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14th China Satellite Navigation Conference, CSNC 2024

作者： Jia, Qiongqiong Li, Weipeng Tianjin Key Lab for Advanced Signal Processing Civil Aviation University of China Tianjin China

ISBN: (纸本)9789819969319

The Popular of Global Navigation Satellite System (GNSS) is attributed to its good performance. However, the performance of a conventional GNSS receiver is severely degraded or even failed to provide services in complex environments. Direct Position Estimation (DPE) combines all the visible satellite signals for energy accumulation in the navigation domain first, and then the navigation solution is estimated directly from the accumulation results. Hence the navigation performance of GNSS can be effectively improved in complex environments by DPE. However, the signal accumulation of DPE requires calculating the correlation values of all the visible satellite signals at each candidate grid in the navigation domain, the computation load of which limits its application. To alleviate this problem, a GPU-based parallel implementation of the DPE receiver is designed, which decomposes the operations involved in the joint accumulation into three levels of parallel processing. The effectiveness of the designed parallel implementation of the DPE receiver is verified by experiment results. With the available hardware in our laboratory, the designed DPE implementation improves the efficiency to approximately 146 times on average over the conventional DPE implementation. © Aerospace Information Research Institute 2024.

关键词： Graphics processing unit

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The DME Interference Mitigation Based Wavelet Thresholding Algorithm for L-DACS Receiver 9

The DME Interference Mitigation Based Wavelet Thresholding A...

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9th International Conference on Intelligent Computing and signal processing, ICSP 2024

作者： Peng, Xiangqing Wang, Jiani Wang, Lei Liu, Haitao Civil Aviation University of China Tianjin Key Lab for Advanced Signal Processing Tianjin China

ISBN: (纸本)9798350376548

The L-DACS operates as an inlay system between two adjacent channels of the Distance Measuring Equipment (DME) system since the spectrum resources in the L-band are scarce and fragmented. This DME signal severely impacts the performance of L-DACS. This paper proposes an approach for mitigating DME interference by integrating spectrum aggregation technology and a wavelet thresholding algorithm. To enhance spectral efficiency, the method utilizes direct wideband aggregation technology at the transmission end to expand the bandwidth. Then, at the receiving end of Orthogonal Frequency Division Multiplexing (OFDM), the received signal is decomposed layer by layer using the wavelet threshold algorithm. The difference between the spectrum-aggregated signal and the DME signal in the wavelet domain is effectively identified to reconstruct the DME signal, thereby achieving interference elimination. Simulation results demonstrate that this method improves spectrum efficiency and data transmission rate while significantly mitigating DME interference, thereby enhancing the link transmission reliability of the L-DACS system. © 2024 IEEE.

关键词： Orthogonal frequency division multiplexing

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A High-Efficiency Doppler Frequency Parallel Acquisition Method Based on A-GPS

A High-Efficiency Doppler Frequency Parallel Acquisition Met...

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2025 International Technical Meeting of The Institute of Navigation, ITM 2025

作者： Jia, Qiongqiong Zhao, Yuchen China Civil Aviation University Tianjin Key Laboratory of Intelligent Signal and Image Processing Tianjin300000 China

ISBN: (纸本)9780936406404

Acquisition is a key step for Global Navigation Satellite System (GNSS) receivers to achieve positioning and other functions, and the acquisition speed directly affects the Time To First Fix (TTFF) of the receiver. The acquisition process typically involves generating local reference signals for all satellite signals and matching them with the received signals. For each satellite signal, this matching involves searching in the unknown Doppler frequency and code phase space. Traditional parallel acquisition methods can only perform parallel processing in either the Doppler frequency dimension or the code phase dimension, and still require linear search in the other dimension. To reduce the computational load and improve the acquisition efficiency, this paper proposes a high-efficiency parallel acquisition method based on A-GPS. This method utilizes the auxiliary information provided by the A-GPS base station to convert the linear search of visible star signals in Doppler frequency into a single parallel search in the Doppler search space, thereby reducing the computational load required for acquisition to 1/N of the conventional method, where N is the total number of frequency bands searched. The paper verifies through theoretical analysis and experimental results that the proposed method can significantly improve acquisition efficiency while ensuring acquisition performance. © 2025 Proceedings of the International Technical Meeting of The Institute of Navigation, ITM. All rights reserved.

关键词： Global positioning system

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Design of Dual-mode DPE Receiver Based on GPS L1/BDS B1C signals

Design of Dual-mode DPE Receiver Based on GPS L1/BDS B1C Sig...

