Joint influence of rain rate and turbulence on radar signal spectrum width

2007 ◽  
Author(s):  
Yahya S. H. Khraisat ◽  
Felix J. Yanovsky
Keyword(s):  
Rain Rate ◽  
Radar Signal ◽  
Signal Spectrum ◽  
Joint Influence ◽  
Spectrum Width

Application of Radar Signal Spectrum Width Estimation to Detect Vertical Airflows

2020 ◽  
Vol 45 (12) ◽  
pp. 876-880
Author(s):  
D. A. Denisenkov ◽  
V. Yu. Zhukov ◽  
Yu. V. Kuleshov ◽  
G. G. Shchukin
Keyword(s):  
Radar Signal ◽  
Signal Spectrum ◽  
Spectrum Width

scholarly journals Using information processing algorithms that factor in the effect of secondary modulation of radar signals

2020 ◽  
Vol 30 (2) ◽  
pp. 42-48
Author(s):  
V. A. Bratkov ◽  
A. A. Sentsov ◽  
V. B. Polyakov
Keyword(s):  
Power Plants ◽  
Spectral Component ◽  
Probability Of Detection ◽  
Radar Signal ◽  
Signal Spectrum ◽  
Spectral Structure ◽  
Detection Range ◽  
Radar Station ◽  
Reflected Signal ◽  
The Impact

The article provides an assessment of the impact the dynamic structures of power systems of aircraft systems have on the spectrum of the reflected radar signal. In the conditions of autonomous actions of the fighter, the tasks of long-range detection of airborne targets are assigned directly to the onboard radar station. It is necessary to resolve the contradictions associated with increasing the detection range without changing the energy indicators of the onboard radar station. This is possible by optimizing the processing of many spectral components of the signal reflected from the propeller and turboprop engine of airborne targets. The location of propeller reflections in the spectrum of the reflected signal is determined by the technical parameters of the power plant and its mode of operation. The percent of the total energy of the reflected signal spectrum outside the main spectral component is comparable with the energy reflected from the airframe of the aviation complex, most of which is the energy reflected from the rotating elements of power plants. Therefore, the development of an algorithm for detecting a signal with a complex spectral structure that maximizes the probability of detection under time and computational resources restrictions is a very relevant scientific task. The scientific novelty lies in the development of an algorithm for detecting a signal with a complex spectral structure and its detection characteristics taking the effect of secondary modulation into account as well as in the development of practical recommendations for optimizing algorithms for detecting airborne targets. Using the developed algorithm in the fighter’s pulse-Doppler radar station will increase the detection range of an air target against the background of interfering reflections from the water surface.

scholarly journals Analysis of the effect of fast and slow multiplicative noise on the distortion of the radiation pattern of the «array-receiver» system.

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
V.M. Artyushenko ◽  
◽  
V.I. Volovach ◽  
Keyword(s):  
Multiplicative Noise ◽  
Beam Pattern ◽  
Signal Duration ◽  
Signal Spectrum ◽  
Smoothing Effect ◽  
Modulation Function ◽  
Receiver System ◽  
Spectrum Width ◽  
Phase Distortions ◽  
Array Receiver

The effect of fast and slow multiplicative noise on the distortion of the beam pattern of the «array-receiver» system in the conditions of the smoothing effect of the receiver and taking into account the time of relative lag from the grating elements was analyzed. Expressions are obtained for instantaneous beam patterns of the «array-receiver» system in the absence and presence of multiplicative noise. It is shown that in the case of action of multiplicative noise the beam pattern of the «array-receiver» system is obtained by averaging the instantaneous pattern on the grating correctness at a time interval equal to the signal duration. Influence of periodic multiplicative noise on distortion of beam pattern of system «array-receiver» is investigted. It is shown that for all signals except frequency-modulated, the beam pattern expression is maximized at the time t0=0. It is also shown that the beam pattern distortion of the «array-receiver» system when exposed to periodic multiplicative noise is less than for the separately considered phased antenna array. The degree of reduction of distortion from smoothing action of matched receiver filter is determined; and the distortion is less, the greater the ratio of the spectrum width of the noise modulation function to the signal spectrum width. Analysis of the influence of fluctuation multiplicative noise on the distortion of beam pattern of «array-receiver» system for the case of matching with signal of receiver filter is performed. The power-average beam pattern of the «array-receiver» system is determined through the energy spectrum of the noise modulation function. It is noted that multiplicative noise, all other things being equal, has less effect on the beam-receiver pattern of the system when using broadband pulse signals without intra-pulse modulation and at the same time resolution in range. It is noted that in case of deep phase distortions for gratings with reversible phases, the distortion of the beam pattern of the «array-receiver» system caused by multiplicative noise is significantly more than those distortions associated with the extremity of the signal spectrum width. The newly smoothing effect of the receiver reduces the expansion of the beam lobe caused by multiplicative noise. An expression is obtained for the average power of the beam pattern of the «array-receiver» system with normally distributed phase distortions of the signal. The effect of the signal duration on beam distortions caused by multiplicative noise was quantified.

