In may 2009 a new radar technique for mapping ice surface topography was demonstrated in a greenland campaign as part of the nasa international polar year activities. Topography mapping with a portable realaperture radar. The shuttle radar topography mission data set, in particular, has had an enormous. Interferometric synthetic aperture radar insar is a method which may provide a means of estimating global topography with high spatial resolution and height accuracy. This geodetic method uses two or more synthetic aperture radar sar images to generate maps. The shuttle also served as an important engineering test bed for developing the radar based mapping technologies that have ushered in a quiet revolution in mapping sciences. The phase of each pixel of a focused sar image is the sum of three distinct contributions. Tomographic formulation of interferometric sar for terrain elevation mapping nick marechal, senior member, ieee abstract topographic mapping with spotlight synthetic aper ture radar sar using an interferometric. Interferometric synthetic aperture radar ifsar utilizes two or more synthetic aperture radar sar images collected from slightly different grazing angles to yield a topographic map of the scene. Synthetic interferometer radar for topographic mapping abstract. Prominent geoscientific applications of radar altimetry include measurement of ocean surface dynamics as well as solid surface topographic mapping. Synthetic aperture radar sar interferometry has emerged a power tool for generating high resolution topographic maps of the earth surface 1. Topographic mapping from interferometric synthetic aperture. Atmospheric artifacts in interferometric sar surface deformation and topographic maps howard a.
Synthetic aperture radar interferometry is an imaging technique for measuring the topography of a surface, its changes over time, and other changes in the detailed characteristics of the surface. Topographic mapping with multiple antenna sar interferometry. The radars 10, 10a are operated in a conventional manner. Graham l c 1974 synthetic interferometer radar for topographic mapping proc. Interferometric synthetic aperture radar, mapping, synthetic aperture radar, terrain mapping, topographic mapping. The integration of optical, topographic, and radar data for. High accuracy algorithm of airborne interferometric. The airsartopsar integrated multifrequency polarimetric and interferometric sar processor jakob j. Topographic maps are typically determined from stereo. Mapping ocean surface topography with a syntheticaperture. The integration of optical, topographic, and radar data for wetland mapping in northern minnesota jennifer corcoran, joseph knight, brian brisco, shannon kaya, andrew cull, and kevin murnaghan abstract. Pdf in this work, the potential of a groundbased synthetic aperture radar gb sar interferometer applied to generation of digital elevation maps. The paper presents a derivation of the signal statistics, an optimal estimator of the interferometric phase. Fixedbaseline insar has been demonstrated from the air with the nasa airborne synthetic aperture radar airsar treuhaft et al.
Synthetic aperture radar sar is a form of radar that is used to create twodimensional images or threedimensional reconstructions of objects, such as landscapes. A method and apparatus for determining three dimensional subvoxel positions using synthetic aperture radar. Interferometric synthetic aperture radar ifsar alaska. Intcrferornctric radar has been been proposed and successflllly demonslrated a. Technology demonstration of kaband digitallybeam formed.
Van zyl, anhua chu, scott hensley, yunling lou, yunjin kim, soren n. The new ifsar data replaces decadesold 60meter elevation data, and is made. The production of highresolution topographic maps derived from interferometric synthetic aperture radar observations of the earth is reported. Interferometric synthetic aperture radar ifsar shuttle. The integration of gps, satellite radar interferometry. Geological survey usgs national geospatial program ngp developed the alaska mapping initiative ami to collaborate with the state and other federal partners to acquire 3dimensional elevation data to improve statewide topographic maps. Rosen jet propulsion laboratory california institute of technology pasadena, california 91109 submitted to. Highresolution interferometric synthetic aperture radar for. A threeantenna synthetic aperture radar interferometer insar with a statistically optimal data processor for threedimensional 3d terrain mapping has been proposed recently to reduce the phase ambiguity and data noise drawbacks of the conventional twoantenna sar interferometry technique. To generate required data, srtm will use a singlepass fixed baseline interferometer sar system composed by the shuttle imaging radar c and by the xband sar successfully flown twice in 1994. Tomographic formulation of interferometric sar for terrain. The production of topographic maps requires two kinds of information. Glistin glacier and land ice surface topography interferometer is a spaceborne interferometric synthetic aperture radar for topographic mapping of ice sheets and glaciers.
