RTK Navigation Update Rate via PPPoS Protocol

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Low-cost RTK positioning systems suffer from limited navigation update rates due to interruptions in the NTRIP data stream caused by using AT commands for communication with 4G/LTE modules, leading to reduced accuracy and increased convergence time.

Innovation Solution

Implementing the PPPoS protocol and LwIP library in conjunction with an RTOS to enable simultaneous retrieval and transmission of NTRIP data streams and location messages using a single 4G network module, allowing concurrent data handling through the HTTP and MQTT protocols.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If AT commands are used for communication with 4G/LTE modules, then device complexity is reduced and ease of operation is improved, but navigation update rate is limited and data stream continuity is disrupted

Engineering Contradiction:

Improveease of operationVSAvoidnavigation update rate

Core Design Contradiction:

Ease of operationVSProductivity

Solution Approach 1:

The patent replaces the AT command communication mechanism with a PPPoS protocol-based communication mechanism. This substitution enables continuous data stream transmission without the interruptions inherent in AT command polling, thereby achieving both ease of operation and high navigation update rates simultaneously.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent implements a continuous NTRIP data stream retrieval mechanism using PPPoS protocol, eliminating the interruptions caused by AT command polling. This ensures uninterrupted data flow for RTK positioning while maintaining ease of operation through automated connection management.

Inventive Principle:

Principle #20Continuity of useful action

2Device complexity

If AT commands are used for communication with 4G/LTE modules, then device complexity is reduced, but data stream continuity is disrupted and positioning accuracy deteriorates

Engineering Contradiction:

Improvedevice complexityVSAvoidpositioning accuracy

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent substitutes the interruptive AT command communication system with a continuous PPPoS protocol-based system. This replacement maintains simple device architecture while ensuring uninterrupted NTRIP data stream retrieval, thereby preserving RTK Fixed positioning accuracy.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent establishes continuous data stream retrieval through PPPoS protocol, preventing the stream interruptions that cause degradation from Fixed to Float or DGNSS states. This ensures reliable positioning accuracy without increasing device complexity.

Inventive Principle:

Principle #20Continuity of useful action

3Ease of manufacture

If microcontroller is used as main processor, then cost is reduced and energy consumption is lowered, but processing power is limited and navigation update rate is reduced

Engineering Contradiction:

ImprovecostVSAvoidnavigation update rate

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

The patent replaces the limiting factor (AT command polling mechanism) with a more efficient PPPoS protocol-based communication system. This substitution allows microcontrollers to achieve high navigation update rates (1 Hz or higher) without requiring expensive high-performance processors, thus maintaining low cost while improving productivity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Productivity

If navigation update rate is increased, then real-time positioning capability is improved, but data stream interruption risk increases and accuracy may deteriorate

Engineering Contradiction:

Improvenavigation update rateVSAvoidpositioning accuracy

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent implements simultaneous NTRIP data stream retrieval and positioning data transmission through the PPPoS protocol. This approach enables high navigation update rates while maintaining continuous data stream flow, preventing accuracy deterioration even at elevated update frequencies.

Inventive Principle:

Principle #20Continuity of useful action

Data Source

PatentUS20250212171A1Method to increase a navigation update rate for a RTK positioning system

Publication Date: 2025.06.26 VIETTEL GRP

AI summary

The invention addresses a method for simultaneously retrieving NTRIP data streams and transmitting positioning data using a 4G network for low-cost RTK positioning systems. This method employs the PPPoS protocol and the LwIP library, along with the implementation process of applying this method to real-world systems. The approach enhances data update rate and ensures high accuracy with a superior RTK “Fixed” positioning rate for affordable RTK systems, significantly optimizing hardware system costs. The effectiveness of the invention has been demonstrated through practical testing, showing a marked improvement and complete resolution of the limitations associated with the previous AT command method.