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Seminar Report on UWB FM -CW RADAR
1. A Study of UWB FM-CW Radar for the Detection of Human Beings in Motion Inside a Building
radar situated outside but in the vicinity of
the
first
wall.
After
modeling
the
propagation through various walls and
Abstract
quantifying the backscattering by the human
Today world is going very fast in
body,
an
analysis
of
the
technical
terms of technology, and triggering to latest
considerations which aims at defining the
technologies,
technologies
radar design is presented. Finally ultra
evolved far back is detecting humans, the
wideband (UWB) frequency modulated
detection of human beings is done in various
continuous
ways like Imaging Techniques, Sensing
proposed, designed, and implemented. The
Techniques, both the imaging and sensing
FM-CW Radar with an extended frequency
techniques will work when the human is in
sweep form 0.5 to 8 GHz is presented it has
front of the equipment or the machine, the
been applied to the TTW human detection.
disadvantage of the imaging and sensing
Some representative trials show that this
techniques can’t detect humans behind the
radar is able to localize and track moving
obstacle, this disadvantage evolved to detect
people behind a wall in real time. This
human beings behind the walls or obstacles
Radar will enable large stand-off distance
this can be achieved using RADAR. We
capabilities and in depth building detection.
one
of
the
know that Radar is conventional and
commercial equipment that had been serving
wave
(FMCW)
radar
is
1. INTRODUCTION
for different purposes in different ways, the
Here we assess human detection through
working nature of radar helped to improve
the wall using UWB (Ultra Wide Band)
the security more by introducing the latest
radars, we know that radar stands for radio
technology i.e, through the wall human
detection and ranging, i.e, using RADAR we
detection.
can find the Range, Direction and angle of
The
technology
through-the-wall
(TTW) radar demonstrator for the
the object, radar uses electromagnetic waves
that are transmitted by the transmitter into
the air to detect the object or reflecting
detection and the localization of people in a
material, the reflected echo signal from the
room (in a no cooperative way) with the
object must be in the direction of the
Receiver to find the range, there are
1
2. A Study of UWB FM-CW Radar for the Detection of Human Beings in Motion Inside a Building
different
types
of
radars
have
been
developed for different applications
which distracts rescuers from locations
where living people can still be found [1].
Due to the ability of electromagnetic waves
The detection of humans hidden by walls
to
penetrate
through
typical
building
or rubble, trapped in buildings on fire or
materials and its significant (in order of
avalanche victims are of interest for rescue,
centimeters) spatial resolution, UWB radar
surveillance and security operations. The
is considered as preferred tool for detection
problem of rescuing people from beneath the
and localization of people. Detection of
collapsed buildings does not have an
human beings with radars is based on
ultimate technical solution that would
movement detection – respiratory motions
guarantee efficient detection and localization
and movement of body parts. These motions
of victims. The main techniques used are:
cause
Cameras with long optical fibers that are
amplitude and periodic differences in time-
injected into the holes or fissures in the
of-arrival of scattered pulses from the target,
collapsed buildings (the usability of such
which are result of periodic movements of
devices and their efficiency depend on the
the chest area of the target [2].
structure of collapsed building and besides,
Typical radar applications are listed here to
when the victim is detected it is difficult in
give an idea of the huge importance of
the most cases to determine its actual
radar in our world.
position). Sledge hammers are used to give a
Surveillance
signal to potential victims, and rescuers with
Military and civil air traffic control, ground-
microphones are waiting for hearing the
based, airborne, surface coastal,
response (obvious limitation of this method
satellitebased
is that unconscious people cannot be
Searching and tracking
detected. Localization of victims is a
Military target searching and tracking
problem as well). Search dogs are deployed
Fire control
in the disaster area. They detect presence of
Provides information (mainly target
victims efficiently by smell, but information
azimuth, elevation, range and velocity) to a
about their actual positions or quantity
firecontrol
cannot be indicated. Moreover, dog is likely
system
to indicate the presence of dead person
Navigation
changes
in
frequency,
phase,
2
3. A Study of UWB FM-CW Radar for the Detection of Human Beings in Motion Inside a Building
Satellite, air, maritime, terrestrial navigation
countries all around the world. It addresses
Automotive
the ability to see behind walls in order to
Collision warning, adaptive cruise control
detect, count, and localize people inside a
(ACC), collision avoidance
building. We would like to remain at large
Level measurements
stand off distances (5-10 or even 50 m) if
For monitoring liquids, distances, etc.
