JP2008051769A - Direction finding system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a direction finding system capable of simply carrying to a high altitude such as a steel tower and accurately measuring an azimuthal angle of an installation such as an antenna. <P>SOLUTION: A substrate having an engaging part to be engaged with an object to be measured is provided. An upright axis is provided on the substrate, and in addition, a line passing through the axis is drawn on a surface of the substrate to form a directional line of the line. A protractor having four points of the compass marked is rotatably put over the axis. A true north measuring device is provided on the protractor with its true north indicating part aligning with a position indicating the north of the protractor. The true north measuring device is rotated together with the protractor, and while the true north indicating part is directed in the true north direction, a difference in angle between the true north and the directional line can be measured by the protractor. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an azimuth measuring apparatus for examining an azimuth angle based on a sun position and measuring an azimuth angle of an installation such as an antenna.

  Conventionally, for example, as a method of confirming the azimuth angle of installation of a base station for a mobile phone, a method of visually confirming the positional relationship between a specific target and the antenna and entering the exact position of the target on a map , The method of measuring the direction with a magnetic compass and confirming the direction and the direction of the antenna, the method of measuring the true north with a true north measuring instrument and confirming the direction of the antenna with respect to the true north, etc. Patent documents 1 to 3).

  In addition, means has been proposed in which a commercially available car navigation system is used to perform positioning from a GPS satellite in the sky and the azimuth angle is obtained from the position information.

  On the other hand, devices that use sunlight (Patent Documents 4 and 5) and devices that use a GPS antenna have been proposed as azimuth angle adjusting devices such as parabolic antennas (Patent Document 6).

Japanese Utility Model Publication No. 61-045447 Japanese Utility Model Publication No. 53-036131 Japanese Patent Laid-Open No. 51-020870 JP 59-97206 A JP 9-36635 A Japanese Patent Laid-Open No. 11-31912

  By the way, the method of visually comparing the map and the landscape (target) cannot confirm the direction when there is no building or structure to be a landmark, and confirm the target by changing the landscape due to the growth of trees, etc. There were problems such as becoming difficult.

  In addition, the direction measurement means using a magnetic compass has low reliability because electromagnetic waves emitted from antennas and electromagnetic waves emitted from buildings, high-voltage lines, vehicles, and equipment using reinforcing bars and steel frames affect geomagnetic measurements. There was a problem.

  In this respect, azimuth measurement with a true north measuring instrument is not affected magnetically, so accurate measurement is possible, but means for accurately reading the angle of the installation azimuth of an antenna etc. with reference to the true north measured There has been a demand for a device that can easily measure the installation orientation of the antenna with respect to the true north.

  In addition, azimuth measurement by the car navigation system includes errors when the car navigation system confirms the position of the GPS satellite, errors between the satellite clock and the clock of the car navigation system, and multipaths (reflected waves) from surrounding buildings. ) Caused an error of several meters in the position measurement, and thus an error was also caused in the azimuth angle obtained from the position information.

  Furthermore, those shown in Patent Documents 4 to 6 are for parabolic antennas and are difficult to apply to other antennas. Further, the device shown in Patent Document 6 requires the use of two GPS antennas, and the device configuration is complicated and expensive. Therefore, a device that can confirm the orientation of an object such as an antenna by a simpler method is required. It was.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an azimuth measuring apparatus that can easily carry around with a simple configuration and can accurately measure the azimuth angle of an object such as an antenna.

In order to solve the above problems, the present invention
First, a substrate portion including a substrate and an engaging means for horizontally engaging the substrate with an object to be measured is provided, an upright shaft is provided on the substrate, and the upright is placed on the plate surface of the substrate. A straight line passing through the axis is drawn to form a direction line, and a protractor with at least the north position on the upright axis is rotatably inserted, and a true north measuring instrument is placed on the protractor north of the protractor. In the state where the true north indicator is aligned with the indicated position, the true north measuring device is rotated together with the protractor, and the true north indicator is oriented in the true north direction. The azimuth measuring device is characterized in that the angle difference from the line can be measured by the protractor.

  The engaging means can be constituted by, for example, four legs (3). The substrate portion can be constituted by the leg (3) and the substrate (2), for example. The protractor can be constituted by, for example, an omnidirectional plate (4). The upright shaft can be constituted by, for example, a bolt (22). If comprised in this way, the said measuring apparatus will be mounted | worn with the said object so that the direction line of a board | substrate may be matched with the direction display (for example, arrow 10) of a measurement object (for example, antenna), and a true north may be measured with a true north measuring device Then, the angle between the true north direction indicated by the true north measuring instrument and the direction line drawn on the substrate can be accurately and easily read by the protractor.

