Unmanned Systems Technology 023 I Milrem Multiscope I Wireless charging I Logistics insight I InterGeo, CUAV London & USA show reports I VideoRay Defender I OS Engines GR400U-FI I Ultrabeam Hydrographic Ultra-2 I IMUs

Furthermore, accelerometers and gyroscopes that exceed certain levels of precision can become subject to export controls. Integrating very accurate IMUs into an unmanned vehicle therefore puts the craft at risk of being difficult to sell overseas. But for relatively high-risk applications such as those mentioned above, if opting for a more cost-effective MEMS gyro means mission failure and the loss of a vehicle, a FOG may be the only choice. Error calibration Following MEMS fabrication and PCB soldering, a range of calibration tests and checks are performed on the IMU. While these will depend in most cases on the type of motion intended for the application – particularly whether it will be undergoing high or low dynamic motion, as well as experiencing high or limited vibration – there are several crucial tests. Temperature calibration is critical for ensuring stable performance and minimal drift across different climates and avionics bays. As an industry standard, this often involves using a temperature chamber to measure from -40 to +85 C, with emphasis on three to five temperature points distributed across this range, and applying a second-order polynomial (quadratic) equation to compensate for bias fluctuations (which can increase strongly with temperature). Higher quality temperature calibrations might involve a large enough chamber for batch testing, a slow rate of temperature change to ensure a high density of point measurements – potentially more than 100 over several hours – and potentially a third- order polynomial (cubic) equation for more closely tailored algorithmic compensations. For testing accelerometer errors, a rate table will typically move the unit across a number of different positions, using previously established and tested values for acceleration or incline, before