New inertial measurement units (IMU) at the AUVSI 2013 show were smaller and more sensitive than ever.
IMUs are critical to in robotic navigation especially for drones (see Alternative UAV Navigation Systems). They are also important in the consumer market as MEMS technology makes IMUs practical for lower cost, mobile applications (see UAV Nav Systems Moves Into Consumer Markets). The increased use of sensor integration is a natural fit for IMUs (see The Essentials Of Hybrid Location Technologies).
The show included a number of IMU vendors with new products. These included Epson, Sensonor and Sparton.
Epson had a range of new IMUs with 6 degrees of freedom (DOF) including 3-axis gyros and 3-axis accelerometers. The tiny V340 (12-mm by 10-mm by 4-mm) uses only 18 mA and sports an SPI/serial interface. It handles operating temperatures from -40° to +85° C . The gyro dynamic ranges is ± 450°/s and the accelerometer range is ± 6g. It has a sample rate of 180 Hz and a 7 degree/hour gyro bias instability.
The V340 has a small connector on the bottom and a cover can be used to hold down the unit in rugged applications. The G350 and G550 are designed for rugged environments. The gyro dynamic ranges is ± 300°/s and the accelerometer range is ± 3g. The G352 has performance characteristics similar to the V340. The G362 has a 3 degree/hour gyro bias instability that approaches the performance of more expensive Fiber Optic Gyro (FOG) and Ring Laser Gyro (RLG) IMUs. The more rugged devices have a sample rate of 2 kHz.
Sensonor's STIM300 IMU has 9 DOF. The mix includes 3-axis gyros, 3-axis accelerometers and 3-axis inclinometers. It is an ITAR-free alternative to FOG and RLG units and it is insensitive to magnetic fields. The gyro bias instability is 0.5 degrees/hour and the gyro dynamic ranges is ± 400°/s. The accelerometer range is ± 10g. The inclinometers provide accurate leveling. The unit has a high speed RS-422 interface.
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