Aircraft Positioning Using Secondary Surveillance Radar Beacons
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Solution Overview
Problem
The aviation industry faces challenges in determining the spatial position of an aircraft independently of GPS measurements, as GPS can experience jamming or malfunctioning.
Innovation Solution
A method and system using one or more Secondary Surveillance Radars (SSR) as beacons to determine the spatial position of an airborne vehicle. This involves determining pulse repetition frequency patterns, estimating transmit and receive times, and calculating distances from the SSR to the aircraft, along with other necessary measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GPS is used to determine aircraft position, then positioning accuracy is improved, but system reliability deteriorates due to susceptibility to jamming and malfunctioning
Solution Approach 1:
The patent introduces SSR (Secondary Surveillance Radar) as an intermediary system to determine aircraft position. Instead of relying directly on GPS signals that are susceptible to jamming, the invention uses SSR ground-based radars as mediators to provide positioning information through alternative measurement methods, thereby maintaining positioning capability when GPS is compromised
Solution Approach 2:
The invention changes the fundamental parameters used for positioning from GPS satellite-based signals to SSR ground-based radar measurements. By transitioning to different physical measurement parameters (radar range and angle measurements instead of GPS time-of-flight), the system achieves positioning reliability independent of GPS signal integrity
2Reliability
If alternative positioning method using SSR is implemented, then system reliability is improved by independence from GPS, but device complexity increases due to need to process PRF patterns and multiple measurements
Solution Approach 1:
The airborne vehicle's navigation system performs self-service by autonomously processing SSR interrogation signals and deriving position information. The system automatically detects PRF patterns, estimates transmit times, calculates distances, and determines position without requiring external assistance, thereby managing the complexity within the aircraft's own navigation equipment
Solution Approach 2:
The patent applies preliminary action by pre-determining PRF patterns during periods when GPS is available and functional. The system stores these predetermined patterns and uses them later when GPS becomes unavailable, avoiding the need to process complex patterns in real-time during emergency situations and reducing operational complexity
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
Enables accurate determination of an aircraft's position without relying on GPS, providing a reliable alternative for navigation in scenarios where GPS is unavailable or compromised.
Implementation Method 1
estimating a first transmit time instant of said at least one of P1, P2 or P3 pulses, based on the first reception time instant and the first PRF pattern, thereby determining the first distance
Implementation Method 2
receiving an interrogation signal, comprising at least one of P1, P2 or P3 pulses, from the first SSR
Data Source
AI summary
Methods and systems are disclosed for determining a spatial position of an aircraft, without replying on measurements from the Global Positioning System. Various embodiments are described using a single Secondary Surveillance Radar (SSR), and multiple SSRs.