GNSS Aiding Module for Faster First Fix in Weak Signals
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Solution Overview
Problem
Existing GNSS receivers in mobile computing devices face challenges in acquiring a location quickly and efficiently, particularly in environments with limited line-of-sight to satellites, leading to prolonged time to first fix (TTFF) and suboptimal battery consumption.
Innovation Solution
Incorporating a GNSS aiding module that processes satellite data to generate aiding data, including code phase, frequency, and time estimates, which is used by the GNSS processor to improve acquisition performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If A-GPS assistance data is used to improve GNSS acquisition, then the time to first fix is reduced in open environments, but the acquisition fails or takes excessively long in difficult environments such as indoors or dense urban canyons
Solution Approach 1:
The system performs preliminary processing of satellite signals to extract aiding data (code phase, frequency, time estimates) before the main GNSS acquisition attempt. This preliminary action creates a head start for the acquisition process, enabling faster convergence even in challenging environments where traditional A-GPS fails.
Solution Approach 2:
The patent introduces an intermediary aiding data processing step between signal reception and final acquisition. This intermediary layer extracts and provides critical parameters (code phase, frequency, time) that bridge the gap between raw signals and successful acquisition, particularly in difficult environments where direct acquisition would otherwise fail.
2Device complexity
If the GNSS processor processes satellite data directly without aiding data, then the device complexity is lower, but the time to first fix is significantly longer and battery consumption is suboptimal
Solution Approach 1:
The system extracts only the essential aiding data parameters (code phase, frequency, time estimates) from the full satellite signal, rather than processing all signal components. This extraction approach provides the necessary acceleration for acquisition while keeping the processing complexity manageable and avoiding the need for overly complex processing systems.
3Productivity
If A-GPS assistance data with 100m location accuracy is used, then initial acquisition is faster, but signal strength sensitivity is reduced in challenging environments
Solution Approach 1:
The system changes the parameters used for acquisition by incorporating precisely estimated code phase, frequency, and time values derived from signal processing. These parameter adjustments enable the receiver to adapt to varying signal conditions and maintain sensitivity even when using assistance data, effectively resolving the trade-off between speed and precision.
Data Source
AI summary
An example method includes obtaining, by a global navigation satellite system (GNSS) processor of a mobile computing device and based on signals received from GNSS satellites, a stream of I/Q samples; providing, by the GNSS processor and for another processor, the stream of I/Q samples; receiving, by the GNSS processor and from the other processor, aiding data that is determined based on the stream of I/Q samples, wherein the aiding data, that includes: a code phase, a frequency, and a time for a GNSS satellite of the GNSS satellites; and processing, by the GNSS processor and based on the aiding data, the stream of I/Q samples to determine a first fix for the mobile computing device.