QoS Evaluation of UAS Real Communications and Analysis of Bottlenecks

Abstract

Open unmanned aerial systems built from commodity components offer no native quality-of-service guarantees for MAVLink. We present a hardware-anchored, dual-layer experimental evaluation using a Cube Orange+ autopilot, a Raspberry Pi 4 companion computer running ROS 2/MAVROS, and a QGroundControl station. Network-layer metrics (latency, jitter, multi-threshold packet loss, throughput) are coupled with application-layer indicators (telemetry continuity, MAVLink mission-transfer success, video integrity) across three stages: (i) controlled tc/netem emulation, (ii) a real MPU5 Wave Relay® tactical radio link tested outdoors at two sites, and (iii) a stepwise ROS 2 stress test with a parallel 1 GB SCP network probe. At 18.2 dBm/chain, the radio maintains a viable real-time link to ~140 m. Contrary to the usual focus on the radio channel, the companion computer—not the link—is the operational bottleneck: the Raspberry Pi saturates at an emergent ~80% CPU ceiling, disrupting video first, then MAVLink mission transfers, while basic telemetry remains uninterrupted.