Probability-Enhanced Anchor-Free Detector for Remote-Sensing Object Detection

Anchor-free object-detection methods achieve a significant advancement in field of computer vision,particularly in the realm of real-time inferences.However,in remote sensing object detection,anchor-free methods often lack of capability in separating the foreground and background.This paper proposes an anchor-free method named probability-enhanced anchor-free detector(ProEnDet)for remote sensing object detection.First,a weighted bidirectional feature pyramid is used for feature extraction.Second,we introduce probability enhancement to strengthen the classification of the object’s foreground and background.The detector uses the logarithm likelihood as the final score to improve the classification of the foreground and background of the object.ProEnDet is verified using the DIOR and NWPU-VHR-10 datasets.The experiment achieved mean average precisions of 61.4 and 69.0 on the DIOR dataset and NWPU-VHR-10 dataset,respectively.ProEnDet achieves a speed of 32.4 FPS on the DIOR dataset,which satisfies the real-time requirements for remote-sensing object detection.

Weakly Supervised Network with Scribble-Supervised and Edge-Mask for Road Extraction from High-Resolution Remote Sensing Images

Significant advancements have been achieved in road surface extraction based on high-resolution remote sensingimage processing. Most current methods rely on fully supervised learning, which necessitates enormous humaneffort to label the image. Within this field, other research endeavors utilize weakly supervised methods. Theseapproaches aim to reduce the expenses associated with annotation by leveraging sparsely annotated data, such asscribbles. This paper presents a novel technique called a weakly supervised network using scribble-supervised andedge-mask (WSSE-net). This network is a three-branch network architecture, whereby each branch is equippedwith a distinct decoder module dedicated to road extraction tasks. One of the branches is dedicated to generatingedge masks using edge detection algorithms and optimizing road edge details. The other two branches supervise themodel’s training by employing scribble labels and spreading scribble information throughout the image. To addressthe historical flaw that created pseudo-labels that are not updated with network training, we use mixup to blendprediction results dynamically and continually update new pseudo-labels to steer network training. Our solutiondemonstrates efficient operation by simultaneously considering both edge-mask aid and dynamic pseudo-labelsupport. The studies are conducted on three separate road datasets, which consist primarily of high-resolutionremote-sensing satellite photos and drone images. The experimental findings suggest that our methodologyperforms better than advanced scribble-supervised approaches and specific traditional fully supervised methods.

Influence of Tilted Angle on Effective Linear Energy Transfer in Single Event Effect Tests for Integrated Circuits at 130 nm Technology Node

A heavy-ion irradiation experiment is studied in digital storage cells with different design approaches in 130？nm CMOS bulk Si and silicon-on-insulator （SOI） technologies. The effectiveness of linear energy transfer （LET） with a tilted ion beam at the 130？nm technology node is obtained. Tests of tilted angles θ=0 ° , 30 ° and 60 ° with respect to the normal direction are performed under heavy-ion Kr with certain power whose LET is about 40？MeVcm 2 /mg at normal incidence. Error numbers in D flip-flop chains are used to determine their upset sensitivity at different incidence angles. It is indicated that the effective LETs for SOI and bulk Si are not exactly in inverse proportion to cosθ , furthermore the effective LET for SOI is more closely in inverse proportion to cosθ compared to bulk Si, which are also the well known behavior. It is interesting that, if we design the sample in the dual interlocked storage cell approach, the effective LET in bulk Si will look like inversely proportional to cosθ very well, which is also specifically explained.

