Introduction to RADAR by NI

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NI AWR Design Environment
Radar Design Solutions

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NI AWR Design Environment - At a Glance
Fully Integrated Design Platform
 Microwave Office - MMIC, RF PCB and module circuit design
 Visual System Simulator – RF/Communications/Radar systems design
 AXIEM - 3D planar electromagnetic (EM) analysis
 Analyst - 3D finite element method (FEM) EM analysis
 Analog Office - Analog/RFIC circuit design
 NEW: AntSyn – Antenna synthesis and optimization
Global Presence (Sales & support office loations)
 California, Wisconsin, Colorado, Massachusetts
 United Kingdom, Finland, France and Germany
 Japan, Korea, Taiwan, China and Australia

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Visual System Simulator for Radar Design
VSS provides detailed behavioral modeling of the RF and signal processing
of a radar system, including simulated or measured 3D antenna patterns
Features at a Glance
• Models include : RF components, Signal
processing and antenna models
• Signal processing blocks
• Moving target indicator (MTI)
• Moving target detection (MTD)
• Constant false alarm rate (CFAR)
• Antenna model
• Accept gain pattern
• Phased array element
• Channel model
• Doppler
• Clutter
• Target model
• Radar cross section (RCS)
• Radar signal generators

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Visual System Simulator for Radar Design
• Supports signal processing algorithm modeling and debugging languages
such as C++, LabVIEW, MATLAB and VBA
• Frequency domain simulation provides
• Budget, line-up and spurious analyses for RF architectures
• Target detection
• Antenna and phased array models based on 3D and planar EM simulators or
data from range measurements
• LabVIEW compatability
Transmitter
Receiver
Pulse
Generator
Signal
Processing
AntennaLO Target
LabVIEW or VSS VSS (SW) or PXI (HW)
VSS VSS
LabVIEW or VSS VSS (SW) or PXI (HW)

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Design-to-Deployment With NI
FURUNO: First Pass Success
The Challenge:
Designed to predict weather and monitor hurricanes and rain fronts, weather
radar systems can be large in size. FURUNO set out to develop a compact,
low-cost weather radar system with flexibility in the signal-processing unit to
accommodate various potential design changes, incorporating a way to verify
the system-level performance by co-simulating the digital and analog
sections.
The Solution:
Adopting the NI platform to take advantage of the co-simulation capability
between Visual System Simulator (VSS) and LabVIEW software allowed us to
realize the system-level simulation of digital and analog sections together.

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Learn More…
Online
• ni.com/awr
• awr.tv
Email
• awr.info@ni.com

Bullock Engineering Research Copyright 2013
8
Introduction to RADAR
Presented For Besser Associates, Inc.
By
Scott R. Bullock
Instructor, Besser Associates
www.BesserAssociates.com

9
Scott R. Bullock
scottrbullock@gmail.com
• BSEE BYU, MSEE U of U, PE, 19 US Patents, 23 Trade Secrets
• Books & Publications
– “Transceiver and System Design for Digital Communications”, 4th edition
• http://iet.styluspub.com/Books/BookDetail.aspx?productID=395134
• http://www.theiet.org/resources/books/telecom/tsddcfe.cfm
– “Broadband Communications and Home Networking”
• http://sci.styluspub.com/Books/BookDetail.aspx?productID=369239
• http://digital-library.theiet.org/content/books/te/sbte002e
– Multiple Articles in Microwaves & RF, MSN
• Seminars - Raytheon, L-3, Thales, MKS/ENI, CIA, NASA, Titan, Phonex, NGC, Others
– Courses for Besser Associates
• Introduction to RADAR - http://www.besserassociates.com/outlinesOnly.asp?CTID=253
• Transceiver and Systems Design for Digital Communications, Radar, and Cognitive Processes – new 5-day course
• http://www.besserassociates.com/Courses/Course-Description/CTID/260 - Includes Directional Volume Search, Acquisition, Track
• Introduction to Wireless Communications Systems - http://www.bessercourse.com/outlinesOnly.asp?CTID=235
• Transceiver and Systems Design for Digital Communications - http://www.bessercourse.com/outlinesOnly.asp?CTID=208
• Cognitive Radios, Networks, and Systems for Digital Communications - http://www.bessercourse.com/outlinesOnly.asp?CTID=251
• College Instructor
– Graduate Presentation on Multiple Access to Polytechnic, Farmingdale//Brooklyn, NY
– Advanced Communications, ITT
– Engineering 201E, PIMA
• Key Designs
– Radar Simulator for NWS China Lake – Acquisition, Target Tracking, Missile Tracking, MTI
– Navy’s Integrated Topside INTOP – Integrate Radar with EW, EA, Comms
– Radar Communications using CP-PSK Modulated Pulses for the SPY-3 Radar and PCM/PPM

10
RAdio Detecting And Ranging
RADAR
RADAR is a method of using electromagnetic waves to
determine the position (range and direction), velocity
and identifying characteristics of targets.

