Microwave altimeter

R&D background

Although the ocean contains huge treasures that can promote the development of human society, it is also the source of many major natural disasters.

The occurrence of marine disasters is often accompanied by abnormal changes in the marine environment, such as an abnormal increase in sea height and sea surface temperature in a local ocean area. The abnormal increase in sea level, such as the "El Niño" phenomenon, is only in the order of decimeters. Only microwave altimeters can keenly capture such subtle changes. At the same time, it is necessary to remove the interference of red tides, tsunamis and storm surges.

Therefore, only when humans have a deep and clear understanding of the safety of the marine environment can they truly develop and use marine resources.

The implementation of the microwave altimeter project can provide direct scientific observation data for the study of the global marine dynamic environment (including sea level height, sea surface wind waves and ocean currents), as well as global energy exchange and climate change research. Indispensable scientific basis.

Working principle

The microwave altimeter uses a small incident angle, dual antennas with one transmitter and two receivers and a dual channel receiver to obtain high-coherent sea echoes, and uses the high-precision interferometric phase measurement of the altimeter Ability and waveform tracking ability to accurately obtain the interference phase information describing the sea surface height within a wide swath range, and accurately restore the geometric relationship between the altimeter dual antenna phase center and the measured sea surface point by processing the interference phase, thereby determining the average sea level height value .

Components

The "Tiangong No. 2" three-dimensional imaging microwave altimeter consists of dual antennas, dual front ends, dual receivers, dual power amplifiers, transmitters, frequency synthesizers, and numerical control units And power supply and other 12 stand-alone components.

Among them, the antenna adopts the form of waveguide slot array antenna, which is the antenna with larger welding size of the same kind of antenna in the Ku-band at present in my country. The Ku-band high-power solid-state power amplifier is also my country's first satellite-borne application of 300W power amplifiers in this band.

Technical features

Compared with the observation swath of the traditional ocean altimeter which is only a few kilometers, the observation swath of the Tiangong-2 microwave altimeter reaches tens of kilometers, and the observation efficiency and performance are obtained. This greatly improves the monitoring efficiency of the marine environment and the ability to forecast marine disasters.

R&D Department

The design and development of the "Tiangong-2" microwave altimeter was performed by Academician Jiang Jingshan of the Key Laboratory of Microwave Remote Sensing Technology of the National Space Science Center of the Chinese Academy of Sciences as the chief scientist, Zhang Yunhua The researcher serves as the chief designer for the team to complete.

The research and development work has received strong collaboration and support from the 55th Research Institute of CLP Science and Technology Group, Chengdu Tianjian Technology Co., Ltd., Aerospace Science and Technology 518 Research Institute, and Aerospace Science and Industry 23. It has also received the Space Application Engineering and Technology of the Chinese Academy of Sciences Important technical support from the center.