An accuracy-improvement method for GPS/INS kinematic levelling for use in linear engineering surveying projects

•We propose a GPS/INS kinematic levelling method for the linear surveying engineering projects.•We construct a least squares collocation (LSC) model to improve the height accuracy.•A sliding least squares collocation (SLSC) model is proposed which performs better than the LSC model.•The corresponding covariance functions for the SLSC model are also presented.

This paper proposes a high-efficiency and continuous levelling method for linear objects, such as highways and railways, by applying a vehicle-borne GPS/INS kinematic surveying system which integrates the Global Positioning System (GPS) and the Inertial Navigation System (INS). Generally, the raw ellipsoid height directly outputted by GPS/INS needs to be transformed to the local orthometric height. However, because of various systematic errors and random errors, such as the measuring error and the quasi-geoid model error, the accuracy of the orthometric height would rarely meet engineering requirements. To solve this problem, a novel sliding least-squares collocation (SLSC) model based on ground control points was constructed to improve the accuracy of GPS/INS kinematic levelling. Two data sets collected from the Chang Ying highway located in Jilin province, China, were used to validate the proposed method. The experimental results indicate that the proposed method improves the trajectory points’ orthometric height accuracy by at least 160%.