This paper discusses the path-following performance of actively-steered articulated vehicles based on measurement signals from two ‘ground-watching’ navigation systems (GWNS). The ground-watching navigation systems are described. These use high-speed USB-3 cameras and an image processing computer to measure and calculate off-tracking distance for a path-following steering controller. Full-scale field tests are performed using an experimental articulated vehicle, tested under both open-loop and closed-loop conditions. Off-tracking distance at the rear camera with respect to the front camera is controlled to be less than 0.1m for tests with both GWNSs.