Recently, an anti-Chinese element outside China posted a satellite image of a civilian satellite on his social account, claiming that China’s Three Gorges Dam has been deformed and the embankment is just around the corner. But the irony is that not only the netizens in the country are laughed at by his rumors, but even some of his colleagues in the country can’t stand it anymore...
After seeing this news, China Aerospace Science and Technology Group specifically produced a high-resolution low-orbit optical remote sensing satellite high-scoring satellite 6 to specifically clarify the matter.
Why is there such a big deviation in the pictures of the Three Gorges Dam taken by the civilian satellites of Google Inc. and its commercial partners? According to an aerospace remote sensing expert who asked not to be named, the reason why Google Maps will occur is that the "Aerospace Technology" Maxar Technologies remote sensing satellite imagery used by Google Maps itself has "technical problems."
Generally speaking, when the remote sensing satellite is imaged, it sometimes causes some distortion of the image due to factors such as the attitude, speed, curvature of the earth, the rotation of the earth, the terrain fluctuations, and the huge height difference caused by the artificial buildings on the surface. These distortions are concentrated in the distortion, offset, etc. of the image. To remove these distortions, it is necessary to use an accurate surface elevation model, accurate reference data, and precise geometric correction algorithms to orthorect the image. If the reference data or algorithm is not accurate, it will cause distortion of the image.
In this satellite image taken by Google Earth, since the Three Gorges Dam is a giant artificial building at an altitude of 185 meters, if the accuracy is not used, or the digital elevation model is not used to "correct" the remote sensing image, it appears. This distortion is not surprising.
High score satellite
The high score No. 6 is a low-orbit optical remote sensing satellite and the first high-resolution satellite in China for precision agricultural observation. The design life is 8 years.
At 12:13 on June 2, 2018, China successfully launched the high-scoring special high-scoring satellite No. 6 with the Long March II carrier rocket at the Jiuquan Satellite Launch Center.
On March 21, 2019, China's high-resolution Earth observation system's high-scoring satellites No. 5 and No. 6 were officially put into use.