possible, according to the allowed emitted
Proximity fuses
power. TTW Radars utilize frequencies
Military use: Guided weapon systems
ranging from UHF to S band in order to
require a proximity fuse to trigger the
have better wall penetration for any kind of
explosive
wall. It is further more recommended to use
warhead
ultrawideband (UWB) modulations in order
Altimeter
to achieve range resolution for human
Aircraft or spacecraft altimeters for civil and
localization
military use
propogation
Terrain avoidance
(TTW)
Airborne military use
electromagnetic “vision” behind walls in
Secondary radar
order to detect, count, and localise people
Transponder in target responds with coded
inside a building. Considering one by one
reply signal
these three objectives: detect, count, and
Weather
localise, it is possible to situate our work
Storm avoidance, wind shear warning,
among the various researches that are
weather mapping
ongoing in the TTW radar field.In order to
Space
detect one or more persons in a room, it is
Military earth surveillance, ground mapping,
necessary to take into account the fact that
and exploration of space environment
these people move. In fact, the radar return
Security
coming from the human body is not high
Hidden weapon detection, military earth
surveillance
Through
and
to
channel.
radar
deal
with
indoor
Through-the-wall
technique
addresses
enough compared to the backscattering of
the indoor environment to ensure detection.
The Wall
(TTW) human
detection using radar is a relatively new
topic that has been investigated in many
So that, Doppler effect has been used
historically to detect motion through walls
[1]. Nevertheless, Doppler radar has also
3
4. A Study of UWB FM-CW Radar for the Detection of Human Beings in Motion Inside a Building
some drawbacks. The first one is its high
considerations which aims at defining the
sensitivity to all kinds of motions bringing
best radar design. And finally, Sections 5
false alarms. The second one is that target
and 6 present the radar implementation and
localisation and Doppler filtering seems
a trial of people detection and localization
incompatible. This is why emphasis was
through a wall.
made on imaging radar with the ability to
count and localise targets.Small TTW radars
based on the technology of UWB pulses
appeared since the 2000s. The famous ones
So many radars have been developed to
detect ranges of any distinct object, the
various radars are
by
1. Pulsed Doppler radar
CAMERO. There is no publication about
2. Continous wave radar
them in the open literature. Besides, some
3. FM-CW radar
radar and signal processing specialized
4. MTI Radar
laboratories
5. Phased Array Radar
are
Radarvision
and
have
then
studied
Xaver
UWB
radar
imaging or SAR imaging applied to through-
6. Synthetic Aperture Radar
wall vision [2, 3].The work presented here
7. Bi Static and Multi Static radar
gives the last advances from our laboratory
8. Passive Radar
in the “see-through” radar topic. It aims at
9. Multimode Radar
giving a global approach of the TTW radar
detection. It shows step by step the design
process
after
radar
modelling:
from
theoretical background to radar realization
followed by experimental assessment.
In
Section
2,
the
through-the-wall
propagation physics has been studied by
simulation
and
also
assessed
by
measurements. Then, in Section 3, the
backscattering strength of the human body is
quantified in an anechoic chamber with
various people under test. Section 4 is
centred
on
an
analysis
of
technical
4
5. A Study of UWB FM-CW Radar for the Detection of Human Beings in Motion Inside a Building
penetrating,
foliage
penetrating;
’ultra
high
frequency’
Long-range
air traffic
control and
surveillance;
'L' for 'long'
L
1–2
GHz
15 cm to
30 cm
S
2–4
GHz
7.5 cm to
15 cm
Terminal air
traffic
control, longrange
weather,
marine radar;
'S' for 'short'
C
4–8
GHz
3.75 cm
to 7.5 cm
Satellite
transponders;
a
compromise
(hence 'C')
between X
and S bands;
weather
radar
X
8 – 12
GHz
2.5 cm to
3.75 cm
Missile
guidance,
marine radar,
weather,
mediumresolution
mapping and
ground
surveillance;
in the USA
the narrow
range 10.525
GHz ± 25
MHz is used
for
airport
radar. Named
X
band
2. Literature Survey
Before moving into the different types of
radars used for different applications, let’s
check the radar frequencies, Bands,
Wavelengths and its applications.
2.1. Radar Frequencies, - Bands,
Wavelength and Applications
Ban
d
HF
Frequen
cy
Wavelen
gth
Application
3-30
Mhz
10m100m
Coastal radar
systems,
over-thehorizon
(OTH)
radars; ’high
frequency’
’P’
for
’previous’,
applied
retrospectivel
y to early
radar
systems
Very
long
range (e.g.
ballistic
missile early
warning),
ground
P
30 to
300 Mhz
1m to 10
m
UH
F
3001000Mh
z
0.3-1m
5
6. A Study of UWB FM-CW Radar for the Detection of Human Beings in Motion Inside a Building
because the
frequency
was
kept
secret during
World War
2.
