Table 1. The teams that participated in the 2014 and 2015 Microsoft Indoor Localization Competitions. Teams in each category are listed in order of the localization accuracy they achieved (highest to lowest) that year. Team Team's Affiliation Country Technical Approach Global Rank Reimann et al. [51] Lambda:4 Germany 2.4-GHz phase offset 1 Li et al. [30] Microsoft Research China Modulated light-emitting diodes (LEDs) 4 Adler et al. [52] Freie Universität Berlin Germany 2.4-GHz time of flight (ToF) 5 Lazik and Rowe [27] Carnegie Mellon University United States Ultrasonic ToF 6 Ashok et al. [43] Rutgers University United States Infrared/radio ToF 8 Nikodem et al. [53] Wroclaw University of Science and Technology Poland 2.4-GHz ToF 9 Dentamaro et al. [54] Nextome Italy Wi-Fi + Bluetooth + inertial measurement unit (IMU) 10 Abrudan et al. [55] University of Oxford United Kingdom Modulated magnetic signals 15 Sark and Grass [56] Humboldt University of Berlin Germany Software-defined radio ToF 16 Pirkl and Lukowicz [42] German Research Center for Artificial Intelligence Germany Modulated magnetic signals 17 Schmid and Lee [57] Greina Technologies United States 2.4-GHz phase offset 18 Jiang et al. [58] Xian Jiaotong University China Wi-Fi + sound ToF 21 Selavo et al. [59] Institute of Electronics and Computer Science Latvia Steerable antennas ToF 22 Beder and Klepal [7] Cork Institute of Technology Ireland Wi-Fi fingerprinting 2 Li et al. [8] University of Cyprus Cyprus Wi-Fi + IMU fingerprinting 3 Zou et al. [60] Nanyang Technological University Singapore Wi-Fi fingerprinting 7 Ferraz et al. [61] Ubee Brazil Wi-Fi + IMU fingerprinting 11 Li et al. [62] Microsoft Research China Wi-Fi + IMU fingerprinting 12 Marcaletti et al. [63] Swiss Federal Institute of Technology/ Madrid Institute of Advanced Studies/ Armasuisse Switzerland/Spain Wi-Fi ToF 13 Xiao et al. [9] University of Oxford United Kingdom Wi-Fi + IMU + maps 14 Zhang et al. [10] Nanyang Technological University Singapore Wi-Fi + magnetic fingerprinting 19 Ghose et al. [64] Tata Consulting Services India Wi-Fi + IMU fingerprinting 20 Lazik and Rowe [27] Carnegie Mellon University United States Ultrasonic ToF 2 Time Domain [49] Time Domain United States UWB 3 Kempke et al. [65] University of Michigan United States UWB 4 Quantitec Intranav [66] Quantitec IntraNav Germany UWB 5 Simon et al. [67] University of Pannonia Hungary Modulated LEDs 6 Klipp et al. [68] Fraunhofer FOCUS Germany IMU + visual markers 7 Chen et al. [69] Nanyang Technological University/ University of California, Berkeley Singapore/United States IMU + Bluetooth low-energy (BLE) beacons 8 Von Zengen et al. [70] Technical University Braunschweig Germany 2.4-GHz phase measurements 9 Symington et al. [71] University College London/University of California, Los Angeles United Kingdom/ United States Wi-Fi + magnetic + ToF 12 Pirkl and Lukowicz [42] DFKI Germany Modulated magnetic signals 14 2014 Infrastructure based Infrastructure free 2015 Infrastructure based (continued) IEEE SIGNAL PROCESSING MAGAZINE | September 2017 | 127