Monitoring and localization of buried plastic natural gas pipes using passive RF tags

Abstract

Abstract.A passive harmonic radio frequency (RF) tag on the pipe with added sensing capabilities is proposed in this paper. Radio frequency identification (RFID) based tagging has already emerged as a potential solution for chemical sensing, location detection, animal tagging, etc. Harmonic transponders are already quite popular compared to conventional RFIDs due to their improved signal to noise ratio (SNR). However, the operating frequency, transmitted power and tag efficiency become critical issues for underground RFIDs. In this paper, a comprehensive on-tag sensing, power budget and frequency analyses is performed for buried harmonic tag design. Accurate tracking of infrastructure burial depth is proposed to reduce the probability of failure of underground pipelines. Burial depth is estimated using phase information of received signals at different frequencies calculated using genetic algorithm (GA) based optimization for post processing. Suitable frequency range is determined for a variety of soil with different moisture content for small tag-antenna size. Different types of harmonic tags such as 1) Schottky diode, 2) Non-linear Transmission Line (NLTL) were compared for underground applications. In this study, the power, frequency and tag design have been optimized to achieve small antenna size, minimum signal loss and simple reader circuit for underground detection at up to 5 feet depth in different soil medium and moisture contents.

Passive Harmonic RFID System for Buried Assets Localization

“…In the work of [ 17 ], a harmonic tag based on silicon PN diode at 150 MHz is proposed for detection of buried object, but only experiments in free space are presented. Harmonic tags based on a varactor diode at 400 MHz have been proposed for the underground detection in the work of [ 43 ], but again experimental results in free space have only been presented up to 76 cm. Several low-frequency (LF) RFID systems (125–135 kHz) have been investigated for the underground detection in the work of [ 52 , 53 ].…”

“…The dielectric constant depends on soil physical properties including bulk density, soil texture, and the level of water content. The dielectric soil properties can be measured following the procedure described in the literature [ 43 ] from the measurement of the S parameters with an especial coaxial fixture. After de-embedding the S parameter of the coaxial line with the soil as a dielectric, the dielectric constant can be found using the Nicholson and Ross algorithm.…”

“…Previous works [ 42 , 43 ] discussed the feasibility of using harmonic tags for buried assets localization with operational frequencies of 2.5 GHz and 5 GHz, and measurements were realized using a high-dynamic range spectrum analyzer. However, a limited distance of interrogation was achieved (about 3 cm [ 42 ]).…”

“…Measurements are performed for different types of soil (dry and wet), showing the possibility of detecting the tag buried at a depth of around 0.6 m, which highlights the potential of the proposed design. In contrast with simple one-bit harmonic tag configurations ([ 17 , 42 , 43 ]), where detection is based on the presence or absence of the tag, this work presents an advanced detection technique allowing the identification of the type of pipeline by specifying a different modulation frequency for each type. The study is completed with a proof-of-concept of a low-cost reader based on a simple Phase-Locked Loop (PLL) synthesizer used as a transmitter and an RTL software defined radio (SDR) used as a receiver.…”

Recent Advances and Applications of Passive Harmonic RFID Systems: A Review

“…For example, the primary clutter object for a body area network (BAN) based sensor or sensor monitoring body vitals is the biological body [ 28 ]. In underground object tagging, the ground is a source of strong clutter [ 29 , 30 ]. Similarly, in industrial environments, metal objects are a source of clutter [ 24 ].…”