11
Radar Applications
• Military
– Search and Detection
– Targeting and Target Tracking
– Missile Guidance
– Fire Control – Acquisition, Track
– Airborne Intercept
– Ground and Battle field Surveillance
– Air Mapping Systems
– Submarine and Sub-Chasers
• Commercial
– Weather, Navigation, Air Traffic Control
– Space and Range
– Road and Speeding
– Biological Research – Bird and Insect Surveillance and Tracking
– Medical – diagnosis, organ movements, water condensation in the lungs, monitor heart
rate and pulmonary motion, range(distance), remote sensor of heart and respiration
rates without electrodes, patient movement and falls in the home
– Miniature – Seeing aids, early warning collision detection and situational awareness

12
Two Basic Radar Types
• Pulse Radar
– Transmits a pulse stream with a low duty cycle
– Receives reflected pulses during the time off or dead time between pulses
– Single Antenna
– Determines Range and Altitude
– Susceptible To Jamming
– Physical Range Determined By PW and PRF
– Low average power
– Time synchronization
• Continuous Wave CW Radar
– Transmits a CW signal and receives a Doppler frequency for moving targets
– Frequency Modulated CW FM-CW also provides both range and velocity
– Requires 2 Antennas and high SNR
– More Difficult to Jam But Easily Deceived
– Simpler to operate, timing not required

13
Pulsed Radar
• Most radar systems are pulsed
• Transmit a pulse and then listen for receive signals, or echoes
• Avoids problem of a sensitive receiver simultaneously operating
with a high power transmitter.
• Radar transmits a low duty cycle, short duration high-power RF-
pulses
• Time synchronization between the transmitter and receiver of a
radar set is required for range measurement.
• Returns that come from the 1st pulse causes distortion in the
returns after the next pulse

14
Radar Modulation
• 100% Amplitude Modulation AM, ON/OFF keying
– Turns on/off a carrier frequency
• Pulse Width PW amount of time that the radar is on for one
pulse
– Determines the minimum range resolution
• Pulse Repetition Frequency PRF = number of pulses per
second
• Pulse Repetition Interval PRI is the time between the start of the
pulses
• Pulse Repetition Time PRT = Pulse Repetition Interval PRI =
1/PRF
• PRF can determine the radar’s maximum detection range

Bullock Engineering Research
15
Copyright 2014www.BesserAssociates.com
Radar Turns on/off the
Carrier Frequency
Pulse Width = 1us
Pulse repetition time = PRI = 7us = 1/PRF
PRF = 1/7us = 143 kHz
V
t
• Burst of Carrier Frequency – Radar burst
• Low duty cycle, high power
• Duty cycle = PW/PRI x 100 = 1us/7us x 100 = 14%
carrier wave = 4cycles/1us = 4MHz

16
Basic Radar Uses On/Off
Keying of a CW Waveform
Oscillator
Modulator
On/Off Switch
Continuous Waveform - CW
Pulse Train: PRF
Radar Pulses
V
t
PW
PRI = PRT
PRF = 1/PRI
t
V
PW
PRI = PRT
PRF = 1/PRI
Radar
PW/PRF
Control

17
Pulse Distortion
P1
PRI = 1/PRF Long P1 returns cause
distortion to P2 returns
t
V
Long returns from P1 causes distortion to the returns of P2
P2

18
Basic RADAR
Transmit Radar Pulse
Radar Directional Antenna
Target
Reflection
off a Target

19
19
Basic Radar Diagram
Transmitter
Reflective
Radar
Surface
Transmit
Channel
Low Noise
Receiver
Receive
Channel
RADAR
TARGET

