LSS Emergency Lane Keeping (ELK)
The Euro NCAP LSS ELK protocol evaluates how effectively a system copes with situations that are likely to end in a serious accident due to the vehicle leaving its lane. These include when the vehicle under test (VUT) leaves the road by drifting out of its lane, crashing into oncoming vehicles after drifting across the centreline and striking another vehicle by changing lanes while being overtaken.
The tests fall into two types: those involving global vehicle targets (GVT) and those involving surveyed edges, such as the edge of the road or the edge of lane markings. The tests are conducted using prescribed curves generating different lateral velocities and timed so that vehicles will strike each other in specific ways if there is no intervention from the system being tested.
While ELK tests can be conducted with a human driver, because of the precise requirements in lateral acceleration and lane positioning, steering and pedal robots are often used. These are easily integrated with our RT and RT-Range Hunter products, which provide the information required to operate the autonomous systems.
Protocol accuracy requirements
- VUT and GVT axes to be in ISO 8855:1991 orientation
- VUT and GVT longitudinal speed to 0.1 km/h
- Update rate at least 100 Hz
- Time is required as a synchronisation DGPS
- Position to 0.03 m
- Yaw velocity to 0.1°/s
- Acceleration to 0.1 m/s²
- Polygon perimeter shapes
Getting the measurements you need
As well as producing vehicle-to-vehicle measurements, the RT-Range Hunter can simultaneously measure from points on the VUT to the edge of lane markings or even the edge of the road. It does this by referencing preloaded files, called line files, which contain the surveyed position of features such as line edges. Therefore the first step in most ELK tests is to survey the edge of the road and the inside edges of any lane markings using an RT and our survey trolley.
Once the lane markings have been surveyed with the RT, it can be installed in the VUT along with an RT-Range Hunter. For Road Edge testing, this is all the equipment required, apart from a base station broadcasting differential corrections in order to allow RTK 1 cm position accuracy. For the Oncoming and Overtaking tests, an additional RT needs to be installed in the GVT.
The RT-Range Hunter in the VUT receives position information via the other RT system and then calculates measurements in real-time. Position, orientation and velocity information can also be passed in real-time to any pedal/steering robot systems.
Once back in the office, data can be downloaded from the systems, post-processed, tested and exported in CSV format for further analysis.