AUV	Autonomous underwater vehicle
EKF	Extended Kalman filter
FOV	Field of view
IMU	Inertial measurement unit
LED	Light-emitting diode
l-UD	Low-cost underwater drone
PD	Proportional derivative
ROV	Remotely operated vehicle
UAV	Unmanned aerial vehicle
UGV	Unmanned ground vehicles
UUV	Unmanned underwater vehicles
PWM	Pulse-width modulation
USBL	Ultra-short baseline
GNSS	Global navigation satellite systems