waveform modeling & option analysis for radar systems ...€¦ · waveform modeling &...
TRANSCRIPT
![Page 1: Waveform Modeling & Option Analysis For Radar Systems ...€¦ · Waveform Modeling & Option Analysis For Radar Systems Using MATLAB MATLAB EXPO 2019 1 Nilang Trivedi Scientist-E,](https://reader036.vdocuments.us/reader036/viewer/2022071218/605316674c57084ef83af412/html5/thumbnails/1.jpg)
Waveform Modeling & Option Analysis For
Radar Systems Using MATLAB
MATLAB EXPO 2019
1
Nilang Trivedi
Scientist-E,
RCI, DRDO, Hyderabad
![Page 2: Waveform Modeling & Option Analysis For Radar Systems ...€¦ · Waveform Modeling & Option Analysis For Radar Systems Using MATLAB MATLAB EXPO 2019 1 Nilang Trivedi Scientist-E,](https://reader036.vdocuments.us/reader036/viewer/2022071218/605316674c57084ef83af412/html5/thumbnails/2.jpg)
Need of Waveform Modeling & Option Analysis
OPERATIONAL SCENARIO & OPERATIONAL
REQUIREMENTS
WAVEFORM
SELECTION & DESIGN
ANTENNA-RADOME SUBSYSTEM DESIGN
RF/MW TRANSCEIVER SUBSYTEM DESIGN
DSP & POWER SUPPLY SUBSYSTEM DESIGN
RADAR SYSTEM DESIGN FLOW
Maximum Unambiguous Range & Doppler
Required Update Rate
Range & Doppler Resolution
INTEGRATED SYSTEM TEST & EVALUATION
Required Tx Power
LPI or LPD
Waveform
Modeling & Option
Analysis2
![Page 3: Waveform Modeling & Option Analysis For Radar Systems ...€¦ · Waveform Modeling & Option Analysis For Radar Systems Using MATLAB MATLAB EXPO 2019 1 Nilang Trivedi Scientist-E,](https://reader036.vdocuments.us/reader036/viewer/2022071218/605316674c57084ef83af412/html5/thumbnails/3.jpg)
Waveform Modeling & Option Analysis
Range Resolution Bandwidth , Pulse Width
ECCM FeaturesLow Probability of Intercept or
Low Probability of Detection
Maximum Unambiguous Range
&
Doppler Tolerance
Ambiguity Plots & Contours For
Specific Type of Waveform
Required Paverage For
Max. Range Detection
&
Measurement Update Time
PRI, Period , Duty Cycle
Coherent & Non-coherent
Integration Time
Doppler Resolution PRI, Period, Integration Time
Blind RangePulse Width or Period in case of
Duty Cycle < 100 %
Dependency of System Parameter on Waveform Design
3
![Page 4: Waveform Modeling & Option Analysis For Radar Systems ...€¦ · Waveform Modeling & Option Analysis For Radar Systems Using MATLAB MATLAB EXPO 2019 1 Nilang Trivedi Scientist-E,](https://reader036.vdocuments.us/reader036/viewer/2022071218/605316674c57084ef83af412/html5/thumbnails/4.jpg)
4
The choice of transmitter waveform depends on the following factors:
• Ease of generation of the waveform
• Peak power required by the waveform
• Extent of compression offered by the waveform and the resultant
resolution
• Doppler tolerance and Range–Doppler ambiguity relation.
• The extent to which the waveform can be detected, intercepted, jammed.
The waveforms considered for analysis:
• Pulsed RF
• Linear Frequency Modulated Waveform.
• Pseudo Randomly Bi-phase Modulated Continuous Waveform.
