{'fraction_non_alphanumeric': 0.023841961852861037, 'fraction_numerical': 0.0006811989100817438, 'mean_word_length': 5.386956521739131, '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}}
The Research of Amplitude Threshold Method in Ultrasound-based Indoor Distance-Measurement System

In this paper, an amplitude threshold algorithm (ATA) is proposed to estimate time of flight (ToF) of ultrasound signal (US) under high signal noise ratio (SNR) in ultrasound-based indoor distance-measurement system. The purpose of the research is to accurately measure ToF of US and further calculate the distance between ultrasound transceiver. ATA determines ToF based on the time when the monitored signal amplitude first goes above a corresponding threshold. ATA can achieve accurate ToF estimation under high SNR. Furthermore, compared to other ToF estimation algorithms, ATA has the lower algorithm complexity leading to shorter processing time, therefore, ATA is appropriate for the real-time dynamic measurement. In this research, an ultrasound-based indoor distance-measurement system was generated to synchronize the input and output of analog signal and provide high-quality signal. ATA estimated the distance between ultrasound transceiver in the range of 5 meters. The experimental result shows that ATA has relatively high accuracy under high SNR and fast processing speed. Based on the distance-measurement system, an ultrasound-based indoor localization system which aims to localize a static object on two dimensions could be established in the future, some preparatory works has been done and the architecture of the localization system is presented.