Design and preliminary experiment of China imaging altimeter

Abstract

The design of the China Imaging ALTimeter (CIALT) and the flight experiment of its airborne model are presented in this paper. The system is aimed for providing observation measure for both oceanic applications and continental topographic mapping in the future. The motivation of this project is to develop a three dimensional imager fitted for small satellites with small volume, mass and power consumption. An experimental airborne model of the CIALT has been developed for verifying the design concept. The CIALT integrates three techniques together, i.e. the height measurement and tracking technique of traditional radar altimeter used for ocean applications, the synthetic aperture technique and the interferometric technique. A robust height tracker has been designed( for meeting the requirements of both oceanic surfaces and continental surfaces (including surfaces of ice continent). The synthetic aperture technique is used for achieving a higher azimuthal resolution along the cross range direction compared with that of a traditional altimeter. The interferometric technique is used for retrieving the height information corresponding to each image pixel and for boresight angle correction of the antennas, which is crucial for accurate height measurement. The CIALT is different from other proposed imaging altimeters, such as SAR altimeter and scanning altimeter, in which no height tracker is involved. Some key technologies regarding the development of imaging altimeter are addressed, such as the antenna design, the transmitter, the receiver and the robust tracking algorithm.

Preliminary Significant Wave Height Retrieval from Interferometric Imaging Radar Altimeter Aboard the Chinese Tiangong-2 Space Laboratory

“…For this purpose, the InIRA uses a similar configuration as an interferometric SAR [17,18], but with low incidence angles and high-capacity solid-state power amplifier. These features guarantee accurate measurements of the SSH with high spatial resolution in both the range and azimuth directions [19][20][21]. The finding concerning the InIRA wave-like stripes in [16] just benefited from the high-resolution performance.…”

Preliminary Evaluation and Correction of Sea Surface Height from Chinese Tiangong-2 Interferometric Imaging Radar Altimeter

“…The SAR technology has also been adopted for improving the azimuthal resolution. Moreover, owing to its short baseline, it achieves a good accuracy (i.e., 0.1 • ) for the interferometric phase measurement on a single-pulse basis [20][21][22].…”

Non‐uniform phase filter for Tiangong‐2 Interferometric Imaging Radar Altimeter

“…Tiangong‐2 interferometric imaging radar altimeter (InIRA) [1–4] was launched on 15 September, 2016, along with the Chinese Tiangong‐2 Space Laboratory. Tiangong‐2 InIRA was developed by National Space Science Centre, Chinese Academy of Sciences.…”