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Partial phase ambiguity solving using dual band for RFID tag localization
  • Mathieu Le Breton ,
  • Nicolas Grunbaum
Mathieu Le Breton
Géolithe Innov
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Nicolas Grunbaum
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Abstract

The accurate localization of RFID tag usually uses phase difference of arrival, that is 2π-ambiguous. We partially solve this ambiguity, up to ±2 phase cycle, by combining 865–868MHz and 915–919 MHz bands. The system needs to resolve an ambiguity A1 of 2.828 meters between the two bands, and an ambiguity A0 of 0.163 meters at a single frequency. The range estimation applied on five days of measurements is compared with topographic instruments. The ambiguity A1 is accurately solved on 92% of the tag-antenna combinations (25/27) taken separately, and resolved in all the cases when taking the median of the array. The ambiguity A0 is partially resolved, with up to 6 cycle values that appeared as a potential candidate. The A0 cycle bias on the five arrays was 0, 0, 1, 2, −2, confirming the partial phase resolution.