Ground Robotics, Agriculture, & Heavy Machinery
Ground robots and other slow moving platforms present a significant challenge for many INS sensors. Slow moving platforms typically do not experience sufficient acceleration during normal operating conditions to perform dynamic alignment. Dynamic alignment occurs when there is sufficient motion present to allow an INS sensor to observe heading based on the correlation between the measurement of acceleration from the IMU and the measured change in velocity measured by the GPS receiver. While dynamic alignment works well for platforms such as fixed wing aircraft, it is typically not suitable for slow moving ground vehicles. As such most ground robot navigation systems rely magnetic sensors to estimate heading. Deriving accurate heading using magnetic sensors is notoriously difficult for ground vehicles, due to to the presence of ferrous material in both the vehicle and the local environment such as rebar in concrete, the vehicle itself, and other nearby objects. Achieving accurate heading measurements using magnetic sensors is only possible in applications where the magnetic environment can be carefully controlled by the user, and where a magnetic calibration is accurately performed on the vehicle itself using a technique known as a hard/soft iron calibration. In most real-world applications, the user has little to no control over the quality of the surrounding magnetic environment, and performing a proper magnetic calibration is a very time consuming endeavor, and in some cases is not possible for certain platforms such as heavy machinery.
The VN-300 is the ideal navigation sensor for outdoor ground robots and heavy machinery due to its ability to accurately estimate heading relative to true North without any reliance on magnetic sensors. This enables autonomous control in conditions where the magnetic environment isn't predictable or for vehicles such as heavy machinery where magnetic calibration and the use of magnetic sensors in general is not feasible. With heading accuracies of better than 0.3 degrees possible, the VN-300 is also ideally suited for agricultural use, where precise heading accuracies are required.