APPARATUS AND METHOD FOR DETERMINING A VEHICLE POSITION IN A FIXED-TRAFFIC-NODE COORDINATE SYSTEM

Abstract

A method and an apparatus for determining a vehicle position in a fixed-traffic-node coordinate system. The apparatus includes at least one receiver for receiving a signal from a traffic-node transmission device, at least one device for determining an item of direction-of-travel information in a global reference coordinate system and at least one evaluation device. A spatial relationship between the global reference coordinate system and the fixed-traffic-node coordinate system is known in advance. The evaluation device can be used to take at least one signal property of a received signal as a basis for determining a position of the traffic-node transmission device in a vehicle coordinate system. The evaluation device can be used to determine the vehicle position in the fixed-traffic-node coordinate system on the basis of the direction-of-travel information and the position of the traffic-node transmission device in the vehicle coordinate system.

Claims

1-11. (canceled)

12. An apparatus for determining a vehicle position in a traffic-node-fixed coordinate system, the apparatus comprising: a receiver unit for receiving a signal of a traffic-node-side transmitter unit; a unit for determining an item of travel direction information in a global reference coordinate system; wherein a spatial relationship between the global reference coordinate system and the traffic-node-fixed coordinate system is known; and an analysis unit; said analysis unit being configured to determine a position of the traffic-node-side transmitter unit in a vehicle coordinate system as a function of at least one signal property of a signal received by said receiver unit; and said analysis unit being configured to determine a position of the vehicle position in the traffic-node-fixed coordinate system is determinable as a function of the item of travel direction information and the position of the traffic-node-side transmitter unit in the vehicle coordinate system.

13. The apparatus according to claim 12, wherein said unit for determining the item of travel direction information is an inertial sensor or includes an inertial sensor.

14. The apparatus according to claim 13, wherein said inertial sensor is a magnetometer.

15. The apparatus according to claim 12, wherein the item of travel direction information is a yaw angle, the yaw angle being an angle between a vehicle longitudinal direction and a reference direction of the global reference coordinate system.

16. The apparatus according to claim 12, which further comprises a transmitter unit for transmitting the vehicle position in the traffic-node-fixed coordinate system.

17. The apparatus according to claim 12, which comprises a route determining unit for route determination of the vehicle, wherein an updated vehicle position is determined as a function of a last determined vehicle position and a covered route.

18. The apparatus according to claim 17, wherein the route determining unit comprises said unit for determining the item of travel direction information, a unit for determining a vehicle acceleration, and/or a unit for determining a vehicle velocity.

19. An arrangement for determining a position of a vehicle in a traffic-node-fixed coordinate system, the arrangement comprising an apparatus according to claim 12 and a traffic-node-side transmitter unit.

20. A method for determining a vehicle position in a traffic-node-fixed coordinate system, the method comprising: receiving a signal of a traffic-node-side transmitter unit by a vehicle-side receiver unit; determining an item of travel direction information in a global reference coordinate system, wherein a spatial relationship between the global reference coordinate system and the traffic-node-fixed coordinate system is previously known; determining a position of the traffic-node-side transmitter unit in a vehicle coordinate system as a function of at least one signal property of the received signal; and determining the vehicle position in the traffic-node-fixed coordinate system as a function of the item of travel direction information and the position of the traffic-node-side transmitter unit in the vehicle coordinate system.

21. The method according to claim 20, wherein the item of travel direction information is a yaw angle being an angle between a vehicle longitudinal direction and a reference direction of the global reference coordinate system.

22. The method according to claim 20, which comprises determining an updated vehicle position as a function of a last determined vehicle position and a covered route.

Description

[0054] The invention will be explained in greater detail on the basis of an exemplary embodiment. In the figures:

[0055] FIG. 1 shows a schematic block diagram of an apparatus according to the invention,

[0056] FIG. 2 shows a schematic top view of a traffic node having multiple vehicles, and

[0057] FIGS. 3a-3c show the exemplary determination of a travel direction.

[0058] Hereafter, identical reference signs identify elements having identical or similar technical features.

[0059] FIG. 1 shows a schematic block diagram of an apparatus 1 according to the invention for determining a vehicle position in a traffic-node-fixed coordinate system. The apparatus 1 is arranged in a vehicle V1, V2, V3, V4 (see FIG. 2). The apparatus 1 comprises a transceiver unit 2. By means of the vehicle-side transceiver unit 2, signals of a traffic-node-side transceiver unit 3 (see FIG. 2) can be received. Furthermore, the apparatus 1 comprises an inertial sensor designed as a magnetometer-compass sensor 7, wherein a yaw angle ? can be determined by means of the magnetometer-compass sensor 7. Furthermore, the apparatus 1 comprises a velocity sensor 4, which detects a velocity of the vehicle V1, V2, V3, V4.

