GNSSIMUsystem

GNSSIMUsystem is a navigation and attitude reference system that combines GNSS measurements with data from an inertial measurement unit to provide robust estimates of position, velocity, and orientation. By fusing satellite-based positioning with high-rate inertial data, it maintains accuracy and continuity even when GNSS signals are intermittent or degraded.

A typical GNSSIMUsystem comprises a GNSS receiver, an IMU (accelerometers and gyroscopes), and a processor or embedded computer with a fusion algorithm. The GNSS subsystem supplies absolute position and velocity, while the IMU provides high-frequency motion increments and short-term attitude information. The two data streams are synchronized and processed to produce unified state estimates and diagnostic information.

Fusion methods include tightly coupled and loosely coupled architectures. In tightly coupled fusion, raw GNSS measurements are integrated with IMU predictions, improving performance under partial satellite visibility and multipath conditions. In loosely coupled designs, a standalone GNSS solution is combined with an inertial solution. Kalman filter-based approaches are common, with complementary or extended versions, and some systems support RTK or PPP corrections to achieve centimeter-level positioning when available.

Outputs typically include position, velocity, and attitude estimates (often expressed as roll, pitch, and yaw or as a quaternion), along with IMU bias estimates and covariance or quality indicators. Update rates vary, with IMU data at high frequency (often hundreds of Hz) and GNSS updates at tens of Hz or lower, depending on configuration.

Applications span aviation, maritime, autonomous vehicles, drones, robotics, and surveying. The GNSSIMUsystem offers improved accuracy, better robustness in challenging environments, and the ability to bridge GNSS gaps, at the cost of increased complexity and calibration needs.