DOI: 10.5061/dryad.7h44j105p
title: AERPAW Air-to-ground channel sounding and multipath measurement with a UAV

description: Uncrewed aerial vehicles (UAVs) have emerged as critical for various use
 cases, both military and civilian. This paradigm shift is poised to
 revolutionize various industries and aspects of modern life, from
 logistics and emergency services to environmental monitoring and
 entertainment. However, the safety of these UAVs hinges on the
 availability of a reliable wireless link between the UAV and the ground
 infrastructure for real-time communication. To effectively harness the
 vast potential of UAVs with safe and reliable wireless link, it is
 essential to model the complex air-to-ground (A2G) channel accurately. In
 this work, we present an open-source channel sounder built with
 software-defined radios (SDRs), which enables real-time measurement and
 characterization of the A2G channel in scenarios with mobility. Our
 measurement campaign conducted in a rural area provides valuable insights
 into the A2G channel’s characteristics, multipath effects, and channel
 impairments. This work provides a foundation for the development of
 accurate A2G channel models that can be used to optimize the design and
 performance of UAV communication systems.
description: # AERPAW Air-to-ground channel sounding measurement on CBRS band with UAV
 This data is acquired at the AERPAW Lake Wheeler Testbed site with USRP
 B210s using the developed open-source channel sounder referenced at the
 bottom. Both ends were synchronized with an external clock and PPS. ##
 Contents The `A2G_Channel_Measurements.zip` contains timestamped folders
 with channel sounder measurement data. Each folder corresponds to a
 specific measurement instance. ### Directory Structure | Folder Name |
 Size | | ------------------ | -------- | | 2023-12-15\_15\_41 | 42.9 MiB |
 | 2023-12-15\_15\_51 | 31.3 MiB | | 2023-12-15\_15\_58 | 43.6 MiB | |
 2023-12-15\_16\_14 | 28.0 MiB | | 2023-12-15\_16\_19 | 29.9 MiB | |
 2023-12-15\_16\_36 | 33.8 MiB | | 2023-12-15\_16\_42 | 27.1 MiB | |
 2023-12-15\_16\_47 | 30.8 MiB | | 2023-12-15\_16\_53 | 42.1 MiB | ###
 Dataset Files Each measurement consists of two types of files: 1.
 **`.sigmf-data` files** – These contain raw signal data. 2.
 **`.sigmf-meta` files** – These contain metadata describing the signal
 data, such as sampling rate, frequency, timestamp, and other relevant
 parameters. More details are provided below. ### File Naming Convention
 `Channel_Sounder_.*` Where ``
 represents the time the measurement was taken. ### **Metadata
 (`.sigmf-meta`)** The metadata file follows the **SIGMF standard**,
 containing: #### **Global Metadata Fields** *
 `"core:sample_rate"` – Sampling rate of the recorded signal. *
 `"core:waveform"` – Type of waveform used in transmission.`ZC`
 for Zadoff-Chu sequence,`PN` for Pseudo-Noise sequence. *
 `"core:tx_gain_ref"`, `"core:rx_gain_ref"` –
 Transmission and reception gain levels in dBm. *
 `"core:zc_root_index"`, `"core:zc_len"` – Zadoff-Chu
 sequence parameters used in the transmitted waveform. #### **Capture
 Fields** Each capture contains: * **Timestamp**: Unix timestamp of the
 measurement. * **Location (`core:tx_location` & `core:rx_location`)**:
 * Latitude, longitude, and altitude. * **Rotation (`core:rotation`)**: *
 Pitch, yaw, and roll values of the UAV during flight. * **Velocity
 (`core:velocity`)**: * Components along X, Y, and Z axes recorded during
 flight. * **Flight information**: * `"core:flight_stage"` –
 Flight stages; Takeoff, Flight, and Landing * `"core:speed"`,
 `"core:dist"` – Speed and distance respective to the
 transmitter. ### Data Files Data files can be opened with the SigMF
 library or numpy. First, install the following dependencies, ```bash $ pip
 install sigmf numpy ``` Then the signal data can be loaded as follows,
 ```python import numpy as np from sigmf import SigMFFile, sigmffile signal
 = sigmffile.fromfile(filename) samples = signal.read_samples() ## or
 samples = np.fromfile(filename) ``` ## Code/Software More information can
 be found at `doi:10.1109/VTC2024-Fall63153.2024.10757825`. The source code
 and post-processing are available at this [Github
 repository](https://github.com/anilgurses/USRP-Channel-Sounder).