Point-Ahead Laser Tracker Wavefront Correction
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Solution Overview
Problem
Existing laser pointer-tracker systems, particularly point-ahead systems, lack the ability to independently sense and correct wavefront aberrations in both transmit and receive directions, relying on dim target images or assuming equal corrections, which affects image quality and beam stability.
Innovation Solution
The implementation of closed-loop point-ahead systems with shared or separate apertures, using marker and designator laser beams to compute point-ahead angles and stabilize both transmit and receive paths, enabling independent wavefront correction in both directions without relying on the target image for corrections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a single marker beam is used in a stable platform point-ahead system, then the transmitted laser beam and common path are stabilized, but the tracker image is not stabilized against jitters in the tracker-marker leg
Solution Approach 1:
The patent divides the stabilization function into two separate beams: one beam (first beam) stabilizes the transmitted laser beam and common path, while a second beam (second beam) specifically stabilizes the tracker image against jitters in the tracker-marker leg. This segmentation allows independent optimization of stabilization for different functional paths without interference.
Solution Approach 2:
The patent creates a system where the stable platform serves multiple stabilization functions through two distinct beams. The first beam handles transmit path stabilization while the second beam handles tracker image stabilization, making the overall system more reliable by addressing multiple stability requirements simultaneously through a unified platform architecture.
2Device complexity
If the dim target image is used to sense wavefront corrections, then no additional local beam is needed, but the correction quality is insufficient due to the low signal level
Solution Approach 1:
The patent introduces a local beam (marker beam or designator beam) as an intermediary that travels along the same path as the received target image. This local beam provides a strong, dedicated signal for wavefront sensing, acting as a mediator between the system's need for correction data and the insufficient quality of the dim target image alone.
Solution Approach 2:
The patent creates a local beam that copies the path and characteristics of the received target image direction. This copy provides identical optical path information but with sufficient signal strength to enable precise wavefront sensing, allowing the system to measure and correct aberrations accurately without relying on the weak target image signal.
3Device complexity
If wavefront correction is assumed to be the same in both transmit and receive directions, then no separate sensing is needed, but actual wavefront aberrations in each direction are not independently corrected
Solution Approach 1:
The patent segments the wavefront correction function into two independent correction systems: one for the transmit direction and one for the receive direction. Each direction has its own local beam and wavefront sensing mechanism, allowing independent measurement and correction of direction-specific aberrations without cross-interference.
Solution Approach 2:
The patent applies local quality by providing direction-specific wavefront correction. The transmit path receives correction based on sensing in the transmit direction, while the receive path receives correction based on sensing in the receive direction. Each path gets customized correction tailored to its specific optical conditions rather than a generic shared correction.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach ensures stable and accurate pointing and tracking with improved image quality and beam stability by independently correcting wavefront aberrations in both transmit and receive directions, reducing reliance on the target image for corrections.
Implementation Method 1
energy returned from the current aimpoint on the target is used in computing the point-ahead angle
Implementation Method 2
full-aperture, high signal level, wavefront aberration sensing beams in both the transmit and receive directions
Implementation Method 3
employ full-aperture, high signal level, wavefront aberration sensing beams in both the transmit and receive directions to enable wavefront correction independently and simultaneously in both the transmit and receive directions
Data Source
AI summary
Point-ahead laser pointer-tracker systems with stabilization and wavefront correction in both transmit and receive directions provide arrangements for sensing the wavefront correction required in two different directions, one in the received target image direction for good image quality in the tracker and the other in the point-ahead direction for good beam quality on the target. In the several embodiments, a marker beam is aligned with the target image. Wavefront aberration correction signals are produced by an output wave sensor that senses the wavefront of the marker beam in the received target image direction and the wavefront of the source laser beam in the point-ahead transmit direction. The alignment is maintained by use of the output wave sensor signals together with signals from the tracker of the target and current aimpoint positions. These signals, compared in selected pairs, control mirrors in various legs of the optical system to put the current aimpoint on the desired aimpoint and to align the marker beam along the received target image direction.