Implemented radar types with example flowgraph:
CW (tested on hardware and simulation)
FSK (tested on hardware and simulation)
Dual CW (tested on hardware and simulation)
FMCW (only simulation)
OFDM (only simulation)

Output methods:
Command line output with inbuild file sink
Time plot (plots time progression of target property)
Scatter plot (combines two target properties, e. g. range/velocity plots)
Spectrogram plot (plots 2D spectra, e. g. OFDM matrices)

Peak detection algorithms:
Max power detection (single peak detection)
OS-CFAR (multi peak detection)
OS-CFAR 2D (multi peak detection, e. g. for OFDM matrices)

Hardware interface and simulator:
Echotimer (UHD interface) for two or one USRP (multi USRP support is in work)
Sync setup for measuring hardware delay
Simulator with multi target capability and range, velocity, rcs and azimuth as target property

Processing blocks:
Crop matrix
Transpose matrix
OFDM cyclic prefix remover
OFDM matrix devision with zeropadding and discarding carriers
Split packages for FMCW and FSK
FFT for tagged streams
Message manipulator and gate for target property messages

Additional blocks:
Single target tracking
RCS estimation
Trigger for command line statements

GRCon14 Poster

GRCon14 Presentation

Dual CW Radar Stats:
Center frequency:       2.4 GHz
Sample rate:                14.25 MHz
Detection time:          150 ms
Velocity resolution:   0.4 m/s
Range resolution:       0.3 m (approx.)
Unambiguous range:  12.5 m

The signal processing is shown at the GNU Radio Companion flowgraph below.

Check out the demonstration video with the hardware setup, additional information and screen capturing of GUI output!

This block can be inserted after any estimator block with range and velocity measurement. Look at the GNU Radio Companion flowgraph below with GUI blocks before and after tracking.

Check out full video example of target trajectory and screen capturing of GUI output for more information.

At the moment there are two kind of GUIs. First a scatter plot of two target attributes, e. g. range and velocity. This GUI is nice to show the state of your target in real time in a single plot. Second there are time/attribute plots available which show a single attribute of your target in a given time range. All GUIs are real time and multi target capable for any given attributes of your targets.

Also check out the demonstration video! There is shown a real time detection with video of the target trajectory and a screen capture of the GUI response.

The main problem is the low doppler frequency of about 15Hz per 1m/s of the target in combination with the high sample rate of 5MHz due to the needed bandwith for a proper maximum range. Higher center frequencies solve this problem. Therefore I am heading for a radar setup in the 5.9 GHz band. That should provide a nice performance boost!

Also check out the video example to get a clue how it works! It shows a low range person detection with the above described setup. Realtime estimation is inbuild but a nice GUI is not finished yet. A simple console output is implemented.

The workflow for a synced radar setup: First connect all hardware and then send a pulsed signal which should be reflected by a near target, e.g. a wall. A signal generator for sync pulses is in the toolbox included. The estimator cross-correlates these two signals and searchs for the best match in regard to a specific signal shift. This number of shifted samples is given in a console output by the print results block or via the inbuild QT scope GUI.

This constant shift has to be evaluated only once for a specific hardware setup! The number of delayed samples is constant for all time and therefore this calibration setup is all you need for synchronized TX/RX streams from two USRPs. Check out following video for comparison of the inbuild USRP sink/source to the gr-radar echotimer!

At the bottom you can get an impression of my work. I’ll present you there a working setup of a FSK radar simulation in GNU Radio Companion. At the moment there is only a simple console output of the estimation but user interface is coming soon!

FSK flowgraph in GNU Radio Companion

Spectrum of FSK radar

Simple console output of FSK estimation. Three input targets with range (10, 20, 50) and velocity (5, 10, 15).

Simulator A simulator with multi target capability and range, velocity, RCS and azimuth as target properties will be written. Motivation is a simulator block which can be easily replaced by hardware.

USRP support USRPs should not be a must-use for this project, but at the moment they are probably the best suitable hardware in combination with GNU Radio. Therefore I will provide  out-of-the-box USRP support with proper input-output synchronization for unproblematic signal analysis.

Modulations First implemented modulations will be CW, FSK and FMCW. For each modulation I will provide a signal generator block and an example signal analysis flowgraph in GNU Radio Companion. Emphasis is on coding highly reuseable blocks and then the possibility to create different modulation analysis flowgraphs without the need of writing new blocks.

Radar setup All new features are tested in software with test cases. But nevertheless a working radar setup is the best proof of functionality. The first setup will be done with two USRP N210 and horn antennas.