FACTORS AFFECTING CHOICE OF WAVEFORM
![Page 5: Waveform Modeling & Option Analysis For Radar Systems ...€¦ · Waveform Modeling & Option Analysis For Radar Systems Using MATLAB MATLAB EXPO 2019 1 Nilang Trivedi Scientist-E,](https://reader036.vdocuments.us/reader036/viewer/2022071218/605316674c57084ef83af412/html5/thumbnails/5.jpg)
Importance of Ambiguity Plots & Contours
For Waveform selection
Max. value of |x(td, fd)|= |x(0,0)|2 = 2E2
|x(-td, -fd)|2= |x(td, fd)|2
Along td Axis |x(td, fd)|2 is a autocorrelation function of u(t)
Along fd Axis |x(td, fd)|2 is a Spectrum of u(t)
Total volume the ambiguity plot is constant : v =2E2
Unattainable
An Approximation to
Ideal Ambiguity Diagram
td
fd
1/B1/T
B=Signal Bandwidth
T=Signal Duration
Properties :
|x(td, fd)|2
E=Energy of signal
Ideal Ambiguity Diagram
5
![Page 6: Waveform Modeling & Option Analysis For Radar Systems ...€¦ · Waveform Modeling & Option Analysis For Radar Systems Using MATLAB MATLAB EXPO 2019 1 Nilang Trivedi Scientist-E,](https://reader036.vdocuments.us/reader036/viewer/2022071218/605316674c57084ef83af412/html5/thumbnails/6.jpg)
Thumb Tack Ambiguity function
Ambiguity Plots & Contours For
LFM & PN Coded Waveform
Knife Edge Ambiguity function
fd
td1/B
T
B
fd
td
6
![Page 7: Waveform Modeling & Option Analysis For Radar Systems ...€¦ · Waveform Modeling & Option Analysis For Radar Systems Using MATLAB MATLAB EXPO 2019 1 Nilang Trivedi Scientist-E,](https://reader036.vdocuments.us/reader036/viewer/2022071218/605316674c57084ef83af412/html5/thumbnails/7.jpg)
7
MATLAB Simulation Results
For
Pulsed RF Signal
![Page 8: Waveform Modeling & Option Analysis For Radar Systems ...€¦ · Waveform Modeling & Option Analysis For Radar Systems Using MATLAB MATLAB EXPO 2019 1 Nilang Trivedi Scientist-E,](https://reader036.vdocuments.us/reader036/viewer/2022071218/605316674c57084ef83af412/html5/thumbnails/8.jpg)
8
Time Domain Plot: Coherent Pulse Train
Ton= 40 nsec, PRI= 200nsec, DC=20 %
![Page 9: Waveform Modeling & Option Analysis For Radar Systems ...€¦ · Waveform Modeling & Option Analysis For Radar Systems Using MATLAB MATLAB EXPO 2019 1 Nilang Trivedi Scientist-E,](https://reader036.vdocuments.us/reader036/viewer/2022071218/605316674c57084ef83af412/html5/thumbnails/9.jpg)
9
Signal Spectrum : Coherent Pulse Train
Ton= 40 nsec, PRI= 200nsec, DC=20 %
Spacing between Spectral Lines= PRF = 5 MHz
![Page 10: Waveform Modeling & Option Analysis For Radar Systems ...€¦ · Waveform Modeling & Option Analysis For Radar Systems Using MATLAB MATLAB EXPO 2019 1 Nilang Trivedi Scientist-E,](https://reader036.vdocuments.us/reader036/viewer/2022071218/605316674c57084ef83af412/html5/thumbnails/10.jpg)
10
Time Domain Plot: Coherent Pulse Train
Ton= 400 nsec, PRI=1000 nsec, DC=40 %