The Quantum Science Experiment Satellite, An Experimental Facility in Space for Testing of Quantum Information Theory

The Quantum Science Experiment Satellite(QUSES) is the first satellite deployed successfully in nearEarth space for quantum scientific experiments in the world, in which experimental study on the fundamental questions of quantum mechanics can be done under the condition of a spatial scale about 500-2000 km. QUSES is performing a Quantum Key Distribution(QKD) experiment from satellite to ground station for testing of the global quantum secure communication network, and performing a Quantum Entanglement Distribution(QED) and Quantum Teleportation(QT) experiments with the purpose of testing the completeness of quantum mechanics theory at a sufficient spatial scale. The payload of QUSES is com posed of a Quantum Key Transceiver(QKT), a Quantum Entanglement Transmitter(QET), a Quantum Entangled-photon Source(QES), a Quantum Experiment Control Processor(QCP) and a Coherent laser Communication Terminator(CCT). This paper introduces the technical scheme of QUSES, including the requirement analysis, composi tion, technical innovation, on-orbit status and prospect of development for the future.

TanSat Mission Achievements： from Scientific Driving to Preliminary Observations

The Chinese global carbon dioxide monitoring satellite(TanSat)was successfully launched in December 2016 and has completed its on-orbit tests and calibration.TanSat aims to measure the atmospheric Carbon Dioxide column-averaged dry air mole fractions(X_(CO_2))with a precision of 4 ppm at the regional scale,and further to derive the CO_2 global and regional fluxes.Progress toward these objectives is reviewed and the first scientific results from TanSat measurements are presented.During the design phase,Observation System Simulation Experiments(OSSE)on TanSat measurements performed prior to launch measurements using a nadir and a glint alternative mode when considering the balance of stable measurements and reduces the flux uncertainty(64%).The constellation measurements of two satellites indicate an extra 10%improvement in flux inversion if the satellite measurements have no bias and similar precision.The TanSat on-orbit test indicates that the instrument is stable and beginning to produce X_(CO_2)products.The preliminary TanSat measurements have been validated with Total Carbon Column Observing Network(TCCON)measurements and have inter-compared with OCO-2 measurements in an overlap measurement.

A New Global Solar-induced Chlorophyll Fluorescence(SIF)Data Product from TanSat Measurements

The Chinese Carbon Dioxide Observation Satellite Mission(TanSat)is the third satellite for global CO2 monitoring and is capable of detecting weak solar-induced chlorophyll fluorescence(SIF)signals with its advanced technical characteristics.Based on the Institute of Atmospheric Physics Carbon Dioxide Retrieval Algorithm for Satellite Remote Sensing(IAPCAS)platform,we successfully retrieved the TanSat global SIF product spanning the period of March 2017 to February 2018 with a physically based algorithm.This paper introduces the new TanSat SIF dataset and shows the global seasonal SIF maps.A brief comparison between the IAPCAS TanSat SIF product and the data-driven SVD(singular value decomposition)SIF product is also performed for follow-up algorithm optimization.The comparative results show that there are regional biases between the two SIF datasets and the linear correlations between them are above 0.73 for all seasons.The future SIF data product applications and requirements for SIF space observation are discussed.

A Dual-Satellite GNSS Positioning Algorithm of High Accuracy in Incomplete Condition

Global navigation satellite system could provide accurate positioning results in signal complete condition. However, the performance is severe when signal denied, especially for the single-mode Bei Dou receiver. This paper proposes a dual-satellite positioning algorithm to promote the positioning performance in the satellite signal gap. The new algorithm utilizes the previous positioning data stored in complete condition to simplify the positioning equations. As the clock bias persists for a short period, this proposed method could work out accurate positioning results by only two visible satellites, without the need of computing the clock bias. Also, the Kalman filtering algorithm is used to smooth the trajectories, and improve the positioning results. During the incomplete period, only two satellites for 30 seconds and three satellites for 60 seconds, the preliminary experiment result shows that, the presented method could provide almost the same positioning results as in complete condition.

