The 1090 Megahertz Riddle - Mode-S

1 The 1090 Megahertz RiddleA Guide to Decoding Mode S and ADS-B SignalsJunzi SUNF aculty of Aerospace EngineeringDelft University of TechnologyTitle: The 1090 Megahertz RiddleSubtitle: A Guide to Decoding Mode S and ADS-B SignalsAuthor: Junzi SunEdition: 2 Keywords: Aircraft surveillance, ADS-B, Decoding, Mode S, Open data, : TU Delft OPEN PublishingCover design: Junzi SunISBN: 978-94-6366-402-8 Copyright 2021 by Junzi SunPublished under CC BY-NC-SA versions of this book are available at: book is dedicated to my sons: William and VincentContentsI Getting Started111 Background: The death ray that saves lives.

2 The primary radar .. The secondary radar .. Mode S .. ADS-B .. Other Mode S services .. Summary ..212 Quick Start: Hardware and Software to Receive Mode S Range .. Antenna .. Receiver .. Software tools ..27II Decoding ADS-B333 ADS-B Message structure .. Capability .. ICAO address .. ADS-B message types .. Example of ADS-B message structure .. Availability and transmission rate .. ADS-B versions ..384 Aircraft identification and Identification (call sign).

3 Wake vortex category .. Decoding example ..425 Airborne An over-simplified example .. Compact position reporting .. Globally unambiguous position decoding .. Locally unambiguous position decoding .. Altitude decoding .. Verification of decoded positions ..596 Surface Movement .. Ground track .. Position .. Decoding example ..637 Airborne Vertical rate .. GNSS and barometric altitudes difference .. Sub-type 1 and 2: Ground speed decoding .. Sub-type 3 and 4: Airspeed decoding.

4 748 Aircraft operation Version 0 .. Version 1 .. Version 2 ..789 Uncertainties in Terminology .. Version 0 .. Version 1 .. Version 2 ..8710 Error control in CRC error control .. ADS-B parity ..90 III Decoding Mode S9311 Basics of Mode S Mode S message structures .. Parity .. ICAO address recovery .. Two s complement coding ..9812 All-call reply10113 Surveillance Message structure .. Altitude code .. Identity code .. 10514 Airborne collision avoidance Background.

5 ACAS with Mode C transponders .. ACAS with Mode S transponders .. ACAS coordination interrogation .. ACAS coordination reply .. 11415 Structure .. BDS .. 11616 Mode S elementary Data link capability report (BDS 1,0) .. Common usage GICB capability report (BDS 1,7) .. Aircraft identification (BDS 2,0) .. ACAS active resolution advisory (BDS 3,0) .. 12317 Mode S enhanced Selected vertical intention (BDS 4,0) .. Track and turn report (BDS 5,0) .. Heading and speed report (BDS 6,0).

6 13218 Mode S meteorological Meteorological routine air report (BDS 4,4) .. Meteorological hazard report (BDS 4,5) .. 13819 Inferencing of BDS BDS codes identification logics .. Identification of BSD 5,0 and 6,0 .. Decoding examples .. 143IV Conclusions14520 Summary and Summary .. Crowd-sourced networks .. Additional data .. Congestion .. The Future of Mode S and ADS-B .. 150 References153 PrefaceThis book provides researchers, engineers, and students a practical guide to de-coding ADS-B and other types of common Mode S messages.

7 It consolidates theinformation from various ICAO documentation and other literature to provide read-ers easy access to key knowledge of Mode S and ADS-B and related topics. The bookextensively uses examples and sample Python code to explain the decoding in 2015, I joined TU Delft to undertake PhD research on analyzing and mod-eling aircraft performance using open aircraft surveillance data. ADS-B data servedas my primary data source. Frustrated with the lack of open literature on ADS-Band Mode S, I created a live online project to document my experience in decodingADS-B data, entitled theADS-B Decoding Guide.

8 As the guide grew in popularity, Istarted receiving questions, feedback, and suggestions from the research communityall over the world. This input greatly helped me to fix and improve the content ofthe decoding then, I also started to incorporate Mode S Enhanced Surveillance data into myresearch, which required me to further develop tools for inferring and decoding newtypes of messages. At the same time, I created more content for the online to the increasing interest expressed and demand from readers, I started writinga more comprehensive book focused on the decoding practice of the data, whichwas the starting point for this book ,the 1090 Megahertz these years of work with ADS-B and Mode S data, I created a Python de-coding library,pyModeS, which welcomed contributions from GitHub users from allover the world.

9 In this book , some decoding examples are shown , knowledge of Python is not required to understand the topics covered inthis 2019, I completed my PhD and continued as a faculty member in the aerospaceengineering faculty of TU Delft. By then, I had time to reflect on aircraft surveillancedata from a new perspective and decided to make a major update of the book result is this text, which is both the second edition ofthe 1090 Megahertz Riddleand one of the first books from TU Delft s OPEN publishing initiative. It is publishedas an open access book , under the CC-BY-NC-SA license.

10 The LATEX source of thebook is also shared on GitHub, where future comments and pull requests are SunDelft, the NetherlandsApril, 20219 Part IGetting Started111 | Background: The death ray that saves livesLike many modern technologies such as computers, the internet, and GPS whoseorigins can be traced back to the military, aviation radar is no fundamental theory of radar started in late 19th century. Since the 1860s, whenthe electromagnetic theory was discovered by James Clerk Maxwell, the foundationfor many science and technology fields was laid out.