Aircraft Vertical Position Determination Using Multilateration

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Solution Overview

Problem

Current air traffic control surveillance systems have limitations in accurately determining the vertical position of aircraft, relying on barometric pressure or radar techniques with limited resolution, which can impact maneuver tracking, altimeter verification, and vertical separation requirements.

Innovation Solution

A system comprising an aircraft emitter and multiple receivers, including at least one above the aircraft, uses time of arrival or travel time signals to determine the vertical position through multilateration or bistatic radar principles, allowing for independent altitude determination without barometric or GPS measurements, enhancing accuracy and reducing the need for special equipment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If barometric pressure or radar techniques are used to determine vertical position, then the system can obtain altitude information, but the measurement precision is limited

Engineering Contradiction:

Improvevertical position determination accuracyVSAvoidspecialized equipment requirements

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent transitions from traditional two-dimensional horizontal multilateration to three-dimensional vertical position determination by adding receivers at different altitudes (including space-based receivers). This dimensional expansion enables precise altitude measurement through the vertical component of signal travel time differences, resolving the limitation of conventional barometric or radar-based vertical position sensing.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent replaces mechanical/barometric pressure-based altitude measurement systems with an electromagnetic signal-based multilateration system. By using signal travel time measurements from multiple receivers at known positions to calculate aircraft vertical position, the system eliminates the need for specialized barometric equipment and achieves higher measurement precision through geometric rather than pressure-based determination.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Loss of information

If traditional surveillance systems are used, then horizontal position can be determined, but vertical position determination is insufficient

Engineering Contradiction:

Improvevertical position informationVSAvoidair traffic control efficiency

Core Design Contradiction:

Loss of informationVSProductivity

Solution Approach 1:

The patent makes the multilateration system universal by enabling it to perform both horizontal and vertical position determination functions simultaneously. The same network of receivers that previously only provided horizontal location data now also delivers accurate altitude information, eliminating the need for separate vertical sensing systems and improving overall air traffic control efficiency through integrated three-dimensional surveillance.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If barometric pressure measurements are used for vertical position, then altitude can be obtained, but the reliability is affected by atmospheric conditions

Engineering Contradiction:

Improvealtitude measurement consistencyVSAvoidatmospheric pressure variations

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the barometric pressure measurement system with an electromagnetic signal-based geometric determination system. By calculating vertical position from signal travel times and receiver positions rather than atmospheric pressure, the system eliminates sensitivity to atmospheric conditions such as pressure variations, temperature changes, and weather patterns, thereby significantly improving measurement reliability and consistency.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 enables precise three-dimensional position determination of aircraft, improving maneuver tracking, altimeter verification, and vertical separation, while reducing the need for specialized flight tests and equipment, thereby enhancing aviation safety and air traffic control efficiency.

Implementation Method 1

uses time of arrival or travel time signals to determine the vertical position through multilateration or bistatic radar principles

Methodology Applied

Scientific EffectTime of arrival measurement: Time of Flight

Data Source

PatentUS11346919B2System and method for determining the position of an aircraft

Publication Date: 2022.05.31 THALES ITALA SPA

AI summary

A system for determining the position of an aircraft comprises an emitter arranged at the aircraft for emitting a signal, at least two receivers arranged at different locations for receiving the signal emitted by the emitter, and an evaluation device which is designed to determine an aircraft position based on the known positions of the receivers at the time of the reception of the signal and on a characteristic of the signal emitted by the emitter and received by the receivers. The invention proposes that at least one of the receivers is located above the aircraft, andthat the evaluation means is designed to determine a vertical position (ALT) of the aircraft from the signal received by the receivers and the known positions of the receivers.