Qualitative comparison of BLE positioning methods
  Beacons Spacing Power Freq. Accuracy
#1 4 4 m --- --- 0.2 - 0.4 m
#2 19 varies -15 dBm 10 Hz < 2.6 m
#3 34 5 m --- 3.3 Hz 1.58 m
#4 9 6 m --- 2.5 Hz 0.5 - 1 m
#5 4 --- --- --- .27-2.25 m
#6 4 2-3.5 m -10-0 dBm --- <1 m
#7 17 ~10 m0 dBm --- .77 m
#8 4 --- --- --- 2-3 m