US Patent 11967021 Cross reality system for large scale environment reconstruction

Various techniques pertaining to methods, systems, and computer program products a spatial persistence process that places a virtual object relative to a physical object for an extended-reality display device based at least in part upon a persistent coordinate frame (PCF). A determination is made to decide whether a drift is detected for the virtual object relative to the physical object. upon or after detection of the drift or deviation, the drift or deviation is corrected at least by updating a tracking map into an updated tracking map and further at least by updating the persistent coordinate frame (PCF) based at least in part upon the updated tracking map, wherein the persistent coordinate frame (PCF) comprises six degrees of freedom relative to the map coordinate system.