Some standard content:
National Standard of the People's Republic of China
Specifications for long range electro-optical distance measurementT Subject matter and scope of application
GB12526—90
This standard stipulates Methods and technical requirements for side length measurement in national and second-class geodetic control networks and instrument inspection items using photoelectric distance meters with a nominal accuracy of not less than ± (5mm + 1ppm.D) and a measuring range of not less than 15km. This standard is applicable to the measurement of the first and second-class lock (net) edges and starting edges and the first- and second-class conductor edges in the national geodetic control network. Other side length measurements of corresponding accuracy may be adopted as a reference. 2 Reference standards
"National Specifications for Triangulation and Precision Wire Measurement", State Administration of Surveying and Mapping, formulated in June 1974. Inspection of the instrument
31
3.1
Inspection of the rangefinder
After the following visual inspections of the newly purchased rangefinder, 3.1 is required. Article 2 provides for inspection. 3.1.1
8.
b.
c.
d.
e.
Appearance inspection;||tt ||Check whether the accessories and accessories of the instrument are complete; check whether the optical parts of the instrument are clean and intact; the connection mechanism of the instrument should be stable and reliable, the moving parts move smoothly, and the braking mechanism should be flexible and effective; check whether the operation keys and knobs of the instrument are flexible to use. , whether the digital display is clear: f
Turn on the power and check the function of the instrument according to the instructions in the instrument manual; g.
Test the dispersion of the distance observation value according to the method in Appendix A (Supplement). 2. Distance meters that have been used in production or have been repaired should be inspected according to the following provisions. 3.1.2
3.1.2.1 Inspection of precision measurement frequency
a. Frequency inspection must be carried out immediately before and after each operation period. When the frequency of the instrument's precision measuring tape is unstable, inspections during the operation period should also be added.
b. The accuracy of the standard frequency source of the frequency measuring instrument should be more than two orders of magnitude better than the frequency being tested, and its second-level stability should be more than three times better than the frequency being tested.
c. Frequency measuring instruments should be calibrated by superior metrology departments on a regular basis every year; it can also be tested by directly receiving the CI3 clock standard frequency transmitted by CCTV color TV and comparing the frequency with the frequency measuring instrument. d. Before inspection, the frequency measurement instrument should be preheated as required; the distance meter to be detected should be preheated for 30 minutes. During the inspection, the gate time of the rangefinder should be selected to be 10s, and the frequency should be read - times every 2 minutes. Each five times is a group, and a total of five groups are measured. Take the median of the five sets of test results as the actual frequency value of the detected distance meter. The detected actual frequency value should meet the requirements of formula (1): The State Bureau of Technical Supervision approved the implementation on 1991-08-01 on 1990-12-06
GB12526-90
Af
sub| |tt|| In the formula; AF——the difference between the actual frequency value and the nominal frequency value, Hz; fo——the nominal frequency value of the distance meter, Hz.
ppn
If the test results exceed the requirements of the above formula, the frequency of the detected distance meter should be adjusted, and then retested after adjustment. Comparison of two adjacent inspection results in the same operation period should comply with the provisions of formula (2): Af
fo
1ppm
where: the actual frequency measured twice adjacently at 4F Difference between values, Hz; fo—.—-Nominal frequency value of the distance meter, Hz. If the results of two consecutive inspections exceed the above regulations, the distance observation value measured in this interval cannot be used. The inspection method is carried out according to Appendix E reference parts). 3.1.2.2 Determination of the added tape number of the rangefinder
(1)
?2)
The added tape number should be measured once before and after the measurement. The difference between the two measured values ??shall not exceed ±6mn. The determination method is carried out according to the provisions of Appendix B (Supplement).
3.1.2.3 Periodic Error Measurement
This measurement provides technical basis for the use or maintenance of the rangefinder, and the distance observation value does not include this correction. The periodic error should be measured every other year, and the absolute value of the measured amplitude value A should be less than 5mm, otherwise it should be sent to the relevant department for maintenance. The period error measurement method and calculation method can be carried out by referring to Appendix F (reference part).
3.1.2.4 Inspection of optical plummet
The rangefinder should be inspected by the optical plummet after transportation, and it can be used only after calibration. The inspection method is carried out according to Appendix C (Supplement).
