China News Agency, Lhasa, June 8 Question: Three questions: 2020 Mount Everest elevation measurement: How to create "an act of history"

　　Author Zhang Weigong Sanlam

　　"The whole process of this year is more tortuous and harder, but the final result is more satisfactory." Recently, the commander of the site of the height measurement activity of Mount Everest (Everest) in 2020, the largest geodetic survey team of the Ministry of Natural Resources of China ") Captain Li Guopeng said in an exclusive interview in Lhasa, Tibet, "This time Mount Everest elevation measurement will also be recorded in history."

What's the new breakthrough of 2020 Mount Everest elevation measurement?

　　"Almost all the theories and methods of geodetic surveying are used in the elevation measurement of Mount Everest, which reflects the highest level of technological development of the times." Li Guopeng said that this time he obtained the GNSS (Global Satellite Navigation and Positioning System), high level level, gravity , Meteorology, ice and snow depth and intersection measurement and other precious data, "The inspection found that all the information is very complete and high quality."

　　"Gravity measurement is to measure the acceleration of gravity on the surface of the earth." In 2005, the Everest elevation re-measurement, Bai Huagang, who is currently the director of the project cooperation department of the national survey team, Zeng and his teammates pushed the gravity measurement to Everest C2 at an altitude of 7790 meters. Camp. "This time we pushed gravity measurement to the top of the world for the first time, providing valuable data for the construction of refined geoid and earth's gravity field in the later period."

　　In addition to gravity measurement, Bai Huagang said that compared to 2005, GNSS data for the first time simultaneously covered four global navigation satellite systems, added meteorological data, and completed the first high-precision aviation gravity for Everest and surrounding areas. According to the survey, the accuracy of the geoid in the Everest region has been further improved, and eventually the "height" of Everest can be obtained with higher accuracy.

Where is the difficulty of measuring Mount Everest in 2020?

　　In the 66 years since the establishment of the team, the national test team has entered the Tibetan unmanned area 51 times and has measured Everest 7 times. To prepare for the 2020 Mount Everest Elevation Measurement Mountaineering Team (referred to as the "Measurement Mountaineering Team"), a large national test team selected members based on physical and psychological qualities, business level, and plateau adaptability, and began systematic training from January 12, but measured mountaineering The team made it to the summit of Mount Everest three times.

　　In response, Wang Yongfeng, the captain of the Chinese National Mountaineering Team, responded, "The two peaking windows on May 12 and May 22 are due to the excessive snow accumulation in the high-altitude area of ​​Mount Everest, the risk of avalanches, and the excessive wind on the mountain. It is measured that the members of the attack team of the mountaineering team have advanced to an altitude of 7900 meters, but can only withdraw."

　　After Tibetan meteorologists entered the Mount Everest Base Camp and provided real-time weather forecasts every three hours, the surveying team seized the summit window on May 27 to climb Mount Everest. Wang Yongfeng said: "The process is still twists and turns. It was originally expected to reach the summit in 6 hours. It took 9 hours for the attacking team members. It only took 45 minutes of measurement work during the exercise. The team members spent 2 and a half hours on the summit."

　　According to Bai Huagang, at the summit of Mount Everest, the oxygen content and air pressure are less than one-third of the sea level, and people's reactions will become dull. It is only successful to set up the target three times after measuring the target. "The measurement target is not well installed, the GNSS receiver cannot receive the signal, and the snow depth radar cannot work."

　　In a hurry, the deputy captain of the measurement mountaineering team, Pu Budunzhu, took off the oxygen mask and reconnected the measurement target under the anaerobic state, and the various measurement data were obtained one after another. And Pupton Pearl also inadvertently created a record of nearly 150 minutes of anaerobic work on the summit of Mount Everest.

How is the performance of China's domestic instruments for the first time being fully responsible?

　　In 2020, the Everest elevation measurement, a total of 120 technicians carried out GNSS survey, leveling, gravity, snow depth, triangle intersection, aerial photography and other surveying work in Everest and the surrounding area, while demonstrating the highest level of Chinese surveying and mapping technology, it also achieved For the first time, China's domestic instruments are fully responsible for breakthroughs.

　　As the person in charge of the equipment, Bai Huagang scored 95 points for the 2020 Everest elevation measurement results, and only gave 85 points for the performance of the equipment. "A lot of equipment is for this task transformation or new development. Yes. Although the measurement task was successfully completed in the windy and cold environment of Mount Everest, there is still room for improvement."

　　Bai Huagang said that this application of snow depth radar has both GNSS signal reception and radar detection functions. When detecting the rock surface under the snow surface, it provides both position and depth data with an accuracy of centimeter level. No similar products. The equipment was quickly developed, but problems came one after another during the test, "The mutual interference of radar waves and GNSS signals is the biggest "blocker."

　　From the beginning of equipment development and commissioning, Bai Huagang and his colleagues have not remembered how many times they travel to and from various equipment manufacturers. "Almost every day new problems are discovered, but fortunately, before the departure of the mountaineering team on May 6, I have enough Let them take the equipment with confidence."

　　"Facts have proved that measuring equipment made in China is fully capable of taking on such a major task." Bai Huagang said that the history of Chinese surveyors and surveyors relying on imported equipment to measure the height of Mount Everest has ended. The first successful application of new research and development equipment has also filled the international The gap in the market. (Finish)