Airborne area-array whisk-broom imaging systems typically adopt constant-speed scanning schemes.For large-inertia scanning systems,constant-speed scanning requires substantial time to complete the reversal motion,redu...Airborne area-array whisk-broom imaging systems typically adopt constant-speed scanning schemes.For large-inertia scanning systems,constant-speed scanning requires substantial time to complete the reversal motion,reducing the system's adaptability to high-speed reversal scanning and decreasing scanning efficiency.This study proposes a novel sinusoidal variable-speed roll scanning strategy,which reduces abrupt changes in speed and acceleration,minimizing time loss during reversals.Based on the forward image motion compensation strategy in the pitch direction,we establish a line-of-sight(LOS)position calculation model with vertical flight path correction(VFPC),ensuring that the central LOS of the scanned image remains stable on the same horizontal line,facilitating accurate image stitching in whisk-broom imaging.Through theoretical analysis and simulation experiments,the proposed method improves the scanning efficiency by approximately 18.6%at a 90o whiskbroom imaging angle under the same speed height ratio conditions.The new VFPC method enables wide-field,high-resolution imaging,achieving single-line LOS horizontal stability with an accuracy of better than O.4 mrad.The research is of great significance to promote the further development of airborne area-array whisk-broom imaging technology toward wider fields of view,higher speed height ratios,and greater scanning efficiency.展开更多
The longitudinal dispersion of the projectile in shooting tests of two-dimensional trajectory corrections fused with fixed canards is extremely large that it sometimes exceeds the correction ability of the correction ...The longitudinal dispersion of the projectile in shooting tests of two-dimensional trajectory corrections fused with fixed canards is extremely large that it sometimes exceeds the correction ability of the correction fuse actuator.The impact point easily deviates from the target,and thus the correction result cannot be readily evaluated.However,the cost of shooting tests is considerably high to conduct many tests for data collection.To address this issue,this study proposes an aiming method for shooting tests based on small sample size.The proposed method uses the Bootstrap method to expand the test data;repeatedly iterates and corrects the position of the simulated theoretical impact points through an improved compatibility test method;and dynamically adjusts the weight of the prior distribution of simulation results based on Kullback-Leibler divergence,which to some extent avoids the real data being"submerged"by the simulation data and achieves the fusion Bayesian estimation of the dispersion center.The experimental results show that when the simulation accuracy is sufficiently high,the proposed method yields a smaller mean-square deviation in estimating the dispersion center and higher shooting accuracy than those of the three comparison methods,which is more conducive to reflecting the effect of the control algorithm and facilitating test personnel to iterate their proposed structures and algorithms.;in addition,this study provides a knowledge base for further comprehensive studies in the future.展开更多
The detection of hypersonic targets usually confronts range migration(RM)issue before coherent integration(CI).The traditional methods aiming at correcting RM to obtain CI mainly considers the narrow-band radar condit...The detection of hypersonic targets usually confronts range migration(RM)issue before coherent integration(CI).The traditional methods aiming at correcting RM to obtain CI mainly considers the narrow-band radar condition.However,with the increasing requirement of far-range detection,the time bandwidth product,which is corresponding to radar’s mean power,should be promoted in actual application.Thus,the echo signal generates the scale effect(SE)at large time bandwidth product situation,influencing the intra and inter pulse integration performance.To eliminate SE and correct RM,this paper proposes an effective algorithm,i.e.,scaled location rotation transform(ScLRT).The ScLRT can remove SE to obtain the matching pulse compression(PC)as well as correct RM to complete CI via the location rotation transform,being implemented by seeking the actual rotation angle.Compared to the traditional coherent detection algorithms,Sc LRT can address the SE problem to achieve better detection/estimation capabilities.At last,this paper gives several simulations to assess the viability of ScLRT.展开更多
针对目前海上风电出力预测方法精度较低的问题,提出一种基于词向量化和长短期记忆网络(word to vector long short-term memory,Word2vec-LSTM)与聚类修正的海上风电出力预测方法。对Word2vec方法进行改进来提取时间序列数据特征,实现...针对目前海上风电出力预测方法精度较低的问题,提出一种基于词向量化和长短期记忆网络(word to vector long short-term memory,Word2vec-LSTM)与聚类修正的海上风电出力预测方法。对Word2vec方法进行改进来提取时间序列数据特征,实现数据信息的高效利用;在长短期记忆神经网络的预测模型基础上,研究了一种基于k-shape聚类结果的预测结果修正算法,对预测结果距离聚类中心超过阈值的数值判定为预测误差偏大的数据并向簇中心进行修正。最后,基于江苏某海上风电场的真实数据进行测试,结果表明,基于Word2vec-LSTM与聚类修正的海上风电出力预测方法的平均绝对误差(mean absolute error,MAE)和均方根误差(root mean square error,RMSE)达到5.04和5.42,相比传统LSTM预测模型的误差平均降低了11.10%和12.25%,为海上风电并网与电网调控提供了技术支持。展开更多
基金Supported by the National Key Research and Development Program(2023YFC3107602)。
文摘Airborne area-array whisk-broom imaging systems typically adopt constant-speed scanning schemes.For large-inertia scanning systems,constant-speed scanning requires substantial time to complete the reversal motion,reducing the system's adaptability to high-speed reversal scanning and decreasing scanning efficiency.This study proposes a novel sinusoidal variable-speed roll scanning strategy,which reduces abrupt changes in speed and acceleration,minimizing time loss during reversals.Based on the forward image motion compensation strategy in the pitch direction,we establish a line-of-sight(LOS)position calculation model with vertical flight path correction(VFPC),ensuring that the central LOS of the scanned image remains stable on the same horizontal line,facilitating accurate image stitching in whisk-broom imaging.Through theoretical analysis and simulation experiments,the proposed method improves the scanning efficiency by approximately 18.6%at a 90o whiskbroom imaging angle under the same speed height ratio conditions.The new VFPC method enables wide-field,high-resolution imaging,achieving single-line LOS horizontal stability with an accuracy of better than O.4 mrad.The research is of great significance to promote the further development of airborne area-array whisk-broom imaging technology toward wider fields of view,higher speed height ratios,and greater scanning efficiency.