![Page 11: Waveform Modeling & Option Analysis For Radar Systems ...€¦ · Waveform Modeling & Option Analysis For Radar Systems Using MATLAB MATLAB EXPO 2019 1 Nilang Trivedi Scientist-E,](https://reader036.vdocuments.us/reader036/viewer/2022071218/605316674c57084ef83af412/html5/thumbnails/11.jpg)
11
Signal Spectrum : Coherent Pulse Train
Ton= 400 nsec, PRI=1000 nsec, DC=40 %
Spacing between Spectral Lines= PRF =1 MHz
![Page 12: Waveform Modeling & Option Analysis For Radar Systems ...€¦ · Waveform Modeling & Option Analysis For Radar Systems Using MATLAB MATLAB EXPO 2019 1 Nilang Trivedi Scientist-E,](https://reader036.vdocuments.us/reader036/viewer/2022071218/605316674c57084ef83af412/html5/thumbnails/12.jpg)
Ambiguity Plot: Coherent Pulse Train
12
![Page 13: Waveform Modeling & Option Analysis For Radar Systems ...€¦ · Waveform Modeling & Option Analysis For Radar Systems Using MATLAB MATLAB EXPO 2019 1 Nilang Trivedi Scientist-E,](https://reader036.vdocuments.us/reader036/viewer/2022071218/605316674c57084ef83af412/html5/thumbnails/13.jpg)
MATLAB Simulation Results
For
Linear Frequency Modulated Signal
13
![Page 14: Waveform Modeling & Option Analysis For Radar Systems ...€¦ · Waveform Modeling & Option Analysis For Radar Systems Using MATLAB MATLAB EXPO 2019 1 Nilang Trivedi Scientist-E,](https://reader036.vdocuments.us/reader036/viewer/2022071218/605316674c57084ef83af412/html5/thumbnails/14.jpg)
LFM Continuous Waveform
Saw-tooth & Triangular Sweeps
14
![Page 15: Waveform Modeling & Option Analysis For Radar Systems ...€¦ · Waveform Modeling & Option Analysis For Radar Systems Using MATLAB MATLAB EXPO 2019 1 Nilang Trivedi Scientist-E,](https://reader036.vdocuments.us/reader036/viewer/2022071218/605316674c57084ef83af412/html5/thumbnails/15.jpg)
Ambiguity Plots of Single Pulse
with Different Pulse Widths
Tp Tp1/Tp
1/Tp
B.W. (B) = 1/Tp
Ambiguity Plot
Pulse Width (Tp)=1 µsec
Ambiguity Plot
Pulse Width (Tp)=50 µsec
15
![Page 16: Waveform Modeling & Option Analysis For Radar Systems ...€¦ · Waveform Modeling & Option Analysis For Radar Systems Using MATLAB MATLAB EXPO 2019 1 Nilang Trivedi Scientist-E,](https://reader036.vdocuments.us/reader036/viewer/2022071218/605316674c57084ef83af412/html5/thumbnails/16.jpg)
Ambiguity Plots of LFM Pulse with Different TxB Products
B»1/ Tp & T*B»1
Slope of Ridge = B/T = 20MHz/µsec
1/B 1/B
1/Tp=2MHz 1/Tp = 2MHz
Tp=0.5 µsec, B=10MHz,
TxB=5
Tp=0.5 µsec, B=20MHz,
TxB=10
Slope of Ridge = B/T = 40MHz/µsec
16
![Page 17: Waveform Modeling & Option Analysis For Radar Systems ...€¦ · Waveform Modeling & Option Analysis For Radar Systems Using MATLAB MATLAB EXPO 2019 1 Nilang Trivedi Scientist-E,](https://reader036.vdocuments.us/reader036/viewer/2022071218/605316674c57084ef83af412/html5/thumbnails/17.jpg)
Amplitude Spectra: LFM Chirp
Effect of Sweep Frequency Bandwidth(B)
LFM Up Chirp: Amplitude Spectra:
Bandwidth = 500 MHz
LFM Up Chirp: Amplitude Spectra:
Bandwidth = 100 MHz
Freq.
Freq.
