An Introduction to SAR Radar
Michael LaGrand, Member IEEE
Engr 302, Professor Ribeiro
Abstract - This paper is to explore the principals of
Synthetic Aperture Radar (SAR), particularly in terms
of its imaging applications. An explanation of basic
radar principles is to be followed by an explanation of
the necessity of a synthetic aperture for high-quality
images. Finally, the theory and calculations leading to
the practical use of an airborne SAR system will be
explored.
I. INTRODUCTION
One of the greatest innovations in the last century of
warfare has undoubtedly been modern radar. While the
development of radar for military applications has caught
the public’s eye, the concepts behind radar are often taken
for granted as overly simple and many non-military
applications are overlooked. There are a great many people
who think that radar operates just by sending out a signal
and waiting for an echo. While this is the main principle of
radar (as well as the most widely utilized), a great deal more
goes into getting today’s accurate returns. In fact, processes
and practices have been developed that allow radar to return
images so precise that they are used for creating images of
the earth from high above it and can return from a satellite
information about height of an area that is accurate to inside
of a meter. The foremost type of radar that is used for this
type of imaging is called Synthetic Aperture Radar (SAR),
which uses the illusion of a larger antenna to gain the
incredible accuracy needed for such imaging.
II. BASIC PRINCIPLES OF RADAR
In order to understand the principles that allow SAR radar
to function, one must start at the beginning. The best way to
understand the governing rules of radar is to explore the
basic radar systems that have been used for years to locate
planes and the like. This standard pulse radar, used mainly
for ranging and tracking is the starting block for SAR, which
is an active way to take a picture of the earth, as it generates
it’s own wave to find the information needed on the target.
Normal photography, on the other hand, is passive, as it uses
the waves of light put out by another source: the sun. SAR
still uses the normal radar style waves and detection, but is
more accurate and takes an array of points. For this reason,
the study of standard radar is applicable.
A. A Brief History
The concept of using radio waves for ranging purposes
was first developed by Sir Robert Watson-Watt in the mid
1930s for the British National Physics Laboratory. He had
stations up by 1936 and was just on time with them for
World War II, in which radar would play a significant part
in the Royal Air Force staving off the German Luftwaffe.
Radar was first used for military purposes in a
floodlight style, checking parts of the sky for any intruders
in a certain sector. These could be manually steered, but
they were extremely inefficient because a system then
needed separate radar signals pointed in all directions. The
British Chain Home system made famous in WWII used a
setup like this. It gave the RAF of England advanced
warning about any German attacks, and, in doing so,
launched radar into the limelight. Soon militaries had
developed rotating radars, which were extremely slow at the
time, but still quite effective. Also, and a polar plot display
was developed in order to allow the operator a 360 degree
field of vision.
B. A Definition of Radar
Radar stands for Radio Detection and Ranging, since
it’s two original uses were to detect an object and to find the
range to said object. Raemer defines radar as “a system that
attempts to infer information about a remotely located object
from reflections of deliberately generated electromagnetic
waves at radio frequencies.” [Raemer 1] It is important to
notice that it is not simply the range of the object that is
important in this newer definition, but information in
general about the remote object is stressed, leaving open
room for information such as the type of material. Such
additional information can be inferred in some cases by the
intensity of the returning wave in relationship to the distance
that it traveled.
C. The Output Signal
The radar wave is a radio-frequency (r-f) wave, and as such
it tends to propagate in a straight line and moves at the
speed of light. The wave is polarized in some direction and
is subject to interference. Typically, radar systems use a
setup that keeps the E-field of the wave parallel to the
horizon. Of course, one of the most important features of
the r-f wave is that it reflects off most surfaces or medium
changes. Without this feature radar would not be possible,
as there would be no returning signal by which to gather
information on an object from. Another important property
of the r-f wave is that it has a phase that can be detected in
longer-wavelength cases.
A rs
  I0 d
4 r
 cos     e
 j R

