A key measurement for lane departure warning systems is the angle of the vehicle within the lane. This can be used, together with the lane curvature, to compute whether the vehicle will depart the lane while following its current path. The lane departure warning system can then alert the user while minimising the chances of false alerts.
The 2011 version of the RT-Range software computes the relative heading of the line markings compared to the heading of the vehicle. One output is available for the line on the left side of the vehicle and another output for the line on the right side.
The RT-Range works using RT Inertial+GPS Navigation Systems so all heading measurements relate to the direction that the vehicle is pointing, not the direction it is travelling. This is an advantage over the GPS-only systems, which have to use the course-over-ground angle. On corners there can be a significant difference between the heading and the course-over-ground, which will appear as an error or difference compared to vision systems. The RT-Range can be used successfully on both corners and during straight sections. This feature is essential when trying to develop and test lane departure warning sensors that work on curved roads.
The RT Inertial+GPS Navigation System already includes tools to make minor adjustments to the heading mount angle in the vehicle. This can be used to accurately align the sensor co-ordinate system to the RT’s co-ordinate system. Aligning the co-ordinate systems removes any constant offset in the relative heading between the sensor’s and the RT-Range’s output.
The RT-Range has already given many engineers an advantage in their research into ADAS (Advanced Driver Assistance Systems). To find out how to maximize your results from your track tests contact OxTS.
