Proceedings of the Symposium on Global and Environmental Monitoring: Proceedings of the Symposium on Global and Environmental Monitoring

Bibliographic data

Multivolume work

Persistent identifier:: 856665355

Title:: Proceedings of the Symposium on Global and Environmental Monitoring

Sub title:: techniques and impacts ; September 17 - 21, 1990, Victoria Conference Centre, Victoria, British Columbia, Canada

Year of publication:: 1990

Place of publication:: Victoria, BC

Publisher of the original:: [Verlag nicht ermittelbar]

Identifier (digital):: 856665355

Language:: English

Document type:: Multivolume work

Volume

Persistent identifier:: 856669164

Title:: Proceedings of the Symposium on Global and Environmental Monitoring

Sub title:: techniques and impacts; September 17 - 21, 1990, Victoria Conference Centre, Victoria, British Columbia, Canada

Scope:: XIV, 912 Seiten

Year of publication:: 1990

Place of publication:: Victoria, BC

Publisher of the original:: [Verlag nicht ermittelbar]

Identifier (digital):: 856669164

Illustration:: Illustrationen, Diagramme, Karten

Signature of the source:: ZS 312(28,7,1)

Language:: English

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

Editor:: International Society for Photogrammetry and Remote Sensing, Commission of Photographic and Remote Sensing Data

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:: [TP-2 SPECTRAL SIGNATURES]

Document type:: Multivolume work

Structure type:: Chapter

Chapter

Title:: ADVANCES IN SIGNATURE MEASUREMENTS - RECENT SENSOR DEVELOPMENTS AT THE CANADA CENTRE FOR REMOTE SENSING. Susan M. Till

Document type:: Multivolume work

Structure type:: Chapter

77 al, 1989; and Cihlar et al, 1990), geological feature mapping, and backscatter characteristics of forestry targets (Wehrle, 1989) . SAR SYSTEM DESCRIPTION The new generation airborne synthetic aperture radar (SAR) is a dual frequency C-Band/ X- Band, dual polarized system that transmits either H or V polarization and receives both polarizations simultaneously (Livingstone et al, 1988). It is fully digitally-controlled, with digital motion compensation across the swath and dynamic antenna stabilization. It also features an onboard 7-look real-time processor and display, and data imaging in one of three selectable operating modes, nadir, narrow or wide. In the nadir and narrow modes, swaths of 22 km and 18 km are imaged from the optimum aircraft altitude of 6 km, with high resolution of 6 m in azimuth and range. Lower resolution (20 m x 10 m) imagery can be obtained over a wide swath of about 63 km, for maximum ground coverage. In all cases, 4096 range pixels are processed across the swath. The system incorporates a high power transmitter, with a low power transmitter as back-up. In-flight outputs from the SAR include high density digital tapes of signal data and image data processed ana recorded in-flight, hard copy print and video display of imagery produced in real-time for quick review, and digital data tapes of navigation parameters. On the ground, the high density image tapes are transcribed to computer compatible format (CCT), and high quality imagery can be generated in strip form as positive or negative print. The signal tapes can be processed to 16-bit image CCTs, using the C- SHARP system in operation at OCRS. RADAR SENSOR DEVELOPMENTS New radar sensor developments at OCRS are underway to utilize the phase of the SAR signal. These developments include interferometric SAR, a new SAR mode with the potential of providing terrain elevation information to better than 10 m rms (Cumming et al, 1990), and polarimetric SAR (Livingstone et al, 1990), to provide enhanced target classification. As well there are upgrades to the airborne system and precision ground processor, to provide an end-to-end capability for data acquisition and processing of phase coherent data. In addition, there have been continuing calibration developments that have increased understanding and ability in radiometric calibration (Lukowski et al, 1990) , to allow more accurate derivation of target signature and intercomparison of multi- temporal data sets. Polarimetric SAR In the past, remote sensing radar applications have required and relied on good image radiometry, but recent research work in the application of image phase has indicated the potential of radar phase information. Polarimetric SAR with phase and amplitude information provides additional target scene parameters and offers the possibility of use as a standard quantitative remote sensing tool, for example in forestry and agriculture classification. CCRS, together with the Defence Research Establishment Ottawa, initiated a project in 1988 to develop a polarimetric SAR capability. The project has involved design and implementation of hardware modifications to the airborne system, and development of software and a PC-based workstation for data processing, analysis and display. Following a study of the feasibility and design of using the CCRS SAR in a polarimetric mode, a simple experimental X-Band polarimeter was implemented. This configuration makes use of a single junction ferrite switching circulator to multiplex H and V polarized pulses. With the radar transmitter running at twice its normal pulse repetition frequency, the returned signals are processed by a single receiver. The signal recording interface allows a full polarimetric data set to be recorded. These recorded signal data are stripped and processed to four spatially registered complex images which are then corrected for system gain artifacts and cross channel leakages prior to the polarization synthesis. The first flights were carried out in August 1988 over urban and rural test sites in Ottawa and Petawawa, and data was used to demonstrate the polarimeter function and to test the workstation. Following further successful airborne acquisition with this prototype X-Band polarimeter, a triple junction ferrite switching circulator was designed and built by ComDev Ltd. to CCRS specification for C-Band frequency, the preferred frequency for polarimetric research. This new switch is designed to have lower cross-channel leakages, and is thermally regulated, to provide higher performance and calibration accuracy. Integration of the C- Band switch into the system is planned for early winter, 1990. Analysis of the X-Band polarimetric data sets has already indicated their potential for enhanced target and terrain differentiation; use of the new C-Band mode should provide excellent data sets for polarimetric application studies. Interferometric SAR, InSAR CCRS is developing an interferometric SAR capability, InSAR, as an additional operational mode of the airborne C-Band SAR. By using the conventional SAR for transmitting and receiving the radar signal, and adding a second antenna and receiving channel, another registered image with a small cross-track parallax is obtained. When the two received channels are processed, interferometric phase patterns are obtained that are modulated by the height variations in the imaged terrain. The phase patterns are then analyzed to obtain the elevation of each pixel in the scene. The resulting digital elevation model should be more accurate than those available from stereo SAR requiring two passes of airborne SAR data which have errors from pass registration and image correlation. From studies of the interferometric process and the sources of error, the modification of the C-Band SAR should lead to relative elevation accuracies of better than 10 m rms, which promise to be of great interest for many survey and mapping applications. Based on the results of these analyses, and preliminary test data, the modification of the airborne system is underway. A second C-Band antenna has been completed and characterized, and is to be installed on the side of the Convair-580 fuselage in the winter of 1990. The ground processor has been developed and will provide differential motion compensation

Access restriction

Copyright

fullscreen: Proceedings of the Symposium on Global and Environmental Monitoring (Part 1)

Multivolume work

Volume

Chapter

Chapter

Table of contents

Cite and reuse

Volume

Chapter

Image

Image fragment

Citation links

Citation recommendation