SBAS Dual-Frequency Synchronization via Auxiliary E5 Signal
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current Satellite-Based Augmentation System (SBAS) standards primarily cater to single-frequency users on the L1 frequency, posing challenges in introducing new services for dual-frequency users L1-L5 without disrupting operational functionality, especially in minimizing the need for additional satellites, modifying consumer receivers, and ensuring service continuity and synchronization.
Innovation Solution
Implementing a servo system that synchronizes the operational message L5 with an auxiliary synchronization message E5, using a secondary feedback loop to adapt the transmission of L5 messages, allowing for simultaneous or bias-corrected transmission of L1 and L5 messages, enabling dual-frequency support without modifying existing L1 stations or adding new satellites.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If new services for dual-frequency users L1-L5 are introduced, then service versatility is improved, but system complexity increases
Solution Approach 1:
The L1 station is designed to perform multiple functions: transmitting both L1 correction messages and L5 synchronization messages through the same ground infrastructure and satellite link. This multi-functionality allows dual-frequency service without requiring separate dedicated L5 ground stations, thereby reducing system complexity while maintaining service versatility
Solution Approach 2:
The L5 message acts as an intermediary synchronization signal that carries timing information from the L1 station to enable precise frequency alignment between L1 and L5 transmissions. This intermediary approach allows coordination of dual-frequency operations without direct complex interaction between separate L1 and L5 system components
2Adaptability or versatility
If additional satellites are added to support L5 frequency, then service capability is improved, but system complexity and cost increase
Solution Approach 1:
Existing L1 satellites are made multi-functional by enabling them to transmit both L1 correction data and L5 synchronization messages. This eliminates the need for separate dedicated L5 satellites, as the same satellite infrastructure supports both frequencies through message multiplexing, thereby reducing the total number of satellites required
Solution Approach 2:
The L1 and L5 satellite services are merged into a unified transmission system where a single L1 station transmits both L1 and L5 messages that are uplinked to the same satellite. This consolidation combines what would traditionally require separate satellite resources into a shared infrastructure, reducing overall system complexity
3Duration of action of stationary object
If L1 and L5 messages are transmitted simultaneously, then service continuity is improved, but synchronization difficulty increases
Solution Approach 1:
A feedback mechanism is implemented where the L5 message includes synchronization timing information derived from the L1 message transmission. The L1 station monitors its own L1 message transmission and uses this timing information to precisely control the L5 message transmission timing, ensuring simultaneous delivery while maintaining simple synchronization through self-referenced feedback
Solution Approach 2:
The synchronization timing for L5 message transmission is predetermined and prepared in advance based on the L1 message schedule. By pre-calculating and pre-positioning the L5 message timing relative to L1 transmissions, the system ensures continuous simultaneous service while avoiding complex real-time synchronization adjustments during operation
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
System and method for transmitting Da information in a dual-frequency satellite navigation system comprising at least one satellite (5), adapted to distribute Da correction data to one or more users, one or more first stations (4) NLES delivering SBAS L1 satellite augmentation services and an auxiliary signal, and one or more second stations (24) NLES delivering SBAS L5 services, wherein: • a first station (4) NLES L1 transmits an SBAS L1 message modulating a UL1 carrier and an auxiliary message E5 modulating a UL5 carrier to a satellite (5), • a second station (24) NLES L5 transmits an SBAS L5 message modulating a UL5 carrier to a satellite (5), • the satellite (5) transmits the L1 and L5 messages to one or more users Ui, • the satellite (5) transmits the SBAS E5 message and the SBAS L5 message to the second station (24) NLES L5,The second NLES L5 station synchronizes in phase and frequency the transmission of the L5 message and its UL5 carrier with the SBAS E5 message and its DL5 carrier so that the L1 and L5 messages are transmitted simultaneously or with a constant bias known to users (Ui) at the SBAS satellite level.