3.1.2.5 If any abnormality in the technical performance of some part of the rangefinder is found during the operation, inspection and testing of the relevant items should be carried out in a timely manner. 3.2 Inspection of meteorological instruments
3.2.1 Technical requirements and inspection cycle
a The technical requirements for meteorological ventilation psychrometers and empty box barometers used for distance measurement should comply with Appendix D (Supplementary Part )Provisions.
b． Meteorological ventilation psychrometers should be sent to the inspection department for inspection every three years; empty box barometers should be sent to the inspection department for inspection once a year. c. All inspected meteorological instruments must obtain an inspection certificate signed by the inspection unit, and hand it in together with the ranging results after each period of operation.
3.2.2 Before measuring the side length of the first side after relocation, a field comparison of meteorological instruments should be made. a. The number of meteorological ventilation psychrometers participating in the comparison shall not be less than 3 sets. When comparing, read two sets of readings according to specified requirements. The time interval between the two sets of readings is 5 to 10 minutes. After the indications of any two thermometers are corrected, the difference between the medians of the two sets of readings shall not exceed ±0.4C. For recording and calculation examples, see Table D1 in Appendix D.
b. The number of empty box air pressure gauges participating in the comparison shall not be less than 5. When comparing, the metal empty box barometers should be placed at the same height. Each barometer should read three sets of readings. The absolute value of the reading difference between the same barometer group should not be greater than 1.3hPa. If it exceeds this value, Skip the re-reading. The absolute value of the difference between the three sets of readings of each barometer plus various correction values ??shall not be greater than 2.6hPa. For recording and calculation examples, see Table D3 in Appendix D.
3.2.3 Before operation, you should go to a nearby meteorological observatory (station) and compare the empty box barometer used with the mercury barometer of the meteorological observatory (station). When comparing, read three sets of readings. The time interval between groups is 10~~15min. After adding the correction value, take the median of the three sets of readings and compare it with the mercury barometer reading of GB12526-90
after adding the correction value. For comparison, the absolute value of the difference shall not be greater than 2.6hPa. For records and calculation examples, see Table D2 in Appendix D. 3.2.4 The comparative inspections specified in Articles 3.2.2 and 3.2.3 above should have complete on-site records as meteorological One of the instrument inspection data. After comparison, if any deviation is found to be beyond the tolerance, the meteorological instrument cannot be used and should be sent to the inspection department for re-inspection. 3.3 Inspection of theodolite
The following inspections should be made before operation:
The optical performance of the telescope shall be inspected in accordance with the provisions of Appendix 48 of the "National Specification for Triangulation and Precision Wire Measurement". a.
The inspection of the correctness of the rotation of the collimation part shall be carried out in accordance with the provisions of Appendix 49 of the "National Standards for Triangulation and Precision Wire Measurement". b. || tt | The measurement of the difference between the horizontal axis and the vertical axis shall be carried out in accordance with the provisions of Appendix 59 of the "National Standards for Triangulation and Precision Wire Measurement".
4 Distance measurement and calculation
4.1 Preparation for distance measurement
4.1.1 Determination and requirements of centering elements
: When the eccentricity is less than 0.3m, centering The determination methods and requirements of elements shall be implemented in accordance with Article 86 of the "National Specifications for Triangulation and Precision Wire Measurement".
b. When the eccentricity is greater than 0.3m and less than 10m, use different starting points of the steel tape to measure directly twice. When the difference is less than 2mm, the middle number is used. If it exceeds, the measurement should be re-measured. c.When making special observations with an eccentricity greater than 10m, a calibrated steel ruler with appropriate tensile force must be used for measurement. A total of five measurements should be taken. The difference between them should be less than 5mm, and the middle number should be used. d. On an eccentric station with an eccentricity greater than 10m, use a theodolite to observe the eccentricity angle and the vertical angle to the central marking stone surface. The horizontal angle is measured with a theodolite for one measurement, and the vertical angle is measured with the middle wire method for two measurements or the three-wire method for one measurement, and the score is taken to the nearest minute. When a measuring station or mirror station operates on a gauge below 8m, projection should be performed before and after the measurement. When the observation is interrupted for more than ten days e
, projection during the measurement and two adjacent projections must be performed. When the difference between the centering correction values ??of the secondary projections does not exceed 5 mm, the median is used. Otherwise, the observations during this time period should be remeasured.
