PARSAX An Informal Look at Radar Technology and Applications within TU Delft

15Mar/100

PARSAX in Radar Labs for MSc

It happened! Our radar has been used first time for the students training. This afternoon we were involved in the radar laboratory practicum for the MSc course Microwaves, Radar and Remote Sensing. Four groups of student visited PARSAX for the radar and measurements demonstration. Now students have to download MATLAB script and datasets from specially created web-page and practically study the Doppler processing of signals, which were reflected from the rain.

  TARA radar - Rain spectrogram

 Rain spectrogtam measured with TARA radar

PARSAX radar - rain spectrogram

Rain spectrogram measured with PARSAX radar

Both radars, TARA and PARSAX, during these measurements looked straight up to zenith. It means that measured Doppler velocity has to be interpreted as vertical movements of cloud particles, rain drops and air parcells.

12Mar/100

We must be assertive… (We moeten assertiever zijn)

Prof.dr.ir. Herman Russchenberg: “We moeten assertiever zijn.” (Foto: Sam Rentmeester/FMAX)An interview with prof. dr. ir. Herman Russchenberg, Chair Remote Sensing of the Environment and EWI's Director of Education, has been published in TUDelta #8. He discusses his vision of the research and education strategy in current situation of financial shortage.

"The government funding should go into research areas that focus on issues that will be important during next ten years. Long-term problems must have priority. This is especially important as we are training students, which will use their knowledge in the next ten years world". As an example of such long-term problems for TU Delft researchers he mentioned research areas on climate change, energy and mobility.

Full text of interview (in Dutch)

Foto: Sam Rentmeester/FMAX

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11Mar/100

Radar can save lives after earthquake

AD.NL logoAD Nieuwsmedia portal published an article "Radar kan levens redden na aardbeving" (Radar can save lives after earthquake) about research project, which has been done in IRCTR, TU Delft by PhD student Amer Nezirovic, who successfully defended his work yesterday. Our congratulations, Amer!

The thesis titled "Trapped-victim Detection in Post-Disaster Scenarios using Ultra-Wideband radar". The main achieved results is the development and experimental verification of an efficient algorithm that is able to detect motion responses from trapped victim in low signal-to-noise ratio conditions overlapped with stationary and non-stationary clutter. New algorithm of signal processing performs better than existing motion detection algorithm, in particular for non-stationary clutter suppression.

 

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5Mar/100

PARSAX News: waveforms up to 100 MHz bandwidth

The radio frequency chains of the PARSAX radar have been developed to work with waveforms that have bandwidth up to 50 MHz. Such bandwidth provides to radar theoretical range resolution 3 m and the value of so called BT-product equal 50.000 (the PARSAX radar operational sweep/repetition time equals to 1 ms). Zhijian Li, our main designer, developer and optimizer of all analog circuits of the PARSAX, spent a lot of time and efforts to achieve best hardware performance inside defined 50 MHz bandwidth in terms of the linear dynamic range maximization and minimization of  amplitude and phase distortions. He did it using novel approach for the system design using the ADS simulation software and making final tuning of real hardware moduls and components. And his final results define very high performances of the PARSAX radar.

But a few days ago we studied that these performances are even higher than expected.

The spectral characteristics of the total radar RF chain (including transmitter and receiver) have been measured using new network analyzer and unexpectedly wide actual bandwidth - up to 100 MHz,- has been found. For 90 MHz bandwidth un-flatness of the amplitude spectral characteristic is less then 1 dB, and 3 dB for 100 MHz.

Stimulated with the on-going discussions about the possibility to use the PARSAX radar for validation of wideband signal processing algorithms, we re-program our flexible radar to operate with new waveforms. All measurement campaign, starting from the initial discussion until final data storage, took about one hour. Some illustrative results are presented below.

PARSAX: range profile with standatd 3 m resolution (signal bandwidth 50 MHz)

PARSAX: range profile with standard 3 m resolution (signal bandwidth 50 MHz)

PARSAX: range profile with 1.5 m resolution (signal bandwidth 100 MHz)

 PARSAX: range profile with 1.5 m resolution (signal bandwidth 100 MHz)

PARSAX: Delft's Chimney  as test targetAn important conclusion follows from these profiles - there is no visible degradation of the system's dynamic range when waveforms with 100 MHz bandwidth are used in comparison with standard 50 MHz bandwidth.

At the same time, in zoomed picture you can easily see real improvement in resolution - the chimney, our lovely test target, clearly can be seen as compound target - its construction, which includes four separated pipes, becomes visible on the radar profile with 1.5 m resolution.(Photo: Microsoft Bing Maps 3D)

Zooming on chimney - 3 m resolution (50 MHz)
Zooming on chimney - 3.0 m resolution (50 MHz)

Zooming on chimney - 1.5 m resolution (100 MHz)

Zooming on chimney - 1.5 m resolution (100 MHz)

It is clear that presented results have preliminary character and only show a feasibility to use wide band signals with PARSAX. More attention necessary to pay for such new radar mode before the moment when the calibrated trustable data will be available for users' applications.

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5Mar/100

Yann, our congratulations!

This morning Yann Dufournet very successfully defended his PhD thesis "Ice Crystal Properties Retrievals using radar spectral polarimetric measurements within ice/mixed-phase clouds". I really enjoyed Yann's presentation before official defense ceremony.

The electronic version of the thesis available on TU Delft's library web-page.

We hope that Yann will be one of the users of the PARSAX radar data and implementation of his algorithms for mixed-phase clouds' parameters retrieval to high-resolution simultaneous polarimetric PARSAX data will provide new information and possibilities for further study of ice cloud microphysics.

Yann Dufournet and TARA Radar

Yann Dufournet and TARA Radar - photo by Sam Rentmeester