Shanghai Astronomical Observatory

Analysis of Triple-Frequency PPP Ambiguity Resolution with Different Ambiguity Fixing Methods

Accurate ambiguity resolution (AR) is critical for precise point positioning (PPP). Triple-frequency observations enable longer wavelength combinations, improving AR performance. This study evaluates four AR algorithms, Integer Least Squares (ILS), Partial Ambiguity Resolution (P...

Radio Sounding Determination of Two‐Dimensional Plasma Structure Velocity

Abstract The Mars spacecraft Tianwen‐1 transmitted radio signals to Earth for its orbit determination. The frequencies of the radio signals exhibited sharp variations when an ICME passed through the Mars‐Earth signal path on 18 June 2021. These sharp variations were observed at d...

Satellite identification and attitude measurement using a multi-reflector laser ranging beacon

Passive identification and attitude measurement of spacecraft are key challenges in space traffic management. Satellite laser ranging offers high accuracy, and using corner cube reflectors as passive beacons brings the benefits of light weight and long lifetime. Based on a specif...

Discovery of a Compact Hub-Filament System in G286.21+0.17 with JWST and ALMA: Insights into Protocluster Formation and Competitive Accretion

Abstract We present a multi-wavelength study of the massive protocluster G286.21+0.17 (G286) using JWST near-infrared (NIR) imaging and ALMA H13CO+(1–0) observations. The JWST images uncover a compact (∼0.5 pc) hub-filament system (HFS), comprising a dense central hub connected b...

High-frequency Earth rotation parameters estimated from VLBI observations during CONT campaigns

The Desai–Sibois high-frequency Earth rotation parameter (HF-ERP) model provides one of the most detailed descriptions of diurnal and sub-diurnal variability up to date. However, it still underrepresents short-period signals, underscoring the need for reliable, observation-based...

The Total and Polarized Radio Emission from the Innermost Jets of a High-Redshift Quasar and a Candidate at Parsec-Scale Resolution

High-frequency very long baseline interferometry (VLBI) polarimetry probes synchrotron-emitting plasma closer to the central engines of radio-loud active galactic nuclei (AGNs), but observations above 43 GHz are technically demanding. We present 22-GHz European VLBI Network obser...