When the measuring station or mirror station is working on a beautiful mark above 8m, it should be projected once before the measurement in each time period. When the difference between the projection corrections is less than 5mm, the median value will be used. If it is between 5 and 10mm, time, use the projection value before each measurement for correction. If it is greater than 10mm, and the difference between each projection correction value is greater than 5mm, the observation results of the time period with the larger difference should be re-measured. 4.1.2 Determination of elevation of measuring stations and mirror stations
Under different field conditions, the method of elevation determination should be carefully selected. a. When the geometric leveling method is used to determine the elevation of the survey station and the mirror station, the height difference between the two end points is not restricted. Its measurement accuracy is not lower than the accuracy requirements of the national fourth-class level measurement, and joint testing is carried out from the national level level point. During joint testing, round-trip testing or one-way dual-line observation methods should be used. When the joint measurement branch line exceeds 20km, the measurement accuracy should be observed according to the third-class level. b. In areas where it is difficult to use geometric leveling for joint measurement, the height difference between the two end points can be determined by triangular height measurement, but the height difference shall not exceed the limit specified in formula (3): 88
hST
c. The vertical angle should be observed in the direction, using the middle wire method for six measurements or the three wire method for three measurements. ++(3)
GB12526—90
d. The heights from the rangefinder, the center of the reflective prism and the horizontal axis of the theodolite to the marking stone surface should be measured with a steel ruler. Take two readings from different starting points on the steel ruler and measure to the nearest centimeter. The difference should be less than 5cm. 4.2 Distance measurement
4.2.1 The technical requirements for distance measurement shall comply with the provisions of Table 1. Table 1·Technical requirements for distance measurement
Item
Total number of measurement rounds observed on each side
Minimum number of observation time periods
Maximum number of measurement times observed per time period|| tt | |tt||Measurement difference limits (mm) after meteorological and centering correction in different time periods, etc.
24
3
10
15|| tt||20
4
5+3·8
Third class
16
round trip or two
different times Section test
10
20
20
(S is in kilometers)
Note: ①The first class in the table includes first and second class The first side, the first three sides of the net. The second class includes the second class two-side net, the first and second class wire sides, ②·One measurement round: The instrument that automatically displays the distance is aimed at the target one time, and four readings are considered one measurement round. ③Time period: The best observation time in each morning or next day is a time period. 4.2.2 Requirements for distance measurement side selection:
a. When selecting the distance measurement side, the best measurement range of the rangefinder used should be taken into consideration. Generally, the length of the measurement line should not exceed the effective measurement range of the rangefinder. In particularly difficult areas, when the above requirements cannot be achieved, the equilateral sides in Table 1 can be observed in sections according to the relevant provisions of the "National Code for Triangulation and Precision Wire Surveying".
b. The measuring line should be higher than the ground or away from obstacles. The first equal side is 6m and the second equal side is 2m. The measuring line should avoid passing through cities with large changes in thermal airflow, over large factories and thermal power plants, or in smog areas. When it is really unavoidable, the measuring line can be shortened or the height of the measuring line can be increased d .When the measuring line is parallel to a high-voltage transmission line above 35kV, the measuring line should be 50m away from the high-voltage transmission line. The measuring station should not be located within a range affected by magnetic fields.
4.2.3 Selection of observation time
a. The best observation time for photoelectric ranging is related to atmospheric stability, visibility in the air, terrain conditions, ground cover, meteorological factors, etc. Generally The best observation time period is 2h to 0.5h before sunset, or 1h to 2.5h after sunrise; b. The observation time can be relaxed on completely cloudy days, and the continuous observation time generally does not exceed 2h in the morning and 3h in the afternoon; c. When the temperature Observation should be stopped during sudden changes and severe weather. 4.2.4 Determination of meteorological elements
4.2.4.1 Placement of meteorological instruments
a. Half an hour before the start of work in each time period, the meteorological instruments used should be placed. The empty box barometer should be placed stably in a ventilated place. The ventilated psychrometer for meteorology should be hung in a shaded and ventilated place, and its bottom should be more than 1.5m above the ground. ; When measuring edges at a high mark, the empty box barometer can be placed on the base plate, and the meteorological ventilation psychrometer should be hung on the windward side, slightly higher than the instrument. b. After the installation of the instrument is completed, immediately open the empty box barometer and add water to the gauze of the humidity thermometer to ventilate it. 4.2.4.2 Determination of meteorological elements
, within one minute before each round of observation, read the dry temperature, wet temperature, air pressure and the value of the attached thermometer on the empty box barometer. The reading requirements are shown in the table 2.
