External GNSS Antenna Layout for Underwater Wearable Tracking
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Solution Overview
Problem
Global Navigation Satellite System (GNSS) signals do not penetrate water well, causing difficulties for electronic devices to receive navigation signals during in-water activities, especially during strokes like breaststroke where the device is submerged for extended periods, leading to inaccurate location tracking.
Innovation Solution
A wearable device with a GNSS antenna positioned externally, such as in the bezel, crown, or band, to receive signals without passing through an air gap within the housing, combined with a processing circuit to calculate and store geographic locations, provide feedback, and send data via wireless links.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the antenna is placed inside the housing with an air gap, then the device structure is compact and protected, but GNSS signal reception is 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 passing through the housing material or air gap, eliminating the signal attenuation problem while the housing remains hermetically sealed for protection.
Solution Approach 2:
The exterior positioning of the antenna creates an intermediary arrangement where the antenna surface becomes the direct interface with GNSS signals. By placing the antenna on the outer surface of the housing, the signal path is simplified and attenuation through multiple interfaces (housing material, air gap, water) is avoided.
2Measurement precision
If the antenna faces outward to receive signals without passing through air gap, then signal reception is improved, but the antenna placement becomes more complex
Solution Approach 1:
The exterior surface of the housing serves multiple functions: it provides structural protection, maintains hermetic sealing, and simultaneously serves as the mounting surface for the GNSS antenna. This multi-functional use of the housing exterior simplifies the overall design by eliminating the need for separate antenna mounting structures.
Solution Approach 2:
The antenna integration is merged with the housing structure itself. Rather than being a separate component requiring additional mounting complexity, the antenna is positioned to utilize the housing exterior as its support structure, combining the housing's protective function with the antenna's signal reception function.
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.