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Objectives: Sampling inspection is a fundamental approach in quality management and controlling of surveying and mapping achievements. The matching degree between the sampling scheme and the quality level of the tested results directly affects the result of quality inspection. Methods: To evaluate the suitability and validity of sampling schemes, we construct the concept of quality uncertainty interval (QUI) for counting sampling schemes. The suitability and validity of the sampling schemes are evaluated by the length of QUI at a given probability level, so as to objectively reflect the two types of risk degrees of the sampling schemes. Results: The correctness and rationality of the method are verified by numerical calculation and analysis of four typical sampling schemes for quality inspection of surveying and mapping results and six simulated sampling schemes. Conclusions: The results show that the proposed method is not only suitable for statistical analysis of surveying and mapping data and quality inspection of results, but also for various count-based sampling scheme designs and two types of risk control. [ABSTRACT FROM AUTHOR]

Objectives: In order to make full use of the observed value information of each frequency, an undifferenced and uncombined integer ambiguity resolution method between BeiDou satellite navigation system (BDS) long-range reference stations is proposed. Methods: First, the error observation equation is established directly by using the observations of different frequencies, and the relative zenith tropospheric wet delay error and ionospheric delay error are estimated by random walk strategy to increase the constraint between epochs. Second,a linear calculation method of undifferenced integer ambiguity real-time is used to obtain the undifferenced integer ambiguity of all satellites in the current epoch of the reference network. It solves the problem that ambiguity needs to be inherited or re-superimposed on normal equations in the reference star transformation. Because the information of each frequency observation is fully utilized, the influence of linear combination amplification noise on integer ambiguity fixing is avoided, and the ambiguity fixing success rate of uncombined method is much higher than that of ionosphere-free combination method. Results and Conclusions: The results show that the average fixed speed of ambiguity of each reference station is 20 epochs (sampling interval 1 s). The integer ambiguity resolution of the carrier phase of the reference station can be realized quickly. [ABSTRACT FROM AUTHOR]

Modern technology of surveying, mapping and geoinformation has been widely used in resource and ecological environment investigation and spatial distribution of population, economy, society, and so on. After the establishment of the Ministry of Natural Resources, surveying, mapping and geoinformation will play an important role in natural resource management. The logical, legal and technical support of surveying, mapping and geoinformation is considered as three key parts in natural resource management. How to fully implement the technical advantages and technical support of surveying, mapping and geoinformation in natural resource management is described in this paper. The characteristics of natural resources, the connotation and application requirements of natural resource management are analyzed. Combining with the layout of tasks related to scientific and technological innovation and development of natural resources in the Outline of Scientific and Technological Innovation and Development Planning for Natural Resources, the main tasks of surveying, mapping and geoinformation technology in natural resource management are put forward. [ABSTRACT FROM AUTHOR]

Based on the maintenance and development of International Terrestrial Reference Frame (ITRF), the development and applications of ITRF by combining GNSS(Global Navigation Satellite System), SLRCSatellite Laser Ranging), VLBKvery Long Baseline Interferometry), DORISCDoppler Orbitography by Radiopositioning Integrated on Satellite), the development of satellite altimetry, satellite gravity, marine surveying and mapping and indoor positioning technique, and GNSS technique are reviewed. Meanwhile, the main applications and developments of CGCS2000 and satellite navigation system are summarized. [ABSTRACT FROM AUTHOR]

The CGCS2000 (China Geodetic Coordinate System 2000) was first released on July 1 in 2008. After that, all location-based GNSS (global navigation satellite system) applications are required to be processed and corrected to CGCS2000. As a matter of fact, big differences exist when different implementation strategies or schemes are adopted, such as reference station selection rules, area partition scheme, and different epoch correction methods et al. All of the above-mentioned factors lead to different results. Some of the differences even reach decimeter level. For instance, the coordinate differences based on plate movement correction with velocity field and the quasi-stable adjustment under CGCS2000 may reach decimeter level. The reason why there exists so big differences in coordinate solutions is the fact that the solution depends on a person's different understanding in various choices by the software. In another word, GNSS data processing is lack of detailed guidance from technical standard. In this paper, a statistic method is proposed. Firstly, supervised clustering is proposed as the rule for reference station selection, Secondly a so-called Spacing Zoning method is used for area partition which is a necessary step facing at a large network. And thirdly a plate movement correction method is applied for correcting position from current epoch to epoch 2000. The station coordinate based on the spacing partition scheme is better than that of the regional dividing scheme, and the coordinate precision of the three-dimensional direction is better than 2 mm. Through the reasonable optimization strategy, the root mean squares of the velocity derived in X, Y, Z directions are reduced from 0.92, 0.72, 0.97 mm/a to 0.19, 0.45, 0.32 mm/a respectively. All of these methods used here obviously have improved the CGCS2000 frame maintenance accuracy. [ABSTRACT FROM AUTHOR]