From: Sensor models and localization algorithms for sensor networks based on received signal strength
Grid-based
x ^ o =arg min x ∈ { x ( 1 ) , x ( 2 ) , … , x ( L ) } V ( x )
Steepest descent
x ^ j o = x ^ j - 1 o - μ k ∇ x [ V ( x ) ]
Newton-Raphson
x ^ j o = x ^ j - 1 o + μ k ( ∇ x [ ∇ x T [ V ( x ) ] ] ) - 1 ∇ x [ V ( x ) ]