Directional Antenna Sequential Scanning for Weak GPS Signal Acquisition
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Solution Overview
Problem
GPS receivers face difficulties in acquiring signals in indoor environments due to signal attenuation and interference from background noise, leading to limited ability to determine location accurately, often requiring fallback to secondary location methods.
Innovation Solution
Employing a high-gain directional antenna that sequentially scans multiple directions to acquire weak GPS signals from multiple satellites, using code phases to compute location even without decodable positioning data, and reorienting the antenna until a sufficient number of satellites are acquired.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a GPS receiver amplifies weak GPS signals, then the ability to detect GPS signals is improved, but the background radio frequency noise is also amplified
Solution Approach 1:
The patent employs a directional antenna with high gain in specific directions to selectively amplify GPS signals from certain spatial locations while rejecting noise from other directions. This spatial selectivity allows the system to improve signal detection without proportionally amplifying background noise across all directions.
Solution Approach 2:
The patent divides the signal processing into multiple time intervals and uses sequential scanning across different directions. By segmenting the acquisition process temporally and spatially, the system can integrate weak signals over multiple intervals while maintaining noise rejection through directional selectivity at each interval.
2Adaptability or versatility
If a conventional GPS receiver uses omni-directional antenna, then it can receive signals from all directions, but the gain for weak signal acquisition is insufficient
Solution Approach 1:
The patent implements a dynamic scanning approach where the directional antenna sequentially steers to different directions over multiple time intervals. This dynamic operation allows the system to maintain high gain in the current scanning direction while eventually covering all possible satellite directions, combining the benefits of directional gain and omnidirectional coverage.
Solution Approach 2:
The patent uses periodic scanning across multiple directions in sequential time intervals. By periodically rotating through different directional beams and integrating results over multiple periods, the system achieves both high signal-to-noise ratio during each scanning period and comprehensive coverage across all directions over the complete scanning cycle.
3Measurement precision
If GPS signals are attenuated by building structures, then the location determination accuracy is improved in line-of-sight conditions, but the ability to acquire signals indoors is reduced
Solution Approach 1:
The patent performs preliminary signal acquisition attempts using high-gain directional scanning before falling back to secondary location methods. By exhaustively searching multiple directions over multiple time intervals with enhanced gain, the system maximizes the chance of acquiring sufficient GPS signals indoors before resorting to alternative location techniques.
Solution Approach 2:
The patent changes the antenna radiation pattern parameters by steering the beam in different directions and adjusting the scanning sequence. This parameter modification allows the system to adapt to indoor environments where satellites may be visible from specific directions, maintaining location determination capability despite signal attenuation from building structures.
Data Source
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AI summary
The effective use of weak GPS signals that are present in various environments enables an electronic device to pinpoint its location in such environments. The electronic device uses an antenna to perform sequential scanning in multiple directions for global positioning system (GPS) signals. The electronic device further analyzes GPS signals obtained from scanning the multiple directions to determine a number of acquired GPS satellites that provided the GPS signals. The GPS signals include code phases of the acquired GPS satellites. The electronic device then computes a location of the electronic device based on the code phases of the acquired GPS satellites when the number of acquired GPS satellites meets a threshold.