KU
12 – 18
GHz
1.67 cm
to 2.5 cm
Highresolution
mapping,
satellite
altimetry;
frequency
just under K
band (hence
'u')
trigger
cameras that
take pictures
of
license
plates
of
carsrunning
red
lights,
operates at
34.300
±
0.100 GHz
Ka
18 – 27
GHz
27 – 40
GHz
1.11 –
1.67 cm
0.75 cm
to 1.11
cm
K band is
used
by
meteorologis
ts
for
detecting
clouds and
by police for
detecting
speeding
motorists. K
band radar
guns operate
at 24.150 ±
0.100 GHz.
Automotive
radar uses 24
– 26 GHz.
Mapping,
short range,
airport
surveillance;
frequency
just above K
band (hence
'a');
photo
radar, used to
40 – 300
GHz
1 mm to
7.5 mm
Q
40 – 60
GHz
5 mm to
7.5 mm
V
K
Mm
50 – 75
GHz
4 mm to 6
mm
Very
strongly
absorbed by
the
atmosphere
W
75 – 110
GHz
2.7 mm to
4 mm
76 GHz LRR
and 79 GHz
SRR
automotive
Millimeter
band,
subdivided
as
below.
The
letter
designators
appear to be
random, and
the
frequency
ranges
dependent on
waveguide
size.
Multiple
letters
are
assigned to
these bands
by different
groups
Used
for
military
communicati
ons
6
7. A Study of UWB FM-CW Radar for the Detection of Human Beings in Motion Inside a Building
radar, highresolution
meteorologic
al
observation
and imaging
delay between the transmitted and received
signal the distance to the plane can be
calculated. Additional information can be gained
from the frequency shift of the received signal,
which is proportional to the speed of the plane.
Receiving a signal of sufficient power by an
adequate power to noise ratio is the biggest
2.2. Radar Equation
The acronym RADAR stands for Radio
Detection And Ranging. Figure 1 shows the
basic principle.
challenge of radar systems. The so called .Radar
Equation. gives hints on the power relations
within the system as indicated in Figure1. The
Radar Equation delivers the received power Pr
as result. According to the Radar Equation
following independent parameters determine the
received power Pr.
Pt: The power transmitted by the antenna,
dimension is dBm. Numeric examples : 63
dBm for real world Radar applications, 13
dBm for laboratory tests
G: Gain of the transmitting antenna,
dimension in dBi. The parameter determines
how much the radiation beam of the antenna
is focused toward the direction of the target.
Numeric examples are 12 dBi for a BiQuad
antenna and 70 dBi for a highly focusing
parabolic antenna.
Figure 1: Basic principle of Radar and its
parameters
σ is
An electromagnetic wave of power Pt is
transmitted to a flying object, for example to a
plane and is partly reflected back to the antenna
The wavelength of the transmitted
signal, dimension in meter. The wavelength
can
be
directly
calculated
from
the
frequency. Numeric examples: 0.03 m for a
with the receiving power Pr. From the time
7
8. A Study of UWB FM-CW Radar for the Detection of Human Beings in Motion Inside a Building
10 GHz signal and 0.12 m for a 2.54 GHz
signal
Parame
Abbrevi
ter
ation
Value Value
,
Exam
Radar cross section, RCS, is a virtual area
Exam
ple 2
representing the intensity of the reflection.
Uni
ple 1
Not all of the radiated power is reflected
Transm
back to transmitting antenna, as indicated by
itted
the small waves close to the plane in Figure
power
1. The .Sigma. ( ) of the objects determines
Gain of
the virtual area of the reflecting object
transmi
(plane) from which all of the incoming
t
radiation energy is reflected back to the
antenna
antenna. The dimension is square meter,
Wavele
.m2. in short. Practical examples are 12 m2
t
Pt
63
13
dB
m
G
28
12
dBi
(f)
0.03
0.12
m(
ngth
(10*1
(2.5*1
Hz)
for a commercial plane, 1 m2 for a person or
(freque
09)
09)
0.01 m2 for a bird. Refer to [18], page 6665
ncy)
12
0,3
m2
R
8114
5
m
Pr
1
17.4*
pW
for further
Radar
examples.
cross
section
R: Distance between the transmitting
Distanc
antenna and the reflecting object. Dimension
e
in m. Numeric examples are 8000 m for real
world applications or 5 m for laboratory
Receive
conditions. It has to be stressed that this
d
parameter reduces the result, i.e. the
power,
received signal by the power of 4, with the
linear
effect that far distant objects are providing
Receive
only a small amount of received power.
d
103
Prlog
-90
-48
dB
m
power,
Table 1: Parameters of Radar Equitation and two
examples
logarith
mic
8
9. A Study of UWB FM-CW Radar for the Detection of Human Beings in Motion Inside a Building
example 1 the received reflected power of
Example 1 shows a a real world example,
example 1 is almost 50 dB lower than the
derived from [Pozar], example 2 shows a
received signal of example 2. The reason is
radar application which can be realized
the smaller wavelength lambda which
under laboratory conditions for example
affects the result by a power of 2 and
in an anechoic chamber.
especially the bigger distance R of example
1 which affects the result by a power of 4.
