INTERNATIONAL JOURNAL OF ELECTRONICS AND  International Journal of Electronics and Communication Engineering & Technology ...
International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN 0976 – 6464(Print), ISSN 09...
International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN0976 – 6464(Print), ISSN 097...
International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN  0976 – 6464(Print), ISSN 0...
International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN0976 – 6464(Print), ISSN 097...
International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN0976 – 6464(Print), ISSN 097...
International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN  0976 – 6464(Print), ISSN 0...
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Performance analysis of radar based on ds bpsk modulation technique

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Performance analysis of radar based on ds bpsk modulation technique

  1. 1. INTERNATIONAL JOURNAL OF ELECTRONICS AND International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN 0976 – 6464(Print), ISSN 0976 – 6472(Online) Volume 4, Issue 2, March – April (2013), © IAEMECOMMUNICATION ENGINEERING & TECHNOLOGY (IJECET)ISSN 0976 – 6464(Print)ISSN 0976 – 6472(Online)Volume 4, Issue 2, March – April, 2013, pp. 137-143 IJECET© IAEME: www.iaeme.com/ijecet.aspJournal Impact Factor (2013): 5.8896 (Calculated by GISI) ©IAEMEwww.jifactor.com PERFORMANCE ANALYSIS OF RADAR BASED ON DS-BPSK MODULATION TECHNIQUE Ami Munshi1, Srija Unnikrishnan2 1 (Watumull Instiute of Electronics and Telecommunication Engg and Computer Technology, University of Mumbai, India) 2 (Fr Conceicao Rodrigues College of Engg, University of Mumbai, India) ABSTRACT Radar (Radio Detection and Ranging) systems are widely used now-a-days as automotive radar for Intelligent Transport System (ITS). In this paper we mainly focus on analyzing the performance short distance radar based on spread spectrum technology. Spread spectrum modulation technique is chosen as it has some significant properties like accuracy of ranging, sensitivity, accuracy of power-estimation, interference suppression etc. The system is implemented in Matlab/Simulink. Keywords: DSSS, BPSK, Spread Spectrum, BER I. INTRODUCTION The electronic principle on which radar operates is very similar to the principle of sound-wave reflection. If you shout in the direction of a sound-reflecting object, you will hear an echo. If you know the speed of sound in air, you can then estimate the distance and general direction of the object. The time required for an echo to return can be roughly converted to distance if the speed of sound is known [[1]][[2]]. In this paper, we focus on analyzing a radar system based on direct sequence spread spectrum modulation technique. The goal is to detect target at a very short distance as near as 20cm with high resolution. The system is developed in Matlab/Simulink. Simulink is a software package for modeling, simulating, and analyzing dynamic systems at any point. The performance is evaluated using Monte Carlo Simulation method. Section 2 gives details of DS-BPSK Radar model. Section 3 gives simulation results followed by conclusion in section 4 and references. 137
  2. 2. International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN 0976 – 6464(Print), ISSN 0976 – 6472(Online) Volume 4, Issue 2, March – April (2013), © IAEMEII. IMPLEMENTATION OF DS-BPSK RADAR DIRECT SEQUENCE SPREAD SPECTRUM MODULATION Spread spectrum is transmission technique in which pseudo noise code, independent of the data is employed as spread the signal energy over a bandwidth much greater than information signal bandwidth. At the receiver, signal is despread using replica of pse pseudo noise code generator [[3]]. In DSSS the spreading of the signal bandwidth occurs at baseband by multiplying the baseband data pulses with a chipping sequence. This chipping sequence is a pseudo chipping pseudo-random binary waveform with a pulse duration of Tc and a chipping rate of Rc=1/Tc. Each pulse is called a chip and Tc is the chip interval. For a given information symbol of duration Ts and a symbol rate of Rs=1/Ts, the duration of each chip is much less than the pulse length of the =1/Ts, information symbol (i.e., Tc<<Ts) and Rc is much higher than the symbol rate (i.e., Rc>>Rs) than Rc>>Rs). In practical systems, the number of chips per symbol must be an integer number with t the transition