{'fraction_non_alphanumeric': 0.013986013986013986, 'fraction_numerical': 0.0, 'mean_word_length': 4.965277777777778, '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}}
SAR AUTOFOCUS AND PHASE CORRECTION TECHNIQUES

Both satellite and airborne SAR data is subject to a number of perturbations which stem from various causes and lead to unknown phase chages in the raw data and subsequent imagery which may be defocussed or non-linear. As part of their SAR processing capability, NASoftware offer a combined autofocus with phase correction capability that allows unknown sensor motions to be derived from the received SAR signal. The derived motions can then be applied in a motion compensation process to correct the sensor track to a straight line. This report illustrates the use of these techniques; as it shows, they enable sharply-focused images to be obtained with objects accurately located in the along-track direction. This is an essential component where accurate SAR imagery is required, such as in change detection.