Example 1 read in clear text : A radar
Small wavelengths, i.e. high frequencies are
transmitting antenna with gain of 28 dBi is
aimed for in most radar systems, especially
transmitting an electromagnetic wave at 10
in antenna arrays, because of the resulting
GHz with a power of 63 dBm to a plane in a
small antenna size. It is obvious also, that in
distance of about 8000 m. The plane has a
radar technology one has to deal with very
radar cross section of 12 m2 . By means of
small receiving power especially for far
the Radar Equation the received power back
distant objects.
at the antenna is calculated to -90 dBm.
2.3. Common Radar types for
Example 2 read in clear text: In a radar test
Common Applications
laboratory implemented in an anechoic
chamber a test transmitter provides 13 dBm
to a matched antenna of 12 dBi with a
2.3.1.Simple Pulse (Range) and Pulse
Doppler (Speed/Range)Radar
frequency of 2.5 GHz. The reflecting object
with a cross section of 0.3 m2 is located in 5
m distance from the transmitting antenna.
According to the Radar Equation the test
receiver is going to receive a reflected signal
of -48 dBm.
When comparing example 1 to example 2
we can conclude that despite much bigger
Basic principle of a simple pulse radar system
transmitting power, better transmit antenna
gain and bigger radar cross section in
9
10. A Study of UWB FM-CW Radar for the Detection of Human Beings in Motion Inside a Building
A simple pulse radar system only provides
receiver, peak power, frequency stability,
range (plus direction) information for a
phase noise of the LO and all of the pulse
target based
parameters.
on the timing difference between the
The AGC circuit of the receiver
transmitted and received pulse. It is not
protects the radar from overload conditions
possible to
due to nearby collocated radars or jamming
determine the speed. The pulse width
counter measures. The attack and decay time
determines the range resolution.
of the AGC circuit can be varied based on
the operational mode of the radar. Since the
roundtrip
of
a
radar
signals
travels
approximately 150 meters per microsecond,
it is important to measure the response of the
AGC for both amplitude and phase response
when subject to different overload signal
conditions. The measured response time will
dictate the minimum detection range of the
radar.
Pulse Doppler radar
Direction information with azimuth angle
determination in a radar system with a rotary
antenna
The direction information (azimuth angle) is
determined from the time instant of the
receive
pulse
with
reference
to
the
instantaneous radiation direction of the
rotating
antenna.
measurements
on
The
important
(non-coherent)
radar
equipment of this sort are the range accuracy
and resolution, AGC settling time for the
A pulse Doppler radar also provides
radial speed information about the target in
addition to range information (and direction
information). In case of coherent operation
of the radar transmitter and receiver, speed
information can be derived from the pulseto-pulse phase variations. I/Q demodulators
are normally used. The latest pulse Doppler
radar systems normally use different pulse
repetition frequencies (PRF) ranging from
10
11. A Study of UWB FM-CW Radar for the Detection of Human Beings in Motion Inside a Building
several hundred Hz up to 500 kHz in order
to clarify any possible range and Doppler
result in added noise contribution
uncertainty.
ambiguities. More advanced pulse Doppler
radar systems also " use "staggered PRF, i.e.
the PRF changes on an ongoing basis to get
Reference
(or
timebase)
clock
stability.
rid of range ambiguity and reduce clutter as
well. Important criteria for achieving good
Jitter or uncertainty due to the
performance in pulse Doppler radar systems
measurement point of the rising edge
include very low phase noise in the LO, low
of
receiver noise and low I/Q gain phase
interpolation or signals that have
mismatch (to avoid "false target indication")
changing
in addition to the measurement parameters
uncertainty.
the
signal
edges
.
rising
impact
edge
this
listed above. When measuring the pulse-topulse performance of a radar transmitter, it
Overshoot and preshoot of the rising
is important to understand the variables that
and falling edges . any ringing on the
can
the
rising and falling edges can impact
measurement system for accurate Doppler
the measurement points adversely on
measurements:
a pulse to pulse basis. It is important
impact
the
uncertainty
of
that the measurement point, or the
Signal-to-noise ratio of the signal the better the signal to noise ratio of
uncertainty
are sufficiently far
away in time from the leading and
the signal, the lower
the
average set of measurement points,
due
to
noise
contribution.