Since the magellan radar mapping of venus in the early 1990s, techniques of synthetic aperture radar interferometry insar have become the standard approach to mapping topography and topographic change on earth. The c radar bat is an electronic assembly to steer the azimuth outboard antenna beam. Topographic synthetic aperture radar how is topographic. Synthetic aperture radar interferometry insar from earthorbiting spacecraft. Geometric aspects of interferometric phase measurement a.
This geodetic method uses two or more synthetic aperture radar sar images to generate maps of surface deformation or digital elevation. Topographic mapping using interferometric synthetic. Topographic information from interferometric synthetic aperture radar ifsar for oil palm plantation design, suitability and management 160 radar images of the earths surface 3. One of 3 conditions must apply in order to remove the topographic. Theory and design of interferometric synthetic aperture radars. Interferometric synthetic aperture radar oilfieldwiki. Interferometric synthetic aperture radar elevation ifsare. Rapid flood and damage mapping using synthetic aperture.
The topsar interferometric radar topographic mapping. Digital cartographic production techniques using airborne. Madsen jet propulsion laboratory, california institute of technology, 4800 oak grove drive pasadena, california 91109. The european space agencys esa envisat satellite was used to map and measure displacement. Insarsatellitebased technique captures overall deformation picture insar interferometric synthetic aperture radar is a technique for mapping ground deformation using radar images of the earths surface that are collected from orbiting satellites. Adoption of improved and detailed elevation data from time to time will provide better interpretations and produced significant accuracy of the mapping. The dem quality of airborne insar system depends on both system hardware performance and data processing methods. Synthetic aperture radar exploits the motion of a radar relative to a surface to create fineresolution images essentially independent of the distance from the radar to the surface. Sar image is equivalent to a phase and amplitude detector two sar images can then be. Usgs eros archive digital elevation interferometric. This geodetic method uses two or more synthetic aperture radar.
Goldstein abstract synthetic aperture radar interferometry is. Radar interferometry i radar interferometry is a simple extension of the young. A sar interferometry radar altimeter nearglobal coverage with 16day repeat orbit same technique as wsoa radar interferometry use of sar to enhance the alongtrack resolution 2 cm measurement precision at 2 km resolution 1 microradian precision in mean sea surface slope at 2 km resolution no data gap near the coast 8 7. Synthetic aperture radar interferometry iopscience. Us5677693a multipass and multichannel interferometric. Phase unwrapping for interferometric synthetic aperture radar by use of helmholtz equation eigenfunctions and the first greens identity. Ami attained interferometric synthetic aperture radar ifsar data to generate digital elevation models dems. The two radar sar antennas act as coherent point sources. Interferometric synthetic aperture radar observations provide a means for obtaining highresolution topographic terrain maps from data acquired simultaneously at two slightly displaced antennas. Synthetic aperture radar interferometry and related. Feasibility study for mapping the polar ice bottom topography. Synthetic aperture radar interferometry is an imaging technique for measuring the topography of. Radar interferometry using freely available software has matured to a stage in which data from different sensors can be routinely processed to interferometric products.
Interferometric synthetic aperture radar ifsar alaska the u. The topsar interferometric synthetic aperture radar system is implemented. Additions that will be made to this hardware to create srtm, a fixedbaseline interferometer optimized for daynight, allweather topographic mapping, include. Zebker h a and goldstein r m 1986 topographic mapping from interferometric synthetic aperture radar. Synthetic aperture radar interferometry insar provides a unique. Interferometric synthetic aperture radar, abbreviated insar or deprecated ifsar, is a radar technique used in geodesy and remote sensing. This was achieved by integrating a kaband singlepass interferometric synthetic radar on the nasa dryden gulfstream iii for a coordinated deployment. Mapping the worlds topography using radar interferometry. Synthetic aperture radar sar is a coherent active microwave imaging method.
