Numerical Investigation on ELF Electromagnetic Field Distribution of Pipeline Robot Tracking and Positioning System Using UAV

Table 1

Electromagnetic constitutive parameters (low frequency and room temperature).

Medium	Relative permittivity ()	Conductivity ()	Relative permeability ()
Oil M1	2.1		1
Gas M1	33.1		1
Metal pipe (carbon steel) M2	∞		10-300
Overlying soil (moist) M3	16		1
Air M4	1.0006		1

Notes: , , , and .