20
Radar Path Budget
• Tracks Signal & Noise Levels from Radar – to Target – back to Radar
– Power Out (PA), Tx Losses, Tx Ant Gain, Channel Losses, Target
Reflectivity, Channel Losses, Rx Ant Gain, Rx Losses, Rx Detect S/N
– Required S/N
• Radar Budget - Allocation of Power and Noise
• Radar Tx PA to Radar Rx Detector (LNA)
• Used in Solving Tradeoffs
– Size, cost, range
• Radar pulses are reflected off targets that are in the transmission path
– Targets scatter electromagnetic energy
– Some of the energy is scattered back toward the radar
– Provides gain referenced to an isotropic reflector, similar to antenna gain

21
21
Effective Isotropic Radiated
Power EIRP
EIRP = Effective Isotropic Radiated
Power = RF Power x Antenna Gain
RF
Power
Gain
RF
Power
Target
Target
ERP = Effective Radiated Power
EIRP = ERP + Gdipole (2.14dB)
ERP = EIRP - Gdipole (2.14dB)

22
22
Sun
Focusing
Sun Rays
To Increase
Power
Focusing Radio Waves
To Increase
Power
Magnifying
Glass
Directional Antenna
Receiver
Focusing Increases Power To
Provide Gain

23
Radar Cross Section RCS
• RCS (s) - size and ability of a target to reflect radar energy m²
• RCS(s) = Projected cross section x Reflectivity x Directivity
• The target radar cross sectional area depends on:
– Target’s physical geometry and exterior features
– Direction of the illuminating radar
– Transmitted frequency,
– Material types of the reflecting surface.
• Difficult to estimate
– Equals the target’s cross-sectional area theoretically
– Not all reflected energy is distributed in all directions
– Some energy is absorbed
– Usually measured for accurate results

24
Radar RCS Patterns
Sphere s = pr2
Flat Plate
Corner Reflector
Similar to
Antenna
Gains

25
25
Radar Transmitter
Power to Target
Freespace
Attenuation
Water
Vapor
Rain
Loss
Oxygen
Absorption
Multipath
Loss
EIRP
LAtmos Lmulti
Transmitter
Reflector
Target
Pt
Gt
Power at Target Including other losses
Lt = LAtmos x Lmulti
Power at Target (ideal)

26
26
Radar Received
Power from Target
LAtmos
Lmulti
Freespace
Attenuation
Water
Vapor
Rain
Loss
Oxygen
Absorption
Multipath
Loss
Receiver
Reflector
Target
GrPr
Ptarg
Power received at Radar (ideal)
Power at Radar including losses

27
27
Radar Antenna Gain and
Channel Losses
Freespace
Attenuation
Water
Vapor
Rain
Loss
Oxygen
Absorption
Multipath
Loss
EIRP
LAtmos
Lmulti
Transmitter
Receiver
Reflector
Target
Duplexer
Pt
Pr
Power at Radar (Ideal)
One-way Loss: Lt = LAtmos x Lmulti
Two-way Losses = Lt x Lt = Lt
2 = Ls
Including other losses in the path
Assume Antenna Gain Gt = Gr
LAtmos
Lmulti
Freespace
Attenuation
Water
Vapor
Rain
Loss
Oxygen
Absorption
Multipath
Loss
Lt = LAtmos x LmultiGr
Gt

28
28
Radar Example
Given: What is Pr in dBm?
f = 2.4 GHz, , l = .125
Pt = 100W
R = 1000m
Gt = Gr = 1000
Total 2-way loss Ls = 10
s= 140 m2
100(1000)2(.125)2(140)
(4p)3 (1000)4(10)
Pr = =1.10235x10-8W = 1.10235x10-5mW
Prdbm = 10log(1.10235x10-5) = -49.6 dBm
Freespace
Attenuation
Water
Vapor
Rain
Loss
Oxygen
Absorption
Multipath
Loss
EIRP
LAtmos
Lmulti
Transmitter
Receiver
Reflector
Target
Duplexer
Gr
Pt
Pr
Gt
LAtmos
Lmulti
Freespace
Attenuation
Water
Vapor
Rain
Loss
Oxygen
Absorption
Multipath
Loss

29
Free Space Attenuation
• Forms of free-space attenuation depends on how it is used
– Afs = (l/(4pR))2 will be less than 1 and multiplied
– Afs = ((4pR)/l)2 will be greated than 1 and divided
– Afs = 10log (l/(4pR))2 = 20log l/(4pR) = will be a negative number and added
– Afs = 10log ((4pR)/l)2 = 20log (4pR)/l = will be a positive number and subtracted
– Important to determine if it is added or subtracted to avoid mistakes
• Given:
– Pt = 100W = 50dBm, l = .125, R = 1000m
– Afs = (l/(4pR))2 = 98.9 x 10-12 need to multiply: Pr = 100W x 98.9 x 10-12 = 9.89 x 10-9
– Afs = ((4pR)/l)2 = 1.01065 x 1010 need to divide: Pr = 100W/(1.01065 x 1010)= 9.89 x 10-9
– Afs = 20log l/(4pR) = -100 dB need to sum: Pr = 50dBm + (-100dB) = -50dBm
– Afs = 20log (4pR)/l = 100 dB need to subtract: Pr = 50dBm - 100dB) = -50dBm

