Ultra-high Accuracy Microwave Positioning System Based on Free Space Frequency Synchronization

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 are often suffer from limited coverage areas, obstruction by objects and high computing load. While the GNSS and canonical radar-like radio frequency (RF) methods are suffered from insufficient accuracy and are not feasible for many scenarios. Now we achieve an inverse GPS microwave positioning system based on ultra-stable frequency synchronization in free space and carrier phase difference principle to surpass the limitation of current methods. The stability of frequency synchronization link is better than 10−13/s. The distance resolution retrieved from phase information is 25 µm and the Mean Squared Error (MSE) of three-dimensional positioning is 16 µm. An ultra-high accuracy positioning system with large coverage area, compatibility and versatility can potentially be achieved gearing to extensive needs. .