Methods and Algorithms for Technical Vision in Radar Introscopy

2019 ◽  
pp. 373-391
Author(s):  
Oleg Sytnik ◽  
Vladimir Kartashov
Keyword(s):  
Signal Processing ◽  
Processing Technique ◽  
Ultra Wideband ◽  
Radar Signal ◽  
Signal Spectrum ◽  
Signal Processing Technique ◽  
Distinctive Features ◽  
Technical Vision ◽  
Probing Signal ◽  
Radio Vision

Optimization of technical characteristics of radio vision systems is considered in the radars with ultra-wideband sounding signals. Highly noisy conditions, in which such systems operate, determine the requirements that should be met by the signals being studied. The presence of the multiplicative noise makes it difficult to design optimal algorithms of echo-signal processing. Consideration is being given to the problem of discriminating objects hidden under upper layers of the ground at depths comparable to the probing pulse duration. Based upon the cepstrum and textural analysis, a subsurface radar signal processing technique has been suggested. It is shown that, however the shape of the probing signal spectrum might be, the responses from point targets in the cepstrum images of subsurface ground layers make up the texture whose distinctive features enable objects to be detected and identified.

Research on Signal "Batch-Increasing" Phenomenon of Superheterodyne Reconnaissance Receiver

2013 ◽  
Vol 347-350 ◽  
pp. 1743-1747
Author(s):  
Yan Zhong Hao ◽  
Hong Liang Zhang ◽  
Fu Chun Zhang ◽  
Wang Hui ◽  
Zheng Dong Xu ◽  
...  
Keyword(s):  
Signal Processing ◽  
Frequency Domain ◽  
Pulse Width ◽  
Radar Signal ◽  
Signal Spectrum

For the superheterodyne reconnaissance receiver detected "signalBatch-increasing" phenomenon, research on radar signal sand the intercepted characteristics of reconnaissance receiver from the frequency domain, pointed out that "Pulse-width split" and "Pulse-width truncated" caused by Emitter signal spectrum loss is the reason of "Batch-increasing",On this basis, analyzed the strategies of "Batch-increasing" signal processing .

An Adaptive Moments Estimation Technique Applied to MST Radar Echoes

2005 ◽  
Vol 22 (4) ◽  
pp. 396-408 ◽  
Author(s):  
V. K. Anandan ◽  
P. Balamuralidhar ◽  
P. B. Rao ◽  
A. R. Jain ◽  
C. J. Pan
Keyword(s):  
Conventional Method ◽  
Signal To Noise Ratio ◽  
Radar Data ◽  
Adaptive Method ◽  
Radar Signal ◽  
Signal Spectrum ◽  
Estimation Technique ◽  
Low Snr ◽  
Wind Speeds ◽  
Mst Radar

Abstract An adaptive spectral moments estimation technique has been developed for analyzing the Doppler spectra of the mesosphere–stratosphere–troposphere (MST) radar signals. The technique, implemented with the MST radar at Gadanki (13.5°N, 79°E), is based on certain criteria, set up for the Doppler window, signal-to-noise ratio (SNR), and wind shear parameters, which are used to adaptively track the signal in the range–Doppler spectral frame. Two cases of radar data, one for low and the other for high SNR conditions, have been analyzed and the results are compared with those from the conventional method based on the strongest peak detection in each range gate. The results clearly demonstrate that by using the adaptive method the height coverage can be considerably enhanced compared to the conventional method. For the low SNR case, the height coverage for the adaptive and conventional methods is about 22 and 11 km, respectively; the corresponding heights for the high SNR case are 24 and 13 km. To validate the results obtained through the adaptive method, the velocity profile is compared with global positioning system balloon sounding (GPS sonde) observations. The results of the adaptive method show excellent agreement with the GPS sonde measured wind speeds and directions throughout the height profile. To check the robustness and reliability of the adaptive algorithm, data taken over a diurnal cycle at 1-h intervals were analyzed. The results demonstrate the reliability of the algorithm in extracting wind profiles that are self-consistent in time. The adaptive method is thus found to be of considerable advantage over the conventional method in extracting information from the MST radar signal spectrum, particularly under low SNR conditions that are free from interference and ground clutter.

