Earth Observation Summit 2017

SAR Tutorial Sessions

June 23, 2017, Montréal, Canada


8:30 to 9:00 – Registration & welcome

9:00 to 10:30 – Tutorial 1: Interferometric Processing

10:30 to 11:00 – Break

11:00 to 12:30 – Tutorial 2: Space-based GMTI radar

12:30 to 13:30 – Lunch

13:30 to 15:30 – Tutorial 3: The role of Spaceborne SAR in Cryosphere Science

This tutorial is only offered in English.
Veuillez noter que cette formation est seulement offerte en anglais.

Tutorial 1: Interferometric Processing

June 23, 2017, 9:00 to 10:30

Existing interferometric processing packages are very often difficult to use. This is due to the fact that until recently most of the available software was developed to address specific sensors and processing configurations. This means that the ability to effectively process interferometric data is generally limited to application experts who also have intimate knowledge of SAR sensors. Typically optimal results can only be achieved after multiple runs of the software with different parameter settings. This constraint limits the commercial acceptance of InSAR processing and hinders the development of new applications. To encourage the use of interferometric data sets, PCI Geomatics has developed an InSAR package that can be easily tailored to work in a fully automatic mode. Most of the required settings are automatically derived from the sensor metadata allowing even novice users with little or no formal SAR training to generate excellent results within a very short period of time.

The goal of the workshop is to describe how to effectively use the new Geomatica InSAR module for end-to-end processing, to exploit the full information content that can be extracted from commercially available interferometric SAR data sets. We will demonstrate how to generate both topographic and deformation information products. We will also show how the deformation products can be automatically sorted into coregistered data stacks for rapid visualization and temporal analysis to provide valuable insights into long term subsidence patterns. We will demonstrate how the flexibility of the system significantly reduces the complexity and redundancy of operational InSAR processing.

Intended Audience

This presentation is directed at the non-SAR expert interested in the highly automated, operational detection, monitoring, and mapping of subtle changes of the earth’s surface. The potential commercial application areas include mapping changes (at the millimeter scale) in surface elevation due to water extraction, mineral extraction, oil and gas extraction, urban infrastructure, and glacial rebound. Security and safety application specialists such as those tasked with monitoring transportation networks (e.g. road, rail and pipelines), or volcano and landslide prediction will also benefit. The presentation is also of interest to non-commercial groups such as educational institutions interested in conducting research to provide training. In addition, government research organizations who are interested in developing and testing new InSAR applications would benefit from attending the session.

Key Information / Knowledge to be Presented:

The presentation will show the key steps in interferometric processing and demonstrate to the non-SAR expert how to run the modules to create InSAR products. Examples of the required input and expected output will be shown for each step. The main topics to be discussed include:
– Pre-Analysis of Interferometric Data Sets
– Data ingest and the extraction of pertinent metadata and geocoding information
– Fully automated image to image co-registration
– Generation of raw or adaptively filtered interferogram
– Removal of flat earth and topographic phase
– Removal of residual phase due to orbital errors
– Unwrapping the interferometric phase
– Calibration of output products (topographic and deformation)
– Temporal ordering and parameter extraction from interferometric stacks
– Enhanced visualization of temporal information

Biography of Presenter:

Gabriel Gosselin joined PCI in 2013 and has participated in the design and implementation of many of the new radar modules in the Geomatica software suite as well as the testing of existing radar modules. He is currently responsible for the development of PCI’s radar courses as well as the delivery of specialized radar training to PCI Geomatics customers. Gabriel holds a PhD degree in Geography from University of Montreal and has more than 14 years of experience in remote sensing applications. Over the course of his career he has been involved in many projects related to the use of polarimetric radar imagery in geospatial applications such as wetland classification, biomass estimation and urban target characterization.

Tutorial 2: Space-based GMTI radar

June 23, 2017, 11:00 to 12:30

There are currently three synthetic aperture radar ground moving target indication (SAR-GMTI) radars on orbit that can measure the motion of cultural and some natural targets on the earth’s surface. Although these radars are synthetic aperture radar imaging systems, they can be configured to detect and measure the velocity of moving objects using what are traditionally called GMTI signal processing algorithms. GMTI is fundamentally a measurement process whose outputs are information vectors which can be inserted into image planes as image points during the processing. This tutorial is intended for an audience that is familiar with SAR imagery and has some familiarity with SAR processing and the complex plane representation of signal information.