falling edges of a pulse. Applying a
Gaussien filter to smooth the impact
of the rising and falling edges can
Bandwidth of the signal - the
reduce this phenomena and is often
bandwidth of the IF acquisition
implemented
system must be sufficient to
measurement system of a radar
accurately represent the risetime of
in
the
Doppler
receiver.
the pulsed signal, however too much
bandwidth can
11
12. A Study of UWB FM-CW Radar for the Detection of Human Beings in Motion Inside a Building
Time between measured signals . due
detecting slow changes in the received field
to the PRI of the measured signal,
strength
due
to
variable
the close-in phase noise of the
interference
conditions that may exist.
measurement system needs to be
considered due to the integration
time at lower offset frequencies.
Radar speed traps operated by the
police use this same technology. Camera
systems take a picture if a certain speed is
The
same
variables
can
also
contribute to the uncertainty in the
exceeded at a specified distance from the
target.
signal generator when testing the
receiver
circuit
and
Doppler
measurement accuracy.
Continuous Wave (CW) Radar:
A continuous wave (CW) radar
system with a constant frequency can be
used to measure speed.However, it does not
provide any range (distance) information. A
signal at a certain frequency is transmitted
via an antenna. It is then reflected by the
target (e.g. a car) with a certain Doppler
frequency shift. This means that the signal’s
Mobile
traffic
monitoring
radar
reflection is received on a slightly different
MultaRadar CD - Mobile speed radar for speed
frequency. By comparing the transmitted
enforcement from Jenoptic
frequency with the received frequency, we
can determine the speed (but not the range).
Here, a typical application is radar for
There are also military applications:
CW radars are also used for target
monitoring traffic.
illumination. This is a straightforward
Radar motion sensors are based on the same
application: The radar beam is kept on target
principle, but they must also be capable of
by linking it to a target tracking radar. The
12
13. A Study of UWB FM-CW Radar for the Detection of Human Beings in Motion Inside a Building
reflection from the target is then used by an
due to the lack of atiming reference.
antiaircraft missile to home in on the target.
However, it is possible to generate a timing
CW radars are somewhat hard to detect.
reference
Accordingly, they are classified as low-
stationary objects using what is known as
probability-of intercept radars.
"frequency-modulated
for
measuring
the
continuous
rangeof
wave"
(FMCW) radar. This method involves
CW radars lend themselves well to
transmitting a signal whose frequency
detecting low-flying aircraft that attempt to
changes periodically. When an echo signal
overcome an enemy’s air defense by
is received, it will have a delay offset like in
"hugging the ground". Pulsed radar has
pulse radar. The range can be determined by
difficulties
between
comparing the frequency. It is possible to
ground clutter and low-flying aircraft. CW
transmit complicated frequency patterns
radar can close this gap because it is blind to
(like in noise radar) with the periodic
slow-moving
can
repetition occurring at most at a time in
pinpoint the direction where something is
which no ambiguous echoes are expected.
going on. This information is relayed to co-
However, in the simplest case basic ramp or
located pulse radar for further analysis and
triangular modulation is used, which of
action. [7]
course will only have a relatively small
in
discriminating
ground
clutter
and
The disadvantage of CW radar is that
unambiguous measurement range.
it cannot detect the Range due to Narrow
Bandwidth of the transmitted signal, to
measure the range we are moving forward to
the Frequency modulated transmitted signal,
which can be used to find the range of ay
distinct object.
FM-CW
Radar
(
Frequency
Modulated – Continuous Wave)
The disadvantage of CW radar
systems is that they cannot measure range
13
14. A Study of UWB FM-CW Radar for the Detection of Human Beings in Motion Inside a Building
Basic principle of FMCW radar. The target’s
velocity is calculated based on the measured delay
t
between the transmit signal and the received
signal, whereas the frequency offset gives the
f
offset vs. the transmitted frequency which is
proportional to their speed (e.g. in linear FM
radar).
range
In pulse radar systems, the pulses
This type of range measurement is
reflected by moving objects have a variable
used, for example, in aircraft to measure
phase from pulse to pulse referenced to the
altitude (radio altimeter) or in ground
phase of the transmitted pulses.
tracking radar to ensure a constant altitude
above ground. One benefit compared to
pulse radar is that measurement results are
provided continuously (as opposed to the
timing
grid
of
the
pulse
used commercially for measuring distances
other
ways,
e.g.
level
Technology
repetition
frequency). FMCW radar is also commonly
in
3. UWB RADAR
indicators.
