An Optimization Method Combining RSSI and PDR Data to Estimate Distance between Smart Devices for COVID-19 Contact Tracing

Table 2

The results of the indoor experiments.

Path index	Designed scenario	Designed path and distance symbol (#1 location-#2 location)		Real distance (m)	Estimation error of typical method (m)	Estimation error of proposed method (m)
1	The second participant entered from the door, and then walked to seat A	#1 I⟶I⟶I; #2 O⟶M1⟶A	d1 (I-O)	5.79	−4.49	−1.14
			d2 (I-M1)	3.11	−1.92	−0.64
			d3 (I-A)	0.83	0.09	2.15
2	The second participant entered from the door, and then walked to seat B	#1 I⟶I⟶I; #2 O⟶M2⟶B	d1 (I-O)	5.79	−4.49	−0.73
			d2 (I-M2)	3.86	−2.35	−0.69
			d3 (I-B)	1.61	−0.76	1.08
3	The second participant entered from the door, and then walked to seat C	#1 I⟶I⟶I; #2 O⟶M3⟶C	d1 (I-O)	5.79	−4.49	−1.79
			d2 (I-M3)	4.35	−3.14	−1.33
			d3 (I-C)	2.69	−1.48	0.88
4	The second participant entered from the door, and then walked to seat D	#1 I⟶I⟶I; #2 O⟶M4⟶D	d1 (I-O)	5.79	−4.49	−1.88
			d2 (I-M4)	4.33	−3.14	−1.33
			d3 (I-D)	3.39	−2.18	0.22
5	The second participant entered from the door, and then walked to seat E	#1 I⟶I⟶I; #2 O⟶M5⟶E	d1 (I-O)	5.79	−4.49	−1.74
			d2 (I-M5)	4.09	−2.51	0.16
			d3 (I-E)	2.79	−1.75	0.47
6	The second participant entered from the door, and then walked to seat F	#1 I⟶I⟶I; #2 O⟶M5⟶F	d1 (I-O)	5.79	−4.49	−1.24
			d2 (I-M5)	4.09	−2.51	−0.06
			d3 (I-F)	1.80	−0.90	1.23
7	The second participant entered from the door, and then walked to seat G	#1 I⟶I⟶I; #2 O⟶M5⟶G	d1 (I-O)	5.79	−4.49	−0.39
			d2 (I-M5)	4.09	−2.51	−0.16
			d3 (I-G)	0.93	−0.26	1.86
8	The second participant entered from the door, and then walked to seat H	#1 I⟶I⟶I; #2 O⟶M6⟶H	d1 (I-O)	5.79	−4.49	−2.12
			d2 (I-M6)	5.55	−4.05	−0.83
			d3 (I-H)	5.81	−3.88	0.47