A NOVEL COMPACT HIS-EBG STRUCTURE AND ITS APPLICATION IN REDUCTION OF PRINTED ANTENNA MUTUAL COUPLING

Anovel compact E shape High Impedance Surface(HIS) Electromagnetic Band-Gap(EBG) comprising Amended Minkowski Fractal Boundary(AMFB),Added Metal Strips(AMS),and metal plated via printed on a Rogers TMM 10i substrate is presented.The first order AMFB and ABS are introduced for equivalent capacitance enhancement and miniaturization with effective space-filling characteristics.The dimension of lattice size is only The proposed structure exhibits a most compact characteristic about 35% size reduction as compared with conven-tional mushroom-like HIS-EBG,and better surface-wave decoupling of around 9 dB at the operating frequency band.Details of design parameters which affect the whole performance of certain band-gap are intensively investigated.A constructed prototype is potential candidate for antenna system per-formance enhancement.

Experiment-based identification of time delays in linear systems

This paper presents an identification approach to time delays in single-degree-of-freedom (SDOF) and multiple-degree-of-freedom (MDOF) systems. In an SDOF system, the impedance function of the delayed system is expressed by the system parameters, the feedback gain, and the time delay. The time delay can be treated as the 'frequency' of the difference between the impedance function of the delayed system and that of the corresponding uncontrolled system. Thus, it can be identified from the Fourier transform of the difference between the two impedance functions. In an MDOF system, the pseudo-impedance functions are defined. The relationships between the time delay and the pseudo-impedance functions of the delayed system and uncontrolled system are deduced. Similarly, the time delay can be identified from the Fourier transform of the difference between the two pseudo-impedance functions. The results of numerical examples and experimental tests show that the identification approach to keeps a relatively high accuracy.

Dark Matter Particle Explorer, the First Satellite of China Space Science Pilot Project

The Dark Matter Particle Explorer(DAMPE) is the first high energy detector satellite in China,whose physics goal is to find evidence of the existence of dark matter particles by investigating the composition and energy spectra of primary cosmic rays,especially those for electrons,positrons and gamma rays,over the dynamic range from 5 Ge V to 10 Te V.DAMPE is a satellite launched by China with the largest payload ratio,where the payload is composed of a BGO(Bismuth Germanate Oxide) Calorimeter,a Plastic Scintillator Detector,a Silicon Tungsten Tracker and a Neutron Detector.This paper introduces the technical scheme of DAMPE,including requirement analysis,composition,technical innovation,on-orbit status and prospect of development for the future.

Optimization of a robust collaborative-relay beamforming design for simultaneous wireless information and power transfer

We investigate a collaborative-relay beamforming design for simultaneous wireless information and power transfer. A non-robust beamforming design that assumes availability of perfect channel state information(CSI) in the relay nodes is addressed. In practical scenarios, CSI errors are usually inevitable; therefore, a robust collaborativerelay beamforming design is proposed. By applying the bisection method and the semidefinite relaxation(SDR)technique, the non-convex optimization problems of both non-robust and robust beamforming designs can be solved.Moreover, the solution returned by the SDR technique may not always be rank-one; thus, an iterative sub-gradient method is presented to acquire the rank-one solution. Simulation results show that under an imperfect CSI case, the proposed robust beamforming design can obtain a better performance than the non-robust one.

Robust UKF orbit determination method with timevarying forgetting factor for angle/range-based integrated navigation system

The angle/range-based integrated navigation system is a favorable navigation solution for deep space explorers.However,the statistical characteristics of the measurement noise are time-varying,leading to inaccuracies in the derived measurement covariance even causing filter divergence.To reduce the gap between theoretical and actual covariances,some adaptive methods use empirically determined and unchanged forgetting factors to scale innovations within the sliding window.However,the constant weighting sequence cannot accurately adapt to the time-varying measurement noise in dynamic processes.Therefore,this paper proposes an Adaptive Robust Unscented Kalman Filter with Time-varying forgetting factors(TFF-ARUKF)for the angle/range integrated navigation system.Firstly,based on a statistically linear regression model approximating the nonlinear measurement model,the M-estimator is adopted to suppress the interference of outliers.Secondly,the covariance matching method is combined with the Huber linear regression problem to adaptively adjust the measurement noise covariance used in the M-estimation.Thirdly,to capture the time-varying characteristics of the measurement noise in each estimation,a new timevarying forgetting factors selection strategy is designed to dynamically adjust the adaptive matrix used in the covariance matching method.Simulations and experimental analysis compared with EKF,AMUKF,ARUKF,and Student's t-based methods have validated the effectiveness and robustness of the proposed algorithm.