Automotive radar is in most cases FMCW
Ultra Wideband technology has been an
extremely evolving technology because of
its appealing characteristics like achieving
high data rates, more capacity as compared
to narrowband systems, and co-existence
radar too
with the existing narrowband wireless
Moving-Target
Identification
(MTI)
technologies. A signal is categorized as
UWB if its bandwidth is very large with
Radar
respect to its center frequency. That results
The idea behind MTI radar is to
suppress reflected signals from stationary
and slow-moving objects such as buildings,
mountains, waves, clouds, etc. (clutter) and
thus obtain an indication of moving targets
such as aircraft and other flying objects.
Here, the Doppler effect is exploited, since
signals reflected by targets moving radially
with respect to the radar system exhibit an
that the fractional bandwidth should be very
high. The FCC defines UWB as a signal
with either a fractional bandwidth of 20% of
the center frequency or 500 MHz (when the
center frequency is above 6 GHz). The
formula proposed by the FCC commission
for calculating the fractional bandwidth is
[3, 4]: Where fH represents the upper
frequency of the -10 dB emission limit and
14
15. A Study of UWB FM-CW Radar for the Detection of Human Beings in Motion Inside a Building
fL represents the lower frequency limit of
frequencies. Impulse radios operating in the
the -10dB emission limit
highly populated frequency range below a
few gigahertz must contend with a variety of
UWB is based on the generation of very
interfering signals. They must also guarantee
short duration pulses of the order of
that they do not interfere with the narrow-
picoseconds. The information of each bit in
band radio systems operating in dedicated
the binary sequence is transferred using one
bands. These requirements necessitate the
or more pulses by code repetition. This use
use of spread spectrum techniques. A means
of number of pulses increases the robustness
of spreading the spectrum of the ultra-
in
In
wideband pulses is to employ time hopping
UWBcommunications there is no carrier
with data modulation accomplished by
used and hence all the references are made
additional pulse position modulation at the
with respect to the center frequency. In Ultra
rate of many pulses per data symbol. The
wideband communications, a signal with a
use of signals with gigahertz bandwidth
much larger bandwidth is transmitted with a
means that multipath is resolvable down to
reduced
This
path differential delays on the order of
approach has a potential to produce signal
nanoseconds or less i.e. down to path length
which has higher immunity to interference
differentials on the order of foot or less. This
effects and improved time of arrival
significantly reduces fading effects even in
resolution. Ultra wide band communications
indoor environments. The advantages of
employ the technique of impulse radio.
UWB
Impulse radio communicates with the help
systems are [3]:
the
transmission
power
of
spectral
each
bit.
density.
over
conventional
narrowband
of base band pulses of very short duration of
the order of nanoseconds, thereby spreading
Large Instantaneous bandwidth that
the energy of the signal from dc to few
enables fine time resolution for
gigahertz. The fact that the impulse radio
network time
system operates in the lowest possible
frequency band that supports its wide
transmission bandwidth means that this
distribution,
precision
location
capability, or use as a radar.
Short duration pulses that provide
radio has the best chance of penetrating
robust
objects which become opaque at higher
performance
in
dense
multipath
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16. A Study of UWB FM-CW Radar for the Detection of Human Beings in Motion Inside a Building
environments by exploiting more
resolvable paths.
Low power spectral density that
allows coexistence with existing
users and has a
Low Probability of Intercept (LPI).
Data rate may be traded for power
spectral
density
and
multipath
performance
3.1Salient Features of Ultrawideband Radars
Maximum range and data rate of different
wireless technologies
3.1.1 High Data rate
Low power consumption
UWB can handle more bandwidthintensive applications like streaming video,
than either 802.11 or Bluetooth because it
can send data at much faster rates. UWB
technology has a data rate of roughly 100
Mbps, with speeds up to 500 Mbps, This
compares with maximum speeds of 11 Mbps
for 802.11b (often referred to as Wi-Fi)
which is the technology currently used in
most wireless LANs; and 54 Mbps for
802.11a, which is Wi-Fi at 5MHz. Bluetooth
UWB
transmits
short
impulses
constantly instead of transmitting modulated
waves continuously like most narrowband
systems do. UWB chipsets do not require
Radio Frequency (RF) to Intermediate
Frequency (IF) conversion, local oscillators,
mixers, and other filters. Due to low power
consumption,battery-powered devices like
cameras and cell phones can use in UWB
[3].
has a data rate of
about1Mbps.
