Radar imaging: an industrial point of view. From the beginning to its applications to large systems

Transcription

1 Radar imaging: an industrial point of view. From the beginning to its applications to large systems Alfonso FARINA (FREng, FIET, FIEEE, EURASIP Fellow Engineering Director of Large Systems Business Unit, SELEX Sistemi Integrati) Taormina, 21 June 2011 GTTI - Gruppo Telecomunicazioni e Tecnologie dell'informazione Hot topics in Radar Signal Processing

2 Outline SAR History o SAR history (from Carl Wiley) o FFT based focusing algorithms o Harmonic analyzer o Tilted plane optical SAR processor (1970) o SeaSAT (1978) SAR in Selenia o ARTS-IP (1985) - Selenia o LABSAR(1990) - Alenia o Multiresolution and multiband SAR fusion o SAR ECCM o ISAR in Alenia Marconi Systems (2005) SAR in Finmeccanica o X-SAR in Alenia Spazio (1994) o COSMO-SkyMed SAR in large systems o SELEX Sistemi Integrati in Finmeccanica new mission o Counter-piracy system: an example of large system o Multi-resolution imaging for wide-area surveillance Conclusions 2

3 SAR history The original concept of SAR was first described by Carl Wiley of Goodyear Aircraft Company in I had the luck to conceive of the basic idea, which I called Doppler Beam Sharpening (DBS), rather than Synthetic Aperture Radar (SAR). Like all signal processing, there is a dual theory. One is a frequencydomain explanation. This is Doppler Beam Sharpening. If one prefers, one can analyze the system in the time domain instead. This is SAR. The equipment remains the same just the explanation changes. S.W. McCandless, B.D. Huxtable, Fundamentals of Synthetic Aperture Radar, Applied Technology Institute, 2004 The Pioneer Award of the IEEE Aerospace and Electronic Systems Society was given to Carl Wiley in 1985 for his work on synthetic aperture radar. 3

4 FFT based focusing algorithms Chirp scaling algorithm ω-k algorithm All processing is done in the 2-D frequency domain Carl Friedrich Gauss Francesco Carlini From: I. Cumming, Perspectives on SAR Processing, University of British Columbia, Oct From: M. T. Heideman, D. H. Johnson and C. S. Burrus, Gauss and the history of the fast Fourier transform, IEEE ASSP Magazine, Oct 1984 Today done by digital processing 4

5 Harmonic analyzer In 1894, German mathematician Olaus Henrici designed a harmonic analyzer for determining the harmonic components of complex sound waves such as those from musical instruments. The device employed several pulleys and glass spheres connected to measuring dials that gave the phase and amplitudes of 10 Fourier harmonic components. 5

6 Tilted plane optical SAR processor Photo provided by Dr. Dale Ausherman of General Dynamics Advanced Information Systems. 6

7 Spaceborne SAR First Digital SEASAT Image From: S.W. McCandless, C.R. Jackson, Principles of Synthetic Aperture Radar, Chapter 1 of SAR Marine Users Manual, NOAA, 2004, p.11. From: Aviation Week, Feb. 26, 1979 Russian Synthetic-aperture radar (SAR) imaging systems, developed by Oleg Rzhiga's team at the Institute of Radioengineering and Electronics, were installed on unmanned Almaz space stations. Two of the 19-ton "Almaz-T" satellites were deployed, as Kosmos-1870 in 1987 and Almaz-1 in

8 SAR in Selenia / Alenia ARTS-IP LABSAR SAR on RPV SAR interferometry

9 ARTS-IP in Selenia ARTS-IP: Adaptive Real Time Strategies for Image Processing E. CHIARUCCI, A. FARINA, F. MARCOZ The ARTS-IP research programme. A European long-term approach to remote sensing. Proc. of Int. Society for Photogrammetry and Remote Sensing-Commission II, Symposium ISPRS, pp , Baltimore, Maryland, May 26-30,

10 Some milestones in Selenia First SAR image from data acquired over Calabria (Dec 1987) Processing of SAR data acquired over Calabria and Pantelleria (1988) Maestro 1 data acquisition campaign (Polarimetric SAR data) 1989 Point scatterer data simulator (1988) RAW scene simulator (1990) SAR interferometric data simulator (1991) Fringes group with phase unwrapping (Feb 1992) Interferometric DEM processing (Sept. 1992) Wrapped interferometric phase obtained from the interferometry of a pair of ERS-1 SAR images of a mountainous region of Sardinia, Italy (gray-level representation). Reconstructed elevation of the scene corresponding to the wrapped phase of the above figure as a function of the azimuth and slant range coordinates (shaded perspective view). 10

11 LABSAR in Alenia 11

12 Multiresolution and multiband SAR fusion x 18.7m) x 18.7m) SIR-C@(25m x 25m) Golden Gate Bridge San Francisco Bay resolution Adapted from: G.Simone, F.C.Morabito, A.Farina, Radar Image Fusion by Multiscale Kalman Filtering, Fusion 2000, Paris, France 12

