Evaluating Smartphone GNSS Accuracy for Geofenced 6 GHz Operations

TL;DR

This study empirically evaluates GNSS accuracy in various real-world environments to ensure reliable geofencing compliance for 6 GHz spectrum operations, highlighting environmental impacts on localization precision.

Contribution

First comprehensive empirical analysis of GNSS reliability for GVP compliance, assessing environmental, device, and constellation factors affecting accuracy.

Findings

Indoor and urban environments significantly degrade GNSS accuracy.

Device hardware influences positional error, but environment is the main factor.

Non-U.S. GNSS constellations are used but not permitted for regulatory geolocation.

Abstract

The recently deployed 6 GHz spectrum in the U.S. utilizes distinct power categories, with the latest proposed "Geofenced Variable Power" (GVP) category permitting indoor and outdoor operations without continuous Automated Frequency Coordination (AFC) by relying instead on local databases of exclusion zones. Consequently, the safe operation of GVP devices depends entirely on reliable GNSS localization to respect these geofences. However, GNSS accuracy is highly variable and significantly degrades in environments like urban canyons or indoors. This paper presents the first comprehensive empirical study evaluating GNSS reliability specifically for GVP compliance. Utilizing the SigCap Android application, we document and compare GNSS accuracy across an extensive array of real-world conditions, encompassing urban versus suburban landscapes, varying mobility states (stationary, walking, driving), and indoor versus outdoor settings. The results demonstrate that while device hardware causes variations in GNSS accuracy, the operational environment is the primary driver of error. Indoor settings and dense urban areas consistently degrade localization. Moreover, outdoor positions adjacent to buildings often surprisingly produce significant inaccuracies, even near low-elevation structures. We further analyze the contribution of different GNSS constellations to device positioning and show that satellites from non-U.S.-licensed constellations-although currently used in a substantial portion of location fixes-are not permitted for regulatory geolocation under FCC requirements.