README ADS-B GHOST

The current air traffic infrastructure operate through primary and secondary radar systems. Among the secondary, one of the most used technologies in civil aviation worldwide is automatic dependent surveillance — broadcast (ADS–B). This system is capable of sending information about the aircraft through its broadcasting. In this repository, ADS–B receiver and transmitter were developed using software-defined radio techniques (SDR), using tools such as GNU Radio, as well as specific peripherals for SDR applications. An ADS–B transmitter was developed on the GNU Radio platform, with external code support in Python. The module was tested using an SDR peripheral called HackRF, an RTL-SDR dongle, and an open source tool called dump1090. In addition, an ADS–B receiver was also developed in GNU Radio, tested through integration with the developed transmitter.

This repository has:

• ADS-B encoder
• ADS-B decoder (imported from Mode-S)
• ADS-B ghost
• CRC calculator
• Ghost aircraft
• Util package with common functions

ADS-B TX (FLYDUTCH)

• This subsystem starts with the “ADS-B encoder” block that is of the source type, therefore, it has no inputs, but outputs a continuous flow of 1 byte (8 bits). ADS-B data is transmitted, created in this block and transmitted in 8-bit pieces. The “Repack bits” and “PPM mapper” blocks, together, take each bit received and modulated in PPM. After this process, the modulated data is sent to the “Stream Mux” block. This block is responsible for creating the framework ADS-B, joining the preamble, the modulated bits and a period of silence. Them, this packet is sended to “Interpolation FIR Filter” block that performs an oversampling, formatting the entry with rectangular pulse. After that, the data is prepared to be sent to HackRF, and then transmitted: initially data are transformed into complex values, then the signal is sent to HackRF from the “osmocom Sink” block.

Requirements

1. python >= 2.7
2. GNU Radio

Running project

In order to test, there is some options:

Tx and Rx together

1. To test the entire system in simulation environment, you can set tx grc and rx grc in the same project and connect the blocks.
2. It's possible to use a HackRF + TX to run transmissor in a host and RTLSDR dongle + RX in another hostname. This well you can see real data with noise.

Tx

1. Use tx project in simulation environment and set a sink block in the end of the system. This way you can see transmited data
2. Use tx project with HackRF to send real data and in another host, use RTL SDR dongle and run dump1090.

RX

1. Use tx project in simulation environment and set a source block in the end of the system. This way you can see how data is processed.
2. Use rx project with RTL SDR and wait real airplanes send ADS-B packets.