This tutorial will introduce the principles of GMTI radar configurations and signal properties, will introduce the signal property basis of SAR image formation, and will look at the impact of the radar signal sampling on the measurement of moving target properties using multiple radar apertures. The Radarsat-2 instrument design will be used to define example GMTI configuration cases. GMTI analysis will be introduced using combined displaced phase center aperture (DPCA) signal subtraction for target detection and along-track interferometry (ATI) concepts for moving target detection and speed measurements. Key points will be illustrated using outcomes from DRDC SAR-GMTI development research. Sampling ambiguity impacts on GMTI processing outcome dependence on signal -channel time registration (interpolation) will be discussed. When data planes from separate channels are correlated in signal processing, the mathematical product operation introduces a quadrature modulation effect that cross modulates moving target and stationary signals. The impact of target-background intermodulation on GMTI analysis is introduced and discussed in terms of measurement outcome variability.

The covariance matrix approach to stationary clutter suppression and moving target detection is introduced. Physically large moving targets appear in SAR-GMTI data as ensembles of moving target samples. Some uses of the ensemble properties are introduced and discussed. When the number of GMTI radar apertures is greater than two, the increased number of mathematical degrees of freedom and be exploited in various ways. Applications to target speed measurement accuracy and sampling ambiguity suppression are discussed.

Biography of Presenter:

Chuck Livingstone has worked with airborne and space-based synthetic aperture radar (SAR) since 1978. His early work on airborne SAR resulted in the development of the multi polarization / polarimetric / interferometric CCRS CV-580 SAR system that supported CCRS SAR research, and the development of RADARSATs 1 and 2. In 1998 he proposed an experimental GMTI mode for RADARSAT-2 and obtained DND support for its development. He worked with MDA on the RADARSAT-2 GMTI mode realization and led a DRDC R&D team to develop SAR-GMTI theory and practice that led to the current RADARSAT-2 experimental GMTI modes.

Tutorial 3: The role of Spaceborne SAR in Cryosphere Science

June 23, 2017, 13:30 to 15:30

We are living in a period where remote sensing plays a crucial role in earth science. The Polar Regions have long been a driver for the use of spaceborne Synthetic Aperture Radar (SAR) data. Lack of daylight in winter combined with frequent cloud cover in the region make the technology a vital asset. SAR data has already proven its value in a number of operational uses, for example sea ice monitoring in Canada (and the rest of the world) has fundamentally changed with the launch of RADARSAT-1. While there is no science SAR mission in operation at the moment, international space agencies work hard to try to meet scientists’ data needs where possible. A significant increase in data availability in recent years has allowed scientists to move from proof of concept studies to providing large scale and in some cases continent wide information products.

This tutorial will provide an overview of the benefits of spaceborne SAR data in cryosphere science. Following a brief introduction of the primary techniques used, the use of SAR data in Polar Regions is discussed based on selected examples. One focal point of the tutorial will be ice sheet and glacier monitoring, however, sea ice monitoring, permafrost monitoring, and snow-monitoring examples will also be discussed. Information needs will be weighed against the information content of SAR data to evaluate possible applications and limitations.

The examples are followed by a more general discussion of data needs for the various application fields and an overview of how space agencies are working to fulfill them. A short overview of future missions concludes the tutorial.

Key Information / Knowledge to be Presented:

The main topics to be discussed include:
1) Some SAR basics
– backscatter
– geometry
– interferometry
– polarimetry

2) An overview of cryosphere science with examples
– Ice sheet & glacier monitoring
– Sea ice monitoring
– Snow applications
– Permafrost applications

3) A few things to know about data
– Data requirements for cryosphere applications
– Data acquisition strategies
– Available data sets and access to data
– Data analysis tools
– Future missions

Biography of Presenter:

Dr. Bernd Scheuchl has more than 18 years of experience with SAR remote sensing. He has a PhD in Electrical Engineering from the University of British Columbia, where he worked in collaboration with MDA and the Canadian Ice Service on evaluating the potential of RADARSAT-2 for sea ice monitoring. Throughout his career, he worked in industrial and academic environments on projects dealing with the development of a wide range of SAR applications. For the past 8 years, Bernd has been working at the University of California, Irvine, where he is involved in a NASA funded project producing ice velocity and grounding line maps of the world’s ice sheets using spaceborne SAR data. Among the research group’s major achievements is the first continent-wide ice velocity map of Antarctica. Bernd serves as a member of the NASA SAR Distributed Active Archive Center advisory group for the Alaska Satellite Facility as well as the ice sheet science coordinator for the Polar Space Task Group. He is a co-investigator the NISAR Science Definition Team.

Organizing Committee

Patrick Plourde – Event coordinator, Canadian Space Agency.

Gabriel Gosselin – Presenter, PCI Geomatics.

Chuck Livingstone – Presenter, Defence Research and Development Canada.

Bernd Scheuchl – Presenter, University of California.

Association Québécoise de Télédétection
Advanced SAR (ASAR) Workshop 2017
Canadian Remote Sensing Society
Université du Québec à Montréal (UQAM)