Y-Axis is in normalized scale
17
![Page 18: Waveform Modeling & Option Analysis For Radar Systems ...€¦ · Waveform Modeling & Option Analysis For Radar Systems Using MATLAB MATLAB EXPO 2019 1 Nilang Trivedi Scientist-E,](https://reader036.vdocuments.us/reader036/viewer/2022071218/605316674c57084ef83af412/html5/thumbnails/18.jpg)
Effect of (Time x Bandwidth) Product
on LFM Autocorrelation
T x B = 20
T x B = 50
T x B = 500
18
![Page 19: Waveform Modeling & Option Analysis For Radar Systems ...€¦ · Waveform Modeling & Option Analysis For Radar Systems Using MATLAB MATLAB EXPO 2019 1 Nilang Trivedi Scientist-E,](https://reader036.vdocuments.us/reader036/viewer/2022071218/605316674c57084ef83af412/html5/thumbnails/19.jpg)
Range–Doppler Coupling Effect in LFM Waveform
Up Chirp: α = +B / T
Down Chirp: α = -B / T
Compressed Pulse shape & SNR are Doppler Tolerant
Shift in peak of Matched Filter OutputΤ = fd x T/B
fd=0.2MHz
fd=-0.2MHz
α = Freq. Sweep Rate
Here, α= 1 MHz/1 usec
Doppler (fd) = 0 KHz
Doppler (fd) = -200 KHz
Doppler (fd) = +200 KHz
19
![Page 20: Waveform Modeling & Option Analysis For Radar Systems ...€¦ · Waveform Modeling & Option Analysis For Radar Systems Using MATLAB MATLAB EXPO 2019 1 Nilang Trivedi Scientist-E,](https://reader036.vdocuments.us/reader036/viewer/2022071218/605316674c57084ef83af412/html5/thumbnails/20.jpg)
Ambiguity Plot: LFM Pulse Train
20
![Page 21: Waveform Modeling & Option Analysis For Radar Systems ...€¦ · Waveform Modeling & Option Analysis For Radar Systems Using MATLAB MATLAB EXPO 2019 1 Nilang Trivedi Scientist-E,](https://reader036.vdocuments.us/reader036/viewer/2022071218/605316674c57084ef83af412/html5/thumbnails/21.jpg)
MATLAB Simulation Results
For
Pseudo-Randomly Bi-phase Coded Waveform
21
![Page 22: Waveform Modeling & Option Analysis For Radar Systems ...€¦ · Waveform Modeling & Option Analysis For Radar Systems Using MATLAB MATLAB EXPO 2019 1 Nilang Trivedi Scientist-E,](https://reader036.vdocuments.us/reader036/viewer/2022071218/605316674c57084ef83af412/html5/thumbnails/22.jpg)
Pseudo-Randomly Bi-phase Coded Waveform
22
![Page 23: Waveform Modeling & Option Analysis For Radar Systems ...€¦ · Waveform Modeling & Option Analysis For Radar Systems Using MATLAB MATLAB EXPO 2019 1 Nilang Trivedi Scientist-E,](https://reader036.vdocuments.us/reader036/viewer/2022071218/605316674c57084ef83af412/html5/thumbnails/23.jpg)
Pseudo-Randomly Bi-phase Coded Waveform
Time Domain Plot
23
![Page 24: Waveform Modeling & Option Analysis For Radar Systems ...€¦ · Waveform Modeling & Option Analysis For Radar Systems Using MATLAB MATLAB EXPO 2019 1 Nilang Trivedi Scientist-E,](https://reader036.vdocuments.us/reader036/viewer/2022071218/605316674c57084ef83af412/html5/thumbnails/24.jpg)
Amplitude Spectra
Pseudo-randomly Bi-phase Coded Waveform
Freq.
Freq.
Single Sided Amplitude Spectra:
Chip Width = 10 nsec
Single Sided Amplitude Spectra:
Chip Width = 25 nsec
24
![Page 25: Waveform Modeling & Option Analysis For Radar Systems ...€¦ · Waveform Modeling & Option Analysis For Radar Systems Using MATLAB MATLAB EXPO 2019 1 Nilang Trivedi Scientist-E,](https://reader036.vdocuments.us/reader036/viewer/2022071218/605316674c57084ef83af412/html5/thumbnails/25.jpg)
Stem Plot
Amplitude spectra of Biphase coded waveform
Y-Axis in normalized scale
25
![Page 26: Waveform Modeling & Option Analysis For Radar Systems ...€¦ · Waveform Modeling & Option Analysis For Radar Systems Using MATLAB MATLAB EXPO 2019 1 Nilang Trivedi Scientist-E,](https://reader036.vdocuments.us/reader036/viewer/2022071218/605316674c57084ef83af412/html5/thumbnails/26.jpg)
Freq.
