Cone Coordinate System for Aircraft Geo-Location Accuracy
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional geo-location systems using line of bearing measurements are limited by requiring straight and level flight, restricting aircraft maneuverability and accuracy when determining target location, especially when the angle between sensors and target is small, leading to significant measurement errors and reduced operational flexibility.
Innovation Solution
The system employs a locus of emitter positions (LEP) approach using a cone coordinate system, which calculates a cone model based on aircraft attitude and multilateration information, allowing for accurate geo-location regardless of aircraft attitude or position, and intersects this model with a 3D earth model to determine the target's position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional line of bearing measurements are used with straight and level flight constraints, then measurement precision is improved, but aircraft maneuverability and operational flexibility are reduced
Solution Approach 1:
The patent transforms the static baseline approach into a dynamic system where the baseline rotates and changes length as the aircraft maneuvers. The system continuously updates the baseline vector based on aircraft position and attitude, allowing accurate geo-location during turns, climbs, and other maneuvers rather than requiring fixed straight-and-level flight
Solution Approach 2:
The patent extends the traditional 2D line of bearing measurement into 3D by incorporating aircraft attitude (pitch and roll) and creating a conical surface of possible target locations. This dimensional extension allows the system to process measurements taken during maneuvers while maintaining accuracy by accounting for the aircraft's orientation in three-dimensional space
2Measurement precision
If fixed standoff distance is required for accurate measurements, then measurement precision is improved, but operational flexibility and response time are reduced
Solution Approach 1:
The system pre-calculates the conical surface of possible target locations based on the measured angle and aircraft attitude, before the aircraft completes its maneuver. This allows the geo-location fix to be computed continuously during the approach rather than requiring the aircraft to first establish a specific standoff distance
Solution Approach 2:
The patent changes the fundamental measurement parameter from fixed distance (standoff) to fixed angle (cone half-angle). By measuring the angle between the baseline and the line to the target and maintaining this angle constant, the system creates a conical surface that intersects the ground to locate the target, eliminating the need for fixed standoff distance constraints
3Adaptability or versatility
If measurements are taken during aircraft maneuvers, then operational flexibility is improved, but measurement precision deteriorates due to spirograph pattern errors
Solution Approach 1:
The system dynamically adapts the baseline orientation to match the aircraft's instantaneous attitude during maneuvers. By continuously updating the baseline vector and recalculating the conical surface based on current pitch and roll angles, the system eliminates the spirograph pattern error that occurs when using fixed baseline orientations during maneuvers
Data Source
AI summary
A method for determining geo-position of a target by an aircraft includes: receiving navigation data related to the aircraft including aircraft attitude information; receiving multilateration information related to the target including an angle to the target; calculating an axis for a cone fixed to the aircraft, based on the received aircraft attitude information; calculating a central angle for the cone from the received angle to the target; generating two vectors orthogonal to the cone axis; calculating a cone model from the axis, the central angle and the two vectors; and intersecting the cone model with an earth model to obtain a LEP curve, wherein the LEP curve is used to determine the geo position of the target.