  Secondly, the true north measuring device includes a flat time scale plate placed on the protractor, an upright plate having the true north indicating portion and orthogonal to the scale plate, and the upright plate. And the time scale plate, and the true north measuring device is rotated together with the protractor so that the projection time of the shade thread on the time scale plate is changed to true sun. When the time coincides, the true north indicating unit indicates true north. The azimuth measuring apparatus according to the first aspect is configured.

  If constituted in this way, true north measurement using sunlight can be performed, and since it is not influenced by geomagnetism or other electromagnetic waves, the orientation of the measurement object can be accurately measured.

  Third, a thin rod is bent into a gate shape to form a gate rod, and the both ends of the gate rod are positioned along the direction line, and the gate rod is erected on the substrate portion. It is constituted by the azimuth measuring device according to the first or second aspect, which is fixed in a state.

  The portal bar can be constituted by, for example, a shooting bar (6). Moreover, the both ends of the said gate-shaped stick | rod can be comprised by each edge part of the perpendicular | vertical part (6a, 6a) of the said imaging | photography stick | rod (6). If comprised in this way, in the state which matched the direction line with the direction of the measuring object, a back view is image | photographed with a camera etc. in the state which matched a pair of support | pillar (vertical part 6a, 6a) of the said gate-shaped stick | rod. This makes it possible to accurately record the position of the measurement object together with the background.

  Fourth, by forming the central hole of the protractor slightly larger than the diameter of the upright shaft, the protractor can be angularly displaced with respect to the horizontal plane of the substrate when the protractor is inserted into the upright shaft. In addition, the azimuth measuring device according to any one of the first to third aspects is provided with an angular displacement means for the protractor with respect to the horizontal plane.

  The angular displacement of the protractor can be realized, for example, by making its central hole (a ') slightly larger than the diameter of the upright shaft. Further, the angular displacement means rotates the adjustment screw in a state where, for example, the adjustment screw is screwed from the protractor upper portion toward the substrate portion, and the tip of the screw is in contact with the horizontal surface of the substrate. It can be configured by means. If comprised in this way, the angle of a shade thread can be adjusted according to the latitude of a measurement point, and a more exact azimuth | direction measurement can be performed.

  According to the azimuth measuring apparatus according to the present invention, it is possible to accurately measure true north without being influenced by geomagnetism or reflected waves, and the orientation of the measurement object from the true north with respect to the true north. The angle difference can be easily measured.

  In addition, it is easy to carry with a simple structure, and the orientation of the measurement object can be accurately recorded together with the background by the gate-shaped bar.

  Hereinafter, an embodiment of an azimuth measuring apparatus according to the present invention will be described in detail with reference to the accompanying drawings. In the present embodiment, a case will be described in which the azimuth measuring apparatus is applied to antenna azimuth measurement.

  FIG. 1 is a perspective view showing an overall configuration of an azimuth measuring apparatus 1 according to the present invention. In the figure, the apparatus 1 includes a circular substrate 2, four legs (engagement means) 3, a circular omnidirectional plate (protractor) 4, a true north measuring instrument 5 fixed to the omnidirectional plate 4, a photographing rod. (Gate-shaped bar) 6, safety wire 7 (FIG. 3), and the like. The antenna 9 in the present embodiment has a cylindrical shape as shown in FIG. 3, and the orientation measuring device 1 according to the present invention is attached to the upper end of the antenna 9 as shown in FIG. Measure.

  As shown in FIG. 2, the substrate 2 is a transparent or translucent resin disk, is made of, for example, an acrylic plate, and has a thickness of 5 mm to 10 mm because it requires strength. A straight line passing through the center P of the substrate 2 is drawn on the surface of the substrate 2, and this straight line constitutes a direction line 21.

  Four legs 3 are fixed to the peripheral edge of the substrate 2 at intervals of 90 degrees. Each of these legs 3 has an inverted L-shape composed of a horizontal portion 3a and a vertical portion 3b that are orthogonal to each other, and each upper surface of the end portion of the horizontal portion 3a is directed to the back side of the substrate 2, It is fixed to the substrate 2 by screwing with a flat bolt 33 from the upper surface side. The two opposing legs 3 and 3 among the legs 3 are attached along the direction line 21, and the remaining two opposing legs 3 and 3 are attached at positions orthogonal to the direction line 21.

