Receiver Position Calculation Using Stored PRN Chips
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Solution Overview
Problem
Current methods for accessing public regulated services in global navigation satellite systems, such as Galileo PRS, require a security module and valid keys, which are complex, power-consuming, and limit access to authorized users, and existing assistance server architectures necessitate a communication link, leading to bandwidth demands and position solution delays.
Innovation Solution
A method where an assistance server transmits PRN code chips to a receiver for storage, allowing the receiver to determine its position using encrypted signals without a security module or valid keys, eliminating the need for a communication link and enabling position calculation during a designated time interval, including the use of stored PRN code chips and encrypted navigation message symbols.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a security module and valid keys are used in the receiver, then access to public regulated services is secured, but device complexity and power consumption increase
Solution Approach 1:
The patent extracts the security module and key storage from the receiver and relocates them to the assistance server. The server performs all security-critical operations including key management, PRN code generation, and position calculation, while the receiver only stores pre-generated PRN codes and processes unencrypted satellite signals. This extraction eliminates the need for complex security hardware in the receiver while maintaining service security through server-side authentication and access control.
2Adaptability or versatility
If an assistance server with security module is used, then access to public regulated services is enabled, but communication link requirements increase bandwidth demands
Solution Approach 1:
The assistance server performs preliminary actions by pre-generating PRN codes for future time intervals and pre-calculating positions during periods when communication links are available. These pre-computed PRN codes and position data are stored in the receiver's memory, enabling the receiver to determine its position offline without requiring real-time communication with the assistance server, thus eliminating ongoing bandwidth demands.
3Measurement precision
If real-time communication with assistance server is maintained, then position accuracy is improved, but position solution delays occur
Solution Approach 1:
The receiver stores copies of PRN codes generated for future time intervals in its memory. These pre-stored PRN code copies enable the receiver to immediately process satellite signals and calculate positions without waiting for real-time communication with the assistance server. The copying approach eliminates position solution delays while maintaining accuracy by using pre-computed reference data that matches the satellite signals being processed.
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 allows for on-time measurements without a communication link, reduces storage requirements, preserves security, and enhances receiver sensitivity by allowing arbitrary correlation times, enabling position determination without a security module and valid keys, while maintaining security and reducing bandwidth demands.
Implementation Method 1
The correlation of locally generated replicas with the received satellite signals is the basis of an acquisition technique, tracking technique, and measurement of the time of flight of the satellite signals for the distance between a satellite and the receiver.
Data Source
AI summary
A method for determining a position of a receiver via use of encrypted signals of a public regulated service. The method comprises transmitting PRN code chips to the receiver by an assistance server. The method further comprises storing the transmitted PRN code chips to be used before a designated time interval by the receiver. The method further comprises receiving the encrypted signals during the designated time interval by the receiver from satellites in line-of-sight to the receiver. The method further comprises determining the position of the receiver via use of the encrypted signals and the stored PRN code chips by the receiver.