13 SAR ECCM (Electronic Counter-CounterMeasures) The threats to a SAR: barrage jamming, spot jamming, random pulse jamming, and repeater jamming. The effect of a wideband noise-like interference: mask the scene visible in the imaged area with a high uniform noise level. The use of antenna nulling techniques to cancel the effects of noise-like interferences over the collected SAR data. No jammer Main beam jammer ERS1 image Catalunya ERS1 image Catalunya From: A. Farina, Electronic Counter-Countermeasures, chapter 24 in M.I. Skolnik, Radar Handbook 3 rd ed, M. Sedehi, D. Cristallini, J. Marini, P. Lombardo, Impact of an electromagnetic interference on imaging capability of a Synthetic Aperture Radar,

14 ISAR in Alenia Marconi Systems Inverse synthetic aperture radar (ISAR) is a technique to generate a two-dimensional high resolution image of a target. ISAR technology utilizes the movement of the target rather than of the emitter to generate the synthetic aperture. 14

15 SAR in Finmeccanica Airborne SAR at SELEX Galileo - GRIFO-M installed on Dassault Mirage III - PicoSAR equipment and images Spaceborne SAR at T-Alenia Space SIR-C/X-SAR 15 With permission

16 X-SAR in Alenia Spazio In 1994, two missions known as SIR-C/X-SAR (Shuttle Imaging Radar-C/X-Synthetic Aperture Radar), designed and carried on by NASA, DLR and ASI (the American, German and Italian Space Agencies) took place in April and October. The SRTM (Shuttle Radar Topography Mission) mission has been an international research effort that obtained digital elevation models on a near-global scale. SRTM consisted of a specially modified radar system that flew on board the Space Shuttle Endeavour, based on the older Spaceborne SIR-C/X-SAR 16

17 COSMO-SkyMed COSMO-SkyMed (COnstellation of small Satellites for the Mediterranean basin Observation) is an Earth observation satellite system funded by the Italian Ministry of Research and Ministry of Defence and conducted by the Italian Space Agency (ASI), intended for both defence and civilian uses. The space segment of the system includes four medium-sized satellites (orbiting at an altitude of 619 km) equipped with SAR sensors (in X band) with global coverage of the planet. Observations of an area of interest will be repeated several times a day in all-weather conditions. The imagery will be applied to defence and security assurance in Italy and other countries, seismic hazard analysis, environmental disaster monitoring, and agricultural mapping. The 1 st satellite was launched on June nd on December rd on October th on November The Italian COSMO-SkyMed constellation is now fully operational and complete with the arrival of the system s fourth satellite in its final orbit position. Courtesy of: Rome, Italy Etna 17

18 Mount Etna as seen from COSMO-SkyMed 18

19 Fukushima as seen from COSMO-SkyMed 19

20 SELEX Sistemi Integrati within the Finmeccanica s Galaxy for Large Systems SELEX Sistemi Integrati key points: SELEX Galileo DRS Technologies Belongs to a multi-domain and multi - platform Group Leads the core Capabilities and Technologies within the Large Systems Domain: Sensors, Command and Control, Integration Ansaldo Energia Ansaldo STS AnsaldoBreda SELEX Sistemi Integrati Telespazio SELEX Elsag SELEX Service Management Thales Alenia Space AgustaWestland Alenia Aeronautica WASS Oto Melara MBDA FINMECCANICA assigned to SELEX Sistemi Integrati the Prime Contractor and Architect mission role A Large System is a group of operators and systems capable of gathering and distributing information, enabling collaboration between the components, sharing the evaluation of situations, and automatically sychronising actions. A Large System has greater capacity and capability than the sum of individual parts, and its effectiveness increases as a result of coordinating and rationalising resources already present, while introducing new enabling technologies. 20

21 Counter-piracy system: an example of large system Detection of steady mothership of pirates is possible, Mother-ship of pirates G. Franceschetti, M. Grossi, Homeland Security Facets: Threats. Countermeasures, and the Privacy Issue, Artech House,

22 time resolution Multi-resolution imaging for wide-area surveillance Fusion Engine SELEX Sistemi Integrati cars 40 m 30 m 5m COP person 25 m cars COP: Common Operational Picture 22

23 Conclusions How about the future of SAR? On March 2011 the Italian Government funded the Cosmo-Skymed II generation program for two new SAR satellites *. The Jet Propulsion Lab has come up with a novel technique called SweepSAR for generating a wide strip map SAR from space which requires 1/6th in power that would be needed if a conventional ScanSAR were used. Joint SIGINT and SAR processing. Compressive sensing. Huge amount of data to efficiently process to extract useful information (*) 23

24 Acknowledgments Francesco Vinelli, SELEX Sistemi Integrati, Italy Matteo Sedehi, SELEX Sistemi Integrati, Italy Tiziano Volpi, SELEX Sistemi Integrati, Italy Professor Hugh Griffiths, University College London, UK Dr. Dale Ausherman, General Dynamics Advanced Information Systems, USA Federica Mastracci, e-geos, Italy Dr. Eli Brookner, Raytheon, USA Andrea Torre, Thales Alenia Space, Italy 24