Continuous Plot
Amplitude spectra of Biphase coded waveform
Y-Axis in dB
26
![Page 27: Waveform Modeling & Option Analysis For Radar Systems ...€¦ · Waveform Modeling & Option Analysis For Radar Systems Using MATLAB MATLAB EXPO 2019 1 Nilang Trivedi Scientist-E,](https://reader036.vdocuments.us/reader036/viewer/2022071218/605316674c57084ef83af412/html5/thumbnails/27.jpg)
Comparison of Ambiguity Plots: PN Codes
Effect Of Code Length
PRN Code:Length=63
PN Code: L=15, T*B=15
PN Code: L=63, T*B=63
Height of Plateu=E2/B*T
Volume under the peak is less
Width of central response is less
27
![Page 28: Waveform Modeling & Option Analysis For Radar Systems ...€¦ · Waveform Modeling & Option Analysis For Radar Systems Using MATLAB MATLAB EXPO 2019 1 Nilang Trivedi Scientist-E,](https://reader036.vdocuments.us/reader036/viewer/2022071218/605316674c57084ef83af412/html5/thumbnails/28.jpg)
Contour Plots: PN Codes
Effect Of Code Length
PN CODE: L=15, TxB =15 PN CODE: L=63, TxB = 63
28
![Page 29: Waveform Modeling & Option Analysis For Radar Systems ...€¦ · Waveform Modeling & Option Analysis For Radar Systems Using MATLAB MATLAB EXPO 2019 1 Nilang Trivedi Scientist-E,](https://reader036.vdocuments.us/reader036/viewer/2022071218/605316674c57084ef83af412/html5/thumbnails/29.jpg)
Zero Doppler cut of Ambiguity plots of PN Codes
Effect Of Code Length
PN Code: L=15, T*B=15 PN Code: L=63, T*B=63
29
![Page 30: Waveform Modeling & Option Analysis For Radar Systems ...€¦ · Waveform Modeling & Option Analysis For Radar Systems Using MATLAB MATLAB EXPO 2019 1 Nilang Trivedi Scientist-E,](https://reader036.vdocuments.us/reader036/viewer/2022071218/605316674c57084ef83af412/html5/thumbnails/30.jpg)
Comparison of Range Sidelobes of
PN CODED & LFM Waveforms
Zero Doppler Cut of PN Coded Continuous Waveform
L=127, TxB =127
Zero Doppler Cut of LFM Waveform
Tp =1µsec, B = 127MHz , T*B=127
30
![Page 31: Waveform Modeling & Option Analysis For Radar Systems ...€¦ · Waveform Modeling & Option Analysis For Radar Systems Using MATLAB MATLAB EXPO 2019 1 Nilang Trivedi Scientist-E,](https://reader036.vdocuments.us/reader036/viewer/2022071218/605316674c57084ef83af412/html5/thumbnails/31.jpg)
Comparison of Autocorrelation Properties
Effect of Different Type of Codes
31
![Page 32: Waveform Modeling & Option Analysis For Radar Systems ...€¦ · Waveform Modeling & Option Analysis For Radar Systems Using MATLAB MATLAB EXPO 2019 1 Nilang Trivedi Scientist-E,](https://reader036.vdocuments.us/reader036/viewer/2022071218/605316674c57084ef83af412/html5/thumbnails/32.jpg)
High Due to absence
of pulse compression.
Reduced Due to pulse compression
Reduced Due to Pulse compression.
