Abstract: A laser centering device (30) that is attached to a survey apparatus by replacing it with a centering telescope optical system is formed of an inner barrel (32) that fixes a pentagonal prism (40) at one end thereof and is internally provided with a laser beam source (42), an intermediate barrel (34) that moves the inner barrel in the axial direction and fixes it so as to adjust the position thereof, and an outer barrel (36) that turns the intermediate barrel around the axis and fixes it so as to adjust the angle thereof, and at the same time, is fixed at the portion (38) for fixing the centering telescope optical system of the survey apparatus (1). The invention provides a laser centering device for which the emission direction of a laser beam is simply adjusted.

Abstract: It is an object of the present invention to provide an electric optical distance wavelength meter detecting the time when the switching is completed and shortening the time required for distance measurement by immediately starting the distance measurement when measurement light and reference light are switched by a light path switching device. An electric optical distance wavelength meter includes a light emitting element for emitting measurement light toward a target placed on a measurement point; a light receiving element for receiving the measurement light coming back after reflecting on the target; a CPU for calculating the distance to the target or the object based on light receiving signals from the light receiving element; and a light path switching device for switching the measurement light so that the measurement light passes through an internal light path from the light emitting element to the light receiving element.

Abstract: When light other than guide light is searched by error, the collimation direction of a surveying instrument is changed by emitting a continuous-operation command from the side of a target toward the surveying instrument, and a process for searching proper guide light can be restarted. When a direction detector receives disturbing light differing from guide light in the process of searching the guide light emitted from a guide light transmitter of a target by means of a surveying instrument, a continuous-operation command is emitted from the target toward the surveying instrument. Accordingly, the light receiving direction of the direction detector is changed by driving an instrument body, and a horizontal or vertical rotation is made to a position deviating from a light receiving range obtained when the direction detector receives the disturbing light, and thereafter the process of searching the guide light is restarted.

Abstract: In a survey system in which guide light is emitted from the side of a target, and, on the side of a surveying instrument, a telescope is directed roughly toward the target by receiving the guide light so as to shorten the time required for automatic collimation, the automatic collimation of the surveying instrument can be reliably performed by removing guide light reflected by reflective objects such as windowpanes. The target has a guide light remitter that emits guide light The guide light transmitter includes a light source, a polarizing plate that changes light emitted from this light source into linearly polarized light, and a quarter-wave plate that changes this nearly polarized light into circularly polarized guide light The surveying instrument includes a direction detector and a collimation preparing means. The direction detector includes a quarter-wave plate and a polarizing plate.

Abstract: An automatic focusing mechanism for mounting on a measuring device has a telescope for sighting a leveling rod with pattern marks marked thereon at an equal pitch between each mark, and a photoelectric device for converting an image sighted by the telescope into an electric signal to thereby automatically adjust a focus on the leveling rod. The mechanism is made up of: a stepping motor for moving a focusing lens of the telescope from one end toward an opposite end of a movable range of the focusing lens; a microcomputer for obtaining the pitch of the pattern marks of the leveling rod at that position on the photoelectric device which is capable of obtaining the pitch in a state before the focusing lens is focused on the leveling rod to obtain a distance to the leveling rod based on the pitch obtained by the microcomputer; and fine adjusting mechanism for moving the focusing lens to a position corresponding to the distance.

Abstract: There is provided a rotary encoder which can eliminate an angle error caused by an eccentricity from a measured angle without strictly adjusting hardware and which can also eliminate a graduation error. Detection of a rotation angle of the rotating section and measurement of an error E (?n) included in the detected angle ? are performed in advance, an error function E(?) represented by a periodic function of the detected angle ? is calculated on the basis of these values, a storing means for storing the periodic function of the calculated error E(?) is arranged, and an angle obtained by subtracting a value obtained by substituting the detected angle ?a for variables in the error function E(?) from the detected angle ?a is displayed on a display unit.

Abstract: There is provided a rotary encoder which can eliminate an angle error caused by an eccentricity from a measured angle without strictly adjusting hardware and which can also eliminate a graduation error. Detection of a rotation angle of the rotating section and measurement of an error E (&thgr;n) included in the detected angle &thgr; are performed in advance, an error function E(&thgr;) represented by a periodic function of the detected angle &thgr; is calculated on the basis of these values, a storing means for storing the periodic function of the calculated error E(&thgr;) is arranged, and an angle obtained by subtracting a value obtained by substituting the detected angle &thgr;a for variables in the error function E(&thgr;) from the detected angle &thgr;a is displayed on a display unit.

Abstract: A laser centering device (30) that is attached to a survey apparatus by replacing it with a centering telescope optical system is formed of an inner barrel (32) that fixes a pentagonal prism (40) at one end thereof and is internally provided with a laser beam source (42), an intermediate barrel (34) that moves the inner barrel in the axial direction and fixes it so as to adjust the position thereof, and an outer barrel (36) that turns the intermediate barrel around the axis and fixes it so as to adjust the angle thereof, and at the same time, is fixed at the portion (38) for fixing the centering telescope optical system of the survey apparatus (1). The invention provides a laser centering device for which the emission direction of a laser beam is simply adjusted.

