Thank you very much.

# Posts made by Amin

Thank you very much , this is so intelligently method, I'll dive to codes, I had a problem with ( inv ) higher order matrix, but we have a inv 3x3 now , and this is so easy . dear dong , pardon me for this question but I like to know, does this method need to calculate kalman gain ( k ) once or seperate for position, velocity and attitude , if so ? we need to separate tuning gain (k) for position, velocity and attitude?

Best regards

Amin

Thank you for the reply, when H is a 3x16 , gain ( K ) will be 16x3 , R is 3x3 , inv (R) is 3x3 and measurement error must be 3x1 , because we can't multiplication matrix 16x3 in 8x1, forasmuch measurement error must be a 3x1 vector , because for calculate X ( state update ) we need to a vector 16x1 ,am I right? If is it true ,please tell me how to define measurement error ( Vk ) ? I can't understand this part.

Best Regards

Amin

Dear dong,

is innovation (measurement error) vk = zk - hk a 9x1 vector in INS mode that include position , velocity , attitude (lat , long, alt , vn, ve, vd, roll , pitch , heading) ,and calculate from gps and ins ? if is it true? so, H (observation matrix) in EKF update is a matrix 9x16, am I right?

I need to some information for simulating in Matlab and programming in my Micro.

Best regards

Amin

Dear Dong,

in INS mode with GPS lost, do you have any information about error rate in the elapsing time and distance? for smooth paths and paths with a maze?

I have an AHRS280ZA-200, I have a problem with it, when I rotate it in any direction very fast, it will freeze for a while ( 1-2 seconds ) it seems it is because of 200d/s gyros used in it, so the algorithm used in it needs to restart itself or something like that. I want to know is openIMU300ZI the same ?

Best regards,

Amin

Dear Dong,

Thanks for your explanation, I need to know if I buy your openIMU300ZA, may I be able to program the ZA module with my own stlink? I want to buy openIMU300ZA not ZI.

and one more question, in AHRS mode, if any GPS lost occurred, do I need to expect any lose of stability in roll, pitch and yaw axes?

Best Regards,

Amin

Dear dong, is static and dynamic accuracy different in a VG or AHRS ? forasmuch as when I used madgwick , mahony or 7 state EKF algorithm and my IMU was on the table, all attitude was true, but when try it in real flight , attitude doesn't follow up true values.

I think this problem is Caused by accelerometer sensor and it need to compensate with a method , am I right ? and forasmuch as , some algorithm as Loosely coupled is using GPS data as velocity (NED), this problem solved ? and are you using IIR filter for LPF ? I see 3rd Butterworth low-pass filter in codes.

Best Regards

Amin

Thank you for the reply, the PX4's algorithm has additional 6 states as Wind Vector and other things.

I'm interested to implementation your 16 states for AHRS very soon, I'll ask many questions.

I'm using ADIS16445 IMU, Ublox neo-M8N , HMC5883l , stm32f4

Best Regards

Amin

Dear dong, the pixhawk has low cost sensors as mpu6050 but that is so good in real flight, they are using EKF with 22 - 24 states with a GPS , would you mind tell me what is different between pixhawk and your 16 states EKF?

I know nav420 (crossbow) has two EKF, 7 and 13 states. is kind of sensors important for optimal result?

Best Regards

Amin

Thank you very much for the reply, I'm interested to buy this product, but many years ago I bought AHRS280ZA-200 and wasn't good and I decide implemented my AHRS with better sensors. I bought an ADIS16445, and designed PCB for that, I tested 7 states EKF algorithms in real flight, but that doesn't follow up true values ( roll , pitch , yaw ), I'm hopeful your algorithm can help me.

is openIMU300ZI suitable for fixed wings?

Best Regards

Amin