The TanSat mission： preliminary global observations

The Chinese global carbon dioxide monitoring satellite （TanSat） was launched successfully in December 2016 and has completed its on-orbit tests and calibration. TanSat aims to measure the atmospheric column-averaged dry air mole fractions of carbon dioxide （XCO2） with a precision of 4 ppm at the regional scale, and in addition, to derive global and regional CO2 fluxes. Progress towards these objectives is reviewed and the first scientific results from TanSat measurements are presented. TanSat on-orbit tests indicate that the Atmospheric Carbon dioxide GratingSpectrometer is in normal working status and is beginning to produce LIB products. The preliminary TanSat XCO2 products have been retrieved by an algorithm and compared to NASA Orbiting Carbon Observatory-2 （OCO-2） measurements during an over- lapping observation period. Furthermore, the XCO2 retrievals have been validated against eight groundsite measurement datasets from the Total Carbon Column Observing Network, for which the preliminary conclusion is that TanSat has met the precision design requirement, with an average bias of 2.11 ppm. The first scientific observations are presented, namely, the seasonal distributions of XCO2 over land on a global scale.

Concept of the solar ring mission:An overview

The concept of the Solar Ring mission was gradually formed from L5/L4 mission concept, and the proposal of its pre-phase study was funded by the National Natural Science Foundation of China in November 2018 and then by the Strategic Priority Program of Chinese Academy of Sciences in space sciences in May 2019. Solar Ring mission will be the first attempt to routinely monitor and study the Sun and inner heliosphere from a full 360-degree perspective in the ecliptic plane. The current preliminary design of the Solar Ring mission is to deploy six spacecraft, grouped in three pairs, on a sub-AU orbit around the Sun. The two spacecraft in each group are separated by about 30?and every two groups by about 120?. This configuration with necessary science payloads will allow us to establish three unprecedented capabilities:(1) determine the photospheric vector magnetic field with unambiguity,(2) provide 360-degree maps of the Sun and the inner heliosphere routinely, and(3) resolve the solar wind structures at multiple scales and multiple longitudes. With these capabilities, the Solar Ring mission aims to address the origin of solar cycle, the origin of solar eruptions, the origin of solar wind structures and the origin of severe space weather events. The successful accomplishment of the mission will advance our understanding of the star and the space environment that hold our life and enhance our capability of expanding the next new territory of human.

Concept of the Solar Ring mission: Preliminary design and mission profile

The Solar Ring mission, a concept to monitor the Sun and inner heliosphere from multiple perspectives, has been funded for prephase study by the Strategic Priority Program of Chinese Academy of Sciences in space sciences. The Solar Ring is comprised of 6 spacecraft, grouped in three pairs, moving around the Sun in an elliptical orbit in the ecliptic plane. The mission costs,including launch fee, deep-space maneuvers, and deployment time of the ring, are highly relevant to the working orbit, deepspace transfer, and phase angle within a group. The preliminary mission profile is analyzed and designed in this paper. The launch way, two spacecraft with one rocket, is adopted. The deployment time, phasing maneuvers, and C_(3) of launch energy are evaluated for the elliptical orbits with the perihelion between 0.7 and 0.9 AU using the rockets of Long March(LM) 3A and 3B.Numerical simulations show two candidate trajectories: fast deployment within 4 years by LM-3B, medium deployment more than 6 years by cheaper rocket of LM-3A. In order to obtain both fast deployment and low launch cost, another orbit profile is proposed by shortening the phase angle within a group. The suggested working orbits and the corresponding costs of launch,deployment time, and phasing maneuvers will strongly support the science objectives.