Interference Immunity
Due
to
low
power
and
high
frequency transmission, USB’s aggregate
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17. A Study of UWB FM-CW Radar for the Detection of Human Beings in Motion Inside a Building
interference is “undetected” by narrowband
technologies
receivers. Its power spectral density is at or
demodulatecomplex
below narrowband thermal noise floor. This
waveforms. In UWB, Due to the absence of
gives rise to the potential that UWB systems
Carrier, the transceiver structure may be
can coexist with narrowband radio systems
very simple. The techniques for generating
operating in the same spectrum without
UWB signals have existed for more than
causing undue interference [3].
three Decades. Recent advances in silicon
modulate
and
analog
carrier
process and switching speeds make UWB
system as low-cost. Also home UWB
wireless devices do not need transmitting
High Security
power amplifier. This is a great advantage
Since UWB systems operate below
over narrowband architectures that require
the noise floor, they are inherently covertand
amplifiers with significant power back off to
extremely difficult for unintended users to
support high-order modulation waveforms
detect [3].
for high data rates [3].
Reasonable Range
Large Channel Capacity
IEEE 802.15.3a Study Group defined
10 meters as the minimum range at speed
100Mbps However, UWB can go further.
The Philips Company has used its Digital
Light Processor (DLP) technology in UWB
device so it can operate beyond 45 feet at 50
Mbps for four DVD screens [3].
The capacity of a channel can be
express
as
the amount
of data bits
transmission/second. Since, UWB signals
have
several
gigahertz
of
bandwidth
available that can produce very high data
rate even in gigabits/second. The high data
rate capability of UWB can be best
understood
Low Complexity, Low Cost
by
examining
the
Shannon’s
famous
capacity equation:
The most attractive of UWB’s
advantages are of low system complexity
and
cost.
Traditional
carrier
based
=
log!(1 + !
!) (1.4)
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18. A Study of UWB FM-CW Radar for the Detection of Human Beings in Motion Inside a Building
Where C is the channel capacity in
dynamically trade-off high-data throughput
bits/second, B is the channel bandwidth in
for range [6].
Hz, S is the signal power and N is the noise
power. This equation tells us that the
Application of UWB
capacity of a channel grows linearly with the
Wireless technology is playing now
bandwidth W, but only logarithmically with
the signal power S. Since the UWB channel
has an 19 abundance of bandwidth, it can
trade some of the bandwidth against reduced
signal power and interference from other
sources. Thus, from Shannon’s equation we
can see that UWB systems have a great
potential
for
high
capacity
wireless
communications [7].
main role in our daily lives. In recent years,
demand of higher quality and faster delivery
of data is increasing day by day. The need of
more speed and quality brought up many
wireless
solutions
communication.
standards
for
The
short
family
rang
of
(IEEE802.11),
Wi-Fi
Zigbee
(IEEE802.15.4) and the recent standard
802.15.3, which are used for wireless local
Resistance to Jamming
The UWB spectrum covers a huge
range of frequencies. That’s why, UWB
signals are relatively resistant to jamming,
because it is not possible to jam every
frequency in the UWB spectrum at a time.
Therefore, there are a lot of frequency range
available even in case of some frequencies
are jammed.
area
networks
(WLAN)
and
wireless
personal area networks (WPAN), can’t meet
the demands of applications that needs much
higher data rate. UWB connection function
as cable replacement with date rate more
than 100 Mbps. Applications of UWB can
be categorized in following section.
Imaging Systems
UWB was firstly used by military
purpose to identify the buried installations.
In imaging system emission of UWB is used
Scalability
as illuminator similar to radar pulse. The
receiver receives the signal and the output is
UWB systems are very flexible
processed
using
complex
time
and
because their common architecture is
frequency functions to differentiate between
software re-definable so that it can
materials at varying distance. The lower part
18
19. A Study of UWB FM-CW Radar for the Detection of Human Beings in Motion Inside a Building
of radio spectrum < 1 GHz have ability to
criminals hidden in shelters. These radars
penetrate the ground and solid surfaces. This
are able to measure the patient’s cardiac and
property makes UWB a best choice for
breathing activity in hospitals as well as at
detection of buried objects and public
home [21].
security and protection organizations.
Home Networks
UWB plays an important role in
medical imagine and human body analysis.
