Range measurement systems may be accurate to 2cm or better in global co-ordinates but the accuracy in the forward and lateral directions vary. This is because the measurements in the north-east co-ordinates (the global co-ordinates) need to be rotated to the forward and lateral directions so that they match the measurements from radar, lidar and vision systems.
This rotation causes a coupling in accuracy between the forward range and the lateral range accuracy. As the forward range increases, the lateral range accuracy (or uncertainty) increases because of the heading error.
The RT Inertial+GPS Navigation System includes an output which tells other systems, like the RT-Range, how accurate the heading is. This can be used, in turn, to estimate the accuracy of the forward and lateral range. The accuracy is computed in the RT-Range and output in a new CAN message. The message includes errors for heading, as well as errors in the global position.
Knowing how accurate the output of the RT-Range is allows engineers to have more confidence in the RT-Range outputs. It gives them a better idea on the accuracy they can expect from the RT-Range at any moment in time. It can also identify faults, like the base-station not working, which can otherwise require tests to be repeated.
The RT-Range is designed and manufactured by OxTS as a reference system for testing active sensors on cars in ADAS applications. OxTS has sold enough systems to equip nearly 100 vehicles worldwide, giving engineers the most comprehensive ADAS test tool available. How can we help you develop your ADAS solutions faster?