Of course, the beam is not all sent out in one concentrated
wave of infinitesimal width. Instead the distribution is in a
conic pattern, which can be quite wide and causes decreased
resolution. This conic distribution can cause objects that are
a distance away from the precise area intended to be pinged
to send a signal back. Once again, the resolution can be
improved by longer wavelengths and also by filtering.
Other than the conic attribute of the output there are also
side lobes as shown in Figure 1 that can be transmitted, and
these can cause some noise. Improved antenna technology
and filtering combat these.
D. Antenna
The most basic form of antenna (receiving and
transmitting), the dipole, consists of two conducting lines
closely spaced but not connected, preferably with the ends
bent going perpendicular to each other, as seen in Figure 2.
Fig. 1. Antenna radiation pattern [5].
One of the main aspects of the r-f wave is it’s intensity.
As can be expected with any wave traveling through a
medium, it loses intensity along the way. The intensity does
not play much of a factor in ranging radar, as the range of
the system is more often limited by the interval between
pulses. However, the intensity reveals information about the
shape or material of the object being “pinged.”
The power output of a monostatic radar transmitter can be
defined as
P R0
P T  A eT0  A eR0   0
2
4
4    r
Where sigma is the peak radar cross section and Pt is the
total transmitter power. The A values are the vector
magnetic potential for the transmitter and receiver, as makes
sense. A monostatic system is one that produces the signal
and receives it again from the same place. There are
actually some systems which have a transmitter and receiver
in a separate place, but these systems are not usually favored
as the algorithms for using the information are more
complicated and often less accurate. Additionally, if the
location of a stationary transmitter is know, the information
can be used by anyone.
The wave travels at the speed of light, c (approximately
3x10^8 m/s), which means it can travel to a target 300 km
away in 1 ms. However, for radar it is a two-way trip, so an
object 300 km away would ping back in after 2 ms. It
should also be noted then that the wavelength of one of
these waves would be given by

c
f
Also, the time that it takes for an object to be detected can
be found using the equation
2R
t
c
It is from this equation that the information so vital to the
military for so long is always obtained.
The frequency used for radar is typically in the microwave
spectrum, which ranges from 300MHz to 30GHz. However,
the frequencies used for SAR radar are typically in the range
of 10MHz to 200MHz [4]. This means, then that while a
typical wavelength is less than 30 nm, for SAR the
wavelength can be up to 10 um. This is a significant
improvement.
Fig. 2. Dipole Antenna [9].
This form can be easily produced, but is relatively useless
for the directional aspect needed for radar. In order to find
the location of an object, a directional antenna needs to be
used for transmission. This can be accomplished through
the use of interference. An array of dipoles can be set up to
cancel out most of the signals that would go in unintended
directions. There would still, though, be issues with some
signals, called side lobes, [vectorsite] that could not be
canceled. The issue that these lobes raise is that objects
close and to the sides can reflect a signal and cause a false
identification of an object. An alternative to this design to a
standard antenna is to use a parabolic dish to direct the
signals that go in or out. These are often rather bulky,
though.
To explore all the possible ways to cancel out unwanted
emissions and make the wave directional would be
extremely complicated and useless without a basic
understanding of the dipole antenna. It is important to note
that the dipoles do not lead to some ground which the
current would flow into or come out of. If some sinusoidal
current is pushed into it, however, that energy is moved out
in the form of the electric wave. For a given half of the
dipole, then, the vector magnetic potential can be found with
Equation XXX as follows.
A zs
  I0 d
4 r
e
 j R

[9]
Converting to a spherical coordinate system proves
convenient here, so the values of the vector magnetic
potential in spherical notation can be found to be Azs times
cos(theta) for the the r dimension and Azs times – sin(theta)
for the theta dimension. This leaves us with the following
values:
del  A
H