Lower than FMCW.
∆R=C x Tp/2Tp=Pulse Width
∆R=C /2 x ∆ F∆ F=Frequency Sweep
Higher range Resolution can be achieved easily.
Higher T * B Product by increase in B = ∆ F.
∆R=C x Tb/2Tb=Chip Width
Limitation on low value of Tb due to ADC technology.
Higher T * B Product by increase in Bandwidth = 1/Tb.
Higher PRI.
Low Duty Cycle.
Req. Of High Peak Power
Longer Waveform Period(T).
100 % Duty Cycle.
Lower sweep rate(∆ F/T)
Higher T * B = T * ∆ F Product by increase in T.
Longer Waveform Period(Tw).
100 % Duty Cycle.
Higher T * B = Tw * B Product by Increase in Tw.
Results: Comparative Evaluation of Radar Waveforms
Pulse Delay
RangingFMCW PN Coded CW Characteristic
Tx
Peak Power
Requirement
Range
Resolution
Long Range
Measurement
![Page 33: Waveform Modeling & Option Analysis For Radar Systems ...€¦ · Waveform Modeling & Option Analysis For Radar Systems Using MATLAB MATLAB EXPO 2019 1 Nilang Trivedi Scientist-E,](https://reader036.vdocuments.us/reader036/viewer/2022071218/605316674c57084ef83af412/html5/thumbnails/33.jpg)
T x B=Tp x 1/ Tp=1(Unity)
Tp=Pulse WidthT=Period, B=Bandwidth
T x B =T x ∆F >>1∆ F=Frequency Sweep
T=Period, ∆F =Bandwidth
T x B=Tw x 1/Tb=L*Tb/Tb=L
L=Code length(no. of bits)Tb= Chip Width
Lower than FMCW Radar.
Very High Lower.
Req. of Weighing filter following the Match filter.
Use of Weighing filter results in reduced SNR.
Lowest.
No Req. of Weighing filter following the Match filter.
Higher SNR achieved.Better Correlation achieved.
Good. Supports doppler shift upto+/- B/10.
Time side lobes performance remains intact with large
doppler shifts.
Fdmax=1/(4*Tw)
Time side lobes performance & the peak of correlation deteriorates with large
doppler shifts.
Pulse Delay
RangingFMCW PN Coded CW Characteristic
T x B
Product
Time Side
lobes
Doppler
Tolerance
Results: Comparative Evaluation of Radar Waveforms
![Page 34: Waveform Modeling & Option Analysis For Radar Systems ...€¦ · Waveform Modeling & Option Analysis For Radar Systems Using MATLAB MATLAB EXPO 2019 1 Nilang Trivedi Scientist-E,](https://reader036.vdocuments.us/reader036/viewer/2022071218/605316674c57084ef83af412/html5/thumbnails/34.jpg)
Less
Due to discontinuous waveform pattern.
Poor Performance.
Operation limited to short range applications
Overall performance improvement by 15-20dB compared to FMCW.
Decrease in spill over by 1/L2 (i.e. 48 dB for L=127) compared to unmodulated radar signal.
No. Yes.
Due to the Frequency Sweep Rate (∆F/T).
No.
No LPI & ECCM features. Better than Pulse delay ranging due to Pulse
Compression.
Better LPI & ECCM capabilitycompared to FMCW.
Pulse Delay
RangingFMCW PN Coded CW Characteristic
Spill over &
Tx Leakage
Range
Doppler
Coupling
Low
Probability of
Intercept
&
ECCM
Results: Comparative Evaluation of Radar Waveforms
![Page 35: Waveform Modeling & Option Analysis For Radar Systems ...€¦ · Waveform Modeling & Option Analysis For Radar Systems Using MATLAB MATLAB EXPO 2019 1 Nilang Trivedi Scientist-E,](https://reader036.vdocuments.us/reader036/viewer/2022071218/605316674c57084ef83af412/html5/thumbnails/35.jpg)
35
Thank You !