Encrypted GNSS Sideband Capture for Low Data Transfer
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Solution Overview
Problem
Current methods for positioning using encrypted GNSS navigation signals require significant data transfer due to high bandwidth, leading to increased complexity, power consumption, and cost in receivers, as well as delayed position fixes, especially with Galileo PRS signals.
Innovation Solution
Capturing and transmitting only one sideband of the encrypted GNSS navigation signal, either through front-end processing or signal processing techniques, reduces data transfer and eliminates the need for a security module in the receiver, allowing for reduced data transmission and increased sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If raw baseband or IF samples of encrypted GNSS navigation signals are transferred to a secured server, then positioning can be performed without a security module in the receiver, but the data transfer load on the communication network becomes extremely demanding
Solution Approach 1:
The patent extracts only the necessary information (encrypted navigation signals) from the complete raw baseband or IF samples before transmission. By selecting and transmitting only the essential signal components required for positioning calculations, the data volume is dramatically reduced while maintaining the ability to perform secure positioning operations on the server.
Solution Approach 2:
The patent changes the sampling parameters by reducing the sample rate from the original high rate (e.g., 32.5 MHz for BOCc(15,2.5) PRS signals) to a lower rate that is sufficient for positioning accuracy. This parameter change maintains positioning functionality while reducing the data transfer load on the communication network.
2Measurement precision
If a high sample rate is used to capture encrypted GNSS signals with large bandwidth, then positioning accuracy is maintained, but the amount of data to be transferred increases significantly
Solution Approach 1:
The patent optimizes the sampling rate parameter to match the actual bandwidth requirements of the encrypted GNSS signal. By analyzing the signal characteristics and determining the minimum necessary sample rate for accurate positioning, the system achieves the required measurement precision while minimizing data transfer volume.
Solution Approach 2:
The patent applies partial action by capturing only the essential signal components needed for positioning rather than the complete signal spectrum. This selective capture provides sufficient positioning accuracy without the excessive data volume that would result from capturing the entire signal bandwidth at high sample rates.
3Reliability
If a snapshot size of several milliseconds to one second is used to calculate position fix, then positioning sensitivity is improved, but the data transfer requirements increase
Solution Approach 1:
The patent changes the snapshot duration parameter to an optimized value that provides sufficient positioning sensitivity. By determining the minimum snapshot length required for reliable positioning calculations and setting the sampling rate accordingly, the system achieves the necessary reliability while keeping the total data volume (snapshot duration × sample rate) minimized for efficient transmission.
Data Source
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AI summary
The invention relates to a method for positioning by using encrypted GNSS navigation signals (12), which are modulated with a Binary Offset Carrier-BOC -method and transmit encrypted information in their sidebands, comprising the acts of: capturing (14, 16, 18, 20, 22) only one of the sidebands of an encrypted GNSS navigation signal, transmitting samples (24) of the captured sideband of the encrypted GNSS navigation signal to a secured server (26) for calculating (28, 30) a position, velocity and/or time - PVT -(32) from the received samples, and receiving the calculated PVT (32) from the secured server (26).