  Further, a hole a is formed through the center P of the substrate 2, and a bolt (upright shaft) 22 is inserted into the hole a from below the substrate 2, and a washer 23 is attached to the bolt 22 from the upper surface side of the substrate 2. Is inserted, and the bolt 22 is fixed to the substrate 2 in an upright state by screwing and tightening a nut 24 to the bolt 22 (see FIG. 6). The bolt 22 is for rotatably mounting the omnidirectional plate 4.

  Three screw holes b are opened on the plate surface in the vicinity of the peripheral edge of the substrate 2 through an angle of 120 degrees, and three horizontal adjustment screws 25 are screwed into the screw holes b, respectively (see FIG. 4). One of the horizontal adjustment screws 25 is located on the direction line 21, and the screw 25 is inserted into a screw hole c provided in the horizontal portion 3 a of the leg 3 located on the direction line 21. Furthermore, it is screwed and penetrates the horizontal part 3a downward. The horizontal adjustment screw 25 is preferably a hexagon socket screw so that the horizontal adjustment can be performed with a hexagon wrench.

  Of the four legs 3, horizontal screw holes d and d along the direction line 21 are respectively opened in the vertical portions 3 b and 3 b of the pair of legs 3 and 3 along the direction line 21. Fixing screws 31, 31 are screwed into the screw holes d, d in the horizontal direction from the outside of the vertical portions 3b, 3b. Further, horizontal screw holes d, d along the straight line perpendicular to the direction line 21 are also opened in the vertical portions 3b, 3b of the other opposing legs 3, 3, respectively. The fixing screws 31, 31 are respectively screwed in the horizontal direction from the outside of the vertical portions 3b, 3b. Therefore, the four fixing screws 31 are provided along straight lines passing through the center P of the substrate 2 and orthogonal to each other, whereby the outer periphery of the object (9 of the cylindrical antenna) for measuring the orientation is 90 It is comprised so that it can clamp from 2 places which mutually have the angle difference of a degree (refer FIG. 4). It is preferable to use a butterfly bolt for each fixing screw 31 so that it can be tightened by hand.

  A level 32 is fixed to each of the one leg 3 on the direction line 21 and the horizontal part 3 a of the leg 3 adjacent to the leg 3.

  An arrow 10 indicating the direction of the antenna is marked on the upper surface 9a of the antenna 9 (see FIGS. 5 and 7).

  The omnidirectional plate 4 is a transparent or semi-transparent disk-shaped member, and is composed of an acrylic plate or the like. The omnidirectional plate 4 is preferably formed slightly thinner than the substrate 2 from the viewpoint of reducing the weight of the apparatus. On the peripheral edge of the omnidirectional plate 4 on the surface side, an angle scale 41 of 360 degrees on the entire circumference is drawn every 10 degrees, and a number representing the angle for each scale 41 is drawn (see FIG. 4). However, an angle scale is drawn every 1 degree between 20 degrees of 350 degrees to 360 degrees and 0 degrees to 10 degrees. This angle scale for every 1 degree may be drawn over all angles from 0 degree to 360 degrees. In addition, “N”, “E”, “S”, and “W” indicating east, west, north, and south are written in place of numbers at 0, 90, 180, and 270 degrees indicating east, west, south, and north, respectively. (See FIG. 4). Further, straight lines L1 and L2 that pass through the center P ′ of the omnidirectional plate 4 are drawn between NS (0 degrees to 180 degrees) and EW (90 degrees to 270 degrees). The character may be displayed at least in the north (N).

  A hole a ′ having a diameter slightly larger than the diameter of the bolt 22 is opened at the center P ′ of the omnidirectional plate 4, and the omnidirectional plate 4 is inserted into the hole a ′. Is rotatably mounted on the substrate 2. That is, since the bolt 22 is inserted into the hole a ′ with some play, the omnidirectional plate 4 is attached to the substrate 2 in a state where it can be displaced to some extent (FIG. 6). (See the two-dot chain line).

  Screw holes e and e are opened at the 0 degree (N) position and the 180 degree (S) position along the north-south straight line L1 of the omnidirectional plate 4, respectively. , E are respectively fitted with inclination adjusting screws 42a, 42b (see FIG. 6). The inclination adjusting screws 42a and 42b are inclined in the north-south direction of the omnidirectional plate 4 with respect to the horizontal plane t (FIG. 6) parallel to the substrate 2 (specifically, the angle θ2 between the shade thread 53 and the horizontal plane t, 10).

