# Tracking 2D positioning with IMU Sensor

I am using a miniature car and I want to estimate the position. We can not use GPS modules and most of the tracking systems that I saw, are using IMU sensor with the GPS module. In our car we are able to find our exact correct location with image processing but for some parts that don;t have enough markings we can not do this. So we want to use the IMU as backup for our positioning. so as long as the positioning is close is good for us.

We are only interested in our 2D position since the car is on a flat ground.

I am using a IMU 9DOF sensor and I want to calculate my movement. I have seen some amazing works with IMU for tracking body movements but no code or simple explanation anywhere about it. So basically, I have the reading from accelerometer, gyro and magnetometer. I also have orientation in quarternions. From the device I am also getting the linear acceleration but even when I am not moving it in any direction the values are not $0$ which is really confusing.

• Hey, hello to DSP.se! We had an influx of not-so-well researched questions lately, and I'm glad to see somebody put an effort in to his (first) question. I hope you get an answer soon. As a side-note, whenever working with sensors of any kind, the output $0$ usually means they're not working -- everything is an estimate, and due to noise or interference, you usually don't get precise values. For detecting non-movement, you should probably determine some small threshold value and proclaim everything below that threshold to be no movement. – penelope Jan 17 '14 at 14:18