基金the National Natural Science Foundation of China(Grant No.61973033)Preliminary Research of Equipment(Grant No.9090102010305)for funding the experiments。
文摘The longitudinal dispersion of the projectile in shooting tests of two-dimensional trajectory corrections fused with fixed canards is extremely large that it sometimes exceeds the correction ability of the correction fuse actuator.The impact point easily deviates from the target,and thus the correction result cannot be readily evaluated.However,the cost of shooting tests is considerably high to conduct many tests for data collection.To address this issue,this study proposes an aiming method for shooting tests based on small sample size.The proposed method uses the Bootstrap method to expand the test data;repeatedly iterates and corrects the position of the simulated theoretical impact points through an improved compatibility test method;and dynamically adjusts the weight of the prior distribution of simulation results based on Kullback-Leibler divergence,which to some extent avoids the real data being"submerged"by the simulation data and achieves the fusion Bayesian estimation of the dispersion center.The experimental results show that when the simulation accuracy is sufficiently high,the proposed method yields a smaller mean-square deviation in estimating the dispersion center and higher shooting accuracy than those of the three comparison methods,which is more conducive to reflecting the effect of the control algorithm and facilitating test personnel to iterate their proposed structures and algorithms.;in addition,this study provides a knowledge base for further comprehensive studies in the future.
基金supported by the National Natural Science Foundation of China(62101099)the Chinese Postdoctoral Science Foundation(2021M690558,2022T150100,2018M633352,2019T120825)+3 种基金the Young Elite Scientist Sponsorship Program(YESS20200082)the Aeronautical Science Foundation of China(2022Z017080001)the Open Foundation of Science and Technology on Electronic Information Control Laboratorythe Natural Science Foundation of Sichuan Province(2023NSFSC1386)。
文摘The detection of hypersonic targets usually confronts range migration(RM)issue before coherent integration(CI).The traditional methods aiming at correcting RM to obtain CI mainly considers the narrow-band radar condition.However,with the increasing requirement of far-range detection,the time bandwidth product,which is corresponding to radar’s mean power,should be promoted in actual application.Thus,the echo signal generates the scale effect(SE)at large time bandwidth product situation,influencing the intra and inter pulse integration performance.To eliminate SE and correct RM,this paper proposes an effective algorithm,i.e.,scaled location rotation transform(ScLRT).The ScLRT can remove SE to obtain the matching pulse compression(PC)as well as correct RM to complete CI via the location rotation transform,being implemented by seeking the actual rotation angle.Compared to the traditional coherent detection algorithms,Sc LRT can address the SE problem to achieve better detection/estimation capabilities.At last,this paper gives several simulations to assess the viability of ScLRT.
文摘针对目前海上风电出力预测方法精度较低的问题,提出一种基于词向量化和长短期记忆网络(word to vector long short-term memory,Word2vec-LSTM)与聚类修正的海上风电出力预测方法。对Word2vec方法进行改进来提取时间序列数据特征,实现数据信息的高效利用;在长短期记忆神经网络的预测模型基础上,研究了一种基于k-shape聚类结果的预测结果修正算法,对预测结果距离聚类中心超过阈值的数值判定为预测误差偏大的数据并向簇中心进行修正。最后,基于江苏某海上风电场的真实数据进行测试,结果表明,基于Word2vec-LSTM与聚类修正的海上风电出力预测方法的平均绝对误差(mean absolute error,MAE)和均方根误差(root mean square error,RMSE)达到5.04和5.42,相比传统LSTM预测模型的误差平均降低了11.10%和12.25%,为海上风电并网与电网调控提供了技术支持。
