# How do I calculate the direction robot is facing, pose from velocity and yaw rate?

I have a simple car robot with four wheels moving relatively slowly (5~10 mph). The robot has a velocity magnitude and yaw rate sensor and the sensor samples about every 0.1 seconds. I want to map the location of the robot in the room in a global coordinates using these two values. What I am doing is robot starts out at location (x=0,y=0). I calculate the location by saying

x = velocity*cos(yaw_rate)*sample_interval
y = velocity*sin(yaw_rate)*sample_interval


So far with this method, the location calculated is actually fairly good as long as the yaw rate is not so large. But if my understanding is correct, yaw rate is the rate of angle change and not the angle changed and to get a better model and the actual direction the vehicle is facing, I will need to say integrate the yaw rate. I want the angle the robot's face normal vector makes to vertical axis so I can figure out the direction robot is facing or it's pose.

Now this must be a very well known equation in robotics and mechanical engineering but my back ground is in programming and I have no idea where to start. I tried searching on google but my search words must not be right since I can't find a good page. Can you point me to the right direction, let me know of a starter page that I can look at?