of the data symbols and the chips occurring at the same time [[3]][[4]].. The ratio of [ ].. chips to symbols is called the spreading gain k or bandwidth expansion factor Be where, k= Be= Nc= Ts/Tc= Rc/Rs (1) RADAR MODEL Fig. 1. Model of Spread Spectrum Radar Fig.1. shows the basic architecture of radar using spread spectrum modulation technique. Baseband part of the transmitter section mainly consists of binary data generation, spreading the data using PN sequence and its modulation (BPSK). By using Bernoulli binary generator block in the communication tool box of Simulink, we can generate binary data stream of 250Kbps. By using PN sequence generator block in the communication tool box, 138
  3. 3. International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN0976 – 6464(Print), ISSN 0976 – 6472(Online) Volume 4, Issue 2, March – April (2013), © IAEMEwe can generate PN sequence of 9Gbps data rate. By using BPSK modulator baseband blockin the communication tool box, we modulate the spread signal [[5]][[6]][[7]]. [At the receiver front end, the received signal power is measured calculated using radar rangeequation as followsPrec = Pt G2 λ2σ (2) (4π) 3 R4 The delay between transmitted and received signal is calculated and accordinglytarget range is obtained. The Error Rate Calculator is used at the receiver to calculate BitError Rate (BER). It calculates the error rate as a running statistic, by dividing the totalnumber of unequal pairs of data elements by the total number of input data elements from onesource. Autocorrelation is the one of the vital part of the system that provides uniqueness to rce.this radar system. The first operation of autocorrelation block is bit by bit synchronism of thereceived and transmitted signal and then bit by bit multiplied, integrated and dumped. The integratedpower of the received signal represents the presence of target and the delay of the autocorrelation block represents the target distance from the transmitter [[8]][[9]][[10] [ [10]]. Fig. 2. Target Model The target model design is shown in Fig 2. Depending on the target range, the 2.transmitted signal is delayed and the signal power is attenuated. This signal is then reflectedtowards the receiver. In the target, there is a provision made to change target cross section,target range, and accordingly the reflected power towards the receiver. receiver 139
  4. 4. International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN 0976 – 6464(Print), ISSN 0976 – 6472(Online) Volume 4, Issue 2, March – April (2013), © IAEMEIII. SIMULATION RESULTS Various graphs are plotted by using following data in the model: Chip rate (fc) 1Gbps Transmitted Power (Pt) 1W Antenna Gain 100 Wavelength(λ) 0.3m Target Cross Section (σ) 1m2 Minimum detectable signal 0.011mW power (Pmin) Velocity of light (c) 3x108m/s Maximum Radar Range 8m (Rmax) Table. 1. Specifications of Spread Spectrum Radar EB/NO VERSUS BER For range (R) = 1m, Eb/No Vs BER graph is plotted using Bit Error Rate Analysis Tool in Matlab/Simulink. Monte Carlo simulation results and theoretical results are in Fig.3. below. We can see that as Eb/No ratio increases, BER decreases. Fig. 3. Eb/No versus BER graph RANGE VERSUS SIGNAL POWER As radar range increases, the signal power received at the receiver decreases. The minimum detectable signal power at the receiver Pmin= 0.000110726W or -39.55dB for Rmax =8m. Fig.4. shows the graph of range versus received signal power. 140
  5. 5. International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN0976 – 6464(Print), ISSN 0976 – 6472(Online) Volume 4, Issue 2, March – April (2013), © IAEME Fig. 4. Range versus Received Power graphCHIP RATE VERSUS MAXIMUM RANGE Relation between chip rate and maximum radar range is given by the followingequation. Rmax= (Pt G2 λ2 σ) ¼ (3) ((4π) 3 Pmin) 1/4 where, λ = c/fc where, c = 3e8 m/s, velocity of light We see that as the chip rate increases, the maximum range of detection decreases.Fig.5. portray this relation. Fig. 5. Chip Rate versus Maximum Range graph 141
  6. 6. International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN0976 – 6464(Print), ISSN 0976 – 6472(Online) Volume 4, Issue 2, March – April (2013), © IAEMETHEORETICAL DISTANCE VERSUS COMPUTED DISTANCE Fig.6. shows the graph of theoretical distance of the target and the distance computedby the radar receiver model. Fig. 6. Theoretical Distance versus Computed Distance graphIDENTIFICATION OF TARGET Fig. 7. Detection of Target of σ = 1m2 at range 4m Fig.7. shows the target of σ= 1m2at 4m range. The received signal power at the =receiver is (-26.52dB). In the figure X-axis represents the target range in meters where as Y 26.52dB). X Y-axis represents the received signal power in dB. Here distance of the target is calculated bycalculating the relative time delay between the received signal and transmitted signal. 142
