the inner panel, a head-up display, or the like.

FIG. 4A is a schematic diagram when the vehicle enters the branch road on a branch road such as an expressway. When the vehicle approaches a branch road or the like, the correction destination road is specified by the method shown in S14 of FIG. At this time, the traveling direction vector theta _p of the vehicle, when the link L _{n + 2} of the link angle theta _L extending in the branch path, the state difference is the threshold value theta _Lth or less, followed without interruption at a predetermined time, the branch Determine to enter the road. Alternatively, it may be determined that the vehicle enters the branch path by operating the direction indicator.

  When it is determined that the vehicle enters the branch road, the vehicle is matched with the branch road. On the other hand, when it is determined that the vehicle does not enter the branch road, the vehicle travels at a current speed or a speed according to the accelerator operation amount of the driver.

  Furthermore, when it is determined that the vehicle enters the branch road, appropriate speed control is realized by decelerating to a necessary speed according to the shape of the curved road ahead. That is, the vehicle is decelerated at an appropriate timing and deceleration so that the target speed corresponding to the curvature radius of the curve is reached at the entrance of the curve. The target speed may be obtained by recognizing a speed limit sign in front of the curve with a camera mounted on the front part of the vehicle or by reading a preset target speed from map information. Good.

  FIG.4 (b) is a schematic diagram in case the own vehicle changes lanes. First, in S11, the map information acquired by the map information acquisition unit 11 is a high-accuracy map in which nodes and link information (including lane distinction, lane width, etc.) are described for each lane.

  A case will be described in which the own vehicle changes lanes from the overtaking lane to the traveling lane on a two-lane road (running lane, overtaking lane). If the method shown by S14 of FIG. 3 is used, since each link which shows 2 lanes is parallel, it is difficult to specify which link is selected in the angle vector difference.

Therefore, the vehicle position correction amount C _{(r C,} theta _C) vehicle position correction at the distance _r C (S15 of (1) is calculated by the shortest distance method), based on the width _{W R} of the lane, By comparing with the lane change determination formula “| r _C | ≧ | W _R / 2 |”, it is determined whether or not to change the lane. When the lane change determination formula is satisfied, it is determined that the lane is changed. Alternatively, a signal from a direction indicator or the like may be used when detecting a lane change.

Further, when the vehicle wander (Δr _C ) in the lane is large, it is possible to prevent lane departure by warning (screen, voice, etc.) to the driver or a steering operation.

  The first embodiment using the azimuth calculation unit 21a has been described above. Hereinafter, a second embodiment using the gradient calculation unit 21b will be described.

  FIG. 5 is a flowchart showing the operation of the host vehicle position calculation apparatus 1 in the second embodiment. Hereinafter, description will be made while paying attention to the difference from the first embodiment (FIG. 2).

In S21 of FIG. 5, the parameters exemplified in Table 1 are detected as shown in S11 of FIG. Here, the map information includes information on the height axis.
N _n (x _n , y _n , z _n ) indicates a node. z _n indicates the altitude of the node.
L _n (r _L , θ _L , σ _L , W _L ) indicates a link. σ _L indicates a road gradient (link angle in the gradient) such as an uphill.
Among the parameters that are illustrated in Table 1, the parameters to be mainly used for the calculation gradient calculating unit 21b is the gradient vector is the vehicle speed VSP, the acceleration A _v and the deceleration A _D, the input torque T _n . S22 is the same as S12.

  And the advancing direction calculating part 21 (gradient calculating part 21b) calculates the advancing direction vector (pitch vector) of the own vehicle (S23). Hereinafter, the details of S23 will be described from S23a to S23d.

  First, each torque acting on the own vehicle is calculated (S23a). Hereinafter, details of each torque to be calculated will be described with reference to FIG.

  FIG. 6 is an explanatory diagram showing an example in which the own vehicle travels on a road on the elevated road composed of two roads on the upper and lower sides. FIG. 6B is a diagram in which a part of FIG. In FIG. 6A, the own vehicle traveling on the lower side of the elevated road climbs the slope of the uphill road and travels on the upper side of the elevated road. FIG. 6B shows torques acting on the own vehicle that is climbing the slope of the uphill road.

λ represents a reduction ratio. The reduction ratio (also referred to as the gear ratio) is the ratio of the engine speed that is decelerated (or accelerated) by the gears of the transmission or the like. That is, in the case of the same engine speed, the larger the speed reduction ratio (speed ratio), the larger the power (force), but the smaller the speed (speed). On the other hand, the smaller the reduction ratio (transmission ratio), the smaller the power (force), but the larger the speed (speed).
T _TB indicates the turbine torque. T _TB is obtained by “input torque T _n × torque ratio”. The torque ratio is a catalog specification value or a measured value by a sensor.
T _D indicates the drive torque. T _D is calculated by the calculation formula “T _D = (T _TB × g) × λ / 2R _T ”. Here, g represents a gravitational acceleration, and _RT represents a tire radius.
R _FV represents a resistance (friction) force. R _FV is calculated by the calculation formula “R _FV = k × W”. Here, k represents a friction coefficient defined by a road type (such as asphalt) and a road surface condition (such as wet or snow), and W represents a vehicle weight.
R _AR indicates air resistance. R _AR is calculated by the calculation formula “R _AR = K × VSP ² ”. Here, K represents a proportionality coefficient.
T _FR indicates a flat running resistance torque. T _FR is calculated by a calculation formula “T _FR = R _FV + R _AR ”.
T _AR represents the acceleration resistance torque. T _AR is calculated by the calculation formula “T _AR = (W + ΔW) × A _V × R _T ”. Here, _{A v} represents a vehicle acceleration.
_Tσ represents the gradient resistance torque. The T _sigma, formulas _- by _{"T σ = T D (T FR} + T AR) " are calculated.

