External GNSS Antenna Layout for Underwater Wearable Tracking
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Solution Overview
Problem
Global Navigation Satellite System (GNSS) signals are severely attenuated during water immersion activities, leading to poor reception and inaccurate location tracking in wearable devices, particularly during swimming strokes where the device remains submerged.
Innovation Solution
Positioning the GNSS antenna on the exterior of the wearable device to avoid the water-to-air interface, using exterior portions such as the bezel, crown, or bands to receive signals directly, and incorporating techniques like ephemeris data compression and wireless signal assistance to enhance signal reception and location calculation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the GNSS antenna is positioned inside the wearable device housing, then the device structure is compact and protected, but the GNSS signal reception is severely attenuated during water immersion
Solution Approach 1:
The GNSS antenna is extracted from the interior of the housing and positioned on the exterior surface. This allows the antenna to receive GNSS signals directly without the signal path being blocked or attenuated by the water-to-air interface at the housing boundary, thereby improving signal reception reliability during water immersion activities
Solution Approach 2:
The exterior housing surface acts as an intermediary structure that supports the antenna while maintaining the protective sealing of the device. The antenna is mounted on the outer surface where it can access GNSS signals directly, while the housing continues to provide environmental protection for internal components
2Reliability
If the antenna receives GNSS signals through the air gap within the housing, then the antenna can be protected from water, but the signal-to-noise ratio deteriorates during water immersion
Solution Approach 1:
The antenna is extracted from the protected interior environment and repositioned on the exterior surface of the housing. This extraction eliminates the water-to-air interface from the signal path, allowing GNSS signals to reach the antenna directly through air without passing through water, thereby dramatically improving the signal-to-noise ratio during water immersion
Solution Approach 2:
The housing structure, which originally created a harmful water-to-air interface for signal propagation, is repurposed as a mounting platform for the antenna. By placing the antenna on the exterior surface, the housing boundary that would normally block signals is transformed into a support structure that enables direct signal access while maintaining device protection
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Improves signal-to-noise ratio and maintains accurate location tracking underwater by bypassing the water-to-air boundary, allowing for reliable navigation and activity monitoring during water-based activities.
Implementation Method 1
receiving a plurality of GNSS signals at the exterior portion of the body using an antenna
Data Source
AI summary
A wearable device that can receive a plurality of Global Navigation Satellite System (GNSS) timing signals using an antenna, where the antenna is located in an exterior portion of the wearable device such that the antenna receives GNSS signals at the external portion of the wearable device, without the GNSS signals first passing through an air gap within a housing of the wearable device. The wearable device is configured to determine a geographic location of the wearable device based at least in part on the GNSS signals. The wearable device is configurable to perform underwater dead-reckoning procedures, measuring energy levels during dwell periods, measuring efficiency of swim strokes, sharing wearable device information with other electronic devices, calibrating the wearable device, or a combination thereof.