Abstract:

: Dynamic performance of a GNSS (Global Navigation Satellite System) positioning device (PD) is of interest to end users of satellite-based auto-guidance systems (AGS) for agricultural vehicles, especially when a low-cost PD is used. This study evaluated the overall dynamic performance in an agricultural environment for the PDs paired with multi-frequency multi-GNSS receivers and antennae, including low-cost and legacy ones. The dynamic performance was evaluated in terms of reacquisition time, heading accuracy, positioning accuracy, and guidance accuracy at short and medium baselines of RTK (Real Time Kinematic) positioning. The dynamic testing was conducted using an instrumented vehicle with test PDs to perform the test runs on agricultural fields and asphalt roads. The test results proved that the dynamic performance of the low-cost PD was not inferior to that of the legacy one and accurate enough to be used as a positioning sensor for the auto guidance of agricultural vehicles. It could reacquire an RTK-fix solution within 4 s after a 3-s GNSS signal blockage and achieve sub-degree-level accuracy of the heading measurement for agricultural vehicles traveling in an open-sky environment. Furthermore, the low-cost PD could obtain a 4-cm-level dynamic RTK positioning accuracy and agricultural vehicle guidance accuracy of less than 3 cm. The techniques and test results from this study provided additional guidelines for determining the overall dynamic performance of the GNSS PDs and AGSs on an agricultural tractor.

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