The Inspector (gr-inspector)

 ## Intorduction This GNU Radio module is developed to realize signal analysis abilities in typical block-structure. The module is capable of the following:

• Energy detection of signals
• Filtering of detected signals
• OFDM parameter estimation (carrier spacing, symbol time)

Installation

To install the Inspector, the following dependencies are required:

• GNU Radio core
• gr-filter
• QT4
• QWT 6.1.0

Install by the following shell commands:

mkdir build
cd build
cmake ..
make -j4
sudo make install

This module is still under development. Please let me know if you run into any issues on the master branch.

Usage

Get inspired by the examples. There are flowgraphs for each block that should explain how to use them.

Blocks

Signal Detector

Performs an energy detection on the input signal. A threshold in dB can be set or an autmatic threshold calculation can be used.

Inspector GUI

GUI where the spectrum is displayed along with signal markers for the detected signals. Also, signal can be selected manually in this block.

Signal Separator

Takes the signal info from the previous blocks and performs a down-mixing, filtering and decimation of each detected signal. The samples for each signal are passed on as a message.

Signal Extractor

Adapter block to extract the samples of one signal out of the messages from the Signal Separator. Output is again a complex stream.

OFDM Estimator

Estimates the parameters subcarrier spacing, symbol time, FFT size and cyclic prefix length for a input signal. The signal should not be oversampled for this block.

Google Summer of Code

This GNU Radio module is part of the Google Summer of Code (GSoC) program 2016. The target is to develop a signal analysis / signal intelligence toolbox with the following capabilities:

• Automatic signal detection
• Automatic modulation classification
• OFDM parameter estimation and synchronization
• GUI feedback
• Doxygen documentation

Read the full proposal here.

The modulation classification is developed by @chrisruk during ESA Summer of Code in Space program.

Contact

Maintainer of this module:

Sebastian Müller
gsenpo[at]gmail.com

If you want to know more about the development process, please visit the blog.

If you have any questions or problems, the GNU Radio mailing list is the right place to get help. There are many people who will provide assistance.