Enhanced Land Vehicular GNSS/INS Combined System by Using Multiple-Antenna With Common Clock

Global Navigation Satellite System (GNSS)/ Inertial Navigation System (INS) combined system is an undoubtedly vital component of Land Vehicular Navigation (LVN). However, the performance of the GNSS/INS integrated system still experiences a decline in GNSS-compromised environments, as the INS drift cannot be entirely suppressed by the insufficient GNSS observations. Before laboriously incorporating other sensors (such as camera, odometer and lidar) as the mainstream solution, it is very important and interesting to assess whether the GNSS information has been fully exploited, especially for the routes that are not completely covered. This manuscript proposes a method to fully utilize GNSS information by using multiple antennas, which is usually driven by the same quartz clock to save cost and volume. Based on the property of equal clock bias, the raw GNSS observations of these antennas are used to tightly combine with INS, which can significantly increase the available GNSS information. Experiment results show that the horizontal position root-mean-square errors (RMSEs) of dual/four-antenna GNSS/INS integrated system are reduced by 42.8/67.8% and 45.1/52.1% with respect to the single-antenna system in two tests, respectively.