scholarly journals MEASUREMENT OF NARROWBAND RESISTANCE FREQUENCY RADIO SIGNAL OF LIMITED DURATION

2021 ◽  
Vol 295 (2) ◽  
pp. 56-63
Author(s):  
S. BARAS ◽  
◽  
L. KRUPELNITSKYI ◽  
O. ONYSCHUK ◽  
◽  
...  
Keyword(s):  
High Speed ◽  
Radio Signal ◽  
Experimental Studies ◽  
Signal Amplitude ◽  
Signal Spectrum ◽  
Time Interval ◽  
Reference Frequency ◽  
Half Cycle ◽  
Spectrum Width ◽  
Limited Duration

The work concerns analog-digital systems that work with radio signals emitted and received by the antenna, and these signals have a limited duration, ie are pulsed. The propagation conditions of such signals and the processes of formation of echo signals affect their amplitude, frequency and phase characteristics in such a way that they form classical narrowband signals. The operation of the system involves the determination of certain parameters of echo signals, and taking into account their pulse nature for such a definition is given a limited time interval. This means that the procedure for determining the parameters must meet the criterion of high speed, and therefore differ from the traditional, built on the use of phase-locked loop. The article is devoted to solving the problem of measuring the reference frequency of a pulsed narrowband radio signal. By analyzing the results of experimental studies, two types of errors in measuring the reference frequency of a narrowband radio signal were identified and the causes of their occurrence were established. These errors are provoked by the peculiarities of the structure of the narrowband signal. The reason for the error of the 1st type, the absolute value of which correlates with the duration of the half-cycle of the reference frequency, is the so-called phase jumps at the point of change of the sign of the bypass. The frequency of such errors within the duration of the echo signal is generally low, although it increases with increasing signal spectrum width. Type 2 errors occur due to the appearance of zones with almost completely suppressed signal amplitude, which may be the result of intrapulse interference and / or signal attenuation. Such errors also occur more often if the spectrum width is larger. A method for measuring the reference frequency of a narrowband pulsed radio signal is proposed, which is based on counting the number of half-cycles of the reference frequency on a time-limited measurement interval and removing from this procedure areas with completely suppressed signal amplitude. An auxiliary highly stable reference frequency is used to establish the numerical value of the reference frequency. The block diagram of the frequency meter and the algorithm of its operation are given, the implementation of which avoids these errors.

scholarly journals Fractional-N PLL Synthesizer for FMCW Signal Generator with Dual-Mode Modulation Pattern

2018 ◽  
Vol 18 (2) ◽  
pp. 46
Author(s):  
R. Indrawijaya ◽  
R. Sariningrum ◽  
B. Edi Sukoco ◽  
D. Muliawandana
Keyword(s):  
Continuous Wave ◽  
Signal Generator ◽  
Experimental Result ◽  
Radar Signal ◽  
Signal Spectrum ◽  
Single Chip ◽  
Dual Mode ◽  
Modulation Pattern ◽  
Realization Process ◽  
Pll Synthesizer

Radar signal generator is a critical component in radar system as it determines the best achievable resolution. Single chip Fractional-N PLL synthesizer with built-in VCO and sweep modulator become more popular as Frequency Modulated Continuous Wave (FMCW) signal generator due to the simplicity and overall cost reduction. This paper presents a realization process and experimental result of dual-mode modulation pattern FMCW signal generator using HMC769LP6CE PLL. The PLL is controlled by ATMega328 microcontroller and Altera EPM240T100C5 CPLD to operate in two difference mode: 1-way sweep mode and 2-way sweep mode. The PLL is programmed with four different sweep bandwidth from 6.75–54 MHz for different range and resolution radar purpose. The performance of FMCW signal generator is measured using the output of passband signal spectrum. The experimental results indicate that the PLL-VCO with 2-way sweep mode has clearer frequency passband compared to 1-way sweep mode.

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