GNSS Receiver Cold Start Authentication via Reverse Signal Calculation
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Solution Overview
Problem
Current GNSS systems are vulnerable to jamming and spoofing attacks, especially when receivers are starting up cold, as they lack effective authentication methods for open signals, and existing encryption techniques are costly and inefficient, failing to ensure accurate position calculation.
Innovation Solution
Implementing a reverse calculation method where the receiver transmits a signal to satellites, allowing a third entity to calculate its position using time of arrival data, and comparing this with forward calculation results to authenticate the position and detect potential attacks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If open signals are used for GNSS communication, then ease of operation and commercial viability are improved, but security against jamming and spoofing attacks deteriorates
Solution Approach 1:
The patent inverts the traditional authentication approach by having the receiver authenticate the satellites instead of satellites authenticating the receiver. The receiver measures satellite signal parameters (frequency, code phase, Doppler) and compares them against expected values calculated from ephemeris data, creating a challenge-response authentication mechanism that works for cold starts without requiring pre-shared secrets
Solution Approach 2:
The patent implements feedback by having the receiver send authentication requests to satellites and receive authentication responses containing verification data. The ground control segment provides feedback by updating ephemeris data with authentication credentials, creating a closed-loop system where authentication information flows from ground to space to user and back
2Reliability
If encryption techniques are implemented to secure GNSS signals, then security against spoofing attacks is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the authentication logic from the satellite signals themselves and places it in the receiver's authentication module. Instead of embedding authentication credentials in the satellite broadcasts (which would increase signal complexity), the system extracts and verifies specific signal parameters (frequency offset, code phase, Doppler shift) that inherently authenticate the satellite without adding encryption overhead
Solution Approach 2:
The patent uses disposable, easily computable authentication credentials based on public ephemeris data rather than expensive, complex encryption keys. The authentication mechanism relies on readily available satellite orbital information that can be independently verified by any receiver, eliminating the need for costly secure key distribution infrastructure
3Reliability
If authentication information is stored in the receiver before cold start, then authentication capability is improved, but loss of information during cold start deteriorates
Solution Approach 1:
The patent performs preliminary action by having the ground control segment pre-calculate and upload authentication-capable ephemeris data to satellites before the receiver needs to authenticate them. This preliminary preparation of satellite orbital and authentication information allows the receiver to immediately begin authentication on cold start without needing to store sensitive credentials locally
Solution Approach 2:
The patent introduces the ground control segment as an intermediary that manages authentication information. Instead of requiring direct authentication credentials in the receiver, the ground control segment mediates by providing authenticated ephemeris data to satellites, which then broadcast it as part of normal navigation signals, allowing the receiver to authenticate satellites through publicly available information
4Measurement precision
If signal strength from satellites is increased, then measurement precision is improved, but energy consumption by satellites deteriorates
Solution Approach 1:
The patent replaces the mechanical approach of increasing satellite transmit power with an information-based authentication system. Instead of boosting signal strength to improve authentication reliability, the system uses precise measurement and verification of signal parameters (frequency, code phase, Doppler) against independently calculated expected values, achieving secure authentication without additional energy consumption
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 method enhances the accuracy and security of GNSS position calculations, reducing the risk of jamming and spoofing attacks, and improves response times in search and rescue operations by providing precise and reliable location data.
Implementation Method 1
recording the time of arrival of the signal from the receiver to each of the satellites
Implementation Method 2
comparing this with forward calculation results to authenticate the position and detect potential attacks
Data Source
AI summary
The method indicates a way to avoid or considerably reduce the possibility of a jamming or spoofing attack successfully affecting the signals from the satellites, allowing the satellites to be detected even in situations where the receiver is starting up cold and makes it possible for the GNSS positions that have been verified using same to be accepted as evidence before a court of law. To ensure that the position calculated by the receiver is valid, the method includes a transmitter in the radio navigation receiver, various functions added to the actual satellites and the ground control segment of the GNSS system, in order to be able to calculate the location/area where the receiver is located. With the information, the position supplied by the receiver can be compared with that calculated by a third entity to detect whether it is correct or, conversely, if it cannot be considered valid.