In the datasheet of ADIS16480, it is mentioned that Static and Dynamic accuracy of angle outputs depends on " 1 Accuracy specifications assume calibration of accelerometers and magnetometers to address sensor drift and local influences on magnetic fields. ". What are the calibration and assumptions considered to achieve this accuracy ? Will i get the mentioned accuracy if the module is switched on on a moving platform ? Can i use the same for applications underwater (inside a tow fish) ?
NevadaMark Please reply.
QUESTION: What are the calibration and assumptions considered to achieve this accuracy?
ANSWER: The intent was to mention the sensitivity to error sources, which the internal algorithms do not account for. While this statement is well-intended, it could use some clarification.
1. The acceleromters do not respond to magnetic fields
2. Accelerometer bias drift, over life, can reach 15-20mg, which correlates to ~1 degree of angle error.
3. Accelerometer offset can be measured by summation of accelerometer response while in both +1g and -1g orientations, divided by 2.
4. Magnetometers do respond to local magnetic fields, so hard/soft iron correction was the key presumption in this statement, but also to highlight that any discontinuity in the fields can impact accuracy.
5. While we do not offer an official calibration method, we have offered some ideas for approaching this, in the following links:
With respect to the last two questions, this product was designed for ground-based applications, which are not moving during the initialization process.
Thanks for the reply. Can i use the same for under water applications. Can you suggest some methods with which initialization issues (turning on IMU) on a moving platform can be fixed.
NevadaMark Please reply