  A true north measuring device 5 is fixed to the upper surface of the omnidirectional plate 4. The main body of the true north measuring instrument 5 includes a rectangular plate-like time scale plate 51 and an upright plate 52 provided upright along one short side of the scale plate 51. The entire main body is L-shaped. There is no. The time scale plate 51 and the upright plate 52 are formed by processing a flat plate of aluminum material, and are configured by screwing the lower end portion of the upright plate 52 to one short side of the time display plate 51 or the like. The reason why the aluminum material is used for the time scale plate 51 is that the shadow of the shade thread 53 projected on the time scale plate 51 can be seen well.

  Further, a shade thread 53 is stretched between the upper end center position (true north indicating section) g ′ of the upright plate 52 and the center position g of the other short side of the time scale plate 51, One end of the shade thread 53 on the upright plate 52 side is locked to a locking pin 58 ′ via a tension maintaining spring 58, and the other end on the time scale plate 51 side is on the scale plate 51. After being inserted into the through-hole 59 provided on the short side, the retaining member 59 is engaged with the retaining pin 59 ′ to prevent the retaining (see FIG. 2). The spring 58 is always applied with an urging force in a contracting direction, and the spring 58 is configured to always apply a constant tension to the shade thread 53. In the figure, reference numeral 57 denotes a groove parallel to the straight line L1 for guiding the shade thread 53 to the center position g '.

  The time scale plate 51 has a rectangular opening 55 formed at a central position near the center position g of the plate surface, and the time scale 56 is radially engraved around the opening 55 from the center position g. It is rare. The time scale 56 is ticked every 10 minutes from 6 am to 6 pm (see FIGS. 4 and 5). The opening 55 is configured such that the straight line L1 can be visually observed from the opening 55, and the straight line 21 of the substrate 2 and the transparent or semi-transparent omnidirectional plate 4 are transparent from the opening 55. An arrow 10 on the antenna 9 can be visually observed through the translucent substrate 2. The inclination θ2 of the shade thread 53 with respect to the time scale plate 51 is set to 35 degrees in the present embodiment.

  The true north measuring device 5 accurately matches the line connecting the noon scale of the time scale plate 51 and the center position g with the straight line L1 between the north and south of the omnidirectional plate 4, and the upright plate 52 The true north indicating portion g ′ is fixed with an adhesive or the like in a state facing the north side (N) of the omnidirectional plate (see FIG. 4). Thus, the true north measuring device 5 and the omnidirectional plate 4 are integrated, and the omnidirectional plate 4 to which the true north measuring device 5 is fixed inserts the center bolt 22 of the substrate 2 into the hole a ′. Then, it is placed on the substrate 2 in a rotatable state concentrically with the substrate 2. In addition, a wing nut 27 for retaining is screwed onto the bolt 22 from the upper surface side of the omnidirectional plate 4.

  By the way, when measuring true north with the true north measuring device 5, it is necessary to match the angle (θ2) of the shade thread 53 with the horizontal plane to the north latitude of the measurement point. In this embodiment, since θ2 = 35 degrees is set in advance, adjustment is not necessary if the measurement point is a point at 35 degrees north latitude. For example, when the north latitude of the measurement point is a value lower than 35 degrees, For example, by screwing the adjusting screw 42b and tilting the omnidirectional plate 4 in the direction of arrow n (north-south direction) around the center point P ′ (+ θ3 direction), the angle θ2 is an angle of the point (less than 35 degrees) ( θ2 ″) (position of true north measuring device 5 ″ in FIG. 10). If the north latitude of the measurement point is higher than 35 degrees, for example, the adjusting screw 42a is screwed and the omnidirectional plate 4 is tilted in the direction of arrow m (north-south direction) around the center point P ′ ( −θ3 direction), the angle θ2 can be adjusted to an angle (θ2 ′) larger than 35 degrees (see the position of the true north measuring device 5 ′ in FIG. 10).

  On a horizontal portion 3a, 3a of each of the legs 3, 3 facing along the extension line of the direction line 21, a gate-shaped photographing rod (gate rod) 6 made of a metal rod is erected and fixed ( (See FIG. 1). The photographing rod 6 is vertically fixed to the horizontal portions 3a and 3a at the positions where the lower ends of the vertical portions 6a and 6a extend on the direction line 21 (positions of the mounting holes f and f). Accordingly, the horizontal portion 6b connecting the vertical portions 6a and 6a is configured to be positioned exactly parallel to the direction line 21. In FIGS. 2 and 3, a part of the upper half of the shooting rod 6 is omitted.