[0060] The vehicle-side transceiver unit 2, the magnetometer-compass sensor 7, and the velocity sensor 4 are connected to transmit signals and/or data to an analysis unit 5, which is also part of the apparatus 1. As explained in greater detail hereafter, a position of the traffic-node-side transmitter unit 3 in a vehicle coordinate system can be determined by means of the analysis unit 5 as a function of at least one signal property of a signal received by the transceiver unit 2. Furthermore, the vehicle position in the traffic-node-fixed coordinate system can be determined as a function of the yaw angle ? and the position of the traffic-node-side transmitter unit 3 in the vehicle coordinate system by means of the analysis unit 5.

[0061] FIG. 2 shows a schematic top view of an intersection 6 having four road sections, wherein each road section respectively comprises one entrance and one exit. Furthermore, a first vehicle V1, which travels along the entrance of a first road section toward the center of the intersection 6 is shown. Accordingly, a second, a third, and a fourth vehicle V2, V3, V4 travel along the entrances of the further road sections toward the center of the intersection 6. A method for determining a vehicle position in a traffic-node-fixed coordinate system is described by way of example for the first vehicle V1. The same method can obviously be used for determining the vehicle position of the further vehicles V2, V3, V4. The first vehicle V1 and all further vehicles V2, V3, V4 can each comprise one apparatus 1 (see FIG. 1).

[0062] The first vehicle V1 can periodically emit request signals by means of the transceiver unit 2. These signals can be received by a traffic-node-side transceiver unit 3. If a received power of a request signal is greater than a predetermined threshold value, the traffic-node-side transceiver unit 3 thus generates a response signal, which is in turn received by the vehicle-side transceiver unit 2.

[0063] As a function of a run time of this response signal, which was emitted by the traffic-node-side transceiver unit 3, a distance of the vehicle-side transceiver unit 2 from the traffic-node-side transceiver unit 3 can be determined in a vehicle coordinate system of the first vehicle V1. The vehicle coordinate system of the first vehicle V1 comprises a vehicle longitudinal axis x.sub.V1, which can be oriented parallel to a roll axis of the vehicle V1. Furthermore, the vehicle coordinate system of the first vehicle V1 comprises a transverse direction y.sub.V1, which can be oriented parallel to a pitch axis of the vehicle V1. A vertical axis of the first vehicle V1, which can be oriented parallel to a yaw axis of the first vehicle V1, is not shown. Furthermore, an origin C.sub.V1 of the vehicle coordinate system of the first vehicle V1 is shown.

[0064] Correspondingly, the coordinate systems of the further vehicles V2, V3, V4 also comprise longitudinal directions x.sub.V2, x.sub.V3, x.sub.V4 and transverse directions y.sub.V2, y.sub.V3, y.sub.V4 and also origins C.sub.V2, C.sub.V3, C.sub.V4.

[0065] A location of the vehicle-side transceiver unit 2 in the vehicle coordinate system of the first vehicle V1 is previously known.

[0066] A location of the traffic-node-side transceiver unit 3 in a traffic-node-fixed coordinate system is also previously known. This traffic-node-fixed coordinate system comprises a longitudinal direction x.sub.N and a transverse direction y.sub.N, wherein the transverse direction y.sub.N is oriented in the direction toward the magnetic north pole.

[0067] Furthermore, an origin C.sub.N of the traffic-node-fixed coordinate system is shown, which is arranged in the center point of the entrances.

[0068] Since the location of the transceiver units 2, 3 in the respective coordinate systems thereof is previously known, as a function of the run time of the signal, a distance between the origin C.sub.V1 of the vehicle coordinate system of the first vehicle V1 and the origin C.sub.N of the traffic-node-fixed coordinate system can be determined. The angle of incidence of the response signal received by the vehicle-side receiver unit in the vehicle coordinate system can also be determined. The angle of incidence and the distance can be coded as a direction vector in the vehicle coordinate system, wherein the direction vector is oriented from the origin C.sub.V1 of the vehicle coordinate system of the first vehicle V1 toward the origin C.sub.N of the traffic-node-fixed coordinate system and wherein the absolute value of the direction vector corresponds to the distance.