Next, the gradient of the road on which the vehicle travels is obtained as a gradient vector from each torque calculated in S23a (S23b). σ _P indicates a traveling direction vector (gradient vector). σ _P is calculated by the calculation formula “σ _P = sin ⁻¹ {T _σ / (W · g · R _T )}”. Here, g represents a gravitational acceleration. The notation of the gradient vector σ _P is a percentage (%) display or a frequency (angle) display based on the road structure ordinance. Further, the gradient vector σ _P may set the value of the road gradient σ _L of the link acquired by the map information acquisition unit 11.

Then, it is determined whether or not the vehicle is traveling on a flat road (S23c). Specifically, the gradient vector σ _P calculated in S23b and the preset threshold value σ _th are compared with the gradient determination expression “| σ _th | ≦ | σ |”. When the gradient judgment formula is satisfied continuously for a predetermined time, the vehicle is traveling on a steep road, and when the vehicle is not established at least once, the vehicle is traveling on a relatively flat road. As the threshold value σ _th , for example, a numerical value of 2% to 5% is set.

When the vehicle is traveling on a steep road slope (S23c, Yes), stores the gradient vector sigma _P updated in S 23 b, etc. are incorporated in a hard disk drive computer, CD-R, etc. DVD-RAM By doing so, it is updated (S23d).

The details of S23 have been described above. As another realization method of S23, a surrounding scene such as a road on which the vehicle travels is photographed using a front camera attached to the front part of the vehicle or a rear camera attached to the rear part of the vehicle, and a road sign included in the photographed image The calculation may be performed by paying attention to such an object and recognizing the degree of change in the vertical direction. Alternatively, the gradient vector σ _P may be obtained from the velocity or acceleration of the pitch axis calculated by the gyro sensor.

Then, based on the gradient vector σ _P calculated in S23, a correction destination road is selected (S24). The calculation of the corrected vehicle position (S23) can be realized by, for example, either (A) gradient presence method or (B) height measurement method.

  (A) The gradient presence / absence method roughly specifies the road on which the vehicle is traveling. For example, suppose that the vehicle is traveling on an underpass road. Thereafter, when it is determined that the host vehicle is traveling on a steep road (S23c, No), the correction destination road is changed to an elevated road. Thereby, since a road can be selected without requiring a detailed value of road height information, detailed map information is not necessary and can be realized at low cost.

  (B) The height measurement method calculates the height difference from the travel distance of the vehicle on the road with the slope σ and the slope σ of the road that has traveled, and the height is the highest according to the map information and the height difference. This is a method of selecting a nearby road. As a result, it is possible to select a road with high accuracy even for a complicated road (such as a ramp on a highway) having multiple levels of height at the same latitude and longitude.

  In addition to the methods (A) and (B), when a vehicle travels on a road such as a place where GPS accuracy is reduced or a mountainous area with many undulations, a two-dimensional travel distance (two-dimensional travel distance) It is possible to match the vehicle to an appropriate position on the map by calculating a travel distance (referred to as a three-dimensional travel distance) in consideration of undulations according to the road gradient. Moreover, you may update to the map information containing an altitude using the above-mentioned three-dimensional traveling distance.

  S25 in FIG. 5 is the same as S15 in FIG. S26 in FIG. 5 is the same as S16 in FIG.

  FIG. 7 is a screen diagram illustrating an example of a screen displayed in S16 and S17. The own vehicle position display column 701 indicates the position of the own vehicle on the map with an icon. The traveling direction display column 702 shows each vector calculated by the traveling direction calculation unit 21 in% display or angle display (degrees) according to the road structure ordinance. Further, the map information displayed on the map is map information corresponding to an actual landscape, such as a building and the type and type of business of the building. As the types and types of business described above, there are signs such as gas stations, convenience stores, stations, schools, and names, names, and the like.

  The correction on / off display field 703 displays whether the vehicle position is corrected in S15 or S25 (ON) or not (OFF). This on / off can be switched by a predetermined operation. When the vehicle is ON, the corrected vehicle position is displayed in the vehicle position display column 701. When the vehicle is OFF, the vehicle position before correction is displayed in the vehicle position display column 701. Alternatively, when ON, the driver and passengers may be informed that the vehicle position on the screen is corrected by matching or flashing in the vehicle position display field 701 or by matching the sound.

