Detection ranges and uncertainty of passive Radio Frequency Identification (RFID) transponders for sediment tracking in gravel rivers and coastal environments

Abstract

Since the earliest use of this technology, a growing number of researchers have employed passive Radio Frequency Identification (RFID) transponders to track sediment transport in gravel rivers and coastal environments. RFID transponders are advantageous because they are inexpensive, durable and use unique codes that allow sediment particle mobility and displacement to be assessed on a clast-by-clast basis. Despite these advantages, this technology is in need of a rigorous error and detection analysis. Many studies work with a precision of~1 m, which is insufficient for some applications, and signal shadowing can occur due to clustering of tagged particles. Information on in-field performance is also incomplete with respect to burial and submergence, especially for different transponders and antennae combinations. The objectives of this study are to qualify and quantify the factors that influence the detection zone of RFID tracers including antenna type, transponder size, transponder orientation, burial depth, submergence and clustering. Results of this study show that the detection zone is complex in shape due to a set of lobes in the detection field and provide a better understanding of transponder detection shape for different RFID transponder/antenna combinations. This study highlights a strong influence of clustering and submergence, but no significant effect of burial. Finally we propose standard operating procedures for tagging and tracking in rivers and coastal environments.

Assessing the Performance of In-Stream Restoration Projects Using Radio Frequency Identification (RFID) Transponders

“…The mean radius of detection for this equipment combination is between 0.05 and 0.41 m depending on the size of tag and the orientation of the tag relative to that of the antenna [55]. A conservative estimate of 1 m was used for a movement classification threshold following previous studies [45,47].…”

“…Statistical tests are described that assess particle mobility and compare travel distance distributions in an urban creek in sections with and without instream restoration. The described method is suited to gravel-bed rivers with active layers that are less than the detection range of the system (~0.30 m [55]). The widespread application of this method would help to bridge the gap between the science of fluvial geomorphology and restoration design.…”

Dynamics and mechanics of bed-load tracer particles

“…PIT RFID tags (32 mm HDX tags supplied by Oregon RFID) were detectable when buried at depths up to 10-20 cm below the river bed for the small wand (depending on tag orientation), and 50 cm for the large wand. The maximum combined survey and detection error is estimated to be 1 m and 45 cm for the large and small wands, respectively (for a discussion of wand detection distances and limitations see Chapuis et al, 2014). All measured tracer motion recorded below the detection threshold was considered to be error and set to zero.…”

Deriving formulas for an unsteady virtual velocity of bedload tracers

“…The recent developments in the technology of radio frequency identification passive integrated transponders (RFID PIT), have led to an increasing deployment of tracers in the field (Lamarre et al, 2005;Bradley and Tucker, 2012;Phillips et al, 2013). Moreover, deployment of these new technologies has yielded unprecedented recovery rates and has, following standard operating procedures such as those suggested by Chapuis et al (2014), reduced bias introduced by lost tracers. The deployment of active radio transmitters enabled the testing of Einstein's theories under field conditions at the Lainbach creek (Schmidt and Ergenzinger, 1992) and Waimakariri River (Habersack, 2001), and further technical adjustment of the tracer by Liedermann et al (2013) allowed tracking of individual grains for more than one year in the much larger Danube River, where water depths exceed 4.5 m at mean discharge.…”