{'fraction_non_alphanumeric': 0.01783264746227709, 'fraction_numerical': 0.0, 'mean_word_length': 5.3478260869565215, '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}}
Estimation of Aircraft Altitude Based on Squint Mode SAR Data

The aircraft altitude relative to the illuminated region is a significant parameter for the geometric correction in squint mode synthetic aperture radar (SAR) imaging. Error in the parameter causes geometric distortion, which degrades the image quality. To circumvent this problem, a relative altitude estimator (RAE) is proposed based on the relationship between the relative aircraft altitude and the range variation of the Doppler centroid. The high performance of the RAE is investigated compared to the Cramér-Rao lower bound of the relative aircraft altitude. Finally, the effectiveness of the RAE in practical applications is verified by real data processing.