30
Two-Way Radar Losses in dB
• Two-way free space loss in dB
– Once for the radar transmitter to target path
– Once for the target to radar receiver path
– Total Free Space Loss = AfsdB + AfsdB = 2 x AfsdB = 2 x 20log l/(4pR)
• Two-way Losses in Radar in dB
– Atmospheric loss 2 x Latmos dB
– Multipath loss 2 x Lmult dB
– T/R switch or Circulator loss 2 x Ltr dB
– Antenna loss, Polarization, Mis-pointing, Radome 2 x Lant dB
– Implementation loss 2 x Li dB
– Losses in dB:
– Ltotal dB = 2 x Latmos dB + 2 x Lmult dB + 2 x Ltr dB + 2 x Lant dB + 2 x Li dB

31
RADAR Equation
to Assess Radar Performance
P r = Radar received power
P t = Radar transmitted power
G t = Transmitter antenna gain
G r = Receiver antenna gain
G2 = Gr Gt assumes the same antenna at the radar
l = wavelength
R = slant range
Ls = total two-way additional losses
s = radar cross section of the target RCS
Log Form
Pr = PtG tG r Afs AfsGtarg1/Ls
10logPr = 10logPt + 10logG + 10logG + 10logAfs + 10logAfs + 10logGtarget - 10log(Ls)
Pr dBm = Pt dBm + 2GdB + 2Afs dB + Gtarget dB – Ls dB
P(mW) = dBm or P(W) = dBw

32
32
Radar Example in dB
AfsdB = 10log(l2/(4pR)2) = 20log(l/(4pR) = 20log[(.125)/(4p1000)] = -100.05dB
Gtarg = 10log(4ps/l2) = 10log(4p x 140/.1252) = 50.5dB
Given: What is Pr?
f = 2.4 GHz, , l = .125
Pt = 100W = 50dBm
R = 1000m
Gt = Gr = 1000 = 30dB
Total 2-way loss Ls = 10 = 10dB
s= 140 m2 Pr dBm = Pt dBm + 2GdB + 2Afs dB + Gtarget dB – Ls dB
Pr dBm = 50dBm + 2 x 30dB + 2 x -100.05 dB + 50.5 dB – 10dB = -
49.6dBm
Freespace
Attenuation
Water
Vapor
Rain
Loss
Oxygen
Absorption
Multipath
Loss
EIRP
LAtmos
Lmulti
Transmitter
Receiver
Reflector
Target
Duplexer
Gr
Pt
Pr
Gt
LAtmos
Lmulti
Freespace
Attenuation
Water
Vapor
Rain
Loss
Oxygen
Absorption
Multipath
Loss

33
Range Determination
• Range calculation uses time delay between objects
– Time delay is measured from source to reflector and back
– Time delay divided by two to calculate one way range
• Sound-wave reflection
– Shout in direction of a sound-reflecting object and hear the echo
– Calculate two-way distance using speed of sound 1125 ft/sec in air
– Measure two way delay of 5 seconds
– Range = 1125ft/sec x 5/2 = 2812ft
– Measure distance to lighting using the time arrival of the thunder

34
34
Sound Wave Reflection
Hi
Hi
Determine the distance using range formula
Listen to multiple echoes off difference distances
Best echo effects when the yell is short – short pulse width

35
35
Sound Wave Reflection
Hi
Hi
Determine the distance using range formula
Listen to multiple echoes off difference distances
Best echo effects when the yell is short – short pulse width

36
Radar Range Calculation
• Radar uses electromagnetic energy pulses
• Pulse travel at the speed of light co
• Reflects off of a surface and returns an echo back to the radar
• Calculates the two-way distance or slant range
• Slant range = line-of-sight distance from radar to target
• Takes in account the angle from the earth
• Ground range = horizontal distance from radar to target
• Slant range calculated using ground range and elevation
• Radar energy to the target drops proportional to range squared.
• Reflected energy to the radar drops by a factor of range squared
• Received power drops with the fourth power of the range
– Need very large dynamic ranges in the receive signal processing
• Need to detect very small signals in the presence of large interfering
signals

