Table 2.

Summary of sensor types used in existing systems.

Ref.	Accelerometer	Speed	Pressure	Sound	GPS	Other	Total
[43]	✔	✕	✕	✕	✔	✕	2
[44]	✕	✕	✕	✕	✔	✕	1
[45]	✔	✔	✕	✔	✕	✕	3
[46]	✔	✕	✕	✕	✕	✕	1
[47]	✔	✕	✕	✕	✕	✕	1
[52]	✕	✕	✕	✕	✕	✔	1
[48]	✔	✕	✕	✕	✔	✕	2
[34]	✔	✕	✕	✕	✕	✔	2
[49]	✕	✕	✔	✕	✕	✕	1
[50]	✔	✕	✕	✕	✔	✕	2
[35]	✔	✕	✕	✕	✔	✕	2
[24]	✕	✕	✕	✕	✔	✔	2
[36]	✕	✕	✕	✕	✔	✕	1
[60]	✕	✕	✕	✕	✔	✕	1
[37]	✔	✕	✕	✕	✕	✕	1
[51]	✕	✕	✕	✕	✕	✕	0
[54]	✕	✕	✕	✕	✕	✔	1
[55]	✕	✕	✕	✕	✕	✔	1
[53]	✕	✕	✕	✕	✕	✔	1
[22]	✕	✕	✕	✕	✔	✕	1
[56]	✕	✔	✕	✕	✕	✕	1
[57]	✔	✕	✕	✕	✕	✕	1
[58]	✕	✕	✕	✕	✕	✕	0
[59]	✕	✕	✕	✕	✕	✔	1
[42]	✕	✕	✕	✕	✕	✔	1
[61]	✔	✕	✕	✕	✕	✔	2
ADRS	✔	✔	✔	✔	✔	✕	5