[0069] The position of the origin C.sub.N of the traffic-node-fixed coordinate system in the vehicle coordinate system of the first vehicle V1 can therefore be determined as the vector (x(C.sub.N).sub.V1;y(C.sub.N).sub.V1).

[0070] Furthermore, a yaw angle ? of the first vehicle V1 is determined. The yaw angle a refers in this case to an angle between the vehicle longitudinal direction x.sub.V1 of the first vehicle V1 and the direction which is oriented toward the magnetic north pole. This direction can also be referred to as magnetic north. This direction forms a reference direction of a global reference coordinate system in this case. The direction toward the magnetic north pole is oriented parallel to the transverse direction y.sub.N.

[0071] In the exemplary embodiment shown in FIG. 2, the yaw angle of the first vehicle V1 is 0?. The magnetometer-compass sensor can possibly detect a yaw angle ? different from 0?, wherein this deviation can be caused by measurement noise, in particular a measurement noise according to a zero-mean Gaussian distribution.

[0072] A standard deviation of this measurement noise can be, for example, between 1? (inclusive) and 5? (inclusive).

[0073] Accordingly, a yaw angle ? of the second vehicle V2 is 90?, a yaw angle ? of the third vehicle V3 is 180?, and a yaw angle ? of the fourth vehicle V4 is 270? or ?90?.

[0074] As a function of the yaw angle ? determined in this manner (see FIG. 3a), a transformation matrix T.sub.R can then be determined. The transformation matrix T.sub.R enables the conversion of the coordinates of the origin C.sub.N of the traffic-node-fixed coordinate system in the vehicle coordinate system of the first vehicle V1 into coordinates of the origin C.sub.V1 of the coordinate system of the first vehicle V1 in the traffic-node-fixed coordinate system. This can be performed, for example, according to

(x(C.sub.V1).sub.N;y(C.sub.V1).sub.N)=T.sub.R.Math.(x(C.sub.N).sub.V1;y(C.sub.N).sub.V1) Formula 1

[0075] The method can be carried out when a vehicle V1, V2, V3, V4 drives into a predetermined region R around the origin C.sub.N of the traffic-node-fixed coordinate system for the first time at an entry point in time. In particular, the described method can be carried out once at the entry point in time. The vehicle position determined in this manner in the traffic-node-fixed coordinate system can then be transmitted via the transceiver unit 2 to a central control unit (not shown), wherein the central control unit can control a traffic flow through the intersection 6 as a function of the transmitted vehicle position.

[0076] Furthermore, the vehicle position in the traffic-node-fixed coordinate system can be determined again after this first point in time. For this purpose, for example, a route of the vehicle V1, V2, V3, V4 between the entry point in time and a later, further point in time can be determined, wherein the route can be determined as a function of items of velocity information and items of travel direction information. The items of velocity information can be determined as a function of the output signals of the velocity sensor 4 (see FIG. 1) and the items of travel direction information can be determined as a function of the yaw angle ? (see FIG. 1). Furthermore, the vehicle position determined at the entry point in time in the traffic-node-fixed coordinate system can be determined as a function of the route covered between the entry point in time and the further point in time.

[0077] FIG. 3a shows an exemplary yaw angle ?, which is determined between a vehicle longitudinal direction x.sub.V and a transverse direction y.sub.N of the traffic-node-fixed coordinate system, wherein the transverse direction y.sub.N is oriented parallel to a direction toward the magnetic north pole. In FIG. 3a, the yaw angle is positive and is approximately 30?. In FIG. 3b, the yaw angle ? is negative and is approximately ?30?.

LIST OF REFERENCE SIGNS

[0078] 1 apparatus [0079] 2 vehicle-side transceiver unit [0080] 3 traffic-node-side transceiver unit [0081] 4 velocity sensor [0082] 5 analysis unit [0083] 6 intersection [0084] 7 magnetometer-compass sensor [0085] x.sub.N longitudinal direction of the traffic-node-fixed coordinate system [0086] y.sub.N transverse direction of the traffic-node-fixed coordinate system [0087] C.sub.N origin of the traffic-node-fixed coordinate system [0088] x.sub.V1, x.sub.V2, x.sub.V3, x.sub.V4 longitudinal directions of the vehicle coordinate systems [0089] y.sub.V1, y.sub.V2, y.sub.V3, y.sub.V4 transverse directions of the vehicle coordinate systems [0090] C.sub.V1, C.sub.V2, C.sub.V3, C.sub.V4 origins of the vehicle coordinate systems [0091] ? yaw angle