  I 0  d
A s
4 r
 sin     e
 j R

From these values, then we can obtain the magnetic field
intensity from which the E and B-fields can be found. The
end results are as follows
that there is a minimum range on any single-antenna system,
small though it may be.
E. The Doppler Effect
Another concept important to radar is the Doppler Shift.
This concept, named after Christian Johann Doppler, who
discovered that the frequency of a wave observed at some
point is relative to it’s movement in relationship to it’s
transmission point. In the case of radar, there is typically
the same reception and transmission point, but the speed of
the object being pinged relative to the object detecting it still
matters. The equation for Doppler Shift can be found in our
fd
E
I0 d
4
 sin     e
I0 d
H
Er
4
I0 d  
2
 j2



2

 r
 j
 sin     e
 cos     e

 j2

 j2 r


1
2
r



j 2  r 

2

 r
 j

3



r 
1
2
2
0
 ( V  r)
case by using the equation
f
Where d is the frequency shift from the original, V is the

velocity vector of the target relative to the radar, and 0 is
the initial wavelength, and r is the unit vector starting at the
object towards the radar source. These can be seen in
Figure 3.

1 

2
3
r
j

2



r



These equations would suggest that the E-fields radiate
outward from the antenna as we already knew they do [9].
D. The Pulse System
Of course, for any signal sent out there must be some way to
determine if the signal hit an object. Were a constant signal
sent, there would be no way to tell which signal was
returning when and there would be much interference. In
response to this problem pulses are used, sending out one
pulse for each chosen interval around a complete circle. As
the radar scans a pulse must be given appropriate time to
return before another is emitted. The maximum usable
range of a radar system is then determined not only by the
power of the system, but by the length of time allowed for a
signal to return before the next pulse is given. The length of
time between pulses is called the Pulse Repetition Rate
(PRR). The range of the system is often limited by this
PRR, as the signal sent out is only good for as much time as
there is between pulses. If an object is far enough away that
the wave must doesn’t return until after the next signal is
sent out, that first signal is useless and should be
disregarded.
The accuracy of the system is also greatly influenced by
the PRR, as systems with faster pulse rates will typically be
set up to pulse more times per revolution of the antenna.
One other advantage to the pulse system is that it is this
concept that enables the antenna to be used for both
transmitting and receiving. This is because there is time
between the signals being sent by the transmitter in which
there is no transmission. Multiplexers within the system can
then be used to switch the modes. This switching does take
a very small amount of time, though, and as such there is a
time during which the antenna does nothing. This means
Fig. 3. Doppler Effect as seen in the case of two aircraft.
So, if radar was to detect a moving object such as a plane,
the returning signal would be at a shifted frequency. This
again applies to if radar were reflected by an object such as
the earth from a higher point such as a plane or satellite. All
that matters is the if the object is moving in relation to the
radar transmitter. If transmitter is moving, then that counts
towards the effect. Information on speed can be gathered
using the Doppler Effect.
F. Reflection Principles
One of the most important concepts pertaining to radar is,
of course, the reflection of r-f waves. Without the proper
reflection there image could not be obtained from a distant
object. Now, the waves used for radar can be regarded, at a
distance, to be similar in principles to uniform plane waves
(of course, uniform plane waves are impossible, but it’s
close enough), and so we will discover information about
the reflection of radar waves through a uniform plane wave
model.
The first case to examine would be the case of normal
incidence, in which a wave strikes a surface at a perfect
right angle. The plane wave
to be started with is defined as
E x1( z t)
E x10  e
  1z


 cos   t   1  x
E
Where x10 is some initial value of the E-field in the x
direction in medium 1 (the air in this case). There is also a
magnetic field associated with the wave which would have a
magnitude proportional to the magnitude of the E-field.
When this wave comes in contact with a surface at a right
angle, two things will happen. First, some of the energy will
continue on in this new medium. This energy would be
given in the equation
E xs2( z t)
E x20  e
  2z


