Ground displacement measurement by radio interferometric ranging for landslide early warning

Abstract

In this paper, we propose a novel approach to measuring ground surface displacement at high accuracy by radio interferometric ranging (RIR) with extremely low-cost devices. A major challenge to RIR in accurate measurement is multipath in mountainous environments. We propose a novel RIR scheme called Downslope Interferometric Phase (DIP) to decouple the effect of reflective path from that of line-of-sight path. With a two-path channel model, we find that the displacement errors in DIP fluctuate periodically with respect to measurement frequencies. Based on such a revelation, we propose to employ multiple carrier frequencies from large enough bandwidth to mitigate multipath. Experiments both in open spaces and dense multipath environments show that millimeter level displacement can be detected by DIP within several minutes. With better performance and much lower cost than carrier phase GPS receivers, DIP provides a promising method to build landslide monitoring and early warning systems covering vast areas at reasonable cost.

Performance of ML Range Estimator in Radio Interferometric Positioning Systems

“…Averaging (5) with respect to f and replacing ϕ i by ( 1) with noise free data, we get the AAF of RSF…”

“…The radio interferometric positioning system (RIPS), a node localization system used in wireless sensor networks, has received significant attention in recent years [1], [2], [3], [4], [5]. The novel ranging scheme introduced in RIPS is key to its success in providing low-cost and accurate localization solutions.…”

“…This letter examines its performance in two measurement configurations including linear step-frequency (LSF) and random step-frequency (RSF). LSF is applied in mobile node tracking and landslide early warning systems [4], [5] whereas RSF can be essential for military applications with inherent anti-jamming capabilities [6].…”

Performance Analysis of the Interferometric Ranging System with Hopped Frequencies against Multi-tone Jammer

“…In range measurement, Zhu extends the deployment area to over one kilometers by optimizing parameters [9], and Qi proposes twofrequency-interval method to keep comparable localization accuracy with large range [10], meanwhile, Wang and Xu calculates the distance directly from closed-form equation based on Extended Chinese Remainder Theorem (ECRT) [11] [12]. In order to mitigate multipath, Ledeczi proposes a one-dimensional indoor tracking approach [13], and Liu employs multiple carrier frequencies from large enough bandwidth to measure ground surface displacement for landslide early warning [14]. Except for the successful applications in asynchronous positioning system by transmitting two slightly different dual-tone signals [15], some researchers also investigate how to improve the estimator's efficiency [16], increase the localization accuracy [17], extend the deployment [18] and analyze the ranging performance [19].…”

Optimization in Multi-Frequency Interferometry Ranging: Theory and Experiment

“…Multi-frequency interferometry (MFI) is an accurate phase-based ranging method, widely used in highaccuracy ranging [4] [23], localization [2] or deformation and ground displacement detection [33], which estimates the range using the phase measurements recorded at multiple frequencies.…”