Multi-sensor vehicle testing: Recording inertial sensors via CAN bus in combination with recorded GNSS RF signals

Abstract

Today, vehicles are equipped with multiple sensors for positioning and navigation to provide accurate and reliable information to the driver and to the Advanced Driver Assistance Systems in order to enhance safety of driving. Sensor data are exchanged via the CAN bus. Traditional test systems allow testing of one or two signals or sensors. But today, there is a need to test as many sensors together as possible. Here we would like to present an integrated test solution combining GNSS RF record and replay with a CAN bus interface which enables the system to provide record and playback of a wide range of vehicle CAN bus data using technology provided by the Automotive industry experts DGtech. During drive tests, signals from Galileo, GPS, GLONASS and Beidou can be recorded as RF, at L1, L2 or L5 with a Spirent Record and Replay System. “A highly specialized, portable unit — in this case, the Spirent GSS6425 — is taken on the drive test, faithfully recording the entire RF environment at each stage, including all GNSS signals, any interference, and any other RF signals present at the location. This is replayed on the bench, as many times as engineers require, to verify and improve performance.” [1] CAN bus messages can be recorded as plain text ASCII data by the systems CAN bus interface which is a DG Tech Gryphon S4C data logger capable of being integrated into a wide range of commercial, industrial and military vehicles. The GNSS signal recordings and the CAN bus recordings are stored in a highly synchronized data stream and can be played back synchronously with a delta difference of less than 15ms. Heading truth data is recorded as serial data via a dedicated high performance GPS-Aided Inertial Navigation Sensor and audio/video source provided by up to 3 web cameras. During replay the GNSS signals are directly presented to the UUT. CAN bus messages are replayed via the CAN bus interface. There is a possibility to drive a rate table with the recorded data. All data streams are time synchronized during replay. Thus the same signal environment is recreated during replay in the laboratory. This system combines GNSS, heading, CAN, video and other sensors, e.g. gyroscopes and accelerometers via CAN, to enable thorough and simultaneous testing of multiple functionalities. It reduces the amount of field tests and provides control and repeatability to the test series in the lab.