Remote sensing for resources development and environmental management: Remote sensing for resources development and environmental management

Damen, M. C. J.

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Multivolume work

Persistent identifier:: 856342815

Title:: Remote sensing for resources development and environmental management

Sub title:: proceedings of the 7th international Symposium, Enschede, 25 - 29 August 1986

Year of publication:: 1986

Place of publication:: Rotterdam; Boston

Publisher of the original:: A. A. Balkema

Identifier (digital):: 856342815

Language:: English

Additional Notes:: Volume 1-3 erschienen von 1986-1988

Editor:: Damen, M. C. J.

Document type:: Multivolume work

Volume

Persistent identifier:: 856343064

Title:: Remote sensing for resources development and environmental management

Sub title:: proceedings of the 7th international Symposium, Enschede, 25 - 29 August 1986

Scope:: XV, 547 Seiten

Year of publication:: 1986

Place of publication:: Rotterdam; Boston

Publisher of the original:: A. A. Balkema

Identifier (digital):: 856343064

Illustration:: Illustrationen, Diagramme

Signature of the source:: ZS 312(26,7,1)

Language:: English

Usage licence:: Attribution 4.0 International (CC BY 4.0)

Editor:: Damen, M. C. J.

Publisher of the digital copy:: Technische Informationsbibliothek Hannover

Place of publication of the digital copy:: Hannover

Year of publication of the original:: 2016

Document type:: Volume

Collection:: Earth sciences

Chapter

Title:: 2 Microwave data. Chairman: N. Lannelongue, Liaison: L. Krul

Document type:: Multivolume work

Structure type:: Chapter

Chapter

Title:: SLAR as a research tool. G. P. de Loor & P. Hoogeboom

Document type:: Multivolume work

Structure type:: Chapter

116 a REFERENCES Sympos Pr = P 7' G\e) л 2 (4тг) 3 R a with: P R received pcwer; P transmitted pcwer; G(9) antennagain function; 9 depression or grazing angle; R distance to target (slant range) in m; C* radar cross-section in m ; X the radar wavelength in m. P and X are constant. The range R to a target is measured directly by the system (the time between the transmission of a pulse and its reception). A special receiver and amplifier make that the output voltage of the system varies linearly with the logarithms of the received pcwer P R . The antenna gain function G(Q) is kncwn iron measurements; these measurements were made on the antenna alone as well as when mounted under the aircraft. In the last case this was done by using test fields with a kncwn backscatter.. Now we arg able to measure O’ the radar cross section in nr . What we need, however, is the backscatter coefficient y : the radar cross-section per m . For a beamfilling target we then must divide the radar cross-section by the cross-section of the illuminating beam at the place of the target: y =<r/ A (A= cross-section of illuminating antenna beam). With pixel values given as the imagery will look better since the angular dependence of y of most natural targets is relatively small for the angular coverage of a STAR. Substitution in the radar equation new gives: - El {4n)} Ri C ° S 6 7 ~ Pt G z (6) \ l PL sin 6 where (l is the antenna beairwidth and L the pulselength_ In this formula alone the antenna gain function G(0) is dependent on aircraft attitude. This attitude is measured together with the place of the aircraft by an inertial navigation system. (INS: LTN 58), which data are recorded simultaneously with the radar data. The height of the aircraft is measured also by the radar system: the first echo is that of the ground immediately under the aircraft. A special algorithms (the PARES algorithms) was developed which takes all these data together and finally gives the data measured by the system as radiometrically and geometrically correct pixels. For a more complete description the reader is referred to Hoogebocm (1983). and Hoogeboam et al (1984), To make the pixel values absolute a reference signal is used. This reference signal is fed into the system using the free time (without echo's) between the transmission of a pulse and the reception of the first echo of the ground beneath the aircraft. On top of the above procedures the system is controlled at regular intervals by mounting corner reflectors with accurately kncwn radar cross- sections in the test areas. Frcm such experiments we know that the absolute accuracy of a pixel is in the order of a 1 to 2 dB and the relative accuracy in the order of 0.3 to 0.4 dB. 4. CONCLUSIONS AND ACKNOWLEDGEMENTS Churchill, P and A. Wright, Human and automatic interpretation of radar images of land cover. Proc. EARSeL Workshop 'Microwave Remote sensing applied to vegetation' Amsterdam 10 - 12 Dec. 1984; ESA publication SP-227, Jan.1985, p.131 - 140 Hoogebocm, P. 1983. Preprocessing of side-looking airborne data. Int.J.Remote Sensing 4: 631 - 637 Hoogeboom, P. 1986. Identifying agricultural crops in radar images. This Proceedings Hoogeboom, P., P. Binnenkade and L.M.M. Veugen 1984. An algorithms for radiometric and geometric correction of digital SLAR data. IEEE Trans. Geosci. and RS GE-22: 570 - 576 de Loor, G.P. 1981. The observation of tidal patterns currents and bathymetry with SLAR imagery of the sea. IEEE J Oceanic Eng. OE-6: 124 - 129 de Loor, G.P. and P. Hoogebocm 1982. Radar backscatter measurements frcm platform Noordwijk in the North Sea. IEEE J Oceanic Eng. OE-7: 15-20 de loor, G.P., P. Hoogebocm and E.P.W. Attema 1982. The Dutch ROVE program. IEEE Trans. Geosci. and RS GE-20: 3-11 Moore, R.K. 1979. SLAR image interpretability - trade-offs between picture element dimensions and non—coherent averaging. IEEE Trans. Aerospace and Electron. Syst. AES-15: 697 - 708 a. An absolute digital SLAR is new available in the Netherlands. It delivers images with pixel values given in dB. The residual speckle in natural targets must be taken into account in the interpretation procedures. The development of this radar system was the carbined effort of the following institutes: the Physics and Electronics Laboratory TNO, The Hague; the National Aerospace Laboratory NLR, Amsterdam; the Delft University of Technology and the Survey Department of Rijkswaterstaat, Delft. b. Fig.l. Radar images of the same agricultural area with different numbers of independent observations ("looks") in a pixel, a. With 2 looks; b. with 30 looks. Images, courtesy NLR. Devek G.Domik VEXCEL C J.Raggan Research C 1. INTRODl Post processin usually meanir kinematic natu Thus the rada complex intera tones of the in be necessary tc One may think e.g. map data, of the image fi give a general an illuminated simulation. S can be combii After rectificat with the image Essential tools overlapping SA integration of t rectification of as archiving an programs and essential SAR ( 2. WHICH 1 Software can 1 There is of cot (a) Gen The non-radar output data and not be available (b) Arc! (c) DEIS The radar softw (d) Groi (e) Sing (0 Stere (g) Stere (h) Rada (i) Stere

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