GB12526--90
The dry temperature value shall be measured again within one minute after the completion of each measurement round. h.
Three minutes before reading, add water to the hygrothermometer. After adding water, the gauze must not be in contact with the metal sleeve, and no water beads are connected. It is forbidden to use water containing minerals. The gauze on the humidity thermometer should be kept clean and replaced frequently. d.
tube.
e.
f.
Where: P
Reading can only be done 2 to 3 minutes after ventilation. At this time, people should face the wind direction and read the data decisively and quickly , it is forbidden to touch the ball or sheath with hands. When measuring temperature, if there is a wind speed of level 5 or above, a windproof cover should be installed on the wind surface. The final air pressure value of the empty box barometer is calculated according to formula (4): P=P. +P+aot+AP#
Last air pressure value, hPa;
Po--
AP-
Direct reading of the empty box barometer, hPa;|| tt||The scale correction value of the empty box barometer is obtained from the calibration curve or the scale correction table, hPa; - The temperature coefficient of the empty box barometer is obtained from the calibration certificate; - The reading on the attached thermometer , ℃:
AP supplement
g.
Where: P
The supplementary correction value of the empty box barometer, using the latest comparison value, hPa. The final air pressure value of the moving cell mercury barometer is calculated according to formula (5): the final air pressure value, hPa;
P. ---Mercury barometer reading, hPa; AR
At
marking correction value, obtained from the calibration table, hPa; temperature correction value, calculated using equation (6): || tt||At =
-mercury barometer reading, hPa
where: Po
2.178t.10-4
1+1.818·10-4| |tt|| An accessory temperature, which is positive when it is above zero and negative when it is below zero; A—latitude gravity correction value, calculated using equation (7): A=—0.00265P.cos2
Longitude The reading value of the mercury barometer after temperature correction, hPa; where: P—the latitude of the measuring place in
;
AH-
where: Pt-
h
Altitude gravity correction value, calculated using formula (8): AH = - 1.96 hP,
The mercury barometer reading value after temperature correction, hPa; determine the elevation of the ground.
1
+.
(4)
-(5)
(6)
..(7)|| tt | 4.3 Recording of observation results
a.All original observations and written records must be true, clear, beautiful and consistent in specifications b. Use a pencil when manually recording raw data, and do not erase in the handbook. When correcting errors, the incorrect numbers or words should be crossed out neatly and the correct numbers or words should be filled in above them. For results that exceed the limit and are crossed out, the reason and the page number where the retest results are located must be noted. The recording and calculation of field observation results must go through c
200% detailed inspection before the station can be moved.
d.
e.
When conditions permit, electronic computer recording can be used. The positioning of various readings and calculations shall be carried out according to the requirements of Table 2. Table 2 Readings and calculation table
item
item
dry temperature t
wet and wet t
air pressure P
phase reading
Instrument height
Vertical angle
Correction values
Eccentricity measurement
Eccentricity measurementbzxz.net
Final distance value||tt ||4.4 Handling of over-limit observation results
Reading position
0.1 c
0. 1 ℃
0.2 hPa
0.1||tt| |0.01m
1
0.001m
15
Calculate the position
0.1℃
0.1 c
0.1 hPa
0.1
0.0001m
0.001m
15
0.001m
Remarks
a. Observation results exceed When the tolerances in Table 1 are specified, retesting should be performed. A complete test run that is re-observed due to an overrun is called a retest. Incomplete test rounds that are retested due to misreading, misremembering, discovery that the instrument has not been adjusted midway, sudden changes in weather, etc. will not be counted in the number of retested rounds, b. When readings and meteorological elements are found to be incorrect or exceed the limit at the work site, the measurement should be re-measured immediately. The invalid data should be crossed out with a slash and the reason should be noted.
If 1/3 of the measurement rounds in the same time period exceed the limit, the observation results of all measurement rounds in that time period should be retested. c.
4.5 Calculation of observation results
4.5.1 Calculation of various correction values
Add constant correction value C to the rangefinder.
a.
The instrument addition constant must be measured before and after the operation. When the difference does not exceed ±6mm, the average value shall be used. b.
Meteorological correction value AS.
