CH Robotics Releases Low-Cost GPS-Aided AHRS

Today CH Robotics released the GP9, a GPS-Aided AHRS that produces reliable position, velocity, attitude, and heading estimates on dynamic platforms.

Typically, low-cost attitude sensors rely on a combination of data from accelerometers, rate gyros, and magnetometers to produce attitude and heading estimates. These attitude sensors tend to work best on slow-moving, slowly-accelerating platforms. Aggressive dynamic maneuvers can cause these low-cost attitude sensors to function poorly.

The GP9 uses its onboard GPS to solve these problems. The GP9 uses its attitude estimate in conjunction with the onboard accelerometers to measure changes in velocity. These velocity estimates are then compared to velocities reported by the GPS and pressure sensors. Since attitude inaccuracy is a major source of velocity measurement error, it is possible to measure attitude by comparing the accelerometer-based velocity with GPS-based velocity. Because attitude correction takes place as the result of changes in velocity, the GP9 actually performs better during aggressive acceleration and deceleration. Other comparably-priced sensors on the market produce estimates that can become arbitrarily poor on moving platforms.

The GP9 also provides yaw and heading outputs without the use of magnetometers.  Magnetometers are often used to estimate yaw by measuring the Earth's magnetic field.  However, magnetometer measurements are notoriously unreliable, especially on or near the ground.  The GP9 measures yaw without relying on magnetic sensors.

In order to produce the best possible accuracy, the GP9 doesn’t just estimate angles – it also estimates biases that can cause angle estimates to drift. The onboard bias estimators ensure that the GP9’s angle outputs remain reliable for as long as possible even when the sensor is not moving.

The GP9 is available for order immediately.  Pre-orders are shipping now, and additional orders will ship in January, 2015.

About CH Robotics

CH Robotics specializes in the development of attitude and heading sensors for industrial, commercial, and research applications. By taking advantage of state-of-the-art MEMS sensing technology in conjunction with a rapidly growing market for low-cost inertial and orientation sensors, CH Robotics delivers high performance sensors at industry-leading prices.