 cos   t   2  x
This equation is the equivalent of the original equation of
the wave, but the value of the initial magnitude must be
different, unless this wave is to pass into the new medium
unaffected. In real life situations there must be some effect
of the boundary, though. In order for there not to be, the
both the electric and magnetic fields would have to be
perfectly preserved across a change in medium. That’s not
going to happen, so the magnitude in the second medium
must be smaller than the value before it went in (we’re not
making energy out of nothing here). However, that energy
does not simply disappear, so it stands to reason that it was
reflected, and in this case, it is moving directly back. We
E
will call the initial magnitude of this wave Rx10 , and
recognize that this wave is of the same form as the initial
wave, but is in the exact opposite direction.
Now, the energy differences at the boundary must be
resolved. To do this we acknowledge that the incoming
energy must be equal to the resulting energy, so (because all
but the magnitudes cancel out)
E x20  E Rx10
Also, the same will be true for the magnetic fields, so
we can obtain
E x10 E x20 E Rx10

1
2
3
E x10
where  is the value of the intrinsic impedance in the
appropriate medium, and E/h is the magnitude of the
magnetic field. Also, values for a reflection coefficient and
a transmission can be found with these equations,
respectively
21

2 1

1 
Of course, every given wave will not necessarily
contact a surface perfectly perpendicular to it, but one must
remember that the output of the transmitter is not going to
be a perfect single wave, but will be energy put out in a cone
like distribution and that will surely result in some normal
incidence contacts. These are the ones that truly matter for
monostatic radar then, as the energy that doesn’t hit in such
a fashion will not be reflected directly back at the source,
but will be reflected off into the abyss.
[[diagrams?]]
III. SYNTHETIC APERTURE RADAR
A. An Introduction to SAR
Now, radar is a method of obtaining information about
distant objects, somewhere along the line someone realized
that distance is not the only interesting information that one
can glean from a the return signal of radar. Determinations
can be made about the type of material being struck and the
shape (or topography) of the object. If one were to make the
target object the earth, significant information could be
found for the uses of geology and topography. Of course, a
satellite or a high flying plan would be needed to get above
the earth for these pictures, and at that range, the images
would be disastrously non-resolute. However, it turns out
that one can get high resolution pictures if a large
wavelength is used, but that requires an extremely large
antenna. So large, in fact, that it would be completely
impractical to put it even on the largest of planes.
That is where SAR comes in. SAR stands for Synthetic
Aperture Radar, and it is a method of essentially
synthesizing an effectively large antenna starting with only a
smaller one, more practical for use on a plane or satellite.
The transmitting vehicle’s own movement is used for this
process as will be detailed later.
SAR has many applications and reasons for further
development to be done. First of all, it is a good way to take
topographical data. The ranging uses of radar can be
applied here to find out about the contours of the earth.
Additionally, much can be found out about the materials of
the surface of the earth, or even slightly under the earth’s
surface. Different reflection indices provide valuable
information here. Moving objects can also be addressed by
the shifted frequencies (compliments of the Doppler Effect)
being filtered and taken note of. Of course, there is also the
potential for reconnaissance work. The accuracy of the
SAR images is not nearly as good as with satellite photos for
right now, but SAR has one large advantage: it is not a
passive system. Photos rely on the sun to provide light, but
radar relies on itself for the energy, and so can image just as
well at night.
B. The Desired Image Output
A great deal of work has been done by engineers to come
up with the equipment and algorithms that enable SAR to
give accurate pictures. The pictures now produced generally
help with geological issues now days, as they show the
different materials that make up the landscapes. In Figure 4
different shades can be seen that make up the picture of the
Mississippi Delta. The shading would typically show relief,
and then color would be used to show the different materials
that make up the land.
While the relief is found using the time it took for the
wave to return (and the phase) the material can be
determined using the distance and the magnitude of the
return signal. This works because the reflected signal will
depend upon the texture of the material (if it is jagged it will
scatter more of the wave) and the material. The angle of the
