GNSS Scan (L4)

Introduction

GNSS scan location has the device capture satellite data and uplink it for cloud-side coordinate resolution. It is a higher-effort mechanism than WiFi scanning, trading more power and acquisition time for coverage where WiFi is unavailable.

How the Cloud Resolves the Fix

The scanned GNSS data is resolved through the AWS IoT Wireless position-estimate service, the same cloud path used for the WiFi scan (L3). As with WiFi, a scan that cannot be resolved produces no location.

GNSS scan (L4) is distinct from GPS-assist (L6): L4 uplinks a scan for Amazon Sidewalk to resolve on its own, whereas L6 is an assisted exchange in which Amazon Sidewalk sends aiding first and the device then produces pseudoranges.

Accuracy and Constraints

• Requires a GNSS-capable device.
• Higher power and longer acquisition time than WiFi scanning.
• Accuracy depends on the number and geometry of satellites the device captured and sky visibility at the time of the scan.

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