The ultra-high accuracy indoor and outdoor positioning is fundamental for a variety of applications such as industrial automation, Internet of Things and structure monitoring. Approaches based on optical methods, ultrasound and computer vision areoften suffer from limited coverage areas, obstruction by objects and high computing load. While the GNSS and conventionalradar-like radio frequency (RF) methods can suffer from insufficient accuracy and are not feasible for many scenarios. Now weachieve an inverse GPS microwave positioning system based on ultra-stable frequency synchronization in free space andcarrier phase difference principle to surpass the limitation of current methods. The stability of frequency synchronization link isbetter than 10−13/s . The distance resolution retrieved from phase information is 25 micrometres and the Mean Squred Error(MSE) of three-dimensional positioning is 16 micrometres. An ultra-high accuracy positioning system with large coverage area,compatibility and versatility can potentially be achieved gearing to extensive needs.