Satellite geodesy is the technique of measuring the shape and dimensions of the Earth using artificial satellites. The field dates back to 1957, shortly after the Soviet Union launched Sputnik, the first artificial satellite. Since then, satellite geodesy has become an important branch of the broader "space geodesy" and has gradually developed into a key tool for studying the Earth's gravity field and locating objects.
The development of satellite geodesy began in 1958 with observations by Explorer 1 and Sputnik 2, which allowed us to accurately determine the oblateness of the Earth.
The technology was further promoted in the 1960s with the introduction of satellite Doppler systems and balloon satellites. The success of these early missions led countries around the world to begin paying more attention to the use of satellites for geolocation and gravity field measurements. The widespread use of the Transit satellite system, particularly in the 1970s, helped to establish the World Geodetic System (WGS).
The main goals of satellite geodesy include determining the shape of the Earth, its gravity field and its temporal variations, and observing Earth dynamical phenomena such as crustal movement and pole shifts. These data are of great value to many fields such as oceanography, navigation, and geophysics.
Satellite geodesy measurement techniques are usually classified according to the instrument platform. Can be divided into three categories:
The Global Positioning System (GPS) is the most well-known satellite navigation system, which uses triangulation from multiple satellites to locate a receiver to within a few meters.
GPS technology allows surveyors to precisely locate locations on the Earth's surface. In addition to GPS, there are many other technologies such as Doppler positioning and laser ranging, which have improved measurement accuracy to varying degrees. These technological developments have allowed us to track the movement of the Earth and precisely measure changes in its gravitational field.
Although the technology of satellite geodesy is advancing with each passing day, there are still many challenges in measuring the height and gravity field of the Earth's surface. For example, how to continuously maintain high-precision measurements and observations in a dynamically changing climate and environment remains one of the current research focuses. As data collection technology advances, we may be able to understand the Earth's operating laws and internal structure more clearly in the future.
Future research will not only look at advances in measurement technology, but will also involve deeper Earth system science. Through satellite geodesy, we will be able to more accurately predict natural disasters, monitor environmental changes, and support global sustainable development efforts.
Satellite geodesy is not only a tool for measuring the Earth, but also a window into understanding our planet.
With the help of these highly precise measurement and observation technologies, can we explore more unknown secrets of the Earth?