Advanced Space-based Solar Observatory (ASO-S), developed by Chinese Academy of Sciences, is utilized for observing the solar magnetic field, coronal mass ejection, and solar flare, as well as studying the relationships among them. As one of the three scientific payloads on ASO-S, Hard X-ray Imager (HXI) is designed for solar hard X-ray imaging with outstanding temporal and spatial resolutions. The spectrometer is an important part of HXI and used to measure the incident photon with a dynamic range of 30–200 keV after Fourier modulation by the collimator. It consists of 99 detector units and front-end electronics (FEE). The FEE can process all the 99 detector units' signals independently in less than 2 μs. The noise of charge measure is less than 500 fC for a dynamic range of 20 pC–900 pC. In this paper, the implementation of FEE is introduced, including the design of electronics, quality control, and performance tests. All these tests show that the FEE can meet the HXI mission requirements.

We applied Persistent Scatterer Interferometric Synthetic Aperture Radar (PS-InSAR) onto the Advanced Land Observing Satellite (ALOS) Phased Array L-band SAR (PALSAR) dataset from December 2006 to February 2011 to monitor the inter-eruption (2006 and 2010) period and the post 2010 eruption of Mount Merapi. L-band is chosen for the long wavelength to improve coherence in vegetated region. We observe periodic uplift and subsidence of less than 0.4 mm/day for the non-eruption period, and a large uplift of 1.8 mm/day immediately before the eruption. ALOS PALSAR is limited by the 46 days repeat pass, but newer L-band satellites will have the potential to monitor active volcanoes such as Merapi.

Persistent Scatterer InSAR (PS-InSAR) technique provides ground deformation monitoring in an accuracy of millimeter, due to its capability of overcoming the atmospheric disturbance, geometrical and temporal decorrelation. The Phased Array L-band Synthetic Aperture Radar (PALSAR) of ALOS (Advanced Land Observation Satellite) provides better capability to penetrate vegetation, which is especially useful in tropical area. In this paper, we have conducted the preliminary study on ground surface change monitoring in Singapore. 18 ascending PALSAR FBS/FBD level 1.l data are used for this study, and the first result has identified several spots that might have small deformation, which need to be further investigated.