ADIS16505 inertial sensing unit

The ADIS16505 is a precision, miniature MEMS inertial measurement unit from Analog Devices, an inertial sensing unit that combines a triaxial gyroscope and a triaxial accelerometer in a single ball grid array module. It is intended for navigation, stabilization and control systems on unmanned aircraft, robots and other platforms where a compact IMU supplies attitude and motion data to a host processor.

The part measures angular rate and linear acceleration on three axes and outputs both over a serial interface. The host flight controller, navigation computer or mission computer uses these measurements for attitude estimation, dead reckoning between GNSS updates and vibration-sensitive control loops. The ADIS16505 does not compute a navigation solution itself; it provides calibrated inertial data to the filter running on the host.

The key figures are those of the sensor core. The accelerometer dynamic range is plus or minus 78.4 m/sec2, equivalent to about 8 g, which covers manoeuvring and gust loads of most multirotor, fixed-wing and eVTOL airframes. The accelerometer in-run bias stability is 26.5 µm/sec2 (about 2.7 µg), a figure that sets how slowly acceleration error builds up during long GNSS outages. The gyroscope is offered in three dynamic range options, plus or minus 125, 500 and 2000 °/sec, so the integrator picks the variant by the expected rotation rate. The best-performing option lists 2.3 °/hr in-run bias stability and 0.13 °/sqrt(hr) angular random walk, which determine heading drift when the filter has no external reference. Axis-to-axis misalignment is plus or minus 0.25 degrees.

Each unit is factory calibrated for sensitivity, bias and alignment. The calibration also corrects gyroscope bias caused by linear acceleration and compensates for the location of the accelerometers relative to the point of percussion. This reduces the per-unit calibration effort for the integrator and lets identical units be exchanged with limited re-tuning of the estimator.

For integration, the ADIS16505 uses an SPI-compatible data interface and a single supply of 3.0 V to 3.6 V. The package is a 100-ball BGA of approximately 15 x 15 x 5 mm, which is soldered to the carrier board, so the designer controls the mechanical coupling to the airframe, including vibration isolation. The operating temperature range is -40 °C to +105 °C, and the module withstands a mechanical shock of 14,700 m/sec2.

Typical applications are flight controllers and inertial navigation systems for drones and eVTOL aircraft, gimbal and payload stabilization, platform stabilization, robotics and other industrial navigation and control equipment.