Ladar Augmented Infra-Red Sensor for Accurate Range Tracking
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Solution Overview
Problem
Stand-alone passive IRST systems lack accurate range and range rate measurements, struggle with target characterization at long ranges, and face challenges with clutter and false alarms, limiting their effectiveness in providing complete situational awareness.
Innovation Solution
A Laser detection and ranging (LADAR) augmented infra-red (LAIR) sensor system that combines an IR fine track sensor, a Laser transmitter, and a Laser receiver mounted on a gimbal, using inertial navigation and a fast steering mirror to determine target direction, range, and brightness by transmitting and receiving a Laser beam, enhancing tracking capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If passive IRST sensing is used for infrared tracking, then the system can detect thermal radiation from targets, but accurate range and range rate measurements cannot be obtained without special maneuvers or multi-lateration
Solution Approach 1:
The patent combines passive IRST sensing with active LADAR ranging capabilities into a single integrated system. The LADAR transmitter and receiver are co-located with the IRST sensor, allowing the system to perform both passive thermal detection and active laser ranging without requiring separate systems or complex maneuvers. This merging resolves the contradiction by providing accurate range measurements while maintaining operational simplicity.
Solution Approach 2:
The patent introduces LADAR technology as an intermediary component that bridges the gap between passive IRST detection and active ranging. The LADAR transmitter sends laser pulses to the target, and the receiver captures the reflected light, providing precise range and range rate measurements that complement the passive thermal sensing capabilities of the IRST system.
2Length of stationary object
If IRST sensors are used for long-range target detection, then targets can be detected at extended ranges, but targets become unresolved providing little information for characterization
Solution Approach 1:
The integrated LAIR system merges passive IRST long-range detection with active LADAR high-resolution ranging and imaging. At long ranges, the system uses passive IRST to detect and track targets, then activates LADAR to obtain resolved range profiles and detailed target characterization information, thereby preventing information loss at extended detection ranges.
Solution Approach 2:
The system dynamically switches between passive and active sensing modes based on operational requirements. For long-range detection, passive IRST mode is used to conserve energy and avoid detection, while for close-range or characterization-critical scenarios, active LADAR mode is activated to provide detailed target information.
3Reliability
If IRST systems switch to single-target-track mode to verify suspicious targets, then target verification can be performed, but the system is pulled away from providing wide-area track-while-scan situational awareness
Solution Approach 1:
The patent merges the functions of target verification and wide-area surveillance into a single integrated operational mode. The co-located LADAR and IRST sensors work simultaneously to provide both detailed target characterization for verification and continuous wide-area situational awareness, eliminating the need to switch between STT and TWS modes.
Solution Approach 2:
The integrated LAIR system achieves multi-functionality by combining passive IRST wide-area surveillance with active LADAR target verification capabilities in a single sensor package. This universal system can simultaneously perform track-while-scan and single-target-track functions, providing both broad situational awareness and detailed target verification without mode switching.
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
The LAIR sensor provides accurate six degree-of-freedom state vectors and highly resolved range profiles, improving target characterization and situational awareness beyond the limitations of passive IRST systems, enabling precise tracking and verification of targets.
Implementation Method 1
transmitting, with a Laser transmitter, a Laser beam towards the direction of the target
Implementation Method 2
receiving, with an infra-red (IR) fine track sensor, an IR signal from the target
Implementation Method 3
stabilizing, with a fast steering mirror (FSM), the reflected Laser signal onto the Laser receiver
Data Source
AI summary
A system, method, and apparatus for detecting and tracking a target are disclosed. The disclosed method involves receiving, with an infra-red (IR) fine track sensor, a IR signal from the target. The method further involves determining, with at least one processor, an estimate of a direction of the target using the IR signal. Also, the method involves transmitting, with a Laser transmitter, a Laser beam towards the direction of the target. Further, the method involves receiving, with a Laser receiver, the Laser signal after it reflects off the target. In one or more embodiments, the Laser receiver is a photon receiver (e.g., a geiger-mode avalanche photo-diode (Gm-APD) receiver).