Table 6.

Summary of techniques used for data fusion-based IPS.

Technique	Advantages	Disadvantages	Accuracy (m)
IMU Fusion	- Robustness to NLoS	- Requires	0.18–2.674
[3,15,86,87,95,101,102,103]	conditions	computation
	- Provides an estimate	resources
	of user position
	- Can reset error drift
Crowdsourcing	- Does not require	- Requires accurate	0.1–4.3
[102,104,105,106,107]	initial site survey	position estimates
	- Can update maps	for map updates to
	dynamically	be reliable
Hybrid Fusion	- Counteracts the	- Requires	0.39
[14,108]	negative aspects	computation
	of involved technologies	resources
	- System becomes robust	- Requires
	against failures	communication
		resources
Heterogeneous Fusion	- Makes system more	- Requires	0.6
[109]	robust to device failure	computation
	- Can counteract	resources
	the negative aspects	- Requires
	of involved technologies	communication
		resources
Homogeneous Fusion	- Makes system more	- Requires	0.03–0.6
[60,65,110,111]	robust to device failure	computation
	- Makes system more	resources
	robust to negative	- Requires
	environment effects	communication
		resources