Northfinding via Celestial Image and Inertial Fusion
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Solution Overview
Problem
Current handheld targeting systems face inaccuracies in target location determination due to errors in digital magnetic compass readings, particularly in urban environments with varying magnetic fields, leading to potential collateral damage. Additionally, celestial northfinding systems are expensive, complex, and have logistical challenges in production and practical limitations such as day-night crossover and obstructed sky views.
Innovation Solution
A target location system that integrates a range sensor, image sensor, inertial sensor, and system processor to determine a 3D location without a separate celestial northfinding module, using image data from celestial bodies and inertial data to modify orientations and calculate bearings, allowing for accurate targeting even under obstructed conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a digital magnetic compass (DMC) is used to determine bearing, then the system is simple and low-cost, but measurement precision deteriorates due to magnetic field variations causing azimuth errors
Solution Approach 1:
The patent introduces celestial bodies (sun, stars, moon) as intermediary reference objects to determine bearing. Instead of directly using magnetic field measurements, the system uses the known positions of celestial bodies as mediators to calculate azimuth, thereby avoiding the harmful effects of local magnetic field variations while maintaining system simplicity
Solution Approach 2:
The patent replaces the magnetic field-based measurement system with an optical/astronomical system. By using image sensors to capture celestial body positions and substituting magnetic bearing determination with celestial-based azimuth calculation, the system eliminates susceptibility to magnetic interference while preserving operational simplicity through software-based processing
2Measurement precision
If celestial northfinding systems are used to improve bearing accuracy, then measurement precision improves, but device complexity increases due to separate cameras and specialized optics
Solution Approach 1:
The patent merges the celestial northfinding function with the existing target acquisition imaging system. The same image sensor used to capture target images also captures celestial bodies for azimuth determination, eliminating the need for separate cameras and specialized optics while maintaining high measurement precision
Solution Approach 2:
The imaging system is designed to serve multiple functions: target acquisition, target identification, and celestial body detection for northfinding. This multi-functionality allows the system to achieve accurate azimuth determination without adding dedicated celestial observation hardware, thereby reducing overall device complexity
3Adaptability or versatility
If digital magnetic compass is used in urban environments, then the system operates in all conditions, but reliability deteriorates due to magnetic interference from steel structures and power lines
Solution Approach 1:
The patent uses celestial bodies as intermediary reference points that are不受affected by urban magnetic interference. By calculating azimuth based on the known positions of sun, stars, or moon relative to the captured image, the system achieves reliable bearing determination in urban environments where magnetic compasses fail
Solution Approach 2:
The system creates a computational model of the celestial sphere and the observed celestial body's position within the image frame. By copying the known astronomical data and comparing it with the actual image capture orientation, the system reliably determines azimuth without being influenced by local magnetic field distortions
Data Source
AI summary
An apparatus for target location is disclosed. The apparatus includes a housing, which includes a range sensor to generate range data, an image sensor to generate image data, an inertial sensor to generate inertia data, and a processor. The processor is configured to receive the image data from the image sensor and determine a first orientation of the housing and receive the inertia data from the inertial sensor and modify the first orientation based on the inertia data to produce a modified orientation of the housing.