The OptoAHRS ICD establishes the total interface for the device. It has all the information you need to develop the product for your application. It servers as the API as well. There is no OptoAHRS SDK.You are correct that the Quick Start Guide does not address the "Set Anchor", "Clear Anchor", "Optical Score" or "Heading Uncertainty" features. Those are explained in the ICD. I will copy some information for your convenience:Set Anchor - From Section 4.7.16. CMD_SET_ANCHOR (0x23) - This command creates an Anchor Frame in Visual Gyro at the current orientation.Clear Anchors - 4.7.17. CMD_CLEAR_ANCHORS (0x24) - This command deletes all Anchor Frames present in Visual Gyro.Optical Score - 4.9.7. REP_MAIN_DATA (0x91) - Feature tracking quality scoreUncertainty - 4.9.7. REP_MAIN_DATA (0x91) - OptoAHRS heading error estimate in milsThe OptoAHRS Visual Gyro is a specialized optical orientation algorithm. It works with the following method:Camera images of the operating environment are scanned for features that can be reliably tracked with computer vision. Periodically, features are stored in memory to create a Reference Frame. Later images are compared to the closest Reference Frame in order to compute the orientation between the two images. The measurement of orientation is incorporated into the Inertial Labs Fusion Filter and is used to stabilize the system heading without the use of magnetometers.Anchor Frames are permanent Reference Frames that can be created by the user with the "Set Anchor" feature. This feature is used to create a permanent zone known by the user where heading errors can be corrected. Anchor Frames can be used as long as the optical image scene where the Anchor Frame was created remains undisturbed. If the user wants to remove their Anchor Frames, they can use the "Clear Anchors" feature.Optical Score indicates the quality of the images being used for tracking, rated from 0 to 10. Images that are dark, noisy, have obstructions, or lack distinguishable features will have a lower Optical Score.Uncertainty is the best estimate of the current OptoAHRS system error. Both gyroscope drift and optical tracking errors contribute to the Uncertainty figure.Does this provide enough information for you?