- O -
	Object classification Object detection Object recognition Object tracking Observability Observation point Observers Observers, nonlinear systems Obstacle avoidance Ocean Ocean acoustic tomography Ocean acoustics Ocean acoustics signal processing Ocean clutter Ocean current Ocean current measurement Ocean echo Ocean front Ocean measurement Ocean measurement system Ocean outfall Ocean technology Ocean towing Ocean wave spectra Ocean waves Oceanic spectrum database Oceanographic equipment Oceanographic regions Oceanographic techniques Oceanography Oil industry Oil pollution Oligopeptide Omega sondes	Omnidirectional Optical fiber cable mechanical factors Optical fiber communication Optical fiber measurement applications Optical fiber telemetry Optical flow Optical image processing Optical images Optical imaging mapping Optical measurements Optical microscopes Optical position measurement Optical radar Optical radiometry Optical refraction Optical scattering Optical scattering by rough surfaces Optical station-keeping Optical velocimeters Optimal control Optimization Optimization methods Organic compounds Oscillating foil OSCR Other telecommunication systems and equipment Other topics in acoustics Output feedback control Overlap correlator Overlapped correlator Overwater radio propagation Oxygen Oxygen sensors

- P -
	Pacific salmon Packet radio Packet switching Paddle-wheel rotor Paidoussis equation Paper Parabolic Parabolic equations Parabolic wave equation Parallel networks Parallel processing Parameter estimation Parametric array Parametric methods: maximum likelihood and nonlinear regression Partial differential equations Particle suspension in water Partition coefficient Partitioning filter Passive detectors Passive sonar Path planning Pattern classification Pattern recognition Penetration Permeability Perturbation methods Petroleum industry PH measurement Phase difference Phase equalizers Phase estimation Phase measurement Phase noise Phase shifters Phase synchronization Phase-locked loop (PLL) Phased arrays Photo-sensing Photodetectors Photography Physical-statistical scatter models Physicochemical groups Piecewise Piezoelectric Piezoelectric transducers Piezomagnetic materials/devices Piles Planar arrays Planning	Planning strategies Plates PLLs Poisson distributions Poisson probability density functions Poles and zeros Pollutant detection Polynomial approximation Polynomials Port area Position control Position estimation Position measurement Power generation economics Power spectrum Pre-whiten Prediction Prediction methods Predictive control, linear systems Predictive maintenance Pressure Pressure control Pressure measurement Pressure transducers Pressure vessels Principal components Probability Probability estimates Process control of earthquakes Process monitoring Propagation Propagation loss Propagation parameters estimation Propeller shaft speed control Proportional control Propulsion Protection/safety Protocols Pseudonoise-coded communication Pseudorandom Pulse Pulse compression Pulse Doppler radar Pulse measurement Pulse propagation Pulse radar Pulse-code modulation Pulse-position modulation PVdF

- Q -
	Quadratic programming Quadrature phase-shift keying Quantization	Quartz Quasi-sliding mode control Queued communications

- R -
	Radar Radar altimetry Radar antennas Radar backscatter Radar clutter Radar cross sections Radar detection Radar imaging Radar imaging/mapping Radar interferometry Radar measurements Radar meteorological factors Radar navigation Radar polarimetry Radar remote sensing Radar resolution Radar scattering Radar scattering cross sections Radar signal analysis Radar signal processing Radar terrain factors Radar theory Radar tracking Radial basis function neural network Radiation transport equation Radio interferometry Radio navigation Radio navigation position measurement Radio navigation terrain factors Radio oceanography Radio position measurement Radio propagation terrain factors Radio spectrum management Radio telemetry Radio tracking Radioactive pollution Radiometry Radiosondes Rain Raman scattering Random arrays Random media Random noise Random number generation Random scattering Random waves Randomly modulated periodicity Range dependence Range gate camera Range-only tracking Ranging system Rational functions Ray chaos Ray model	Rayleigh channels Rayleigh fading RCS (radar cross section) Real time processing Real underwater acoustic signals Real-time Real-time systems Realizations Receivers Reconfigurable control UUV Recursive estimation Recursive filters Reduced rank beamforming Redundancy Redundant systems Reflection coefficients Reflector antennas Remote handling Remote sensing Remote sensing by radar Remote sensing of sea state Remotely operated vehicles Renavigation Replica correlation Resistivity measurement Resolved motion control Resonance Resource management Reverberation Reverberation measurements Reverberation modeling Reverberation models Reviews RF communication Rician fading Ring arrays Risk assessment Robot dynamics Robot hand Robot kinematics Robot vision Robot vision systems Robotic fish Robotics Robots Robots, locomotion Robust classification Robust control Robustness Robustness, linear systems Robustness, nonlinear systems Rough surface scattering Rough surfaces Roughness power spectrum Rubber materials/devices