L波段数字航空通信系统(L-band digital aeronautical communication system,LDACS)作为未来航空数据链的重要技术手段之一,非常容易受到相邻波道的测距机系统信号的干扰。为此,提出一种基于稀疏贝叶斯推断的LDACS波束形成方法。首先,将...L波段数字航空通信系统(L-band digital aeronautical communication system,LDACS)作为未来航空数据链的重要技术手段之一,非常容易受到相邻波道的测距机系统信号的干扰。为此,提出一种基于稀疏贝叶斯推断的LDACS波束形成方法。首先,将LDACS地面站的粗略来向信息作为先验,并根据空域信号来向的稀疏性构建稀疏信号。随后,通过贝叶斯推断估算干扰和噪声的功率,估计各个信源的来向。最后,重构干扰噪声协方差矩阵,获得波束形成权矢量。该方法无需知晓干扰数量、干扰来向等信息。仿真结果表明,该方法在低信噪比和少快拍条件下也能稳定输出波束方向图,表现出较好性能。展开更多
针对L波段数字航空通信系统(L-band digital aeronautic communication system,LDACS)可用频谱资源有限且易受大功率测距仪(distance measuring equipment,DME)信号干扰的问题,提出一种基于降维循环谱和残差神经网络的频谱感知方法。首...针对L波段数字航空通信系统(L-band digital aeronautic communication system,LDACS)可用频谱资源有限且易受大功率测距仪(distance measuring equipment,DME)信号干扰的问题,提出一种基于降维循环谱和残差神经网络的频谱感知方法。首先理论推导分析了DME信号的循环谱特征;然后利用Fisher判别率(Fisher discriminant rate,FDR)提取循环频率能量最大的向量,通过主成分分析(principal component analysis,PCA)进行预处理特征增强;最后给出数据处理后的循环谱向量与卷积神经网络相结合的实现过程,实现了DME信号的有效检测。仿真结果表明,该方法对噪声不敏感,当信噪比不低于-15 dB时,平均检测概率大于90%。当信噪比不低于-14 dB,检测概率接近100%。展开更多
L波段数字航空通信系统(L band digital aeronautical communication system,LDACS)是未来航空宽带通信重要的基础设施之一,针对LDACS信号容易受到相邻波道大功率测距仪(distance measuring equipment,DME)信号干扰的问题,提出了联合正...L波段数字航空通信系统(L band digital aeronautical communication system,LDACS)是未来航空宽带通信重要的基础设施之一,针对LDACS信号容易受到相邻波道大功率测距仪(distance measuring equipment,DME)信号干扰的问题,提出了联合正交投影干扰抑制与单快拍稀疏分解的波达方向(direction of arrival,DOA)估计方法。通过子空间投影抑制DME干扰,然后使用单快拍数据构建伪协方差矩阵,对伪协方差矩阵求高阶幂,之后进行奇异值分解,并利用约束条件求解稀疏解得到期望信号来向的估计值。所提方法使用高阶伪协方差矩阵降低了噪声影响,仅用单快拍就可以准确估计LDACS信号的入射方向。仿真结果表明,改进单快拍高级幂(improved single snapshot high order power,ISS-HOP)L1-SVD算法的估计精度优于ISS-HOP-MUSIC算法。该方法可以有效抑制DME干扰,提高OFDM接收机性能。展开更多
Most of the traditional taxi path planning studies assume that the aircraft is in uniform speed,and the optimization goal is the shortest taxi time.Although it is easy to solve,it does not consider the changes in the ...Most of the traditional taxi path planning studies assume that the aircraft is in uniform speed,and the optimization goal is the shortest taxi time.Although it is easy to solve,it does not consider the changes in the speed profile of the aircraft when turning,and the shortest taxi time does not necessarily bring the best taxi fuel consumption.In this paper,the number of turns is considered,and the improved A*algorithm is used to obtain the P static paths with the shortest sum of the straight-line distance and the turning distance of the aircraft as the feasible taxi paths.By balancing taxi time and fuel consumption,a set of Pareto optimal speed profiles are generated for each preselected path to predict the 4-D trajectory of the aircraft.Based on the 4-D trajectory prediction results,the conflict by the occupied time window in the taxiing area is detected.For the conflict aircraft,based on the priority comparison,the waiting or changing path is selected to solve the taxiing conflict.Finally,the conflict free aircraft taxiing path is generated and the area occupation time window on the path is updated.The experimental results show that the total taxi distance and turn time of the aircraft are reduced,and the fuel consumption is reduced.The proposed method has high practical application value and is expected to be applied in real-time air traffic control decision-making in the future.展开更多
文摘L波段数字航空通信系统(L-band digital aeronautical communication system,LDACS)作为未来航空数据链的重要技术手段之一,非常容易受到相邻波道的测距机系统信号的干扰。为此,提出一种基于稀疏贝叶斯推断的LDACS波束形成方法。首先,将LDACS地面站的粗略来向信息作为先验,并根据空域信号来向的稀疏性构建稀疏信号。随后,通过贝叶斯推断估算干扰和噪声的功率,估计各个信源的来向。最后,重构干扰噪声协方差矩阵,获得波束形成权矢量。该方法无需知晓干扰数量、干扰来向等信息。仿真结果表明,该方法在低信噪比和少快拍条件下也能稳定输出波束方向图,表现出较好性能。
文摘L波段数字航空通信系统(L band digital aeronautical communication system,LDACS)是未来航空宽带通信重要的基础设施之一,针对LDACS信号容易受到相邻波道大功率测距仪(distance measuring equipment,DME)信号干扰的问题,提出了联合正交投影干扰抑制与单快拍稀疏分解的波达方向(direction of arrival,DOA)估计方法。通过子空间投影抑制DME干扰,然后使用单快拍数据构建伪协方差矩阵,对伪协方差矩阵求高阶幂,之后进行奇异值分解,并利用约束条件求解稀疏解得到期望信号来向的估计值。所提方法使用高阶伪协方差矩阵降低了噪声影响,仅用单快拍就可以准确估计LDACS信号的入射方向。仿真结果表明,改进单快拍高级幂(improved single snapshot high order power,ISS-HOP)L1-SVD算法的估计精度优于ISS-HOP-MUSIC算法。该方法可以有效抑制DME干扰,提高OFDM接收机性能。
基金supported by the National Key R&D Project(No.2020YFB1600101)National Natural Science Foundations of China(Nos.U1833103,71801215)Civil Aviation Flight Wide Area Surveillance and Safety Control Technology Key Laboratory Open Fund(No.202008)。
文摘Most of the traditional taxi path planning studies assume that the aircraft is in uniform speed,and the optimization goal is the shortest taxi time.Although it is easy to solve,it does not consider the changes in the speed profile of the aircraft when turning,and the shortest taxi time does not necessarily bring the best taxi fuel consumption.In this paper,the number of turns is considered,and the improved A*algorithm is used to obtain the P static paths with the shortest sum of the straight-line distance and the turning distance of the aircraft as the feasible taxi paths.By balancing taxi time and fuel consumption,a set of Pareto optimal speed profiles are generated for each preselected path to predict the 4-D trajectory of the aircraft.Based on the 4-D trajectory prediction results,the conflict by the occupied time window in the taxiing area is detected.For the conflict aircraft,based on the priority comparison,the waiting or changing path is selected to solve the taxiing conflict.Finally,the conflict free aircraft taxiing path is generated and the area occupation time window on the path is updated.The experimental results show that the total taxi distance and turn time of the aircraft are reduced,and the fuel consumption is reduced.The proposed method has high practical application value and is expected to be applied in real-time air traffic control decision-making in the future.
