About ADIS16480

Hello! Please help to understand a several things regarding the ADIS16480

1. ADIS16480 datasheet p. 31, table 95, bit 8 "Adaptive EKF enable". Do I understand correct that if the bit 8 value is equal to "1" then Adaptive EKF is enabled? And if the Adaptive EKF is disabled how it will affect ROLL_C23_OUT, PITCH_C31_OUT, YAW_C32_OUT outputs?
2. What stands for Static accuracy and typical value in ADIS16480 datasheet? How it was calculated? Do I understand correct that static accuracy by itself is an angle error in ADIS16480 output if to talk about one application (automotive, for example) and this value shows 1 sigma (RMS) value of the angle error. But as the 1 sigma angle error value can be different for different applications and test conditions the typical value is used for Accuracy value which is calculated as a mean value of 1 sigma (RMS) values for different applications and conditions? Does this value shows accuracy in dynamics (dynamic accuracy)? If to test ADIS16480 unit on the fixed based located on the ground (the unit is not moving) does it means that the maximum errors (maximum deviation of an angle output) will be within +/- 3 sigma range with a chance of 99,8%?
3. Page 9 of datasheet. Phrase "Extended exposure to temperatures that are lower than −40°C or higher than +105°C can adversely affect the accuracy of the factory calibration". Is there any difference if ADIS was exposed to the temperatures out of the stated range while it was switched of or switch on? Is it because of some unrecoverable changes in mechanics? Is there any indicator which can show that the unit is exposed to the temperatures out of that range?
4. According to datasheet it is possible to load user corrections of scale factors and bias of accelerometers and gyros. As I can imagine the factory calibration of sensors and the AHRS system by inself includes not only bias and scale factor calibration but also calibration of scale factor and bias changes vs Temperature. Is it possible for a user to make corrections in that area?

    •  Analog Employees 
    on Mar 23, 2019 4:25 PM

    Thank you for your post. We typically try to encourage one question per discussion thread, as all of your questions could create complicated discussion threads.  Let me start by offering some simple responses

    1. ADIS16480 datasheet p. 31, table 95, bit 8 "Adaptive EKF enable". Do I understand correct that if the bit 8 value is equal to "1" then Adaptive EKF is enabled? And if the Adaptive EKF is disabled how it will affect ROLL_C23_OUT, PITCH_C31_OUT, YAW_C32_OUT outputs?

    ANSWER: You are correct.  The impact on the angle outputs will be very application and condition dependent.  The point is, the adaptive EKF will use sensor covariance analysis to correct the EKF weighting factors, on a real-time basis.  This is something that you probably just need to  try out.  

    2. What stands for Static accuracy and typical value in ADIS16480 datasheet? How it was calculated? Do I understand correct that static accuracy by itself is an angle error in ADIS16480 output if to talk about one application (automotive, for example) and this value shows 1 sigma (RMS) value of the angle error. But as the 1 sigma angle error value can be different for different applications and test conditions the typical value is used for Accuracy value which is calculated as a mean value of 1 sigma (RMS) values for different applications and conditions? Does this value shows accuracy in dynamics (dynamic accuracy)? If to test ADIS16480 unit on the fixed based located on the ground (the unit is not moving) does it means that the maximum errors (maximum deviation of an angle output) will be within +/- 3 sigma range with a chance of 99,8%?

    ANSWER: I will do some digging into the characterization and see if I can find some plots/test descriptions to share with you. 

    3. Page 9 of datasheet. Phrase "Extended exposure to temperatures that are lower than −40°C or higher than +105°C can adversely affect the accuracy of the factory calibration". Is there any difference if ADIS was exposed to the temperatures out of the stated range while it was switched of or switch on? Is it because of some unrecoverable changes in mechanics? Is there any indicator which can show that the unit is exposed to the temperatures out of that range?

    ANSWER: the operational state does not matter. The risk is in the mechanical response of the MEMS sensors, to the exposure. 

    4. According to datasheet it is possible to load user corrections of scale factors and bias of accelerometers and gyros. As I can imagine the factory calibration of sensors and the AHRS system by inself includes not only bias and scale factor calibration but also calibration of scale factor and bias changes vs Temperature. Is it possible for a user to make corrections in that area?

    ANSWER: The user does not have access to the factory-programmed correction routines, only to registers that apply additional scale and bias correction, after the factory calibration.