|
|
|
题名
|
作者
|
年代
|
出处
|
被引量
|
| 1 | Spaceborne GPS receiver antenna phase center offset and variation estimation for the Shiyan 3 satellite显示文摘In determining the orbits of low Earth orbit(LEO) satellites using spaceborne GPS, the errors caused by receiver antenna phase center offset(PCO) and phase center variations(PCVs) are gradually becoming a major limiting factor for continued improvements to accuracy. Shiyan 3, a small satellite mission for space technology experimentation and climate exploration, was developed by China and launched on November 5, 2008. The dual-frequency GPS receiver payload delivers1 Hz data and provides the basis for precise orbit determination within the range of a few centimeters. The antenna PCO and PCV error characteristics and the principles influencing orbit determination are analyzed. The feasibility of PCO and PCV estimation and compensation in different directions is demonstrated through simulation and in-flight tests. The values of receiver antenna PCO and PCVs for Gravity Recovery and Climate Experiment(GRACE) and Shiyan 3 satellites are estimated from one month of data. A large and stable antenna PCO error, reaching up to10.34 cm in the z-direction, is found with the Shiyan 3 satellite. The PCVs on the Shiyan 3 satellite are estimated and reach up to 3.0 cm, which is slightly larger than that of GRACE satellites. Orbit validation clearly improved with independent k-band ranging(KBR) and satellite laser ranging(SLR) measurements. For GRACE satellites, the average root mean square(RMS) of KBR residuals improved from 1.01 cm to 0.88 cm. For the Shiyan 3 satellite, the average RMS of SLR residuals improved from 4.95 cm to 4.06 cm. | Gu Defeng Lai Yuwang Liu Junhong Ju Bing Tu Jia | 2016 | Chinese Journal of Aeronautics2016，29，5： | 11 |
| 2 | Basic performance of BeiDou-2 navigation satellite system used in LEO satellites precise orbit determination显示文摘The visibility for low earth orbit(LEO) satellites provided by the BeiDou-2 system is analyzed and compared with the global positioning system(GPS). In addition, the spaceborne receivers' observations are simulated by the BeiDou satellites broadcast ephemeris and LEO satellites orbits. The precise orbit determination(POD) results show that the along-track component accuracy is much better over the service area than the non-service area, while the accuracy of the other two directions keeps at the same level over different areas. However, the 3-dimensional(3D) accuracy over the two areas shows almost no difference. Only taking into consideration the observation noise and navigation satellite ephemeris errors, the 3D accuracy of the POD is about30 cm. As for the precise relative orbit determination(PROD), the 3D accuracy is much better over the eastern hemisphere than that of the western hemisphere. The baseline length accuracy is 3.4 mm over the service area, and it is still better than 1 cm over the non-service area. This paper demonstrates that the BeiDou regional constellation could provide global service to LEO satellites for the POD and the PROD. Finally, the benefit of geostationary earth orbit(GEO) satellites is illustrated for POD. | Liu Junhong Gu Defeng Ju Bing Yao Jing Duan Xiaojun Yi Dongyun | 2014 | Chinese Journal of Aeronautics2014，27，5： | 9 |
| 3 | Precession–nutation correction for star tracker attitude measurement of STECE satellite显示文摘Space Technology Experiment and Climate Exploration(STECE) is a small satellite mission of China for space technology experiment and climate exploration. A new test star tracker and one ASTRO 10 star tracker have been loaded on the STECE satellite to test the new star tracker's measurement performance. However,there is no autonomous precession–nutation correction function for the test star tracker,which causes an apparent periodic deflection in the inter-boresight angle between the two star trackers with respect to each other of up to ±500 arcsec,so the precession and nutation effect needs to be considered while assessing the test star tracker. This paper researches on the precession–nutation correction for the test star tracker's attitude measurement and presents a precession–nutation correction method based on attitude quaternion data. The periodic deflection of the inter-boresight angle between the two star trackers has been greatly eliminated after the precession and nutation of the test star tracker's attitude data have been corrected by the proposed method and the validity of the proposed algorithm has been demonstrated. The in-flight accuracy of the test star tracker has been assessed like attitude noise and low-frequency errors after the precession–nutation correction. | Lai Yuwang Liu Junhong Ding Yonghe Gu Defeng Yi Dongyun | 2014 | Chinese Journal of Aeronautics2014，27，1： | 7 |
