Method and device for locating a vehicle
A method for locating a vehicle involves detecting an elevation profile of a roadway of the vehicle and in which image features on the roadway are detected as landmarks and are compared with landmarks stored on a digital map. A transformation of the detected and/or stored landmarks into a common perspective performed to compare the landmarks. The transformation is carried out based on model parameters of a parametric model of the elevation profile of the roadway and a parametric model of a vehicle inclination. The model parameters are determined by determining an expected elevation profile of the roadway from the parametric models of the elevation profile and the vehicle inclination and minimizing a difference between the expected elevation profile and the detected elevation profile by varying the model parameters.
1. A method for locating a vehicle on a roadway, the method comprising:
detecting, by a first sensor unit of the vehicle, the roadway in an environment of the vehicle to generate a plurality of measurement points;
detecting an elevation profile of the roadway in the environment of the vehicle based on the plurality of measurement points;
determining a set of parametric models, which includes a first and second parametric model, wherein
the first parametric model is of the detected elevation profile of the roadway and comprises (1) a parameterizable curve for a longitudinal direction of the detected elevation profile, and (2) a parametrizable curve for a transverse direction of the detected elevation profile, and
the second parametric model is of an inclination of the vehicle and has pitch angle and roll angle as parameters;
determining an expected elevation profile of the roadway based on the set of parametric models;
determining parameters of the first and second parametric models, including the pitch angle and roll angle parameters, by minimizing a difference between the expected elevation profile and the detected elevation profile;
detecting, by a second sensor unit, landmarks in the environment of the vehicle;
transforming, using the determined parameters of the first and second parametric models, one of the detected landmarks or the landmarks stored on the digital map into a common perspective with the other one of the detected landmarks or the landmarks stored on the digital map; and
comparing, using the common perspective, the detected landmarks with landmarks stored on the digital map to determine a position of the vehicle; and
determining a position of the vehicle based on the comparison of the detected landmarks with the information from the digital map.
2. The method of claim 1 , wherein
the parametrizable curve for the longitudinal direction is a second-order polynomial having two model parameters, and
the parametrizable curve for the transverse direction is a fourth-order polynomial having four model parameters.
3. The method of claim 1 , wherein the parametric model of the vehicle inclination describes a deflection of a longitudinal axis and transverse axis of the vehicle with respect to a contact area of the vehicle with the roadway.
4. The method of claim 3 , wherein the parametric model of the vehicle inclination is generated based on a tangent function of a pitch angle of the vehicle and a tangent function of a roll angle of the vehicle.
5. The method of claim 4 , wherein a time series of the pitch angle and/or the roll angle is used to calibrate the first sensor and/or the second sensor, respectively.
6. The method of claim 1 , wherein the first sensor unit or the second sensor unit comprises at least one of:
lidar unit,
radar unit,
stereo camera unit, and
ultrasonic sensor unit.
7. The method of claim 1 , wherein the first sensor unit and the second sensor unit are a same sensor unit.
8. The method of claim 7 , wherein the same sensor unit is a stereo camera.