Composite PRN Code Tracking for Lower Time-of-Arrival Error
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Solution Overview
Problem
Conventional PRN codes with higher chip rates require greater signal bandwidth, leading to reduced signal resolution due to filtering, which undermines their effectiveness in ranging accuracy.
Innovation Solution
A composite PRN code is generated by assembling a given PRN code with its compressed version, forming a code with a higher effective chip rate without crossing data boundaries, achieved through sample-to-sample multiplication of noiseless and noisy PRN codes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional PRN codes with higher chip rates are used, then ranging accuracy is improved, but signal bandwidth increases causing filtering and reduced signal resolution
Solution Approach 1:
The patent segments the PRN code generation process by creating a composite code from multiple component codes with different chip rates. Instead of using a single high-chip-rate code that requires excessive bandwidth, the solution divides the code structure into segments that can be processed separately and combined, achieving high effective chip rate without proportionally increasing bandwidth requirements
Solution Approach 2:
The patent applies composite material principles by constructing a composite PRN code from multiple component codes. This composite structure combines the advantages of different code types (e.g., long and short codes, different chip rates) to achieve superior ranging accuracy while maintaining manageable bandwidth requirements, similar to how composite materials combine different substances to achieve superior properties
2Measurement precision
If higher chip rate PRN codes are used, then time of arrival error is reduced, but filtering effects increase due to greater bandwidth requirements
Solution Approach 1:
The patent changes key parameters of the PRN code system by creating a composite code structure that achieves a higher effective chip rate without linearly increasing the actual chip rate of individual components. This parameter transformation allows the system to benefit from higher chip rate characteristics (narrower correlation mainlobe, lower TOA error) while avoiding the bandwidth and filtering issues that would result from actually transmitting at those higher chip rates
3Measurement precision
If the composite PRN code is generated through sample-to-sample multiplication, then correlation mainlobe is narrowed, but processing complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-generating and storing multiple component PRN codes with different characteristics before the actual ranging operation. These component codes are prepared in advance and can be efficiently combined through sample-to-sample multiplication during tracking, reducing real-time processing complexity while achieving the desired narrow correlation mainlobe
Data Source
AI summary
Generating a composite pseudo random noise (PRN) code is provided. The method comprises receiving a wireless transmission having a noisy received original PRN code multiplexed with navigation data. A noiseless local replica original PRN code is generated within the receiver. A noiseless local replica compressed PRN code is then generated based on the noiseless local replica original PRN code. The noiseless local replica compressed PRN code has the same length as the noiseless local replica original PRN code and a higher chip rate. A sample-to-sample multiplication operation on the noisy received original PRN code and the noiseless local replica compressed PRN code generates a noisy received composite PRN code. The received wireless transmission is then tracked according to the noisy received composite PRN code.