Now a day’s ultra wideband radars are used
for heart treatment. All of inner body parts
of human being can be imaged by adjusting
In a home environment, variety of
devices are operating such as DVD players,
HDTVs, STBs, Personal video recorders,
MP3 players , digital cameras, camcorders
and others. The current popular usage of
the emitting pulse power [21].
home networking is sharing date from PC to
PC and from PCs to peripherals. Customers
Radar Systems
are demanding multiplayer gaming and
In early days military used UWB
video distributions in home network. These
technology in radar system to detect the
all devices are connected using wires to
object in high-density media like ground, ice
share contents at high speed. UWB is a wire
and air targets. Research and studies in this
replacement
area found, radar can be used everywhere
bandwidth more than 100 Mbps. These all
where we need sensing of moving objects.
devices can be connected in a home network
Radar systems can be installed in vehicle to
to share multimedia, printers, scanners and
avoid accident during driving and parking.
etc. UWB can connect a plasma display or
UWB radars can be used in guarding
HDTV to a DVD or STB without using any
systems
detect
cable. UWB also enables multiple streaming
unauthorized entrance into the territory.
to multiple devices simultaneously, that
These radars can be used to find objects or
allows viewing same or different content on
peoples in collapsed buildings by detecting
multiples devices. For example, movie
the movement of person; but in case person
content can be shared on different display
is not moving, it can still be detected by
devices in different rooms [1] [3]. The home
heart
Police
networks are directly connected to a
department can use such radars to find
broadband through a residential gateway.
as
beat
alarm
and
sensors
thorax
to
beats.
technology
provides
high
19
20. A Study of UWB FM-CW Radar for the Detection of Human Beings in Motion Inside a Building
This approach is cost effective but is
systems. These systems enable us to locate
ineffective for whole house coverage.
and
Cables are installed to connect different
equipment’s, nurses, doctors and patients in
devices
a hospital [2]. Furthermore these systems
with
Internet
in
a
home
track
be
objects
used
in
including
factories
facilities,
environment. With a right UWB solution
can
to
Internet traffic from multiple users in a
track
equipment’s, employees and visitors.
home can be routed to single broadband
connection. UWB enable devices can be
connected in
an ad-hoc manner
like
Bluetooth to share contents. For example a
camera can be connected to a printer directly
to print pictures; MP3 player can be
connected to another MP3 player and shared
music.
Sensor Networks
Wireless sensor networks are an
important area of communication. Sensor
networks have many applications, like
building
control,
surveillance,
medical,
factory automation etc. Sensor networks are
operated under many constraints such as
energy
consumption,
communication
performance and cost. In many applications
sensor size is also considered to be smaller.
UWB use pulse transmission, with very low
energy consumption. This property enables
us to design very simple transmitters and
thus long time battery operated devices.
These sensors can be used in locating
hospitals,
tracking
and
communication
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21. A Study of UWB FM-CW Radar for the Detection of Human Beings in Motion Inside a Building
21
22. A Study of UWB FM-CW Radar for the Detection of Human Beings in Motion Inside a Building
Finally, the speed of the digital back-end
The Future of Radar
Developments
equipment handling the radar raw data will
need to
In the future, we can expect to
encounter
multisensory
systems
that
combine radar and infrared (or other)
increase i.e. through parallel processing in
order to handle data rates as needed for high
resolution radar operating modes.[12]
systems[11]. This will make it possible to
combine the benefits of the different types
of
systems
while
suppressing
REFERENCES
certain
weaknesses [11].
Military onboard radar systems will
1. Merrill I. Skolnik,1990, Radar
be increasingly confronted with the stealth
Handbook, Second Edition McGraw-
characteristics of advanced aircraft. The
Hill
contradiction
between
the
different
2.
Merrill I. Skolnik,1990, Radar
requirements imposed on aircraft must be
Handbook, Second Edition McGraw-
solved (i.e. planes should exhibit stealth
Hill, Chapter 7
properties while not revealing their position
through the use of onboard radar). One
possibility involves the use of a bistatic
radar system with a separate illuminator and
only a receiver on-board the aircraft.
In the future, radar antennas will in
many cases no longer exist as discrete
elements with suitable radomes. Instead,
they will be integrated into the geometrical
structure of the aircraft, ship or other
platform that contains them. The next
generation of AESA radars used on-board
aircraft will have more than one fixed array
in order to be able to handle greater spatial
angles.
3. http://www.radartutorial.eu/index.en.
html
4. http://www.radartutorial.eu/rrp.117.h
tml
5. http://de.wikipedia.org/wiki/Syntheti
c_Aperture_Radar
6. http://keydel.pixelplaat.de/uploads/Fi
le/vorlesung07-08/SAR.pdf
7. http://www.h2g2.com/approved_entr
y/A743807
8. http://www.armedforces.co.uk/releas
es/raq43f463831e0b7
9. http://www.pa.op.dlr.de/poldirad/BIS
TATIC/index.html
10. Silent Sentry.Passive Surveillance
22
23. A Study of UWB FM-CW Radar for the Detection of Human Beings in Motion Inside a Building
11. http://defenseupdate.com/20110721_superhornets-future-eo-radar
12. radar-technology-looks-to-thefuture.html
13. http://www.radartutorial.eu/06.anten
nas/an17.en.html
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