material will also affect the return. A flat surface will often
reflect very little to the radar because the viewing angle is
on an angle, so water returns a very dark image. A rough
surface, though, will return some for all viewing angles, so
something like a forest will show up bright. Despite that a
large body of water will be dark due to it being flat, wetter
objects tend to show up brighter because they reflect r-f
waves better.
get the required large wave length (which is needed for
reasons to be seen later). However, to scan the desired
areas, an aerial mount is needed, so a gigantic antenna is not
practical.
Instead, an larger antenna aperture is simulated (hence
the name synthetic aperture radar). This is accomplished by
using the fact that a plane or satellite with the radar mounted
on it will be moving. This way, a very large wavelength can
be used, which allows interferometry to be performed and
higher resolution to be obtained.
The first large advantage of the long wavelength is that
it is perfect for penetrating mild obstacles. With smaller
wavelengths clouds and non-solid obstructions could cause a
problem. However, SAR can penetrate these conditions. In
fact, some systems use very low wavelengths to actually
penetrate the ground to find what the underground soil is
made of.
The second large advantage from a longer wavelength
is the phase of the wave changes only a small amount for a
significant distance, so, within that bit of error already
associated with normal radar the distance can be figured
more closely using phase angles.
As for the synthesis of the longer aperture, it is the
movement of the vehicle on which the radar is mounted that
is used. Aperture refers to the “opening” that is used to
take in the signal. It’s not actually an opening in this case,
like it would be on the camera, but is instead related to the
antenna size. The Figure 5 gives an idea of how this works
Fig. 5. Echoes and SAR [4].
Fig. 4. SAR Image of the Mississippi Delta [4].
C. The Synthetic Aperture
Now, it has been illustrated that object detection through
radar is possible, but the creation of an image is another
story all together. The fact remains that conventional radar
can have errors of up to 8 meters due to the timing issues at
the heights necessary for large-scale pictures of the earth.
With the r-f wave moving at the speed of light, the
difference between two close objects can be considered
negligible, and an area of relief would not stand out from the
surrounding area.
In order to accommodate the need for greater accuracy, a
system with an extremely large antenna would be needed to
As the antenna moves along it receives signals (called
echoes in this case) which are then stored for future
reference when reconstructing the result. The radar is
focused at a point in the middle of its path so that it is
approaching it for half the time and moving away from it the
other half. This way, there is a Doppler Shift, first negative,
then positive. [JPL website] This way, many signals can be
put out to the same target and can be sorted by the variation
in the returning frequency. Of course, much accuracy in the
relative speeds is needed to find the exact Doppler Shifts
needed, but that is extremely feasible with today’s modern
airplanes and satellites. The compilation of these echoes
over the distance simulates a longer antenna, enabling a
long wavelength.
Additionally, it is worth noting that in an SAR
application, the direction the vehicle is moving in is referred
to as the azimuth direction, and the direction directly
perpendicular to the azimuth but parallel to the ground is the
range direction. The range resolution for SAR is very good,
but the azimuth resolution, without some interpolation, is
lacking.
C. Interferometry Background
Interferometry is the practice of using interference to find
how a wave has traveled. With longer wavelengths that are
afforded by SAR, the phase of the returning signal can
provide key information for ranging. The key is all in the
interpretation. Used in conjunction with the amount of time
that the signal took to return, the results can be extremely
accurate.
An interferometer can be defined as any
instrument that uses interference for measurement.
The interferometry most people are familiar with is that
used in a telescope or a Michelson interferometer. These are
both optical applications, but their principles carry over
directly to electromagnetics. The treatment of light in the
case of interferometry is as a wave of the same manner as an
r-f wave, so the cases seen in these optical applications
actually are even more suitably applied to electromagnetics
(seeing as light waves aren’t true sinusoidal waves in every
sense).
To go into more detail about the nature of
interferometry, we shall start with a simple setup with two
antennae A1 and A2 as in Figure 6 (interferometry does
require two antennae for the interaction of the waves).
      2 2

