Estimation of image centroid, size, and orientation with laser radar

Area of Science:

• Optics and Photonics
• Radar Systems Engineering
• Signal Processing

Background:

• Monopulse laser radar systems require precise angular tracking for target designation.
• Image-based centroid tracking offers a method for estimating target position and orientation.
• Understanding noise limitations is crucial for optimizing radar performance.

Purpose of the Study:

• To investigate the angular tracking capabilities of monopulse laser radar using image centroid estimation.
• To analyze the influence of target characteristics and system parameters on tracking accuracy.
• To evaluate the impact of noise sources, including shot noise and laser speckle, on performance.

Main Methods:

• Sensing image irradiance distribution using an array of noncoherent photocounting detectors.
• Processing detector counts to estimate image centroid, size, and orientation.
• Deriving mean and variance of centroid and second moment for various target types and conditions.

Main Results:

• Quantified the mean and variance of centroid and second moment for optically rough and smooth targets.
• Analyzed the impact of coherence, target extent, resolution, and integration time on accuracy.
• Identified shot noise and laser speckle as key limiting factors for tracking precision.

Conclusions:

• Image centroid tracking is a viable method for angular tracking in monopulse laser radar.
• Target properties and system parameters significantly influence tracking accuracy.
• Shot noise and laser speckle impose fundamental limits on the achievable accuracy.