Dual GNSS Receiver Cold Start With Fast-to-Accurate Positioning
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Solution Overview
Problem
There is a trade-off in existing GNSS receiver technologies between the speed of cold start and the accuracy of location determination for stationary nodes, with potential random noise affecting the precision of the location determination during startup.
Innovation Solution
Implementing multiple GNSS receivers with different startup durations, where a first receiver performs a fast-start sequence followed by a second receiver's longer slow-start sequence, and optionally restarting the second receiver to refine the location determination, using statistical analysis to combine multiple location assessments for improved accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the GNSS receiver performs a longer startup sequence, then the location determination accuracy is improved, but the cold start speed deteriorates
Solution Approach 1:
The system divides the location determination process into two segments: a fast startup sequence that provides initial location data quickly, and a longer refinement sequence that improves accuracy. The first receiver performs the fast startup while the second receiver performs the longer sequence, segmenting the overall process to achieve both speed and accuracy.
Solution Approach 2:
The first GNSS receiver performs a preliminary location determination during the fast startup sequence before the second receiver completes its longer startup sequence. This preliminary location data is used immediately to establish time/frequency reference, and then refined later when the second receiver completes its more accurate determination.
2Measurement precision
If the GNSS receiver performs a longer startup sequence, then the random noise in location determination is reduced, but the productivity deteriorates
Solution Approach 1:
The system segments the location determination task between two receivers: the first receiver provides quick initial determination with acceptable precision, while the second receiver performs a longer sequence to reduce random noise and refine the location data. This segmentation maintains productivity while reducing noise.
Solution Approach 2:
The system uses feedback from both receivers to continuously refine the location determination. The first receiver's fast determination provides initial feedback, and the second receiver's refined determination provides corrective feedback that reduces random noise and improves overall precision without sacrificing productivity.
Data Source
AI summary
A stationary node (e.g., telecom router/switch) having at least two GNSS receivers. When the node is powered on, both GNSS receivers perform a startup sequence with the duration of the startup sequence for the second receiver being longer than that for the first receiver. When the first receiver finishes its startup sequence, a “fast-start” location is determined, and the first receiver switches to the normal operating mode using that fast-start location. When the second receiver finishes its longer startup sequence, a “slow-start” location is determined. Because its startup sequence duration is longer, the slow-start location should be more accurate than the fast-start location. As such, the first receiver transitions from operating in the normal mode using the fast-start location to operating in the normal mode using the slow-start location, thereby achieving both fast startup and accurate location determination.