Dear All
,
I have been assigned with the task to develop a system that detects the azimuth (pitch and roll) of a inland ship using a gyroscope, an accelerometer and a magnetometer.
The system to be build has its main function to tell the change in azimuth (
Since accelerometers and gyroscopes suffer from random walk, temperature influence and bias instability, there are a few options i've come up with.
I have been doing research to this topic, and I've come to the following possible solutions for a possible design approach:
1. Using a (cheaper) MEMS 9 DoF, consisting of a MEMS 3 Axis Accelerometer, 3 Axis gyroscope and 3 Axis magnetometer in one package like the Invensense MPU-9250, with filtering options like Kalman or a complementary filter. (Like this one:
http://eu.mouser.com/applications/sensor_solutions_mems/) I'll be using an Atmel SAMV71 micro for this.
2. Using a more expensive and more precise single axis gyroscope (And add two more for a 3-axis system), and seperate magnetometer and accelerometer for measuring position and velocity
3. Use 4 All-in-One 9 DoF sensors, and average all sensor outputs. (A thesis report here concludes that the noise levels reduce by 1 / sqrt(Amount of samples), so 16 sensors appearantly in 4 times better readings
http://epublications.marquette.edu/cgi/viewcontent.cgi?article=1326&context=theses_open)
Note: There will be GPS onboard, maybe the NMEA data from the GPS can be used to correct the position over time? A small offset to be integrated in the accelerometer reading will result in a huge error over time. (because of the double integration of the acceleration)
Is this a good design approach, and wich one would you choose? Maybe there is a better approach?
Thanks in advance!
Kind regards,
Sjoert
Netherlands