Measurement method for reducing errors in azimuth angles of tunnel ground control network

Abstract

The invention discloses a measurement method for reducing an error in an azimuth angle of a tunnel ground control network, which is characterized by comprising the following steps of: constructing thetunnel ground control network, respectively forming a geodetic quadrangle or triangle by control points at an inlet end and an outlet end of a tunnel, carrying out ground precise distance measurementon all short edges, adopting GNSS measurement to obtain all short edges of an inlet end and an outlet end and independent baselines of connecting edges between the inlet end and the outlet end, performing elevation plane modification on a ground precise distance measurement result of a tunnel ground control network to obtain ground distance measurement data of a control point, under a construction coordinate system, performing two-dimensional joint adjustment on GNSS observation values and the ground precise distance measurement data to obtain a two-dimensional joint adjustment result, and obtaining azimuth angles and errors in the azimuth angles of the independent baselines. According to the method, errors in the short-side azimuth angles of the inlet end and the outlet end can be obviously reduced, and larger transverse through errors can be reduced for the long tunnel.

Description

technical field [0001] The invention relates to the technical field of engineering surveying and mapping, in particular to a measurement method for reducing errors in the azimuth angle of a tunnel ground control network. Background technique [0002] In the prior art, the tunnel ground control network generally adopts the GNSS control network. However, for long tunnels, the distance between the control points at the entrance and exit of the tunnel is limited by terrain conditions, and the side length is short (less than 500m). Due to the systematic error of GNSS, the median error of the GNSS baseline can reach 5mm. The error in the side azimuth is relatively large, which has a great influence on the lateral penetration error of the tunnel. [0003] Therefore, how to reduce the error in the azimuth angle of the tunnel ground control network has become an urgent problem to be solved by those skilled in the art. SUMMARY OF THE INVENTION [0004] The purpose of the present i...

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Problems solved by technology

However, for long tunnels, the distance between the control points at the entrance and exit of the tunnel is limited by the terrain conditions, and the side length is relatively short (less than 500m). Due to the GNSS system error, the medium error of the GNSS baseline can reach 5mm, so the GNSS control network is short. The large error in side azimuth angle has a great influence on the tunnel transverse penetration error

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