Virtual Reference Receiver Switching for GNSS Positioning
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Solution Overview
Problem
Current navigation systems, particularly those using Global Navigation Satellite Systems (GNSS), face challenges in efficiently changing virtual reference receivers (VRRs) associated with targets, especially in mobile scenarios where the distance between the VRR and the target increases, or the line of sight deteriorates, requiring frequent VRR changes to maintain accurate positioning.
Innovation Solution
The system allows for efficient VRR changes by sending a request message for a new VRR, receiving periodic positioning assistance data, and transitioning from the old to the new VRR, with options for launching new transactions or modifying existing ones, enabling continuous reference measurement assistance during the switch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If VRR changes are performed frequently to maintain positioning accuracy in mobile scenarios, then positioning accuracy is improved, but system complexity and data flow management become more difficult
Solution Approach 1:
The system performs preliminary actions by requesting and receiving assistance data for the new VRR before actually switching. The target device requests assistance data for the new VRR in advance, and the server provides the necessary data (ephemeris, clock parameters, etc.) before the switch occurs. This ensures that when the VRR change is executed, all necessary data is already prepared and available, preventing positioning interruptions and reducing the complexity of handling incomplete data transitions.
Solution Approach 2:
The patent ensures continuity of useful action by maintaining the ability to receive assistance data from both the old and new VRRs during the transition period. The target device can continue receiving assistance data for the old VRR while simultaneously receiving data for the new VRR, ensuring uninterrupted positioning capability. This overlapping data reception period smooths the transition and avoids positioning gaps, effectively managing the complexity of frequent VRR changes.
2Reliability
If continuous periodic assistance data is requested for VRR changes, then positioning reliability is improved, but data transmission time and bandwidth consumption increase
Solution Approach 1:
The server performs preliminary action by providing all necessary assistance data for the new VRR in advance, before the target device needs to switch. This includes pre-loading ephemeris data, clock parameters, and other necessary information. By preparing this data beforehand, the actual switch time is minimized, and the target device can quickly transition without needing to request and receive data in real-time during the switch moment, thus reducing transmission time while maintaining reliability.
Solution Approach 2:
The system dynamically adjusts the data request and provision mechanism based on the VRR change scenario. Instead of a rigid continuous data stream, the system dynamically requests assistance data only when needed for VRR changes, and the server dynamically provides the necessary data packets. This dynamic approach optimizes the balance between reliability (ensuring data is available when needed) and time consumption (avoiding unnecessary continuous transmission).
3Adaptability or versatility
If VRR switching is implemented to handle mobile scenarios, then adaptability is improved, but measurement continuity and baseline integrity become more difficult to maintain
Solution Approach 1:
The patent applies preliminary action by requesting and receiving assistance data for the new VRR before executing the switch. This ensures that all necessary positioning parameters (ephemeris, clock data, reference measurements) are already prepared and valid for the new VRR. By preparing this data in advance, the system can execute smooth VRR transitions without disrupting the baseline integrity, as the new VRR's measurement data is already validated and ready to take over seamlessly from the old VRR.
Solution Approach 2:
The system maintains continuity of useful action by allowing the target device to receive and process assistance data from both the old and new VRRs during the transition period. This overlapping period ensures that measurement continuity is maintained, as the device can continuously receive reference measurements from both sources. The baseline integrity is preserved because the system can use the known relationship between old and new VRRs (through their spatial relationship and shared reference frame) to maintain measurement consistency during the switch, avoiding baseline discontinuities that would occur with abrupt switches.
Data Source
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AI summary
An apparatus and method are provided for handling a periodic assistance session flow. Each periodic assistance data provision includes a session identification so that interlinked messages within the periodic assistance data delivery can be linked in the receiving end. Any modifications to the session are handled via the periodic session identification so that the changes to the assistance data delivery can be pointed to the right session.