5. Motivation [1] Gintautas Palubinskas and Hartmut Runge. Rasar Signatures of a Passenger CAR. IEEE Geoscience and Remote Sensing Letters, Vol.4,No.4,2007 [2] D. Hounam, S. Baumgartner, K. H. Bethke, M. etc. , “An autonomous, non-cooperative, wide-area traffic monitoring system using space-based radar (TRAMRAD),” in Proc. IGARSS, Seoul, Korea, Jul. 2005, pp. 2917–2920.
8. Experiment data （ A ） Medium truck （ B ） Carriage （ C ） larger truck （ D ） Tank truck Radarsat-2 quad polarimetric SAR images what size of the truck can be detected? How to change the characteristics with aspect angle? How do truck structure affect characteristics? Site Center frequency (Hz) Pixel space (m) (R A) Incidence angle Orbit Range bandwidth (Hz) Look numbers Hainan 5.4E9 4.73 4.92 22.16°-24.09° Ascending 3.0E7 1 1 Jiangsu 5.4E9 4.73 4.74 38.37°-39.84° Descending 3.0E7 1 1 Hubei 5.4E9 4.73 5.06 47.56°-48.74° Descending 3.0E7 1 1
11. Analysis methods and discussion Incidence angle: Calculated on the ellipsoid surface aspect angle: ∠ S = A + ∆A+∆B A : measured by compass ∆ A: local magnetic declination ∆ B: inverse calculated by the four corners’ geographic coordinates in SAR image
12. Analysis methods and discussion Aspect angle Intersection angle As the left and right sides of truck are symmetrical, the scope of aspect angle can be reduced from [0, 360] to [0, 180]. The front and rear shape of truck are almost similar. To facilitate comparison, the aspect angle can be approximately replaced by the minimum intersection angle which is the angle between x-direction and long side of truck. So the intersection angle is in the range of [0, 90]. 0/0,225/45,270/90 180/0,225/45,270/90 181/1,193/13,206/26 217/37,223/43,229/49 239/59,251/71,262/82,272/92 2/2,351/9,151/29,45/45
13. Analysis methods and discussion the area of one pixel in SAR image stands for the area integral at the position of (c, t)
14. Discussion of SPAN value A B C D Four types truck SPAN value characteristic pattern with intersection angle and incidence angle. Incidence angle: A < C < D Truck size : A < C < D SPAN value: D < A < C which factor is more impacted on RCS value within incidence angle and size? structure is the key factor
15. Discussion of background value Four types truck SPAN value characteristic For the wavelength of Raradarsat-2 beam is 5.5 cm and roads are relatively smooth, the clutter of background shows lower at larger incidence angle, which will improve truck detection ratio. Considering the impact of incidence angle on the translation of slant range to ground range, it can be concluded that same truck will occupy more pixels on slant range and bring stronger backscatter on larger incidence angle image. In short, the larger incidence angle SAR image will be more favorable to truck detection.
16. Discussion of the impact aspect angle the higher SPAN value between 43° and 71° is due to the odd bounce which may be caused by the rough truck tarpaulin roof. the even bounce is always bigger than other Pauli components except at the intersection angle around 45°. The smooth and bare cylindrical structure of tank truck lead to the odd backscatter bounce very weak.
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