Implementation of an ADS-B/Mode-S Receiver in GNU Radio

Application Note Number

AN-363

Revision History

Date	Author	Details
2016-05-01	Nate Temple	Initial creation

Abstract

This AN guides the reader through the implementation of an ADS-B/Mode-S receiver using the gr-air-modes Out-of-Tree (OOT) module for GNU Radio. An explanation of ADS-B is also provided, and several real-world, over-the-air examples and profiled.

Overview

The Ettus Research™ USRP™ (Universal Software Radio Peripheral) is used for a number of military and aerospace applications. In this example, the USRP N210 and WBX daughterboard is used to receive and decode ADS-B and Mode-S beacons from real-world aircraft. While a USRP N210/WBX is used for this demonstration, a B200/B210/B200mini/B205mini/E310/E312 or X300/X310 with an appropriate daughter board will also work. The information from these beacons is displayed on a Google Earth map. This demonstration shows the flexibility offered by GNU Radio, an open source package and it's strong user-base.

The GNU Radio Out-Of-Tree module (OOT) gr-air-modes will be use to receive ADS-B/Mode-S with the USRP.

Introduction

Automatic Dependent Surveillance – Broadcast (ADS–B) is a surveillance technology in which an aircraft determines its position via satellite navigation and periodically broadcasts it, enabling it to be tracked. The information can be received by air traffic control ground stations as a replacement for secondary radar. It can also be received by other aircraft to provide situational awareness and allow self separation.

ADS–B is "automatic" in that it requires no pilot or external input. It is "dependent" in that it depends on data from the aircraft's navigation system.

Requirements

• Python >= 2.5
• PyZMQ
• NumPy and SciPy
• SQLite 3.7 or later
• CMake 2.6 or later
• Gnuradio >= 3.5.0
• Ettus UHD >= 3.4.0

Installation

You will need to have a working installation of GNU Radio and UHD to proceed with this Application Note. If you do not yet have GNU Radio and UHD installed, please reference the Building and Installing the USRP Open-Source Toolchain (UHD and GNU Radio) on Linux, OS X or Windows Application Notes.

The instructions below will install the required dependencies, build and then install the Out-Of-Tree module gr-air-modes.

   $ sudo apt-get install sqlite3 libsqlite3-dev python-zmq python-numpy python-scipy
   $ git clone https://github.com/bistromath/gr-air-modes.git
   $ cd gr-air-modes/
   $ mkdir build
   $ cd build
   $ cmake ../
   $ make
   $ sudo make install
   $ sudo ldconfig

Usage

After successfully building and installing the gr-air-modes OOT, you will have two applications to receive Mode-S.

• modes_rx
  • Command line based, textual output of data received

• modes_gui
  • GUI based interface with Google Maps integration

Additional Resources

For additional information on gr-air-modes please see the gr-air-modes Github Repository.