DJI Assistant 2 is the only way - that I know of - to calibrate the VPS system if ever needed. The reason for this is due to the larger screen that is required for this interface, and a typical PC/Mac has this. I also use it to reset the copter to its factory settings and/or refresh the firmware if I detect glitches that could be resolved by doing so. The big thing is the VPS calibrations though. It's another thing to do on a rainy day, or more importantly, if DJI GO4 tells you to because of some error it sensed...