Aircraft-Mounted Sensor Calibration Using Lidar Backscatter
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Solution Overview
Problem
Existing sensor calibration methods for aircraft-mounted remote sensing systems, such as those described in US Pat. No. 9,052,236 B2, fail to adequately account for atmospheric influences, leading to inaccuracies and limited flexibility in measurement accuracy due to the use of short laser pulses and theoretical atmospheric corrections, and specifying calibration conditions that do not align with actual measurement conditions.
Innovation Solution
A method and arrangement that determines actual atmospheric properties by detecting the backscattered portion of electromagnetic radiation emitted from a celestial body, using a lidar system to calibrate aircraft-mounted sensors, taking into account atmospheric attenuation and adjusting measurement data accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If short laser pulses are used to eliminate atmospheric influences, then atmospheric attenuation is reduced, but calibration accuracy is still compromised due to inability to fully account for atmospheric conditions
Solution Approach 1:
The patent employs feedback by using a lidar system to measure actual atmospheric properties (backscattered radiation, aerosol content, humidity, temperature) during calibration and using these measurements to correct the calibration data. This closed-loop approach continuously adjusts for atmospheric conditions rather than attempting to eliminate them through pulse duration alone.
Solution Approach 2:
The patent introduces an intermediary atmospheric correction system that mediates between the laser radiation and the sensor calibration. The lidar system acts as an intermediary measurement device that characterizes the atmospheric state, and this information is used as a corrective intermediary step in the calibration process.
2Device complexity
If theoretical atmospheric correction is used, then calibration process is simplified, but measurement accuracy is reduced due to insufficient accounting for actual atmospheric conditions
Solution Approach 1:
The calibration system performs self-service by using the lidar system mounted on the same platform to automatically measure and characterize the atmospheric conditions during calibration. The system self-corrects for atmospheric influences without requiring external ground-based measurements or complex manual atmospheric profiling.
Solution Approach 2:
The lidar system serves multiple functions: it characterizes atmospheric properties for correction, provides backscattered radiation measurements for calibration, and can potentially measure atmospheric constituents. This multi-functionality reduces the need for separate atmospheric measurement systems while improving correction accuracy.
3Adaptability or versatility
If calibration is performed under specific conditions (nighttime, clear sky, specific geographic areas), then atmospheric interference is minimized, but flexibility is reduced and measurement accuracy suffers when actual measurement conditions differ from calibration conditions
Solution Approach 1:
The patent transitions from static calibration conditions to dynamic atmospheric correction. Instead of requiring fixed calibration conditions (nighttime, clear sky, specific locations), the system dynamically measures and corrects for atmospheric variations in real-time during calibration, allowing calibration to be performed under diverse and changing conditions.
Solution Approach 2:
The system changes the approach from controlling environmental parameters (time, location, weather) to measuring and compensating for atmospheric parameters (aerosol content, humidity, temperature, backscattering coefficient). This parameter transformation allows calibration flexibility while maintaining accuracy through active compensation.
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 significantly enhances calibration accuracy by accounting for variable atmospheric conditions, increasing flexibility and ensuring accurate measurement data without the need for predetermined calibration times or locations, thereby improving overall measurement precision.
Implementation Method 1
detecting a portion of radiation backscattered by the atmosphere of the celestial body
Implementation Method 2
using a lidar system to calibrate aircraft-mounted sensors
Implementation Method 3
atmospheric influences that could attenuate the emitted electromagnetic radiation before it reaches the sensor
Data Source
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AI summary
The invention relates to a method for calibrating flying-object-mounted sensors (16), comprising the steps of: - emitting electromagnetic radiation from the surface of a celestial body (14) or from a radiating flying object (13); - sensing a component of the radiation, which component is backscattered by the atmosphere of the celestial body (14); - sensing the emitted radiation by means of at least one sensor (16), which is mounted on a flying object (12) moving relative to the celestial body (14) or the radiating flying object (13), and deriving measurement data on the basis of said sensing; and - calibrating the sensor (16) on the basis of the measurement data and the backscattered component of the emitted radiation. The invention also relates to an assembly (10) for calibrating flying-object-mounted sensors (16), to a method and an assembly (10) for determining an atmosphere correction value, and to a method and an assembly (10) for sensor calibration outside of the atmosphere.