Abstract: A vibration sensor is provided in a telescope. When vibrations are detected by the vibration sensor, the vibrating state of a reflecting mirror is estimated by the vibration sensor. When an image signal is captured by an image sensor, the frequency or period of capturing the image signal is varied depending on the state of vibrations of the reflecting mirror. In this manner, the time required for measurement is shortened, or the measuring error due to the swinging of the reflecting mirror is minimized.

Abstract: A leveling rod for an electronic level has a plurality of bar-shaped marks disposed adjacent each other in a longitudinal direction along the leveling rod in parallel with each other and perpendicular to a length of the leveling rod. The marks are arranged at a constant pitch. The width dimensions of the marks in the longitudinal direction of the leveling rod are represented by a plurality of integers. A permutation of predetermined number of values chosen from a sequence of numbers made up of a sequential array of the ratios of the width dimensions is arranged to be different from a permutation chosen from any other portion of the sequence of numbers.

Abstract: In an electronic level in which a leveling rod is collimated to convert the result of collimation into an image signal in the form of an electric signal and then graduated numerical values are automatically recognized as characters to thereby compute the collimated position, recognition cannot be made with small graduated numerical values when the distance between a telescope 1 and the leveling rod is large. If the graduated numerical values are enlarged, recognition can neither be made when the distance is small because the graduated numerical values go beyond the field of view. As a solution, two kinds of large and small graduated numerical values A, B are indicated on the leveling rod. From the pitches of graduation patterns M1, M2 in the image signals, the distance between the telescope and the leveling rod is obtained. Then, depending on the distance, the graduated numerical value to be recognized is selected out of the graduated numerical values A, B.

Abstract: In automatically obtaining a height h of a collimated position by collimating a leveling rod 1 to which bar marks 11 are attached, if the height h is obtained by an image pattern of the leveling rod 1, the size of the image pattern of the leveling rod 1 must be corrected inside an electronic level 2 depending on the distance between the leveling rod 1 and the electronic level 2. A long time is required for the computation processing for this correction. In this invention, on the other hand, the ratios of the distances between respectively adjoining bar marks 11 are obtained and the height h is obtained from the manner in which the ratios are arrayed.

Abstract: A coaxial electro-optical distance meter has optical elements on light transmitting side which are located behind an objective lens such that light from a light transmitting member is reflected from a first reflecting surface disposed adjacent to an optical axis of the objective lens. The reflected light is emitted as transmitted light to a reflecting member disposed ahead of the objective lens. Optical elements on light receiving side are arranged such that received light from the reflecting member is reflected from a second reflecting surface disposed behind the first reflecting surface for guiding it to a light receiving member disposed beside the optical axis. The first reflecting surface is disposed such that the optical axis is positioned inside a luminous flux of the transmitted light.

Abstract: Four kinds of dielectrics in the form of a mixture of ZrO.sub.2 and TiO.sub.2 having a refractive index of 2.07, MgF.sub.2 having a refractive index of 1.37, Al.sub.2 O.sub.3 having a refractive index of 1.61, and TiO.sub.2 having a refractive index of 2.27 are laminated on a transparent glass substrate in twenty layers. Two kinds of unpolarized light beam splitters having ratios of the reflected light to the transmitted light of 7:3 and 8:2, respectively, are thereby obtained. Both kinds of unpolarized light beam splitters have the twentieth layer, that is the outermost layer, formed with MgF.sub.2. The difference between the reflectance of the polarizing P component and the reflectance of the polarizing S component of the reflected light is set to be below 10%.

Abstract: The encoder disc rotating device for a surveying instrument comprising a vessel-shaped cover member 30 rotating coaxially with a rotating axis 22 of an encoder disc rotating knob 21 and having an opening formed at the arcuate lateral side for protruding to expose the encoder disc rotating knob 21, in which the encoder disc rotating knob 21 is protruded to expose or concealed by the rotation of the cover member 30. The cover member can ensure a large space for arranging the operation system without changing the machine height and cover the encoder disc rotating knob for preventing erroneous operation without hindering the operation.

Abstract: A method of measuring machine height of a surveying machine includes setting a surveying machine such that the machine center situates on a vertical line passing through a measuring point defining a crossing point between a horizontal line passing through the machine center of the surveying machine and the side of the machine as the machine height point, determining a point symmetrical with the machine center with respect to a segment connecting the machine height point and a measuring point as the machine center symmetrical point, and measuring the distance between the determined machine center symmetrical point and the measuring point as the machine height. A machine height measuring device for a surveying machine includes an elongate bar and a cursor slidably disposed on the bar such that the cursor is perpendicular to the bar. The bar has a linear scale provided thereon and a tapered tip end which allows the measuring point to be indicated as a point.