For the accuracy of the positional tracking for the ZED cameras i.e. +- (0.01, 0.1, 0.1) in meters for x, y, z-axis, the accuracy depends on the scene you are looking at (since the ZED camera is a stereovision camera).
Using the ZED SDK, we also provide you with the possibility to ingest IMU data into our tracking algorithms.
To give you more information that might be helpful, we have given on our website the average accuracy in normal/good conditions (light, texture, etc.) :
Motion: 6-axis Pose Accuracy
Position: +/- 1mm
Frequency: Up to 100Hz
Technology: Real-time depth-based visual odometry and SLAM