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2025 International Technical Meeting of The Institute of Navigation, ITM 2025

作者： Jia, Qiongqiong Guo, Qiqi Tianjin Key Laboratory of Intelligent Signal and Image Processing Civil Aviation University of China Tianjin300000 China

ISBN: (纸本)9780936406404

With the expanding applications of the Global Navigation Satellite System (GNSS), its operating environment has become increasingly complex, with challenges such as multipath effects, non-line-of-sight (NLOS) propagation, and signal attenuation caused by tall urban buildings and trees. This complexity poses additional challenges for traditional GNSS receivers. Direct Position Estimation (DPE) addresses some of the limitations of traditional receivers by accumulating signals from all visible satellites directly in the navigation domain. However, when severe obstructions result in a reduced number of visible satellites, DPE may fail to function properly. The introduction of multiconstellation satellite signals can help mitigate the issue of insufficient visible satellites in complex environments. Based on this, this paper designs a dual-mode DPE receiver utilizing Global Positioning System (GPS) L1 signals and BeiDou Navigation Satellite System (BDS) B1C signals. © 2025 Proceedings of the International Technical Meeting of The Institute of Navigation, ITM. All rights reserved.

关键词： Global positioning system

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Geometric Algebra Based Kalman Filter Trajectory Prediction 3

Geometric Algebra Based Kalman Filter Trajectory Prediction

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3rd International Symposium on Aerospace Engineering and Systems, ISAES 2024

作者： Li, Taiyu Jiao, Weidong Civil Aviation University of China Tianjin Key Laboratory of Intelligent Signal and Image Processing Tianjin China

ISBN: (纸本)9798350350418

To improve the safety and efficiency of aviation operation, a Kalman filtered trajectory prediction algorithm based on geometric algebra is proposed in this space. Firstly, the Kalman filter equations for trajectory prediction in geometric algebraic space are given by taking position, velocity and acceleration as state variables and position, velocity and acceleration in a typical trajectory as observations. Secondly, the matrix operation in the geometric algebraic space is simplified to the matrix operation by establishing a composite geometric algebraic space. Then, the versor operator in the conformal geometric algebraic space is introduced into the Kalman filter, and the steps of geometric algebra-based Kalman filter trajectory prediction are given to improve the prediction rate and accuracy. The experimental results show that the proposed trajectory prediction algorithm has the highest accuracy and the operation efficiency is improved by 27.66% compared with the Kalman filter algorithm in Euclidean space and the DBSCAN clustering algorithm. © 2024 IEEE.

关键词： Trajectories

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Conformal Geometric Algebraic Description of Flight Collision Detection Algorithm Based on Cylinder Protection Zone 3

Conformal Geometric Algebraic Description of Flight Collisio...

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3rd International Symposium on Aerospace Engineering and Systems, ISAES 2024

作者： Wu, Haobo Jiao, Weidong Civil Aviation University of China Tianjin Key Laboratory of Intelligent Signal and Image Processing Tianjin China

ISBN: (纸本)9798350350418

In order to provide sufficient reaction time for air traffic controllers and pilots, a Flight Conflict Detection Algorithm (FCDA) based on Cylindrical Protection Zone (CPZ) in the Conformal Geometric Algebra (CGA) is proposed. Initially, the CGA description of the CPZ is represented by using the CGA forms of the central circle and central axis segments of the cylinder. Then based on the inner and outer product and geometric product operations of CGA, the positional relationship of the two CPZs is judged to determine whether a flight conflict occurs or not. Subsequently, we compared the performance of flight conflict detection methods based on rectangular protection zones, spherical protection zones, and cylindrical protection zones through experiments in CGA and Euclidean space, respectively, the experimental results show that in CGA, the proposed method has a faster speed than the flight conflict method based on cuboids, and is basically equivalent to the method based on spherical protection zones. Significantly, all CGA-based methodologies demonstrated superior speed over their Euclidean space counterparts. Considering the propensity of rectangular and spherical zones to elicit false alarms due to their expansive coverage of airspace, the CGA-CPZ-FCDA method emerges as the superior choice. © 2024 IEEE.

关键词： Spheres

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A novel strategy for fine-grained semantic verification of civil aviation radiotelephony read-backs

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Chinese Journal of Aeronautics 2022年第12期35卷 266-277页

作者： Guimin JIA Junxian LI Tianjin Key Lab for Advanced Signal Processing Civil Aviation University of ChinaTianjin 300300China College of Electronic Information and Automation Civil Aviation University of ChinaTianjin 300300China

During the flight of the aircraft,the pilot must repeat the instruction sent by the controller,and the controller must further confirm these read-backs,in this way to further ensure the safety of air ***,fatigue,tension,negligence and other human factors may prevent the controller from realizing read-back errors in time,which is a huge hidden danger for the safety of civil aviation *** paper proposes a novel strategy to implement fine-grained semantic verification of radiotelephony read-backs by introducing interaction layer and attention mechanism at the output of BiLSTM *** with the traditional twochannel verification strategy,the interaction layer is added to obtain fine-grained semantic matching relation representation,rather than connecting the BiLSTM output vectors to obtain the overall semantic representation of the *** by adding attention layer,the new strategy can capture the potential semantic relation between the read-backs and the instructions,which is applicable to non-standard diction and abbreviated read-backs in real radiotelephony *** experiments are conducted and the results show that the proposed new strategy is more effective than the traditional method for read-backs checking,and the average test accuracy of the new strategy based on the Chinese ATC radiotelephony read-backs corpus can reach 93.03%.

