Because of Global Positioning System(GPS)is easily interferenced by other signal,this paper design an anti-jamming GPS receiver based on the vector tracking loop(or vector lock loop-VLL),which improve its anti-jamming...
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ISBN:
(纸本)9789811009334
Because of Global Positioning System(GPS)is easily interferenced by other signal,this paper design an anti-jamming GPS receiver based on the vector tracking loop(or vector lock loop-VLL),which improve its anti-jamming performance on the tracking *** traditional scalar tracking loop(or scalar lock loop-SLL)track the satellite *** is no information exchange between each channel,which ignores the relationship between the receiver’s navigation information(position and velocity)and the tracking loop information(code phase and Doppler frequency).The vector tracking loop take the advantage of this relationship,and combine the navigation filter with tracking loop in a Kalman filter,which improve the receiver’s anti-jamming ability and *** simulation analyses the influence on the tracking loop whether there has an interference,and this paper gives the comparison of position and velocity ***,the weighted least squares method is used to compare the variance of predicted pseudo-range error of the two tracking loop when the power of the interference *** paper concluded that the vector tracking loop has better antijamming ability.
Airborne weather radars are used by pilots to identify areas containing significant precipitation, turbulence, and wind shear on the flight path. The different atmospheric hazards can be determined by airborne weather...
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ISBN:
(纸本)9781509021505
Airborne weather radars are used by pilots to identify areas containing significant precipitation, turbulence, and wind shear on the flight path. The different atmospheric hazards can be determined by airborne weather radar using the spectral moments of radar echoes. The pulse pair processing method and the FFT based method are the most widely used spectral moments estimators. However, the performance of these method is poor under low SNR conditions as it is a nonparametric method. A parametric spectral moments estimation method is proposed based on subspace analysis of the covariance matrix of the echoes with Gaussian-shaped spectrum. A fast algorithm for this method is also implemented for demonstration, in which the 2D-search problem is decomposed into two 1D-search routines. The numerical analysis verifies that the presented method functions effectively in low SNR scenario.
In Global navigation satellite systems(GNSS),when the receiver carrier is in the situation of attitude high dynamic,the directions of arrival(DOA)of signal and interference will change rapidly over *** this point,conv...
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ISBN:
(纸本)9789811009334
In Global navigation satellite systems(GNSS),when the receiver carrier is in the situation of attitude high dynamic,the directions of arrival(DOA)of signal and interference will change rapidly over *** this point,conventional adaptive anti-jamming algorithms become *** this paper,According to the structure shape of practical attitude high dynamic carrier,the DOAs changes of signal and interference in the case of uniform circular array are analyzed,and the Capon-Laplace algorithm based on uniform circular array(UCA)was provided to suppress the *** effectiveness of the algorithm is verified by simulation *** the analysis of attitude high-dynamic parameter,the paper compared the feasibility of the algorithm in different degrees’attitude highdynamic circumstances,giving a further verification on the effectiveness of the algorithm.
In safety-critical systems such as transportation aircraft, redundancy of actuators is introduced to improve fault tolerance. How to make the best use of remaining actuators to allow the system to continue achieving a...
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In safety-critical systems such as transportation aircraft, redundancy of actuators is introduced to improve fault tolerance. How to make the best use of remaining actuators to allow the system to continue achieving a desired operation in the presence of some actuators failures is the main subject of this paper. Considering that many dynamical systems, including flight dynamics of a transportation aircraft, can be expressed as an input affine nonlinear system, a new state repre- sentation is adopted here where the output dynamics are related with virtual inputs associated with the intended operation. This representation, as well as the distribution matrix associated with the effectiveness of the remaining operational actuators, allows us to define different levels of fault tol- erant governability with respect to actuators' failures. Then, a two-stage control approach is devel- oped, leading frst to the inversion of the output dynamics to get nominal values for the virtual inputs and then to the solution of a linear quadratic (LQ) problem to compute the solicitation of each operational actuator. The proposed approach is applied to the control of a transportation air- craft which performs a stabilized roll maneuver while a partial failure appears. Two fault scenarios are considered and the resulting performance of the proposed approach is displayed and discussed.
Pulse blanking is a widely used method to eliminate impulsive interference in orthogonal frequency division multiplexing (OFDM) receiver. To analyze the effect of Inter Carrier Interference (ICI) caused by pulse blank...
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As a kind of renewable and clean energy, wind energy has been widespread concerned by countries around the world. However, it is shown that wind turbines will have a serious impact on Air Traffic Control (ATC) communi...
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Wind turbines could have a serious impact on Air Traffic Control (ATC) radar system because of the complex electromagnetic scattering properties. In this paper, matching pursuit technology is studied to mitigate the w...
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ISBN:
(纸本)9781849199940
Wind turbines could have a serious impact on Air Traffic Control (ATC) radar system because of the complex electromagnetic scattering properties. In this paper, matching pursuit technology is studied to mitigate the wind turbines interference. Due to the large amount of calculation in the conventional MP algorithm, rotation rate of wind turbine and radar azimuth are firstly estimated based on the priori information, then matching pursuit algorithm is applied to mitigate the wind turbine clutter. Effectiveness of the proposed method is verified via simulation experiments.
The weakness of ADS-B signals makes it vulnerable to jamming. In order to suppress jamming, the paper proposes an ADS-B anti-jamming approach with low-complexity based on a cross-antenna array. First, down-sampling th...
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ISBN:
(纸本)9781479989522
The weakness of ADS-B signals makes it vulnerable to jamming. In order to suppress jamming, the paper proposes an ADS-B anti-jamming approach with low-complexity based on a cross-antenna array. First, down-sampling the digital IF signals received by array, and estimating the covariance matrix using the down-sampled snapshots. Because of the different duration and different features of DOAs between ADS-B 1090ES signals and jamming, the larger eigenvalues of the estimated covariance matrix mainly consist of jamming. Then the array weight vector could be conducted by power inversion algorithm based on the covariance matrix obtained from the first step. Finally, jamming can be nulled by the array weight vector. Thus the proposed method would almost only suppress jamming and the output SINR would be improved sharply. Down-sampling reduces the complexity of the algorithm. Simulation and experiments results show the effectiveness of the proposed approach.
?As a kind of renewable and clean energy, wind energy has been widespread concerned by countries around the world. Recently, the global wind power installed capacity is growing exponentially. ?Wind turbines will have ...
ISBN:
(纸本)9781479989522
?As a kind of renewable and clean energy, wind energy has been widespread concerned by countries around the world. Recently, the global wind power installed capacity is growing exponentially. ?Wind turbines will have a serious impact on Air Traffic Control (ATC) communication, navigation and surveillance systems due to the complex electromagnetic scattering properties.
In this paper, a new algorithm of runways detection based on classification is proposed for PolSAR image, in which scattering similarity and structural characteristics of airport runways are used as target feature for...
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ISBN:
(纸本)9781479989522
In this paper, a new algorithm of runways detection based on classification is proposed for PolSAR image, in which scattering similarity and structural characteristics of airport runways are used as target feature for classification. Firstly, training sample templates are built by initial terrain classification with scattering similarity. Then, Bayesian classification is used to classify the whole image. Finally, morphology filtering and the runways structural features such as parallels, topologic property are used to detect real runways. Multi-look fully polarimetric SAR data acquired by U.S. UAVSAR systems is used to verify the proposed algorithm. Experimental results show that the novel method can detect runways effectively and has a low false alarm rate. Besides, the detected runways keep an intact structure and clear outlines.
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