High-Resolution Doppler-Polarimetric FMCW Radar with Dual-Orthogonal Signals

Transcription

1 High-Resolution Doppler-Polarimetric FMCW Radar with Dual-Orthogonal Signals Oleg Krasnov, Leo Ligthart, Zhijian Li, Galina Babur, Zongbo Wang, Fred van der Zwan International Research Centre for Telecommunications and Radar (IRCTR), Delft University of Technology Mekelweg 4, 2628 CD, Delft, The Netherlands 1

2 Outline Introduction System Design Waveforms Agility Possible Applications First Measurements Results Conclusions 2

3 Development motivation Modern demands for radars require that they have to be not only detecting but multi-functional instruments. They have to detect, trace, classify and recognize targets, to estimate and retrieve their parameters. And all this tasks have to be solved in the framework of different missions and in variable scenarios, environment and weather conditions. Such requirements can not be satisfied with traditional fixed radar architecture. Modern radars has to be highly reconfigurable. This is especially important for the research radars. 3

4 PARSAX: highly reconfigurable research radar PARSAX In IRCTR, TU Delft we created a new radar Full Polarimetric (2 independent highly linear polarimetric RF channels both in transmitter and receiver) High-Resolution (bandwidth up to 100 MHz up to 1.5 m) High-Sensitive (the transmit power - up to +50 dbm per channel, the receivers noise floor - around -93 dbm) Doppler (up to 5100 complex samples in coherent real-time range profile for secondary Doppler processing) Continuous Wave (range processing of sounding signals with BT-product up to in real time ) Software Defined Radar (digital generation of agile waveforms and their matched processing on Intermediate Frequency in 4 parallel channels, FPGA-based, fully programmable digital receiver) Modular (can be converted in X-band system using additional RF front-end) 4

5 PARSAX: S-band Polarimetric Agile Radar Analog subsystem Digital subsystem S-band Transmit Antenna V S V IF V V Digital Wave-Form Generator H S H IF H H Frequencies Block VH Digital Receiver S-band Receive Antenna V H S V S H IF V IF H VV HH HV 5

6 Technological Challenges New approach for the whole system s design optimization using simulation software (ADS, MATLAB, Simulink) results in Dynamic Range (SFDR) ~ 70 db; High Sensitivity; Close Matching of the channels characteristics in the operational frequency band with width up to 50 MHz: better then 1 db in amplitude (better 3 db in 100MHz); a few degrees in phase. Synchronous conversion of the received and reference signals into digital form on IF (125 MHz) using sampling rate 400 MSPS, 14 bits. Implementation of waveform-specific (de-ramping for LFM) and universal (matched filtering) real-time processing algorithms in programmable FPGA-based digital receiver. 6

7 Antenna System 3.5 Direct coupling: 1.8 HH < -100 db VV < -85 db 7

8 PARSAX Radar Design Optimization Using Agilent Advanced Design System (ADS) ADS: Initial model of the system System specification and requirements ADS: Optimization of the initial model Components specification and requirements Components selection and ordering ADS: Realistic model of system ADS: Realistic models of components LAB: Components measurements ADS/LAB: System design validation LAB: System measurements LAB: System assembling 8

9 PARSAX Design Optimization Using ADS: Matching Between Channels Amplitude matching Phase matching Receiver Transmitter 9

10 System Linearity Improvement using Automatic Control of the Transmit Power Spur-Free Dynamic Range of the PARSAX radar receiver 10

11 Polarimetric radar sounding signals with dual orthogonality in polarimetric and in time-frequency spaces * U = E HT () t E VT () t dt 0 * Uij ( τω, d ) = E it ( t) E jr ( t τω, d ) dt 0 i, j = H, V; i j Widely known examples of such signal pairs are The pair of chirp signals (linearly frequency modulated) with positive and negative frequency excursion (LFM CW or pulse) The pair of signals with phase modulation by orthogonal codes (PCM with pseudo-noise, Barker, etc. codes) 11

12 The PARSAX radar design in case of LFM signals and de-ramping processing

13 PARSAX: Waveform-Agile Software Defined Radar: Signals and Algorithms Library of of Waveforms Library of of Algorithms Orthogonal LFM Orthogonal PCM Multi-Period Signals Cross-Channel Interference Suppression Cross-Period Processor De-Ramping Real De-Ramping Complex Matched filter Fixed multi-channel RF/IF Front-End 13

14 Architecture of the PARSAX radar system Rx HH HV VH VV Digital Receiver Scattering Matrix Estimation, Primary Calibration Doppler Spectra Estimation, Processing, Filtering, Calibration Tx H V Waveform Generator Radar Control Algorithms Library Waveforms Library Application- Dependent Polarimetric and Doppler Post- Processing 14

15 PARSAX Radar: Current Configuration PC-3 Host Comp Remote Control Net PC-2 LabView PCB EN1 EN2 H V Antennas engines Software for PARSAX radar control, data acquisition, visualization and processing Net Sync CTR CH1 Clk H-in Transmitter/Calibration Switchers AWG 5014B CH2 CH3 V-in Transmitter Net CH4 Syn4 Syn3 Syn2 Syn1 Clk Network Router ADC HD 01 X5-400M PCB-1-1 ADC Clk Hrf PC1 Asus P6T7 WS Supercomputer Sync Vrf Hrc Receiver Sync HD 02 X5-400M PCB-1-2 Clk ADC Vrc Net Memory ADC Sync Syncro-pulse 1 ms ADC HD 03 X5-400M PCB-1-3 ADC Clk PARSAX Padar Sync esata External HD HD 04 X5-400M PCB-1-4 Sync Clk ADC Clk 400 MHz ADC Output data ratio: 40 MB/s/ch = 5120 ranges x 8 bytes 15

16 PARSAX, IRCTR TU Delft Observation area with resolution 3 m 16

17 Applicable Polarimetric Formalisms Scattering Matrix Covariance Matrix 17

18 Horizontal Scanning of Precipitations Drizzle cloud Azimuthal Scan with Elevation +5 degrees 18

19 Google map of TU Delft Techno Park To The Hague PARSAX Roundabout To Rotterdam 19

20 Polarimetric radar map of TU Delft Techno Park 20

21 Doppler Selection of Targets: Highway A13 To The Hague Roundabout Green Palette Stable Targets Red Palette Positive Doppler Velocity Blue Palette Negative Doppler Velocity Doppler aliasing: somebody was changing the line and moving faster 22.4 m/s To Rotterdam 21

22 Chimney Measurements with Resolution 3 and 1.5 m 22

23 Quality of the System and Signals : Polarimetric Doppler Spectra of Stable Target 23

24 Conclusions Using the orthogonal waveforms as orthogonally-polarized components of the radar sounding signal gives the possibility to measure all elements of the polarization backscattering matrix simultaneously The technological development gives the possibility to implement this principle in the high-resolution radar system for the remote sensing application The basic principles of the PARSAX, high-resolution high-sensitive Doppler polarimetric radar for simultaneous measurement of all elements of scattering matrix, has been demonstrated. The radar has very flexible architecture in terms of sounding signals and processing algorithms. If you have any new ideas about signals, algorithms and applications for the polarimetric radar we are open for cooperation 24

25 Thank you for the attention! Questions? 25