37
Slant Range
Slant Range = Rslant
Radar
Directional
Antenna
Target
Ground Range = Rgnd
Elevation = EL
Rslant
2 = Rgnd
2 + EL2: Rslant = (Rgnd
2 + EL2)1/2
Sinf = El/Rslant: Rslant = El/sinf
Cosf = Rgnd/Rslant: Rgnd = Rslant x cosf
f
Given:
Elevation = 5000 ft
Angle = 300
Calculate Slant Range =
Rslant = El/sinf = 5000/sin(30) = 10,000 ft
What is the Ground Range =
Rgnd = Rslant x cosf = 10,000 x cos(30) = 8660.25 ft
Rslant
2 = Rgnd
2 + EL2: Rgnd = (Rslant
2 - EL2) 1/2 = (10,0002 - 50002) 1/2 = 8660.25ft

38
Range Calculation
Electromagnetic energy pulse travels at the speed of light co
Given: tdelay = 1ms
Calculate Slant Range =
R = (1ms x 3 x 108 m/s)/2 = 150km
R = slant range
tdelay = two way time delay – Radar-Target-Radar
co = speed of light = 3 x 108 m/s

39
39
Radar Range Equation
Double the range requires 16 times
more transmit power Pt
Radar detection range = the maximum range at which a
Target has a high probability of being detected by the radar
Basic Radar Equation
Radar Range Equation (solving for Rmax range for minimum signal Smin):

40
Range Ambiguity
• Caused by strong targets at a range in excess of the pulse repetition
interval or time
• Pulse return from the first pulse comes after the second pulse is sent
• This causes the range to be close instead of far away
• Radar does not know which pulse is being returned
• Large pulse amplitude and higher PRF amplifies the problem
• The maximum unambiguous range for given radar system can be
determined by using the formula:
Example: PRI = 1msec, T = 1us
Calculate Max unambiguous Range = (1ms – 1us) x 3 x 108/2 = 149.9km

41
Range Ambiguity
P1 P2
PRI Range Ambiguities
t
V

42
Range Ambiguity Mitigation
• Decreasing the PRF reduces the range ambiguity
– Longer the time delay, higher free-space loss, smaller the return
• Transmit different pulses at each PRF interval
– Higher receiver complexity
– Requires multiple matched filters at each range bin and at each azimuth
and elevation
– Increases rate of the DSP required for each separate transmit pulse and
matched filter pair
• Vary the PRF, depending radar’s operational mode
– Requires changing the system parameters
– Used most often to mitigate range ambiguity
– Used in the presence of other jamming pulses
– Desired returns from the second pulse move with the PRF
– Undesired returns do not move since they are reference to the first pulse
– Changing the PRF allows Radar Communications using PPM

43
Minimum Detectable Range
• Radar minimum detectable range – return cannot come back during pulse width
T = Pulse width, Trecovery = time for pulse to recover
• Very close range targets equivalent to the pulse width not be detected
• Typical value of 1 μs for the pulse width of short range radar corresponds to a
minimum range of about 150 m
• Longer pulse widths have a bigger problem
• Typical pulse width T assuming recovery time of zero:
• Air-defense radar: up to 800 μs (Rmin = 120 km)
• ATC air surveillance radar: 1.5 μs (Rmin = 225 m)
• Surface movement radar: 100 ns (Rmin = 15 m)
P1
t
V R1
R2
R3
Minimum Detectable
Range Pulse
Does not interfere with
the Radar pulse
Tmin for Rmin = Pulsewidth

44
Plan Position Indicator (PPI)
• The return is displayed on a Plan Position Indicator
(PPI)
– Rotating Search Radars illuminates the targets on the PPI
according to the angle received
– Range is displayed according to the distance from the center
of the PPI
– Uses a range gate to lock on the range of the PPI

45
PPI and A-Scope Displays
N
S
00
900
1800
2700
AoA = 770
Range
Gate
PPI
A-Scope
Range
Gate
V
t

Besser Associates
©Besser Associates, Inc. 2015 All rights reserved
Thank you for Attending !
For more information on this subject and more, please consider
attending;
Transceiver and Systems Design for Digital
Communications, Radar, and Cognitive Processes
August 22 to 26 in San Jose, CA
Contact us at info@besserassociates.com

Introduction to RADAR by NI

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