A5056551189- Radio Astronomy Observations and Technology
- GNSS positioning and interference
- Geophysics and Gravity Measurements
- Inertial Sensor and Navigation
- Planetary Science and Exploration
- Astronomical Observations and Instrumentation
- Robotics and Sensor-Based Localization
- Advanced Measurement and Metrology Techniques
- Astro and Planetary Science
- Solar and Space Plasma Dynamics
- Antenna Design and Optimization
- Optical Wireless Communication Technologies
- Indoor and Outdoor Localization Technologies
- Advanced Mathematical Theories
- Adaptive optics and wavefront sensing
- Radio Wave Propagation Studies
- Biliary and Gastrointestinal Fistulas
- Atmospheric Ozone and Climate
- Advanced Frequency and Time Standards
- Distributed Control Multi-Agent Systems
- Space Exploration and Technology
- Blind Source Separation Techniques
- Scientific Research and Discoveries
- Antenna Design and Analysis
- Military Defense Systems Analysis
China Telecom (China)
2024
As the environment of battlefield is increasingly complex, single UAV(Unmanned Aerial Vehicle) has problem in reconnaissance mission, which needs cooperative multi-UAV. However, multi-UAV mission planning trouble searching excellent solution, because its large space but sparse solution space. Heuristic algorithm, widely used at present, difficult to find a reliable initial limiting rate convergence. Aiming this problem, paper proposes statistical physics method: small world network and...
With the implement of China's Lunar Exploration Program in three stages,which consist orbiting,landing,and returning, deep space TT&C(Tracking,Telemetry and Command)system has been built up. The future Mars will further enhance full capability system. In this paper, development TT&C system is reviewed,including details key technology research,top design,and construction. trend discussed based on latest technologies.
The remarkably long distances covered by deep space probes result in extremely weak downlink signals, which poses great challenges for ground measurement systems. In the current climate, improving comprehensive utilization of signal power to increase detection distance or enhance accuracy is significance exploration. Facing this problem, we analyze delta Differential One-way Range (ΔDOR) error budget X-band China Deep Space Network (CDSN). Then, propose a novel interferometry method that...
Abstract The determination of reference points for telescopes is crucial obtaining the local‐tie vector a multi‐technology co‐located station. Traditional methods suffer from labor‐intensive fieldwork, long execution cycles, and systematic errors due to incident angle total station's laser beam on prism. In this paper, we propose an algorithm aligning prism pointing with prism‐to‐total station introduce pan‐tilt platform Tianma VGOS telescope sub‐millimeter unmanned point monitoring. Our...
Abstract An integrated ranging and differential one-way range (DOR) signal design is implemented. The utilizes the regenerative pseudo-noise scheme one pair of dedicated DOR tones for deep space United X Band system. To demonstrate its effectiveness, it was applied to China’s Tianwen-1 orbiter compared with classic normal designs. Using link budget error analysis methods, measurement accuracy communication ability were assessed. Results show that novel achieves better performance In case,...
This paper presents a comparative study of different frequency sequences which are used for Very Long Baseline Interferometry (VLBI) Bandwidth Synthesis (BWS) in recent astrometric and geodetic VLBI campaigns. The Peak Sidelobe (PS) level Delay Resolution Function (DRF), Normalized Effective (NEB) Frequency Ratio (FR) defined as the metrics comparison. Considering case loss channel sequences, its effect on performance also evaluated.
This paper presents the simulation analysis of analytic cross correlation approach and phase for time delay estimation down-converted signals with difference, which is induced in down-converting process. Second Welch spectrum are utilized better performance domain frequency approach, respectively. Comparing statistics results these algorithms a variety signal-to-noise ratios (SNRs), it shows that second method exhibits little at moderate SNR while based on much low SNR.
This paper presents the algorithm and results of designing optimal frequency sequences for Very Long Baseline Interferometry (VLBI) Bandwidth Synthesis (BWS) in VLBI experiments conducted jointly by Chinese Deep Space Stations (CDSS) (CVS). The optimization based on global search is intended to get lower peak side lobe level delay resolution function larger normalized Root Mean Square (RMS) bandwidth, both which are totally determined sequences. Since effective receiver bandwidth quite...
To improve the accuracy of spacecraft position determination, phase referencing technique had been introduced from radio astronomy. But influencing factors this new method in deep space navigation are still not very clear. This paper first gives a brief overview basic principle technique, and then analyzes simulates effects several main it. Finally, based on results experimental data Cassini Chang'E-3, we confirm that baselines shorter than 1000 km necessary to reduce observation time...
Abstract: The relative angular position error covariance model of two deep space probes is propagated based on the analysis method, and used for multiple probes. differential time delay Same Beam Interferometry (SBI) about right ascension declination established, information matrixes ground-based baseline measurements are obtained. influence measurement geometry analyzed. results show that in appropriate Mars probe order 0.1nrad when pico-second.
A novel fitting method for in-flight pointing calibration of large spaceborne parabolic antennas is proposed in this paper, including the model and adjustment algorithm. For verification method, two case studies 4.2m antenna onboard Queqiao 2.5m on board Tianwen-1 orbiter presented. Results show that curve coincides with selected data very well. Compared classic $\sigma_{0}$ post-fit residuals reduced by $4 \sim 5$ times, 3$\sigma$ precisions error estimates are improved from 0.004/0.005 deg...
The fast slewing rate and wide band of the VLBI2010 Global Observing System (VGOS) telescopes are beneficial to procure more observations obtain VLBI reference points (RPs) high precisions. Meanwhile, with development synchronous tracking fixed targets on during observing, RPs also can be determined in near real time based a frame defined by other techniques. These opportunities provide us possibility explore geodetic resolution VGOS telescopes. We design thermal variation RP as true values,...
Downlink noise of deep space transponder (DST) in some cases would have significant effects on the ground station tracking spacecraft. This paper proposes an experimental approach for downlink determination DST, based derived equation DST measurement. Not relying specific designs proposed could be applied to any DST. A successful application a micro-satellite is then introduced this paper, which convincible results been obtained and discussed. As approach, good electromagnetic environment...
This paper proposes a new approach for spin motion estimation in-orbit spacecraft using doppler measurements of ground stations. The magnitude the angular velocity vector is firstly estimated spectrum induced velocity, and its direction then adjustment algorithm. Simulations have been conducted validation proposed approach, which demonstrates effectiveness estimation.
This paper proposes a new approach for improving the ranging precision using adjustment algorithm with doppler measurements. As data processing technique, proposed requires no additional supports of specifically designed hardware or software, which mainly takes advantages accurate Simulations have been conducted and convincible results obtained, validates effectiveness approach. Results also show that weights measurements should be carefully treated in practice, would significantly affect coherency.
Abstract As a key technique in deep space navigation, radio interferometry can be used to determine the accurate location of spacecraft plane-of-sky by measuring its signal propagation time delay between two remote stations. To improve measurement accuracy, differential phase without ambiguity is usually desired. Aiming at difficulties resolving with few stations and narrowband downlink signals, new method proposed this work taking advantage Earth rotation. The high calibrator achieved not...