Tuesday, November 1, 2011

ADIS16488 "Tactical Grade" Inertial Sensor

Analog Devices newest inertial sensor is now available with a new 'Tactical Grade' rating on the data sheet. The specs seem ideal for flying robotics with ±450°/sec gyros, ±18 g accelerometers, ±2.5 gauss magnetometer, and an integrated 300-1100 mbar pressure sensor. There is also an embedded temperature sensor included but for some reason they chose to limit themselves to 'Ten Degrees of Freedom'.

The inertial  sensor has a low profile package measuring 44mm x 47mm x 14mm, and does away with the ribbon cable used by Analog's other integrated inertial sensors.

The communication interface is via SPI and operates at 3.0-3.3VDC at temperatures from −40°C to +85°C. Interestingly there are four integrated FIR filter banks which could be very useful for removing internal noise sources such as motor vibrations. Alarms and digital I/O round out the feature set.

If you are buying a 'Tactical Grade' gyro, you would expect the best in terms of accuracy, precision and sample rates. The sensor has an internal factor calibration and has optional support to compensate for the effect of linear acceleration on gyroscope bias. Gyros and accelerometers sample at 2.46 kHz after averaging and decimation. The barometric pressure sensor runs at 51.25 Hz. The IMU uses a 32bit twos-complement register to store most measurements. The gyro for example uses the upper 16bits in twos-complement format with a LSB of 0.02°/sec. For the lower 16bits, "[t]he MSB has a weight of 0.01°/sec, and each subsequent bit has 1⁄2 the weight of the previous one". The datasheet could use some more statistical details on the A/D conversion process but it is only Rev. 0.

Integrate the ADIS16488 iSensor® MEMS IMU into your sUAS for only $1,619.00 in quantities of 100 to 499.

I look forward to seeing the 'Ultra Mega Tactical Grade' IMU from Analog Devices in the future. This sensor should include an on-board GPS with external antenna connector, additional pressure sensors for airspeed measurement, humidity sensor and integrated real-time quantum clock. The on-board 64bit ARM core provides for maximum bandwidth to the sensors.

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