The dynamic environment of the worlds growing radar programs is exciting to. Radar generates highresolution topographic map of the moon. Pdf synthetic aperture radar interferometry researchgate. Pdf open radar interferometry software for mapping surface. Synthetic interferometer radar for topographic mapping. Atmospheric effects on insar measurements and their mitigation. Forest mapping and monitoring with interferometric synthetic. Insar technique for the estimation of height topography. Atmospheric artifacts in interferometric sar surface. Sircxsar is a multifrequency, multipolarization imaging radar system that was designed to meet a number of scientific objectives. The new data is acquired using interferometric synthetic aperture radar technology, and is commonly referred to as ifsar. First, the detail to be placed on the map sheet must be identified.
Two sar images taken from slightly different viewing angles are combined to form an interferogram. Interferometric synthetic aperture radar, also abbreviated insar or ifsar, is a radar technique used in geodesy and remote sensing. The topsar interferometric radar zi,bker, madsen,lax. Topographic synthetic aperture radar listed as topsar. Synthetic aperture radar sar is used to produce twodimensional maps or images of radar reflectivity for terrestrial scenes. Highresolution interferometric synthetic aperture radar. In conventional interferometric processing phase unwrapping is used to estimate the absolute phase. During the aftermath of typhoon hagibis, we made flood and damage proxy maps, rapidly derived from synthetic aperture radar sar data using change detection approaches. The topsar interferometric radar topographic mapping instrument. Topographic mapping from interferometric synthetic. Interferometric synthetic aperture radar observations provide a means for obtaining high. Sarscape is one of the latest contributions to publicdomain radar interferometry software. The software, called generic mapping tools synthetic aperture radar gmtsar, is an opensource gnu general public license insar processing system designed for users familiar with generic mapping. May 01, 2010 interferometric synthetic aperture radar insar or ifsar a technique for extracting topographic and thematic information using the wave characteristics of radar signals sar phase data generating phase difference images from two or more repeat pass data collections the images called interferogram coherence maps.
Accurate and current wetland maps are critical tools for water resources management, however, many existing. Forest attributes from radar interferometric structure and. Improved topographic mapping through highresolution sar. Interferometric synthetic aperture radar ifsar shuttle radar topography mission srtm the interferometric synthetic aperture radar ifsar program represents an effort to ingest and process. Radio band the range of wavelengths or frequencies of electromagnetic radiation designated as radio waves. Jpl develops new radar system for topographic mapping. The application of sar interferometry insar in topographic mapping is usually limited by geometrictemporal decorrelations and atmospheric effect, particularly in repeatpass mode. Sar uses the motion of the radar antenna over a target region to provide finer spatial resolution than conventional beamscanning radars. Remote sensing synthetic aperture radar geodesy digital elevation model intermap technologies radarsat1 shuttle radar topography mission roi pac radar imaging radar phase waves. This geodetic method uses two or more synthetic aperture radar sar images to generate maps of surface deformation or digital elevation, using differences in the phase of the waves returning to the satellite or aircraft. Synthetic aperture radar interferometry to measure earths surface.
In this paper, to improve the accuracy of topographic mapping with highresolution insar, a new approach to estimate and remove atmospheric effect has been developed. Figure 3 interferometric sar for topographic mapping uses two apertures. The glacier and land ice surface topography interferometer. Pdf groundbased radar interferometry for terrain mapping. It is designed as a specialized software package for processing of. Us200800743a1 method and apparatus for 3d subvoxel. Synthetic aperture radar sar interferometry, commonly referred to as insar, ifsar or sari, is a synthesis of the sar and the interferometry techniques.
