Consumer-Grade GNSS Receivers for Direct L5 Acquisition

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Solution Overview

Problem

Conventional GNSS receivers face challenges in directly acquiring L5 band signals without prior acquisition of L1 band signals, leading to duplication of radiofrequency components and excessive memory requirements, particularly in processing L5 band signals.

Innovation Solution

A GNSS receiver directly acquires L5 band signals without L1 band signals, utilizing shared cache memory between application processors and a GNSS processing system, on-demand generation of GNSS PRN codes, and array processing architecture to reduce memory usage and improve sensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional GNSS receivers acquire L1 band signals first to obtain time and frequency information before acquiring L5 band signals, then the acquisition reliability is improved, but the device complexity increases due to duplication of radiofrequency components

Engineering Contradiction:

Improvesignal acquisition reliabilityVSAvoidradiofrequency component duplication

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and removes the L1 band signal acquisition functionality from the system, enabling direct L5 band signal acquisition without requiring L1 band signals. This eliminates the duplication of radiofrequency components while maintaining acquisition reliability through direct L5 band processing using modernized signal structures

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The radiofrequency front end is designed to universally process both L1 and L5 band signals, but the system is configured to operate independently on L5 band signals alone. This multi-functionality allows the same hardware to support direct L5 acquisition without requiring separate L1-specific components

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If conventional GNSS receivers store and use pseudorandom noise (PRN) codes for both L1 and L5 GNSS signals, then the signal processing capability is improved, but the memory requirements increase excessively

Engineering Contradiction:

Improvesignal processing capabilityVSAvoidmemory requirements

Core Design Contradiction:

Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The patent removes the requirement to store L1 band PRN codes from the system memory, retaining only L5 band PRN codes. This extraction reduces memory requirements while maintaining full signal processing capability for L5 band signals, which are the primary focus of the modernized receiver

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The system changes the operational parameter from dual-band (L1 and L5) to single-band (L5 only) operation. This parameter change allows the receiver to optimize memory allocation for L5 band processing only, reducing overall memory requirements while maintaining adaptability through efficient use of retained L5 PRN codes

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If GNSS receivers directly acquire L5 band signals without L1 band signals, then the memory requirements are reduced and device complexity is minimized, but the acquisition difficulty increases

Engineering Contradiction:

Improvesystem component countVSAvoidsignal acquisition difficulty

Core Design Contradiction:

Device complexityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent changes the signal acquisition parameter from indirect (via L1 band) to direct (L5 band only). This parameter change is enabled by modernized L5 signal structures that provide sufficient inherent information for direct time and frequency acquisition, reducing acquisition difficulty despite eliminating L1 band assistance

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The L5 band signal acquisition system is designed to be self-sufficient, obtaining all necessary time and frequency information directly from L5 band signals without requiring L1 band signals. This self-service capability reduces acquisition difficulty through optimized L5 band processing algorithms and modernized signal characteristics that provide adequate acquisition information

Inventive Principle:

Principle #25Self-service

4Quantity of substance

If GNSS receivers use shared cache memory between application processors and GNSS processing system, then the memory efficiency is improved, but the access conflict increases

Engineering Contradiction:

Improvememory efficiencyVSAvoidmemory access control

Core Design Contradiction:

Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent introduces a memory controller as an intermediary between the application processor and GNSS processing system that manages shared cache memory access. This intermediary resolves access conflicts through arbitration and coordination, enabling high memory efficiency while maintaining system complexity at an acceptable level through centralized memory management

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS12442931B2Modernized global navigation satellite system (GNSS) receivers and commercially viable consumer grade GNSS receivers

Publication Date: 2025.10.14 ONENAV INC

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.