  As shown in FIG. 3, the safety wire 7 for preventing the fall is engaged with the two fixing screws 31, 31 by hooks 71 at both ends thereof. Reference numeral 72 denotes a fall prevention hook.

  Since the azimuth measuring apparatus according to the present invention is configured as described above, an antenna azimuth measuring method using the measuring apparatus will be described next.

  The usage conditions of the azimuth measuring device 1 are that the weather is sunny or lightly cloudy and the object needs to form a shadow by sunlight. In addition, since it is necessary to know the exact Japanese standard time, the time of the clock is set in advance by a time signal.

  Further, when measuring true north with the true north measuring device 5, it is necessary to match the time of true sun at the point with the shadow time of the shade thread 53 in the true north measuring device 5. It is necessary to calculate true solar time. Since the true solar time of the land can be obtained from the time difference between the solar south-central time of the land and Japan standard time, the time difference is read from the existing conversion time difference table (see FIG. 9) showing the time difference.

  For example, if the orientation measurement is performed in Saga City on December 2, the position of Saga City is approximately 33 ° 10'N 130 ° 20'E, so the conversion time difference table at 130 ° 20'E (Figure 9) Read the time difference from Japan Standard Time. In this case, since the time difference is 7 minutes and 51 seconds, it indicates that the sun goes south at 12:07:51, which is 7 minutes and 51 seconds later than Japan standard time of 12:00:00 (noon). . Since it is convenient for work to change the time of the clock here, the time of the clock adjusted to the Japan standard time is set back by 7 minutes 51 seconds. For example, if the current time is 10:07:51, the time is set to 10:00:00. As a result, this clock becomes a clock indicating true sun time (a clock indicating 12:00 when the sun goes south), and the sun goes south when it shows 12:00:00.

  Next, the azimuth measuring device 1 is placed on top of a cylindrical antenna 9 as shown in FIG. At this time, the direction line 21 of the substrate 2 is aligned with the direction of the arrow 10 indicating the orientation of the antenna drawn in advance on the antenna (see FIG. 5). Thereafter, the three horizontal adjustment screws 25 are brought into contact with the upper surface 9a of the antenna 9, and the position of the substrate 2 is adjusted horizontally while viewing the level 32 with the adjustment screws 25. Then, the four fixing screws 31 of the legs 3 are screwed in, the tip portions of these screws 31 are brought into contact with the outer peripheral surface of the antenna 9, and the antenna 9 is clamped. (See FIG. 5). In addition, when the work is a high place such as a steel tower, the fall prevention wire 7 is passed through the support of the antenna 9, or the hook 72 of the wire 7 is hooked on its own belt or the like to take a fall prevention measure.

  Next, by adjusting the inclination of the omnidirectional plate 4 with respect to the horizontal plane, the inclination θ2 of the shade thread 53 is corrected to match the latitude of the land. Here, assuming that the measurement point is Saga City, the latitude is 33 ° 10 ′ north. Therefore, by screwing the adjusting screw 42b from the state in which the omnidirectional plate 4 is in a horizontal state, the omnidirectional plate 4 is moved to the center point P ′. Is tilted 2 degrees in the direction of the arrow n (θ3 = 2 degrees) and θ2 = 33 degrees (see FIGS. 6 and 10). If the orientation measurement is performed in Naha City located at 26 ° 10 ′ north latitude, θ2 = 26 degrees may be set by the same adjustment. The above-described adjustment of θ2 is performed by, for example, an operation of placing a semicircular protractor on the end of the substrate 2 and loosening one of the two inclination adjusting screws 42a and 42b while screwing the other. Further, since the latitude correction can be performed in advance, it may be performed before the orientation measuring device 1 is attached to the antenna 9.

  Next, the current solar time is examined by looking at the clock, and the shadow of the shade thread 53 created by the sunbeam is aligned with the time scale 56 of the time scale plate 51 corresponding to this time (see FIG. 5). This is done by rotating the omnidirectional plate 4 with respect to the substrate 2. For example, if the current time is 10:00, the shadow K of the shade thread 53 is aligned with the time scale of 10:00 on the time scale plate 51. At this time, the 12:00 direction of the time scale plate 51 (the direction of N of the omnidirectional plate, the direction of the arrow V) indicates true north, and the omnidirectional plate 4 accurately indicates east, west, south, and north. (See FIG. 5).

