Reconfigurable GNSS Code Generator for Multi-Satellite PRN Recovery
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Solution Overview
Problem
Global navigation satellite system (GNSS) receivers face complexity and cost increases due to the need for generating multiple pseudo-random codes to recover navigation signals from different satellites, which complicates the recovery of navigation information.
Innovation Solution
An adjustable code generator is introduced, capable of generating a set of spread-spectrum code signals with distinct lengths, utilizing a programmable shift register, feedback loop, and control logic to reduce complexity and cost by configuring the code generation for various satellite systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the receiver includes circuitry for generating many different pseudo-random codes to recover navigation signals from different satellites, then the receiver's ability to recover navigation signals from multiple satellites and mitigate inter-satellite interference is improved, but the device complexity and cost increase
Solution Approach 1:
The patent applies a single universal code generator that can generate multiple different pseudo-random codes by changing its configuration parameters. The code generator uses a feedback shift register that can be programmed with different feedback polynomials and initial states to produce various PRN codes, eliminating the need for separate dedicated circuitry for each satellite system.
Solution Approach 2:
The code generator is made dynamically reconfigurable through control logic that can change the feedback polynomial and initial state of the shift register based on the required satellite system. This dynamic adaptation allows the same hardware to generate different codes on demand, reducing the need for static dedicated circuitry for each code type.
2Adaptability or versatility
If the receiver includes circuitry for generating many different pseudo-random codes to support various GNSS systems, then the receiver's support for multiple GNSS systems is improved, but the manufacturing cost increases
Solution Approach 1:
The patent implements a single universal code generator that can generate codes for multiple GNSS systems (GPS, GLONASS, GALILEO, etc.) by programming different feedback polynomials and initial states into the shift register. This universal approach replaces the need for multiple separate code generation circuits, thereby reducing manufacturing cost while maintaining multi-system support.
3Device complexity
If the receiver uses a single adjustable code generator configured for specific code lengths, then the device complexity is reduced, but the receiver's ability to handle codes with different lengths may be limited
Solution Approach 1:
The patent uses parameter changes in the feedback polynomial and initial state to generate codes of different lengths from the same shift register structure. By changing these parameters, the generator can produce codes with different periods (e.g., 1023 bits for GPS C/A code, 511 bits for GLONASS code), maintaining complexity reduction while achieving code length adaptability.
Data Source
AI summary
An adjustable code generator is configurable to generate any of a plurality of spread-spectrum code signals. The adjustable code generator includes a feedback polynomial mask table to contain a set of feedback polynomial masks. Respective feedback polynomial masks of the set correspond to respective spread-spectrum code signals of the plurality of spread-spectrum code signals. The adjustable code generator also includes control logic to select any of the feedback polynomial masks of the set contained in the feedback polynomial mask table, and further includes a shift register to provide, at an output, a respective spread-spectrum code signal that corresponds to a feedback polynomial mask selected by the control logic and to receive feedback generated using the feedback polynomial mask selected by the control logic.