AS
where: s-observation slope distance, m;
P.
barometric pressure reading, hPa ;
N
80.94P-11.27e)
273.16 + t
Water vapor pressure, hPa; calculated using the following formula: e=E--0.000662. P.(tt)
General state: F water=4.58×1037.8%. X10-6.S
(9)
Icing state: B*=4.58×102
Dry temperature reading, ℃;
GB12526-90||tt ||Ne = (nm— 1)× 10-
—the reference refractive index at the meteorological reference point of the rangefinder. o
N for different types of instruments. The values ??are also different, respectively: N-308.50RM for AGA-8 and AGA-600 rangefinders - N=309.84 for sub-type rangefinders.
Home correction value AS.
(10)
As. [s2 + ei -- 2Seicos9 +e? - 2Sezcosb2 + 2erezcos(0} +f2)}+ - s ....(11) where: s --Observation slope distance, m;
e,
ez
g
92
One measuring station eccentricity, m;||tt| |Mirror station eccentricity, m;
is the measuring station eccentricity angle, measured clockwise from the measuring station eccentricity to the angle of the observation direction, (°, \); mirror station eccentricity angle, measured from the mirror station eccentricity The angle measured clockwise to the observation direction, (°,). Channel curvature correction value AS
d.
ASk =- (2h - )
s3
24R
where: S-||tt ||-observation slant distance, m;
-mean radius of curvature of the reference ellipsoid, m:
R
&——atmospheric refractive index.
In laser ranging, the following empirical values ??can also be used: k=0.13 on a clear day; k=0.20 on a cloudy day
e.
Frequency correction value AS:
The frequency correction value should be calculated according to the formula (13) using the median of the frequency values ??measured before and after the operation: AS,=|| tt||-frequency correction value, m;
where: AS—
fo nominal frequency value, Hz
f——the median of the frequency values ??measured before and after the operation, Hz;s—observation slant range after meteorological correction, m. 4.5.2 The tilt distance S' of the ranging edge is calculated according to formula (14): fo f
fo
S
s =$ + C+ aS,+ AS.+AS+ AS
In the formula: 8-
-observation slant range, m;
C - rangefinder constant correction value, m;
(12)|| tt||(13)
(14)
AS.
Meteorological correction value, m
AS. ——Centering correction value, m;
ASt
ASt
Channel bending correction value, m;
Frequency correction value, m.
GB12526—90
4.5.3 The inclination distance of the ranging edge is reduced to the side length on the reference ellipsoid surface and calculated according to formula (15): S = s- Ci - Cz - Ca + C ,
where:
Ch :
C2
22
2.s
A
2|| tt||Ahd
8.S3
+
A6
16.9r5
fs
C
(RA +A
H(S\ -- Cr.- C2)
C
Ra+H
C4
The inclination distance of the ranging edge, m:
-H2—H1
H=++
H2-H++52;
Hi, H--the normal height of the two end points of the ranging edge , m; 1, t2
51, 52—
Instrument height of measuring station and mirror station, m;
(St- C, —C, C,)||tt ||24
The elevation anomaly of the two end points of the ranging edge, m.
RA
Where, b,es,er2.
B1, A12||tt ||-[e/*cos*B,cos2Aj2(1—er2cos\B,cos?A12)]R
-e'sin'B
Reference ellipsoid constant ||tt| |The geodetic latitude of endpoint 1 of the ranging edge and the geodetic azimuth angle of endpoints 1 to 2. 4.5.4
Observation accuracy estimation
a.
Equal precision observation, one measurement round. The error in distance measurement is calculated according to formula (22): (VV)
The error in distance measurement side length is calculated according to formula (23): M=±
In the above two formulas: V||tt ||The difference between the observed value and the average value, mm;
(VV)
Vn(n-1)
·(15)
(16)|| tt||(17)
(18)
(19)
(20)
(21)
-*(22)|| tt||(23)
b.
n
The number of observations
The relative error of side length
where: D—| |tt||-The average horizontal distance of the ranging edge, m.
4.6 Submit information
.
b.
c
d.
e.
f.
GB12526-90
M,
D
Inspection data of distance meters, meteorological instruments and theodolite. Ranging observation handbook and meteorological observation handbook. Paper and calculation materials for centered projection.
Measurement data of the height difference between the two end points of the ranging edge.
Calculation of the slant distance side length and its related correction values. Technical summary.
D
Mp
.(24)
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