GB12526-1990
Specifications for long range electro-optical distance measurement
远程光电测距规范
GB 12526-1990 is a current mandatory Chinese national standard for Specifications for long range electro-optical distance measurement. It appears in the Machinery compliance cluster with a testing methods focus and has an implementation date of Aug 1, 1991.
Applicability depends on product scope, certification route, competent authority notices and transition rules. Requst for the translation or verify source before using this record in a compliance decision.
Compliance overview
Scope and applicability
This standard applies to long-range electro-optical distance measurement using instruments with a nominal accuracy of no less than ±(5mm+1ppm·D) and a measurement range of no less than 15km. It covers side length measurements for national first- and second-order geodetic control networks, including baseline sides and traverse sides. It is mandatory for all surveying activities involving national first- and second-order geodetic networks in China. Other distance measurements of comparable precision may reference this standard.
Technical requirements
The standard specifies comprehensive technical requirements for instrument verification, including frequency testing, additive constant determination, periodic error measurement, and optical centering checks. Instruments must undergo frequency verification before and after each observation period, with frequency deviation limits set at less than 1ppm. The additive constant must be determined before and after fieldwork, with a maximum discrepancy of ±6mm between two determinations. All instruments must pass verification before deployment in geodetic surveys. The standard also defines meteorological instrument requirements, including ventilation psychrometers (3-year calibration cycle) and aneroid barometers (annual calibration cycle), with specific comparison tolerances for field use. For distance measurement, the standard prescribes observation requirements including total observation sets (24 for first-order, 16 for second-order), minimum time segments, and maximum permissible discrepancies between observation sets. Environmental conditions such as line-of-sight clearance above ground and avoidance of electromagnetic interference sources are also specified.
Testing methods
Key testing methods include: frequency verification using calibrated frequency counters or color TV subcarrier comparison (per Appendix E); additive constant determination via segmented baseline comparison method on certified baselines of 600–2000m (per Appendix B); periodic error measurement using the platform method with precision rails (per Appendix F); observation value dispersion testing through 30+ consecutive readings (per Appendix A); and optical centering verification for both instrument-mounted and tribrach-mounted optical plummet systems (per Appendix C). Meteorological instrument comparison tests are also required at each station relocation.
FAQs
What types of instruments are regulated under GB 12526-1990?
GB 12526-1990 applies to electro-optical distance meters with a nominal accuracy of ±(5mm+1ppm·D) or better and a measurement range of at least 15km. Common instrument models referenced include the RM-III, AGA-8, and AGA-600 laser distance meters.
What are the key differences between first-order and second-order measurement requirements?
First-order measurements require 24 total observation sets across at least 3 time segments, while second-order measurements require 16 sets with either reciprocal observations or two different time segments. The permissible within-segment discrepancy after meteorological correction is 15mm for first-order and 20mm for second-order.
How does GB 12526-1990 relate to international standards?
GB 12526-1990 is a national standard specific to China's geodetic control network framework, referencing the Specifications for National Triangulation and Precise Traverse Survey (1974). It does not directly adopt ISO standards but establishes equivalent precision requirements for long-range electro-optical distance measurement in the Chinese geodetic context.
The summary above provides a high-level overview of GB 12526-1990. To ensure complete compliance for your surveying instruments and geodetic projects in the Chinese market, a precise and professional translation of the full technical specifications is essential. Purchase our high-quality English translation of GB 12526-1990 today to access all detailed parameters, calculation formulas, observation tables, and testing procedures.
Applicability hints
- Type
- Method
- CCS
- A76
- ICS
- 17.180.30
- Competent department
- Ministry of Natural Resources (Surveying, Mapping and Geography)
- Technical committee
- National Technical Committee on Geographic Information of Standardization Administration of China