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Terminology, Acronyms and Symbols

SAR Glossary

Azimuth Direction aligned with the relative spaceborne platform velocity vector.
Detection Processing step in which the phase information is removed and only the signal amplitude is preserved. Normally the detection uses a magnitude squared method and has units of voltage square per pixel.
Focusing Data processing finalized to focus the SAR image in range and azimuth through bidimensional signal compression.
Geocoded The data contains geographic information or coordinates corresponding to the location of the data.
Georeference The internal coordinate system of the image can be related to a ground system of geographic coordinates
Ground range Projection of the slant range into the ground.
Incidence angle Local incidence angle on ground calculated using the ellipsoidal Earth model.
Looks Image obtained using only part of the spectrum to focus the image (subaperture). It can be done in range and in azimuth, and normally is used to reduce the speckle noise from SAR images through incoherent sum (multi-look process).
Range Direction orthogonal to the satellite velocity.
Slant range vector Line-Of-Sight distance between the antenna and the target on ground.
Slant range plane Plane containing the relative sensor velocity vector and the slant range vector for a given target.

|Orthorectification |A subtopic of georeferencing— The process of converting images into a form suitable for maps by removing sensor motion and terrain-related geometric distortions from raw imagery. |

List of Acronyms

ASCII American Standard Code for Information Interchange
BSD Berkeley Software Distribution
CF Calibration Factor
Cn Coefficient ‘n’ in a polynomial
DC Doppler Centroid
DN Digital Number
ECEF Earth-Centered, Earth-Fixed
GR Ground Range
GRD Ground Range Detected
GRSR Ground Range to Slant Range conversion
HDF Hierarchical Data Format
KML Keyhole Markup Language
PNG Portal Network Graphics
PRF Pulse Repetition Frequency
RMSE Root Mean Square Error
RPC Rapid Positioning Capability (or Rational Polynomial Coefficient)
SR Slant Range
SAR Synthetic Aperture Radar
SLC Single Look Complex
UTC Coordinated Universal Time
VV Polarization (Vertical transmitted and Vertical received)
WGS84 World Geodetic System (1984)
XML eXtensible Markup Language