Cellular OTDOA Aircraft Positioning via Base Station Timestamps
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Solution Overview
Problem
Current aircraft positioning systems, especially in general aviation, face challenges due to limited space, energy constraints, and the inability to detect non-metallic aircraft, with existing solutions offering inadequate accuracy and reliability, particularly in indoor environments and being susceptible to jamming.
Innovation Solution
A low-energy, on-board device using cellular network OTDOA technology with a SIM or USIM card for identification, coupled with a location-based server to determine aircraft position with 50-100 m accuracy, sending validated data to the aircraft and a public database, without relying on satellite navigation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional on-board navigation and surveillance equipment are used, then positioning accuracy can be improved, but the device weight and energy consumption increase significantly
Solution Approach 1:
The patent uses cellular base stations as intermediary objects for positioning. Instead of relying on heavy on-board navigation equipment, the system employs ground-based cellular infrastructure to determine aircraft position through OTDOA measurements, thereby achieving accurate positioning without adding significant weight to the aircraft
Solution Approach 2:
The patent replaces traditional mechanical/electronic on-board navigation equipment with a signal-based positioning system. By substituting physical navigation instruments with cellular network signal processing, the system achieves positioning functionality with minimal on-board hardware
2Measurement precision
If traditional on-board navigation equipment is installed, then positioning capability is enhanced, but available space and energy supplies are consumed
Solution Approach 1:
The cellular network acts as an intermediary that provides positioning services without requiring energy-intensive on-board navigation equipment. The aircraft simply needs to receive signals from cellular base stations, leveraging external infrastructure to reduce on-board energy demands
Solution Approach 2:
The cellular network serves multiple functions including communication and positioning simultaneously. By using the same cellular infrastructure for both voice/data communication and location determination, the system eliminates the need for separate dedicated navigation equipment and its associated energy consumption
3Measurement precision
If GNSS system is used for positioning, then location data can be obtained, but the system is vulnerable to jamming and spoofing attacks
Solution Approach 1:
The patent converts the potential harm of signal-based positioning vulnerabilities into a benefit by using terrestrial cellular signals that operate in different frequency bands and propagation characteristics than satellite signals. This diversity makes simultaneous jamming of both systems difficult, and the ground-based nature of cellular networks provides inherent resistance to certain types of spoofing attacks
Solution Approach 2:
The system uses a composite positioning approach by combining cellular network OTDOA positioning with optional GNSS data fusion. This multi-source positioning strategy creates a more robust system where each positioning method compensates for the weaknesses of the other, enhancing overall reliability
4Difficulty of detecting and measuring
If surveillance systems detecting metallic objects are used, then air traffic monitoring is enabled, but non-metallic aircraft such as plastic UAVs cannot be detected
Solution Approach 1:
The cellular on-board device serves as an intermediary that enables detection of any aircraft regardless of material composition. Instead of relying on radar reflection from metallic surfaces, the system uses the presence and position data from cellular signals to detect and track aircraft, making material composition irrelevant
Solution Approach 2:
The patent replaces passive radar detection (which relies on metallic reflection) with active cellular signal-based detection. By substituting electromagnetic reflection principles with cellular communication signal processing, the system can detect any aircraft equipped with cellular capability, independent of its material composition
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 and reliable aircraft positioning within 50-100 m, even in urban environments, reducing the risk of accidents by providing real-time, validated position data and integrating with air traffic management systems, while being lightweight, low-power, and resistant to jamming.
Implementation Method 1
time stamp signals from at least three, but ideally four to six base stations are recorded, then observed time difference of arrival (OTDOA) data of these signals, proportionate to the distance from the cellular base stations, are calculated
Data Source
AI summary
A procedure for a positioning of an aircraft is provided. An airspace user initiates using of a service provided by an air traffic manager and sends identifying data to the air traffic manager, the air traffic manager registers an aircraft identifier, carries out a standalone positioning. As the aircraft identifier, an International Mobile Subscriber Identity (IMSI) number of a code card connected to a switched on on-board device and placed on board the aircraft is used, the airspace user logs in to a cellular network contracted by the air traffic manager, time stamps emitted by at least three cellular base stations are recorded, then observed time difference of arrival data proportionate to a distance from the at least three cellular base stations are calculated, the observed time difference of the arrival data are sent through the cellular network to a location based server.