Multi-Quadrant Photodetector Checks for Laser Target Deviation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing target detection systems using multi-quadrant photodetectors face accuracy degradation due to atmospheric turbulence and parasitic signals, leading to unreliable deviation measurements in semi-active laser guidance systems.
Innovation Solution
A method for target detection using a multi-quadrant photodetector that includes processing signals from each quadrant to determine deviation, comparing measured indicators with theoretical distributions, and applying a consistency check through a comparison criterion to validate or invalidate deviation measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a multi-quadrant photodetector is used to measure target deviation, then the capability to track and guide weapons towards the target is enabled, but measurement accuracy degrades due to atmospheric turbulence and parasitic signals
Solution Approach 1:
The patent pre-calculates and stores theoretical energy distribution indicators for multiple possible deviation values before actual measurement. During operation, the measured indicators are compared against these pre-computed theoretical values to identify the most likely true deviation, thereby compensating for measurement errors caused by atmospheric turbulence and parasitic signals
Solution Approach 2:
The system implements a feedback mechanism where the measured energy distribution indicators are continuously compared with theoretical indicators corresponding to different deviation values. This comparison provides feedback that enables identification and correction of erroneous measurements, improving the overall reliability of the deviation measurement system
2Ease of operation
If signal processing is performed to determine deviation from quadrant signals, then target location capability is achieved, but erroneous readings occur due to atmospheric turbulence and parasitic light sources
Solution Approach 1:
The patent pre-computes and stores a database of theoretical energy distribution indicators corresponding to various deviation values. This preliminary preparation enables rapid validation of measured signals during operation by comparing them against expected theoretical distributions, thereby identifying and rejecting erroneous readings caused by atmospheric turbulence or parasitic light
Solution Approach 2:
The system uses feedback comparison between measured and theoretical indicators to validate measurement results. When measured indicators deviate significantly from theoretical expectations, the system can identify the measurement as erroneous and request re-measurement, thereby improving the validity of the final deviation value used for target tracking
3Adaptability or versatility
If laser flux scattered by the target is used for semi-active laser guidance, then guidance capability towards the target is provided, but the measurement is disturbed by parasitic sources and atmospheric conditions
Solution Approach 1:
The patent pre-calculates theoretical energy distribution patterns for various target positions and stores them for comparison. This preliminary preparation enables the system to distinguish between legitimate laser flux variations caused by target position changes and variations caused by parasitic sources or atmospheric turbulence, thereby maintaining guidance accuracy
Solution Approach 2:
The system implements feedback validation where measured energy distribution from the photodetector is compared against theoretical distributions. This feedback mechanism allows the system to reject measurements that do not conform to expected patterns, thereby maintaining measurement precision despite the presence of parasitic light sources and atmospheric disturbances
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
Enhances the reliability of deviation measurements by identifying and correcting erroneous readings, thereby improving the accuracy and consistency of target location and guidance systems.
Implementation Method 1
the laser flux scattered (backscattered) by the target is then used to measure the deviation
Implementation Method 2
a four-quadrant photodetector whose photodetector surface is in the shape of a disc or square cut into four equal and independent photodetection surfaces
Implementation Method 3
a high-power, low-divergence laser beam emitted by a designator marks the target
Implementation Method 4
the scene environment influences the propagation of the wavefront of the designator laser towards the target then from the target towards the sensor; the turbulence present on these paths generate scintillation-type effects which result in modulations of illumination inside the optical pupil of the sensor
Implementation Method 5
the turbulence present on these paths generate scintillation-type effects which result in modulations of illumination
Data Source
Figure 1~2
Figure 3a~4
Figure 5
AI summary
The invention relates to a method for locating a target by means of a detecting device comprising a photodetector comprising NxM quadrants positioned with respect to a sighting axis of the detecting device, the photodetector being configured to detect optical signals from the target to be detected, said method being implemented in a processing unit of said device and comprising the following steps, the target scattering an optical signal: - acquiring the signals detected by each quadrant, which correspond to the signals scattered by the target toward the quadrants; - processing the acquired signals to determine an elevation angle error and an azimuth angle error of the direction of the target with respect to the sighting axis of the device; - processing the acquired signals with a view to deducing therefrom indicators of the distribution of the signals detected by the quadrants; - processing the determined elevation angle error and azimuth angle error with a view to deducing therefrom indicators of the theoretical distribution of the signals in the quadrants for these angle errors; - verifying the coherence of the theoretical distribution indicators with the distribution indicators obtained using the acquired signals so as to determine whether the measured angle error is valid.