{'fraction_non_alphanumeric': 0.024337866857551897, 'fraction_numerical': 0.004294917680744453, 'mean_word_length': 5.502325581395349, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
A Novel Baseline Measuring System Based on Femtosecond Comb Laser and High-Resolution Camera

Precise baseline measurement plays an essential role in interferometric SAR (InSAR) mission. In order to obtain high-accuracy of land elevation, baseline measurement system with high precision is currently required at large inter-antenna distance. In recent years, baseline estimation method and GPS-based measurement system have made some progress in practical applications. However, such two measurement schemes are highly dependent on massive ground post-processing techniques, which prevent from real-time implementation. As a promising alternative, laser and camera measurement system has drawn widespread attention for InSAR utilization nowadays. In this paper, by incorporating a femtosecond comb laser into the laser-camera system, we propose a novel framework for baseline measurement, which could realize high-accuracy observation in real time. After calibrating the laser and camera compartments simultaneously, we validate the performance of the proposed system using a laser tracker as a reference equipment on a hyper-stable platform. The experimental results have shown that the errors of position and attitude are less than 0.2 mm and 15 arcseconds at 60 m distance respectively, which have demonstrated the sub-millimeter precision, long-range and high-speed capabilities of our system.