Patent ID: 9618340
Date: 2017-04-11
CPC Classifications: G01C

Claim:
1. A surveying instrument comprising a frame unit rotatable in a horizontal direction, a telescope unit as mounted rotatably in a vertical direction on said frame unit and further for sighting an object to be measured, a horizontal driving unit for rotating and driving said frame unit in a horizontal direction, a vertical driving unit for rotating said telescope unit in a vertical direction, a horizontal angle measuring unit for detecting a horizontal angle of said frame unit, a vertical angle measuring unit for detecting a vertical angle of said telescope unit and a control device, wherein said control device is adapted to calculate a solar altitude at a time moment by setting up coordinates of where said surveying instrument is installed and said time moment, and to make said telescope unit to set to the solar altitude as calculated by controlling said vertical driving unit, to control said horizontal driving unit, to execute searching of the sun by horizontally rotating said frame unit at the solar altitude as set up, to capture the sun, to sight the sun, to detect a horizontal angle under the sighted condition based on said horizontal angle measuring unit, and to survey a true north based on the horizontal angle as detected.