关键词： Attention mechanism BiLSTM Interaction layer Radiotelephony read-backs Semantic verification

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ESA-Net:A Network for Enhancing Small Target Detection Performance in SAR imagery Aircraft

ESA-Net:A Network for Enhancing Small Target Detection Perfo...

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IET International Radar Conference 2023, IRC 2023

作者： Han, Ping Zhao, Han Tianjin Key Lab for Advanced Signal Processing Civil Aviation University of China Tianjin China

ISBN: (纸本)9781839539954

In synthetic aperture radar (SAR) image aircraft target detection, aircraft small targets have a lower AP than aircraft targets and large targets due to the small number of pixel points they occupy and background clutter interference. To solve this problem, this paper proposes a network for enhancing the performance of aircraft small target detection for SAR images(ESA-Net). The network is designed based on yolov5s with a backbone network BH-CSPDarknet and a detection head TFA-Head. BH-CSPDarknet allocates more computational resources in the shallow layer of the network to process high-resolution feature maps, which effectively extracts richer feature information of aircraft small targets. TFA-Head provides appropriate feature preferences for classification and localisation tasks to provide TFA-Head provides appropriate feature information for classification and positioning task feature preferences, which can effectively suppress the background clutter interference while enhancing the aircraft small target features. The experimental results using the SAR-ADRD dataset show that the method improves the average accuracy of YOLOv5s by 1.9% and the average accuracy of aircraft small targets by 15.6%. © The Institution of Engineering & Technology 2023.

关键词： Synthetic aperture radar

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PolSAR image Classification Based on Deep Features 8th

PolSAR Image Classification Based on Deep Features

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8th China High Resolution Earth Observation Conference, CHREOC 2022

作者： Han, Ping Men, Lunan Chen, Zetao Tianjin Key Lab for Advanced Signal Processing Civil Aviation University of China Tianjin China

ISBN: (纸本)9789811982019

The interpretation of polarimetric synthetic aperture radar (PolSAR) images has wide and important applications in target identification, disaster survey, urban planning, road detection and image classification. In PolSAR image classification tasks, some algorithms often obtain different polarimetric scattering features by different target decomposition methods which can generate feature redundant. To solve the problems of complex processing and excessive time consumption caused by multiple dimensional features, a deep feature-based PolSAR image classification algorithm is given in this paper. The algorithm first extracts the original feature set from the PolSAR image which is used to pre-train the Restricted Boltzmann Machine (RBM) model. The redundant features in the original feature set are rejected according to the error which is calculated by the reconstruction error of the input features. The RBM network is initialized by the remaining features and corresponding weights, then train the Deep Boltzmann Machine (DBM). Finally, the softmax classifier is trained with the training samples containing the deep features to achieve image classification. The experimental results show that the proposed algorithm has good feature selection timeliness and the deep features obtained from the algorithm can improve the image classification accuracy. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

关键词： image classification

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Infrared Small Target Detection Algorithm Based on Improved DeeplabV3+ 8

Infrared Small Target Detection Algorithm Based on Improved ...

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8th International Conference on Intelligent Computing and signal processing, ICSP 2023

作者： Qi, Mengfei Jia, Guimin Civil Aviation University of China Tianjin Key Lab for Advanced Signal Processing Tianjin China

ISBN: (纸本)9798350302455

Infrared small target detection aims to segment small targets from the infrared images. Aiming at the problem of infrared small target detection, an improved algorithm is proposed based on DeeplabV3+ network. For the encoding part of DeeplabV3+, considering the small size of infrared small targets, the dilation rate of ASPP module is adjusted to capture the features of small targets more effectively. For the small targets are prone to lose spatial information during feature extraction, a location enhancement module is introduced to supplement accurate location information and to improve the accuracy of detection. In order to preserve detail information, an additional feature map is added from the backbone network to fuse detail information and semantic information for the decoding part of DeeplabV3+. Experimental results have demonstrated that the proposed algorithm is capable of enhancing the detection performance of DeeplabV3+ network in the infrared small target detection task. © 2023 IEEE.

关键词： Feature extraction

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