In this paper we propose a different approach to insar processing for retrieving the height of ground points independently from each other, unlike most conventional phase unwrapping procedures, which operate in the spatial domain. Interferometric synthetic aperture radar geodesy caltech gps. This radar mapping technology is an effective tool for collecting data under challenging. Many physical and geometric parameters of the imaged scene contribute to the grey value of a sar image pixel. In its proceedings of the third airborne synthetic aperture radar. The topographic phase of the radar signal, obtained with the gamma radar software suite, is transformed into elevation at radar azimuth and range to provide a digital elevation model strozzi et. To derive large scale topographic and thematic maps. Although the technique of using radar interferometry for mapping terrain has. Interferometric synthetic aperture radars ifsars are powerful tools for topographic mapping. Synthetic aperture radar interferometry ieee conferences. The technique uses the synthetic aperture radar sar images captured by several orbiting satellites, processed in a special way known as the differential interferometric sar dinsar to extract terrain. Synthetic aperture radar sar systems record the time delay, amplitude, frequency and phase of the backscattered signal. Tomographic formulation of interferometric sar for terrain elevation mapping nick marechal, senior member, ieee abstract topographic mapping with spotlight synthetic aper ture radar sar using an interferometric technique is studied.
The interferometric synthetic aperture radar elevation ifsare was developed by environmental research institute of michigan erim, ann arbor, mich. Topographic contour maps of mars are compiled by the synthesis of data acquired from various scientific experiments of the mariner 9 mission, including sband radioocculation, the ultraviolet spectrometer uvs, the infrared radiometer irr, the infrared interferometer spectrometer iris and television imagery, as well as earthbased radar. Basics of synthetic aperture radar interferometry and applications. In remote sensing it is used for mapping the scattering properties of the earths surface in the respective wavelength domain. Nordic geodetic commission nkg autumn school, nordic geodesy towards the 21st century, august 28september 2, fevik, norway. Wiesmann, sar interferometry for topographic mapping and surface deformation monitoring, photogrammetric j. Abstracta interferometric radar technique for topographic mapping of surfaces promises a highresolution approach to the generation of digital elevation models. It enabled a realtime monitoring of the alongtrack antenna electrical alignment for each c radar subswath and could automatically compensate for up to 0. The apparatus includes at least four noncoplanar, phasecoherent synthetic aperture radar sar platforms comprising a plurality of phasesynchronized local oscillators cohered to a common reference clock, a first sar platform of the sar platforms operable to transmit a radar waveform. Interferometric synthetic aperture radar insar or ifsar a technique for extracting topographic and thematic information using the wave characteristics of radar signals sar phase data generating phase difference images from two or more repeat pass data collections the images called interferogram coherence maps.
The instrument, called topsar for topographic synthetic aperture radar, has many potential commercial and scientific uses and will be about three times more accurate than any topographic mapper now readily available, said dr. Slant range to the target provides registration in one dimension. Interferometric synthetic aperture radar is one of the most important technologies for topographic mapping. Digital mapping techniques 04 workshop proceedings u. A synthetic aperture radar sar is an active sensor transmitting pulses of polarized electromagnetic waves and receiving the backscattered radiation.
Insar is a powerful technology for topographic and ground surface deformation mapping. Two alternative implementations, one using a 2 cm radar, and one using a 24 cm radar, are technologically fe. Sar sensors at different wavelengths and with different polarimetric capabilities are being used in remote sensing of the earth. By creating images from two spatially separated radars, an interferometric image can be derived containing topographic information. The interferometric phase map called an interferogram is. The launch and successful operation of the earth resources satellite1 synthetic aperture radar ers1 sar over the past two years has lead to development of several important new.
Synthetic aperture radar interferometry insar technique. Geological survey openfile report 20041451 digital cartographic production techniques using airborne interferometric synthetic aperture radar ifsar. Sar interferometry at venus for topography and change. Two distinct implementation approaches have been discussed for topographic radar. Xsar was designed to use the c radar bat signals as input for its semiautomatic. Interferometric sar for topographic mapping uses two apertures separated by a. Shuttle radar topography mission srtm the interferometric synthetic aperture radar ifsar program represents an effort to ingest and process highresolution elevation data produced through a.
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