1. Performance Analysis of LFM Pulse Compression Radar under Effect of Convolution Noise Jamming
Eng.: Ahmed Abdo AbouelFadl
Assoc. Prof. Dr: Alaauddeen Hussien Asseesy
Dr. :Mohamed Samir Abdellatif
Assoc. Prof. Dr.: Fathy Abdel Kader

2. Outlines Introduction. Problem Statement and Objectives. Radar Model.
Convolution Jamming Model.
LFM-PC Radar Response to Convolution Jamming.
Conclusions.

3. How to solve this contradiction?
Introduction
Radar designer has two choices for the radar pulse width
Long Pulse Width
High Average Power
High Detection Range
Poor Range Resolution
Short Pulse Width
Low Average Power
Short Detection Range
High Range Resolution
How to solve this contradiction?

4. Introduction Pulse Compression What about modulation inside the pulse?
Good Range Resolution
High Detection Range
High Processing Gain
High Jamming Immunity
Pulse Compression
What about modulation inside the pulse?

5. Introduction Pulse Compression Waveforms Supports high Doppler shifts.
Frequency Modulation
LFM
NLFM
Stepped Frequency Waveform (SFW)
Costas Codes
Phase Coding
Binary Phase Coding
Frank Codes
Pseudo-Random (PRN) Codes
Supports high Doppler shifts.
Time side lobes performance remains excellent with high Doppler shifts.
Used with high-speed targets with extremely high time bandwidth products.
Compression Ratio = Time Bandwidth Product (B.T)

6. Problem Definition and Objectives
To study the effect of convolution jamming on the detection of LFM-PC radar which has been proposed earlier against SAR.
To determine the minimum required Jamming –to –Signal Ratio (JSR) by convolution noise jamming to be effective against LFM-PC search radars.

7. Problem Definition and Objectives
To achieve these objectives, the following tasks have been done:
LFM PC radar simulation model
Quantitative and qualitative verification of the radar model
Modeling and simulation of convolution jamming
Studying the response of LFM-PC radar to convolution jamming

8. Doppler Processor and CFAR
Radar Model
Radar Block Diagram
Waveform Generator
Mixer
Power Amplifier
Duplexer
Antenna
Low Noise Amplifier
Mixer
Weighting Filter
Matched Filter
IF Amplifier/Filter
Doppler Processor and CFAR
Video Amplifier
Display

9. Radar Model Radar Model Parameters Radar Model PRF[Hz] PW[µs] BW [MHz]
Compression Ratio
Date
VARIANT 10 6 60
2003
TRS-3033
Fractions of 5300
2.7
3.7
APS-143C
200, 1500, 800, 400
5 ,17
10, 14
50,240
2007
SPY-1
12.7
127
2012
DA-08
500,1000
34,68
1.7
57,115
2013
LW-08
500,100
35,69
58,117

10. Radar Model Radar Model Parameters Target Parameters PRF[KHz] PW[µs]
BW [MHz]
Compression Ratio
Fs[MHz] 2
100 15
1500
67.1
Range[Km]
Doppler[KHz]
Velocity [Km/min] 7 21

11. Radar Model Radar Model Simulation Block Diagram
min
Generated Radar Signal
Time Domain
Frequency Domain
Sidelobes
Matched Filter
Target location
Output Waveform
Output SNR
Improvement Factor
MTD (Doppler Processor)
Output Doppler
Processing gain
Probability of Detection
Fixed Threshold
CA-CFAR
GO-CFAR
Weighting windows

12. Matched Filter Improvement 38.7dB Total Radar Processing Gain 50.7dB
Radar Model
Radar Model Processing Gain
Matched Filter Improvement 38.7dB
MTD Gain 12dB
Total Radar Processing Gain 50.7dB
Signal Improvement Factor
31.7 dB
Noise Loss Factor
7 dB

13. Radar Model CA-CFAR Comparator Decision Threshold Doppler Cell#1
window
window
Guard Cells
Doppler Cell # M
Cell Under
Test (CUT)
Constant Factor
Comparator
Average
Decision
CA-CFAR
Threshold

14. Radar Model GO-CFAR Comparator Decision Threshold Doppler Cell#1
window
window
Guard Cells
Doppler Cell # M
Cell Under
Test (CUT)
Constant Factor
Comparator
Greatest Of
Decision
GO-CFAR
Threshold

15. Radar Model
Radar Detection

16. Convolution Jamming Model
FFT
IFFT
Convolution Jamming Signal
Intercepted Radar Signal
FFT
Pulsed Jamming

17. Convolution Jamming Model
The convolution jamming signal can be expressed as:

18. Convolution Jamming Model
In frequency domain, the power spectral density of the convolution jamming signal can be expressed as:

19. Convolution Jamming Model
JSR=-5 dB and SNR= -30 dB

20. LFM-PC Radar Response to Convolution Jamming
The output of MF to convolutional jamming is:

21. LFM-PC Radar Response to Convolution Jamming
JSR=15 dB and SNR= -30 dB
JSR=25 dB and SNR= -30 dB

22. LFM-PC Radar Response to Convolution Jamming
JSR=25 dB and SNR= -30 dB
MTD
CA-CFAR
GO-CFAR
Fixed Threshold

23. LFM-PC Radar Response to Convolution Jamming
CA-CFAR
GO-CFAR

24. Conclusions
An LFM-PC search radar model has been introduced. It provides more than 50 dB processing gain over conventional pulse Doppler radars.
To be effective, convolution jamming signal needs about 30 dB JSR against the proposed radar model for both detector types (CA-CFAR and GO-CFAR).
Although the advantage it introduces over conventional AWGN(which needs 34 dB), convolution jamming still requires high JSR which may be unpractical in many cases.

25. Thank You Any Questions?