US Patent 10330788 Measuring instrument

The invention provides a measuring instrument, which comprises a measuring instrument main unit and an installment base unit for rotatably supporting the measuring instrument main unit in an up-to-bottom direction and in a left-to-right direction, wherein the measuring instrument main unit has a measuring unit for projecting a distance measuring light toward an object to be measured and for performing a distance measurement by receiving a reflected light from the object to be measured, and an attitude detecting device integrally provided with the measuring unit, wherein the attitude detecting device has tilt sensors for detecting a horizontality and relative tilt angle detectors for tilting the tilt sensors and for detecting a tilt angle of the measuring unit with respect to the horizontality under such condition that the tilt sensors detect the horizontality so that the horizontality is detected by the tilt sensors, and wherein the installment base unit has an up-to-bottom motor for rotating the measuring instrument main unit in the up-to-bottom direction, a left-to-right motor for rotating the measuring instrument main unit in the left-to-right direction and a left-to-right angle detector for detecting a rotation angle in the left-to-right direction, and wherein the distance measurement of the object to be measured is performed by the measuring instrument main unit, a vertical angle of a measuring point is determined based on the result of the tilt detection by the attitude detecting device, and a horizontal angle is measured based on the result of the detection by the left-to-right angle detector.