| 4 | Integrating BDS and GPS for precise relative orbit determination of LEO formation flying显示文摘Low-Earth-Orbit(LEO) formation-flying satellites have been widely applied in many kinds of space geodesy. Precise Relative Orbit Determination(PROD) is an essential prerequisite for the LEO formation-flying satellites to complete their mission in space. The contribution of the BeiDou Navigation Satellite System(BDS) to the accuracy and reliability of PROD of LEO formation-flying satellites based on a Global Positioning System(GPS) is studied using a simulation method. Firstly, when BDS is added to GPS, the mean number of visible satellites increases from9.71 to 21.58. Secondly, the results show that the 3-Dimensional(3 D) accuracy of PROD, based on BDS-only, GPS-only and BDS + GPS, is 0.74 mm, 0.66 mm and 0.52 mm, respectively. When BDS co-works with GPS, the accuracy increases by 29.73%. Geostationary-Earth-Orbit(GEO) satellites and Inclined Geosynchronous-Orbit(IGSO) satellites are only distributed over the Asia-Pacific region; however, they could provide a global improvement to PROD. The difference in PROD results between the Asia-Pacific region and the non-Asia-Pacific region is not apparent. Furthermore, the value of the Ambiguity Dilution Of Precision(ADOP), based on BDS + GPS, decreases by 7.50% and 8.26%, respectively, compared with BDS-only and GPS-only. Finally, if the relative position between satellites is only a few kilometres, the effect of ephemeris errors on PROD could be ignored. However, for a several-hundred-kilometre separation of the LEO satellites, the SingleDifference(SD) ephemeris errors of GEO satellites would be on the order of centimetres. The experimental results show that when IGSO satellites and Medium-Earth-Orbit(MEO) satellites co-work with GEO satellites, the accuracy decreases by 17.02%. | Bin YI Defeng GU Xiao CHANG Kai SHAO | 2018 | Chinese Journal of Aeronautics2018，31，10： | 7 |
| 5 | Phase Residual Estimations for PCVs of Spaceborne GPS Receiver Antenna and Their Impacts on Precise Orbit Determination of GRACE Satellites显示文摘In-flight phase center systematic errors of global positioning system(GPS) receiver antenna are the main restriction for improving the precision of precise orbit determination using dual-frequency GPS.Residual approach is one of the valid methods for in-flight calibration of GPS receiver antenna phase center variations(PCVs) from ground calibration.In this paper,followed by the correction model of spaceborne GPS receiver antenna phase center,ionosphere-free PCVs can be directly estimated by ionosphere-free carrier phase post-fit residuals of reduced dynamic orbit determination.By the data processing of gravity recovery and climate experiment(GRACE) satellites,the following conclusions are drawn.Firstly,the distributions of ionosphere-free carrier phase post-fit residuals from different periods have the similar systematic characteristics.Secondly,simulations show that the influence of phase residual estimations for ionosphere-free PCVs on orbit determination can reach the centimeter level.Finally,it is shown by in-flight data processing that phase residual estimations of current period could not only be used for the calibration for GPS receiver antenna phase center of foretime and current period,but also be used for the forecast of ionosphere-free PCVs in future period,and the accuracy of orbit determination can be well improved. | TU Jia GU Defeng WU Yi YI Dongyun | 2012 | Chinese Journal of Aeronautics2012，25，4： | 4 |
| 6 | Reduced Dynamic Orbit Determination Using Differenced Phase in Adjacent Epochs for Spaceborne Dual-frequency GPS显示文摘我们为卫星转菠的双频率的 GPS 在邻近的时代用 differenced 阶段在减少的动态轨道决心上学习。这个方法不仅克服缺点时代差别当观察几何学是差的或观察是不够的时,运动学的方法不能被使用,而且避免在零差别的减少的动态方法解决歧义。因为时代差别方法不对阶段的影响敏感,周期滑倒,它罐头降低困难在阶段观察预处理滑动察觉。在答案策略,我们由把长观察弧分解成很多条短弧解决高度维的矩阵计算问题。由重力恢复和气候实验(优雅)卫星绕决心转并且与 GeoForschungsZentrum ( GFZ )相比张贴科学轨道因为时代差别减少了动态方法,光线、横向、正常的部件的根平均数广场( RMS )是 1.92 厘米, 3.83 厘米和 3.80 厘米,并且在三种尺寸的 RMS 是 5.76 厘米。答案的精确性比得上零差别的减少的动态方法。 | GU Defeng YI Dongyun | 2011 | Chinese Journal of Aeronautics2011，24，6： | 4 |