  It should be noted that when the traveling direction of the road is not appropriate to the traveling direction of the road shape by comparing the traveling direction of the road shape with the traveling direction (direction, gradient) of the vehicle based on the driver's steering operation (the steering wheel For example, the driver may warn the driver that the steering operation is not appropriate by blinking the traveling direction display field 702 or by a sound such as “buzzy”.

  Also, comparing the road gradient with the speed of the vehicle, if the speed of the vehicle is not appropriate (such as excessive speed on the downhill), a flashing of the traveling direction display field 702 and a sound such as “beep / beep” Thus, the operator may be warned that the speed is not appropriate for the road.

  Further, the correction of the vehicle position displayed in the correction on / off display field 703 is performed by individually correcting the vehicle azimuth calculated by the azimuth calculation unit 21a and the vehicle gradient calculated by the gradient calculation unit 21b. On / off may be specified. For example, in an area where there are no elevated roads around, the calculation amount can be reduced by turning off the correction processing by the gradient calculation unit 21b.

  As described above, the corrected vehicle position is displayed on the screen of the in-vehicle terminal device based on the vehicle traveling direction according to the driver's steering operation and the vehicle posture such as the gradient of the running road. By calculating, it is possible to display the accurate vehicle position on the map and notify the driver and passengers of the accurate vehicle position and vehicle state. As a result, it is possible to improve the reliability of the in-vehicle terminal device for displaying the corrected vehicle position and the comfort during driving.

It is a block diagram which shows the own vehicle position calculating apparatus regarding one Embodiment of this invention. It is a flowchart which shows operation | movement of the own vehicle position calculating apparatus regarding 1st Embodiment of this invention. It is explanatory drawing which shows the vehicle position before correction | amendment regarding the 1st Embodiment of this invention, and the vehicle position after correction | amendment. It is a schematic diagram which shows the case of the branch road and lane change regarding 1st Embodiment of this invention. It is a flowchart which shows operation | movement of the own vehicle position calculating apparatus regarding 2nd Embodiment of this invention. It is explanatory drawing which shows an example which the own vehicle drive | works the road on an elevated road in the elevated road comprised from two upper and lower roads regarding 2nd Embodiment of this invention. It is a screen figure which shows an example of the screen displayed regarding one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Own vehicle position calculation apparatus 10 Own vehicle position calculation part 11 Map information acquisition part 12 Own vehicle position detection part 13 Uncorrected own vehicle position calculation part 14 Parameter detection part 15 Own vehicle information acquisition part 20 Own vehicle position correction part 21 Traveling direction Calculation unit 21a Direction calculation unit 21b Gradient calculation unit 22 Correction destination road selection unit 23 Corrected vehicle position calculation unit 30 Vehicle position display unit

Claims (5)

A vehicle position calculation device for correcting the vehicle position displayed on the navigation screen,
For a link indicating a road, a map information acquisition unit that acquires map information including the direction of the link from the storage means;
A vehicle position detection unit for detecting the vehicle position by communication means;
An uncorrected own vehicle position calculation unit that associates the own vehicle position detected by the own vehicle position detection unit with the map information acquired by the map information acquisition unit and sets the own vehicle position before correction;
By detecting the steering operation to the vehicle, and the azimuth calculation section for calculating a square position in the traveling direction of the vehicle,
For each link around the vehicle, wherein the person-position of the vehicle, a link differencing is minimized with the direction position of the link, and a correction destination road selecting unit that selects a link showing a correction destination road,
A corrected vehicle position calculation unit that determines a position on the link selected by the correction destination road selection unit as a corrected vehicle position;
The corrected vehicle position determined by the corrected vehicle position calculation unit is displayed in association with the map information acquired by the map information acquisition unit, and the corrected vehicle position from the vehicle position before correction And a vehicle position display unit that displays a warning that the vehicle is staggered when the distance to the vehicle varies . The corrected host vehicle position calculation unit calculates a position closest to the host vehicle position detected by the host vehicle position detection unit from among the positions on the link selected by the correction destination road selection unit. Characterized as determined
The own vehicle position calculation device according to claim 1 . The vehicle position display unit, when any one of the vehicle position before correction or the corrected vehicle position is designated, the designated vehicle position is displayed on a map. The own vehicle position calculation device according to claim 1, wherein the vehicle position calculation device is displayed. A vehicle position calculation method for correcting the vehicle position displayed on the navigation screen,
Computer
For a link indicating a road, map information including the direction of the link is acquired from the storage means,
The vehicle position is detected by communication means,
The detected vehicle position is associated with the map information acquired by the map information acquisition unit as the vehicle position before correction,
By detecting the steering operation to the vehicle, it calculates the square position in the traveling direction of the vehicle,
For each link around the vehicle, wherein the person-position of the vehicle, a link differencing is minimized with the direction position of the link, select a link showing a correction destination road,
Determine the position on the selected link as the corrected vehicle position,
The determined corrected vehicle position is displayed in association with the map information acquired by the map information acquisition unit, and when the distance from the corrected vehicle position to the corrected vehicle position varies, A vehicle position calculation method characterized by displaying a warning that the vehicle is wobbling . A host vehicle position calculation program for causing a computer to execute the host vehicle position calculation method according to claim 4 .

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