  7. 7. International Journal of Electronics and Communication Engineering & Technology (IJECET), ISSN 0976 – 6464(Print), ISSN 0976 – 6472(Online) Volume 4, Issue 2, March – April (2013), © IAEMEIV. CONCLUSION The work presented here gives design, implementation and analysis of radar transmitter- receiver using Matlab/Simulink. With chip rate of fc=1 GHz and target cross section σ=1m2 this radar model is based on radar range equation to detect maximum range of 8m and minimum range of 20cm. The peculiarity of this radar is that it is able to detect objects placed at a very short distance. The performance is examined using Monte Carlo simulation. It is observed that the system is more accurate in computing the distance of the target towards the maximum range. It is also noted that as the signal to noise ratio (Eb/No) increases the Bit Error Rate (BER) decreases. We can vary the detection range by changing the chip rate. There is also a provision for changing target cross section and antenna gain and accordingly the detection range can be varied. In this work, autocorrelation is one of the vital parts of the system that provides uniqueness to this radar system. The auto correlated value obtained from the align signal block represents the presence of target and the delay represents the target distance from the transmitter. The technology uses DS-BPSK signals to create noise like modulation, making the transmitted signal virtually undetectable to other receivers. The system developed has virtues such as high reliability, robustness, good efficiency, interference suppression, low power consumption etc., due to coding of the baseband pulses with PN sequence. REFERENCES [1] Christian Wolff. Radartutorial.eu. December 20, 2009. http://www.radartutorial.eu/druck/index.en.html (accessed February 15, 2012). [2] M Richards, J Scheer, W Holms. Principles of Modern Radar. Raleigh, NC 27615: Scitech, May 2010. [3] Meel, J. "De Nayer Instituut." October 1999. sss-mag.com/pdf/Ss_jme_denayer_intro_print.pdfSimilar (accessed February 15, 2012). [4] Duke, Peter Smith. Direct sequence spread spectrum modulation for utility packet transmission in under water acoustic communciation network . Thesis, Monterey, California: Naval Postgraduate School, September 2002. [5] Kanna, Ravikanath. Design of Zigbee Transmitter Receiver IEEE 802.15.4 using Matlab/Simulink. Masters Thesis, Rourkela, Odhisha: National Institute of Technology, 2011. [6] Y. Ayogi, T Fukuchi, H Endo, M Kusunoki, Y Iso, K. Inoue, H. Ishizu, R. Kohno. "76Ghz Spread Spectrum Radar for Autonomous Intelligent Cruise Control." Intelligent Transportation System, 1997. ITSC 97., IEEE. 1997. 677-682. [7] L. Sakkila, P. Deloof ,Y. Elhillali ,A. Rivenq ,S. Niar. "A real time signal processing for an anticollision road radar system." Vehicular Technology Conference. IEEE, 2006. 1-5. [8] Soumyasree Bera, Debasish Bhaskar, Rabindranath Bera. www.ursi.org. 2011. www.ursi.org/proceedings/procGA11/ursi/F05-4.pdf (accessed February 27, 2012). [9] Mathworks. 2012. www.mathworks.com/help/toolbox/comm/ref/alignsignals.html (accessed March 5, 2012). [10] Ami Munshi, Srija. Unnikrishnan. (May-June 2012). Implementation of Radar Transmitter- Receiver using DS-BPSK Modulation Technique. International Journal of Engineering Research and Applications (IJERA), 126-132. [11] Sanjay M Trivedi and B. S. Raman, “Design of a Unified Timing Signal Generator (UTSG) for Pulsed Radar” International journal of Electronics and Communication Engineering &Technology (IJECET), Volume 3, Issue 1, 2012, pp. 252 - 261, ISSN Print: 0976- 6464, ISSN Online: 0976-6472. [12] P.Ravi Kumar, G. Suresh , Dr. Y.Bhavani Kumar and D. Arun Kumar, “Laser Radar System for the Characterization of Boundary Layer Meteorology using Modified Wavelet Covariance Transform” International journal of Electronics and Communication Engineering &Technology (IJECET), Volume 3, Issue 2, 2012, pp. 474 - 483, ISSN Print: 0976-6464, ISSN Online: 0976-6472. 143

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