Added ADS-B-Decoder.md

Added ADS-B-Decoder.md to the advanced projects section.

Projects/3-Advanced/ADS-B-Decoder.md

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+# ADS-B Decoder
+
+**Tier:** 3-Advanced
+
+All modern commercial aircraft transmit Automatic Dependent Surveillance-Broadcast (ADS-B) messages multiple times a second for the duration. These messages contain multiple different types of messages along with data about the flight and the current conditions of the flight.
+This project idea is to build a "simple" decoder to find out what each message contains and data from some of the messages! This is an advanced project, even when building a simple decoder due to how complex the ADS-B system is. You can take this project a lot further to put your skills to the test! Resources for learning more about ADS-B or ADS-B Datasets can be found in the useful links and resources section.
+
+## User Stories
+
+-   [ ] Convert the original message from hexadecimal to a more useful binary format
+-   [ ] Filter out any message that is not 112 bits long
+-   [ ] Split the message into 5 sections corresponding to the sections of an ADS-B message as follows:
+        Downlink Format (DF)
+        Transponder Capability (CA)
+        ICAO Aircraft Address (ICAO)
+        Data Payload
+        Parity 
+-   [ ] Determine the type of each message
+-   [ ] Determine the call sign of the aircraft
+
+## Bonus features
+
+-   [ ] Determine the altitude and/or speed of the aircraft
+-   [ ] Sort the messages by aircraft
+-   [ ] Determine the current status of the aircraft
+-   [ ] Check for errors in the message using the parity section of the message
+
+## Useful links and resources
+
+-   [1090MHz Riddle - A Guide for Decoding ADS-B Signals](https://mode-s.org/decode/)
+-   [Sample Data](https://www.adsbexchange.com/data-samples/)
+
+## Example projects
+
+-   [Python ADS-B Decoder](https://github.com/junzis/pyModeS)