[EN] In recent years, the localization for capsule endoscopy applications using ultrawideband (UWB) technology has become an attractive field of investigation due to its potential benefits for patients. The literature concerning performance analysis of radio frequency-based localization techniques for in-body applications at UWB frequencies is very limited. Available studies mainly rely on finite-difference time-domain simulations, using digital human models and on experimental measurements by means of homogeneous phantoms. Nevertheless, no realistic analysis based on multilayer phantom measurements or through in vivo experiment has been reported yet. This paper investigates the performance of the received signal strength-based approach for 2-D and 3-D localizations in the UWB frequency band. For 2-D localization, experimental laboratory measurements using a two-layer phantom-based setup have been conducted. For 3-D localization, data from a recently conducted in vivo experiment have been used. Localization accuracy using path loss models, under ideal and non-ideal channel estimation assumptions, is compared. Results show that, under nonideal channel assumption, the relative localization error slightly increases for the 2-D case but not for the in vivo 3-D case. Impact of receivers selection on the localization accuracy has also been investigated for both 2-D and 3-D cases. This work was supported in part by the European Union's H2020 through the MSCA: ITN Program "Wireless in-Body Environment Communication-WiBEC" under Grant 675353, in part by the Programa de Ayudas de Investigacion y Desarrollo, Universitat Politecnica de Valencia under Grant PAID-01-16, and in part by the Ministerio de Economia y Competitividad, Spain, through the European FEDER Funds under Grant TEC2014-60258-C2-1-R. Barbi, M.; Garcia-Pardo, C.; Nevárez, A.; Pons Beltrán, V.; Cardona Marcet, N. (2019). UWB RSS-based Localization for Capsule Endoscopy using a Multilayer Phantom and In Vivo Measurements. IEEE Transactions on Antennas and Propagation. 67(8):5035-5043. https://doi.org/10.1109/TAP.2019.2916629