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Expedition Survey of Belize’s Great Blue Hole with Ellipse INS sensor
During Belize's Great Blue Hole expedition survey, SBG Ellipse INS was integrated to Kongsberg's sonar equipment to create a 3D sonar map of the sinkhole
AHRS – Attitude and Heading Reference Systems
SBG Systems offers a wide line of AHRS suitable whether your applications requirements are size or performance.
What is an Attitude and Heading Reference System (AHRS)
An Attitude and Heading Reference System, also called AHRS, acts as a motion sensor. It contains an IMU (3 gyroscopes, 3 accelerometers, and 3 magnetometers) and adds a central processing unit (CPU) that embeds the Extended Kalman Filter. This allows to calculate highly reliable attitude and heading relative to magnetic north, in addition to roll, pitch, and yaw. Thanks to this sensor fusion, the drift from gyroscopes is compensated by vectors such as gravity and the Earth’s magnetic field.
The sensor can be connected to an external GNSS receiver to improve its performance. Indeed, GPS-aided AHRS delivers additional navigation.
What Difference between an IMU, an AHRS, and an Inertial Navigation System?
An Inertial Measurement Unit (IMU) is an electronic device that measures and reports acceleration, orientation, angular rates, and other gravitational forces. It is composed of 3 accelerometers, 3 gyroscopes, and depending on the heading requirement – 3 magnetometers. It delivers roll, pitch, and yaw data.
An AHRS adds a central processing unit (CPU) to the IMU. It embeds the Extended Kalman Filter that provides attitude and heading information.
Inertial Navigation Systems (INS) are composed of an IMU and additionally embed a GPS/GNSS receiver. An INS fuses inertial, navigation, and aiding data (odometer, DVL, etc.) thanks to the Extended Kalman Filter. This GNSS and IMU sensor fusion provides roll, pitch, heading, position, and velocity.
Inertial Navigation Systems with consistent behavior in all conditions
At SBG Systems, every inertial sensor is calibrated in temperature from -40 to 85°C, ensuring a consistent behavior in all environments.
Calibration greatly improves sensor quality:
- Gain and bias temperature compensation for accelerometers and gyroscopes
- Gain temperature compensation for magnetometers
- Cross-axis and misalignment effects compensation for accelerometers, gyroscopes and magnetometers
- Non linearity correction for gyroscopes
- Gyro-G effect compensation for gyroscopes
Attitude and Heading Reference System Market
The typical heading reference system market is unmanned aerial vehicles. GPS-aided AHRS sensors are mainly used in aerospace applications such as UAV navigation, UAV-based Surveying etc. Often installed in the aircraft, they are part of the aerospace electronic system during the flight.
Because they act as a motion unit, they can be used for all applications integrating motion tracking and monitoring, such as instrumented buoy or camera orientation.
For the unmanned ground vehicles market, IMUs or GPS-aided inertial navigation systems (integrating dead reckoning) would be the best fit, depending on the accuracy needs of the application.
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