GNSSIMU

GNSSIMU stands for GNSS Inertial Measurement Unit. It refers to a navigation sensor that combines a Global Navigation Satellite System (GNSS) receiver with an inertial measurement unit (IMU) to provide robust, high-rate positioning, velocity, and attitude estimates. The GNSS component delivers absolute position and velocity by tracking satellite signals from constellations such as GPS, GLONASS, Galileo, and BeiDou, while the IMU supplies fast, high-frequency measurements of angular rate and linear acceleration. A processing unit runs sensor-fusion software, typically based on Extended or Unscented Kalman Filters, to merge GNSS and IMU data into a coherent state estimate.

Standalone GNSSIMUs may include integrated antennas and on-board processing, while others are compact sensor packages designed to plug into robotics, aviation, or automotive platforms. Typical outputs include position, velocity, and attitude in standard reference frames, along with quality indicators and sometimes clock bias estimates. Update rates vary from tens to hundreds of hertz, depending on hardware.

Applications span autonomous vehicles, aerial and ground robotics, surveying, maritime navigation, and mobile devices. The main advantages are improved short-term accuracy and robustness during GNSS outages, since the IMU can bridge gaps while the fusion algorithm re-converges to the GNSS solution when signals return. Limitations include IMU drift over time and the need for proper calibration and initialization. System performance depends on sensor quality, the fusion algorithm, initialization procedure, and accurate sensor alignment.