ADS-B Multilateration for UAV Location Accuracy
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Solution Overview
Problem
Compact aircraft systems, such as unmanned aircraft systems (UAS), face challenges in determining their location accurately due to design restrictions and resource limitations, as they often cannot support Global Navigation Satellite System (GNSS) hardware, and existing multilateration techniques require multiple satellite-based signals.
Innovation Solution
A system that uses directional or omnidirectional antennas to receive secondary surveillance radar (SSR) signals from at least four proximate non-satellite objects, processing these signals to determine the ownship location using multilateration and position metrics, such as accuracy data from Automatic Dependent Surveillance-Broadcast (ADS-B) signals, without relying on satellite-based navigation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GNSS-based hardware is used for positioning, then location accuracy is improved, but size, weight, power consumption, and cost increase
Solution Approach 1:
The patent uses ADS-B signals from other aircraft as an intermediary means to determine position. Instead of directly using GNSS hardware, the system receives position information from nearby aircraft that are broadcasting their GPS-derived locations, thereby obtaining positioning capability without carrying heavy GNSS equipment.
Solution Approach 2:
The system copies position information from other aircraft's ADS-B transmissions. By receiving and processing the broadcast position data from multiple aircraft, the system reconstructs its own position indirectly through multilateration, using copied data rather than direct satellite measurement.
2Measurement precision
If GNSS-based hardware is used for positioning, then location accuracy is improved, but device complexity increases
Solution Approach 1:
The patent extracts only the necessary positioning function from the complex GNSS system. By receiving ADS-B signals that already contain processed position information from other aircraft, the system extracts positioning capability without implementing the entire GNSS receiver chain, reducing complexity while maintaining accuracy.
3Measurement precision
If multiple satellite-based signals are used for multilateration, then location determination accuracy is improved, but the system becomes incompatible with compact aircraft designs
Solution Approach 1:
Instead of using satellite-based signals as the primary positioning source, the patent inverts the approach by using ground-based or air-based ADS-B transmitters (other aircraft) as the positioning sources. The receiving aircraft determines its position by measuring signals from these non-satellite sources, reversing the traditional satellite-to-ground signal flow.
Data Source
AI summary
A system and related methods for location determination aboard a subject vehicle not equipped with a GNSS-based positioning system receives position signals transmitted by non-satellite atmospheric vehicles and surface objects, which may include precise locations of the transmitting objects or position metrics associated with containment regions within which the transmitting objects should be to a particular certainty level. The received position signals may include ADS-B signals transmitted by proximate aircraft and facilities. The system may determine ownship location via multilateration of received position signals, via processing the received position metrics and corresponding containment regions, or via combining or correlating the two to determine accurate ownship location data of the subject vehicle.