Rapid repetition survey of engineering control network based on the concept of Internet of Things

The engineering control network provides a unified spatial reference for engineering construction, and the repetition survey is to check the stability of the control points and maintain the reference. Classical repetition survey method with total station requires manual adjustment of the orientations of target prisms, leading to high human cost and low efficiency. In this paper, a method for rapid repetition survey of engineering control network based on the concept of Internet of Things is proposed. A repetition survey assistant system is first developed by adding multiple sensors to the circular prism, which realizes remote automatic orientation adjustment through LoRa technology from the station point. Then repetition survey is accomplished automatically with a robotic total station. Experiments show that the differences in horizontal and vertical angle readings under different directions of the 360° prism can be up to 11″ and 6.8″, and its angular misclosure is easy to exceed the limit, which verifies the necessity of the developed remote-controlled prism. Actual repetition survey project shows that remote-controlled prisms assisted method can achieve submillimeter-level precision, which is comparable to classical one with total station only. And the efficiency can be improved by 67 %-133 %. Considering that environmental occlusions may affect the precision of some control points when repetition survey with GNSS, the proposed method has precision advantages and good application prospects despite slight lower efficiency than GNSS.