  B   cos   
2 



z( y ) h 
  
2  B  sin       

 2 
While the method of checking one spot from multiple
points is the most common, there are some systems that
actually require planes to do the same run and gather
information on different points on different occasions to get
more or less the same results as in the previous example.
This is only possible because of the extreme precision in
which modern technology helps our tracking techniques
now days, so that the exact location of the radar antenna can
be known at all times and recorded for later use. However,
there is the distinct possibility that the landscape could
change due to weather or the actions of humans or some
other event between passes.
The process of obtaining information on topography
through use of phase angle is referred to as interferometry.
The reason for this is that the phase of the wave is obtained
using it’s interaction with other waves, or its interference.
By setting up some test wave against the incoming wave, the
interference patterns can be used to find out with just what
phase angle the wave is coming in at, making all of this
possible.
D. Phase Unwrapping
Fig. 6. Two-antenna interferometry geometry [4].
If A1 transmits and receives and A2 receives only (as in the
first two echoes taken for SAR), the difference in distance
the ground and antenna can be found by looking at the phase
angle when the return signal hits either antenna as long as
the difference can be presumed to be within one wavelength
so that the 2*pi factor is not ambiguous.
To find the difference in the phase angle for the
system in Figure 6 then we can apply the rule of cosines and
obtain
   2
  B  2   B  cos    90   
2
2
Where roe is the distance from the point being looked at to
the antenna. Within the bounds of one wavelength, the
difference in distances from A1 to z and A2 to z can be
summed as follows

 
2
Where the phi is the phase angle.
Plugging this into
Equation XXX and doing a bit of rearranging we can then
get
The major conflict in interferometry is that the phase,
when detected, is “wrapped.” This means that the phase has
been forced in between negative pi and pi. This is to
accommodate the sine wave form, of course, and the wave
keeps no record of how many times it has gone through a
phase. Somehow this count must be extracted from the
information at hand. The current phase angle must be
unwrapped to reveal the true phase of the wave.
There are two main phase unwrapping methods: pathfollowing and minimum-norm. The path-following methods
unwrap the phases by integrating the gradients along certain
paths. The minimum-norm methods minimizes the distance
between the gradient of the wrapped phase and some model
it compares it to. The issue, however, is that there is a good
deal of noise present in real life, and the algorithms for
unwrapping the phase are extremely complicated.
E. Imaging
Of course, not every point on the earth can be looked at
individually, so what ends up being taken is an average of
the an array of different points is taken. This average is not
a constant for the entire field being looked at, but is instead
a moving average that can approximate what should be
where fairly well.
The results that comes from some SAR receiver
before imaging might look similar to that in Figure 7. The
first graph gives the values along a distance. These values
would be for the input after “de-chirping” which is the
process of reassembling the return signal from the echoes
recorded by the SAR. Some resolution then has to be
chosen that represents the pixel spacing for the image. This
pixel spacing is what determines the resolution. The values
for each pixel are then averaged in that moving average
form, and this would then be one row of the image. Now,
the actually SAR system would have an array of sensors to
cover some greater width, and there would be similar graphs
for each, creating the second dimension of the image. A
typical SAR antenna array is 10m x 1m. The resolution in
the direction perpendicular to the vehicle’s flight but parallel
to the earth would be dependent upon the characteristics
built into the radar on board the ship and would not depend
on the processing so much.
Fig. 7. Example return signal [2].
Since the electromagnetic waves returned to the SAR
system consist of chirps of a certain bandwidth along a
carrier frequency a technique called shift theorem can be
used to extract the pertinent information. The signal can be
multiplied by
i2 o t
e
in order to make the Forier Transform of the signal shift up

