Remote Sensing: Background research (1978 – 1989)

 

Remote Sensing: background research (1978 – 1989)

 
Unfortunately, not much has been recorded about the period 1978-1989. Still, it was an important time, as the work that began with NIWARS continued in a systematic manner. For a number of years, radar measurements were taken on agricultural crops, soils, water waves, sea surface (first years on the Noordwijk measuring platform, the old REM island, and later also at other places and from ships), etc. These activities led to a deepening of the insight into the physics behind the observations. In the meantime, modelling and simulation have made much more progress. It led to the insight that more accurate measurements had to be taken. Calibration was necessary and the equipment had to become stable.

The flying radar recorded the observations on wet film. That medium was replaced by magnetic tape recording in the late 1970s. That soon proved to be not enough. Work started on a digital SLAR built with a ship’s radar unit. Advancing digitisation helped to improve quality, for example by using image processing equipment (Comtal), digitisation equipment and the rise of the PC in 1980. 

The Comtal image processing system
The Comtal image processing system

Great results were achieved with the visual material. Crop classification, for example, but also the measurement of wave direction spectra at sea. The insight grew that the equipment had to be improved and that this aim was achievable. A coherent radar that can do phase measurements and accurate amplitude measurements had to be developed. In 1986 this led to the start of a coherent radar study, which resulted in the later development of a Dutch SLAR, the PHARS and PHARUS systems. In August 1986, SLAR images were made of the Flevopolder (3 by 5 km). So a lot of time has passed from these first ideas to the first PHARS image in the 90s.

 

Acknowledgement

Prof. Peter Hoogeboom provided additional information on the period 1978-1989.  

References
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  2. H.M. Oudshoorn: “The use of radar in hydrodynamic surveying”; Procs Seventh Conference on Coastal Engineering, edited by J.W. Johnson (The Hague: Council on Wave Research, The Engineering Foundation), 1960, pp. 59 – 76.
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  6. RWS werkgroep, nota: “Radar en infra-rood luchtopnamen”, door Afd. Havenmonden bij brief nr. 128 dd. 10 jan. 1969 aangeboden aan de HID RWS in de Directie Benedenrivieren.
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