GNSS Receiver Architecture for Direct L5 Signal Acquisition
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Solution Overview
Problem
Conventional GNSS receivers face challenges in directly acquiring L5 band signals without first acquiring L1 band signals, leading to duplication of radiofrequency components and excessive memory requirements, particularly when using discrete Fourier transform computations.
Innovation Solution
A GNSS receiver directly acquires L5 band signals without L1 band signals, sharing cache memory with application processors, using on-demand generation of GNSS PRN codes and array processing, and employing array processing architectures to reduce memory usage and improve sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional GNSS receivers acquire L1 band signals first to obtain time and frequency information before acquiring L5 band signals, then the acquisition process is simplified, but radiofrequency components are duplicated and device complexity increases
Solution Approach 1:
The patent extracts and removes the L1 band signal acquisition step from the conventional two-stage process. The receiver now directly acquires L5 band signals without requiring prior L1 band signal processing, eliminating the need for separate L1 radiofrequency components and simplifying the overall system architecture.
Solution Approach 2:
The radiofrequency front end is designed to universally process both L1 and L5 band signals through a single integrated path. The same radiofrequency components handle signal reception, mixing, and downconversion for both bands, eliminating duplication and enabling flexible band selection based on signal availability.
2Ease of operation
If conventional GNSS receivers store pseudorandom noise codes for both L1 and L5 band signals, then signal acquisition is facilitated, but memory requirements become excessive
Solution Approach 1:
The patent extracts and removes the storage requirement for L1 band pseudorandom noise codes from the system. Since direct L5 band acquisition is implemented, the receiver only generates and stores pseudorandom noise codes for L5 band signals, significantly reducing memory requirements while maintaining acquisition capability.
Solution Approach 2:
The system changes the operational parameter from storing codes for multiple bands (L1 and L5) to storing codes for a single band (L5). This parameter change in code storage strategy reduces memory usage while the same code generation algorithms are applied to the L5 band signals.
3Device complexity
If GNSS receivers directly acquire L5 band signals without L1 band assistance, then device complexity and memory requirements are reduced, but acquisition sensitivity and reliability become more difficult to achieve
Solution Approach 1:
The patent applies preliminary action by pre-generating pseudorandom noise codes for L5 band signals and pre-configuring the radiofrequency front end for direct L5 band processing. This preparation enables the receiver to immediately acquire L5 band signals upon signal availability, achieving reliable direct acquisition without requiring L1 band assistance.
Data Source
AI summary
GNSS receivers and systems within such receivers use improvements to reduce memory usage while providing sufficient processing resources to receive and acquire and track E5 band GNSS signals directly (without attempting in one embodiment to receive L1 GNSS signals). Other aspects are also described.