by the carrier frequency o . Now the segment of the
Forier Transform that was at -wo is at 0 and the rest of the
garbage can be filtered out with a low-pass filter. Now
sampling the signal can be done much more efficiently and a
digitized version of this would be what is taken from the
assembly on the or satellite.
The next step would be for something called range
processing to be performed on every echo. The
compression is usually carried out by using Fourier
transformation to achieve convolution of received signals
and a reference function. The reference function of range
compression is the complex conjugate of the transmitted
signal. Then what is looked at is called “range migration.”
This is the change in the slant angle to the object being
looked at as the radar apparatus moves along its course.
This migration is expressed in a quadratic equation with the
variable being time.
Now, azimuth compression is performed. This
compression is what leaves the aperture officially
synthesized. The theory behind this is that two points at
different places on an azimuth will have two distinct
Doppler frequency shifts. A matched filter corresponding to
the reverse characteristics of chirp modulation can be used
then to improve the resolution in the azimuth direction,
which is otherwise very poor. The reference of azimuth
compression is a complex conjugate of the modulated signal
by chirp modulation. The results of these two compression
processes can be seen in Figure 8.
Fig. 8. Compression Results [7]
The term “matched filter” refers to integrating the
received signal against a shifted complex conjugate of the
transmitted signal. This would be the equivalent of
matching a received signal to the corresponding signal that
would have been received from a surface at the point being
dealt with. This is also called “backprojection” and
basically sums all the signals to which some surface at a
point being dealt with could have contributed. This means
that all spheres that pass through that point would be
subjected to the summing. The same process is applied to
each possible antenna location that is taken over the course
of one run for the synthetic aperture, and that summing is
what simulates a longer aperture.
IV. CONCLUSION
Radar is an extremely complex topic that gives a very
good example of the practical applications of
electromagnetic waves. Radar has uses beyond military,
including the fascinating field of SAR imaging. SAR
images not only give us a glimpse at the shape of the land
around us, but of what it is made of. This topic continues to
be developed for a variety of purposes, and has much room
for the perfecting with better systems and algorithms. The
mathematical models for imaging are very complex and are
just one of the aspects of radar that engineers are still
forging ahead in.
REFERENCES
[1] G. Goebel. (2003, February 01). Basic Principles of
Radar. V1.0.0. Available:
http://www.vectorsite.net/ttradar1.html
[2] European Space Agency. (2004, May 16). Radar Course
III. Available:
http://earth.esa.int/applications/data_util/SARDOCS/sp
aceborne/Radar_Courses/Radar_Course_III/
[3] B. Chapman. (1995, September 8). Basic Principles of
SAR Interferometry.
[4] Cheney, Margaret. Introduction to Synthetic Aperture
Radar (SAR) and SAR Interferometry. JPL. Available:
http://southport.jpl.nasa.gov/scienceapps/dixon/report2.
html
[5] Basic Radar Principles and General Characteristics.
National Geospacial Intelligence Agency. (2004, May
15). Available:
http://pollux.nss.nima.mil/NAV_PUBS/RNM/RnmTOC
.pdf
[6] H. Raemer, Radar System Principles. Boca Raton: CRC
Press, 1997.
[7] Remote Sensing. Japan Association of Remote Sensing,
1996. Available:
http://www.profc.udec.cl/~gabriel/tutoriales/rsnote/cont
ents.htm
[8] G. Dardyk and I. Yavneh. A Multigrid Approach to 2D
Phase Unwrapping. January 12, 2003. Available:
http://www.mgnet.org/mgnet/Conferences/CopperMtn0
3/Papers/dardyk.pdf
[9]W. Hayt, Jr. and J. Buck.
Engineering
Electromagnetics. Boston: McGraw-Hill, 6th Edition,
2001.
Michael LaGrand (M ’03) was born in Grand Rapids,
Michigan, April 21, 1982. He will be graduating in 2004
from Calvin College with a Bachelors in Electrical
Engineering.