  Next, the angle θ1 between the direction line 21 of the substrate 2 and the true north direction (N) of the omnidirectional plate 4 is read from the angle scale 41 of the omnidirectional plate 4. This is the azimuth angle of the antenna 9. In FIG. 5, θ1 = 280 degrees.

  Here, the installation angle with respect to the true north of the antenna 9 is determined in advance, and if the installation angle is 280 °, the antenna 9 is accurately positioned and there is no deviation in the installation direction. Become. On the other hand, if the predetermined installation angle is θ1 = 290 degrees, for example, it can be confirmed that the antenna 9 has a deviation of 10 degrees from the installation angle. In this case, for example, if the antenna 9 is rotated with the omnidirectional plate 4 fixed, and the arrow 10 can be rotated to a position of 290 degrees of the omnidirectional plate, the antenna angle can be corrected. .

  When the installation position of the antenna 9 is accurate, the scene behind the shooting bar 6 is shot with a camera from the direction in which the vertical portions 6a and 6a of the shooting bar 6 appear to overlap each other at the position (FIG. 8). reference). As a result, the scenery in the correct direction at the antenna installation position can be recorded as a record. In FIG. 8, H is a target in the scenery.

  In the above embodiment, the case where the azimuth measuring device of the present invention is used for antenna azimuth measurement has been described. However, if the direction of an object whose azimuth is to be measured is known, the direction line 21 of the azimuth measuring device 1 is set in the direction. At the same time, true north is measured by the same method as described above, and the omnidirectional plate 4 is directed to true north, whereby the angular difference between the direction of the measurement object and true north can be accurately measured. Therefore, the present invention is not limited to an antenna, and can measure various azimuth angles.

  The azimuth measuring device according to the present invention can be easily carried, can accurately measure azimuth, and can be used in high altitude environments, so it is suitable for use in fields such as telecommunications, civil engineering and architecture. It can also be used for general purposes.

It is a perspective view of the direction measuring device according to the present invention. It is a disassembled perspective view of an apparatus same as the above. It is a side view of an apparatus same as the above. It is a top view of an apparatus same as the above. It is a top view at the time of true north measurement of an apparatus same as the above. It is a side view of the true north measuring device vicinity of an apparatus same as the above. It is a perspective view of the front-end | tip part of the antenna which measures an azimuth | direction with an apparatus same as the above. It is a figure which shows the state which image | photographs scenery with an apparatus same as the above. It is a figure which shows a part of conversion time difference table used when setting a clock at the time of true sun. It is a figure which shows the relationship between angle (theta) 2 at the time of angle-adjusting an omnidirectional board, and a horizontal surface.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Direction measuring device 2 Board | substrate 3 Leg 4 Omnidirectional board 5 True north measuring device 6 Shooting stick 6a Vertical part 7 Safety wire 9 Antenna 21 Direction line 22 Bolt 31 Fixing screw 42a, 42b Tilt adjusting screw 51 Time scale plate 52 Upright plate 53 Shadow thread a 'center hole

Claims (4)

A board portion provided with a board and an engagement means for horizontally engaging the board with a measurement object;
Providing an upright axis on the substrate and drawing a straight line passing through the upright axis on the plate surface of the substrate to form a direction line by the straight line;
A protractor with at least the north position on the upright shaft is rotatably inserted,
A true north measuring device is fixed on the protractor in a state where the true north indicating portion is aligned with the position indicating the north of the protractor,
In the state where the true north measuring device is rotated together with the protractor and the true north indicating portion is oriented in the true north direction, the angular difference between the true north and the direction line can be measured by the protractor. A characteristic orientation measuring device. The true north measuring device includes a flat time scale plate placed on the protractor, an upright plate having the true north indicating portion and orthogonal to the scale plate, the upright plate, and the time scale. Has a shade thread stretched between the board,
When the true north measuring device is rotated together with the protractor so that the projection time of the shade thread on the time scale plate coincides with true sun time, the true north indicating unit indicates true north. The azimuth measuring apparatus according to claim 1, wherein:   A thin rod is bent into a gate shape to form a gate rod, and the gate rod is fixed upright on the substrate portion with both ends of the gate rod positioned along the direction line. The azimuth measuring device according to claim 1, wherein the azimuth measuring device is a device. By forming the central hole of the protractor slightly larger than the diameter of the upright shaft, the protractor is configured to be angularly displaceable with respect to the horizontal plane of the substrate in the inserted state of the protractor to the upright shaft,
The azimuth measuring apparatus according to claim 1, further comprising an angular displacement means for the protractor with respect to the horizontal plane.

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