| 7 | Enhanced baseline determination for formation flying LEOs by relative corrections of phase center and code residual variations显示文摘Formation flying Low Earth Orbiters(LEOs)are important for implementing new and advanced concepts in Earth observation missions.Precise Baseline Determination(PBD)is a prerequisite for LEOs to complete specified mission targets.PBD is usually performed based on space-borne GNSS data,the relative corrections of phase center and code residual variations play crucial roles in achieving the best relative orbit accuracy.Herein,the influences of antenna Relative Phase Centre Variations(RPCVs)and Single-Difference(SD)Melbourne-Wu¨bbena(MW)Combination Residuals Variations(SD MWVs)on PBD are studied.The methods were tested using flight data from Gravity Recovery And Climate Experiment(GRACE)and GRACE Follow-On(GRACE-FO).Results showed that the maximum values for RPCVs and SD MWVs were 14 mm and 0.32 cycles,respectively.Then,the RPCVs correction significantly enhanced the baseline accuracy;the K-Band Ranging(KBR)measurement consistency improved by 30.1%and 37.5%for GRACE and GRACE-FO,respectively.The application of SD MWVs further improved the accuracy and reliability of PBD results.For GRACE,the ambiguities fixing success rate increased from 85.1%to 97.9%and a baseline consistency of 0.57 mm was achieved for the KBR measurements.It was found that the correction of both RPCVs and SD MWVs reduced the carrier phase observation minus computation residuals from double-difference ionosphere-free combination.In addition,in-flight data processing demonstrated that RPCVs and SD MWVs estimations for the current period could be used for the previous and subsequent periods. | Bin YI Defeng GU Bing JU Kai SHAO Houzhe ZHANG | 2022 | Chinese Journal of Aeronautics2022，35，2： | 0 |
| 8 | Precise orbit determination for TH02-02 satellites based on BDS3 and GPS observations显示文摘The Tianhui-202(TH02-02)satellite formation,as a supplement to the microwave mapping satellite system Tianhui-201(TH02-01),is the first Interferometric Synthetic Aperture Radar(InSAR)satellite formation-flying system that supports the tracking of BeiDou global navigation Satellite system(BDS3)new B1C and B2a signals.Meanwhile,the twin TH02-02 satellites also support the tracking of Global Positioning System(GPS)L1&L2 and BDS B1I&B3I signals.As the spaceborne receiver employs two independent boards to track the Global Navigation Satellite System(GNSS)satellites,we design an orbit determination strategy by estimating independent receiver clock offsets epoch by epoch for each GNSS to realize the multi-GNSS data fusion from different boards.The performance of the spaceborne receiver is evaluated and the contribution of BDS3 to the kinematic and reduced-dynamic Precise Orbit Determination(POD)of TH02-02 satellites is investigated.The tracking data onboard shows that the average number of available BDS3 and GPS satellites are 8.7 and 9.1,respectively.The carrier-to-noise ratio and carrier phase noise of BDS3 B1C and B2a signals are comparable to those of GPS.However,strong azimuth-related systematic biases are recognized in the pseudorange multipath errors of B1C and B3I.The pseudorange noise of BDS3 signals is better than that of GPS after eliminating the multipath errors from specific signals.Taking the GPS-based reduced-dynamic orbit with single-receiver ambiguity fixing technique as a reference,the results of BDS3-only and BDS3+GPS combined POD are assessed.The Root Mean Square(RMS)of orbit comparison of BDS3-based kinematic and reduced-dynamic POD with reference orbit are better than 7 cm and 3 cm in three-Dimensional direction(3D).The POD performance based on B1C&B2a data is comparable to that based on B1I&B3I.The precision of BDS3+GPS combined kinematic orbit can reach up to 3 cm(3D RMS),which has a more than 25%improvement relative to the GPS-only solution.In addition,the consistency between the BDS3+GPS combined reduced-dynamic orbit and the GPS-based ambiguity-fixed orbit is better than 1.5 cm(3D RMS). | Houzhe ZHANG Bing JU Defeng GU Ying LIU Kai SHAO Xiaojun DUAN Zhiyong HUANG | 2023 | Chinese Journal of Aeronautics2023，36，5： | 0 |
| 9 | The application of indocyanine green in guiding prostate cancer treatment显示文摘Objective:Indocyanine green(ICG)with near-infrared fluorescence absorption is approved by the United States Food and Drug Administration for clinical applications in angiography,blood flow evaluation,and liver function assessment.It has strong optical absorption in the near-infrared region,where light can penetrate deepest into biological tissue.We sought to review its value in guiding prostate cancer treatment.Methods:All related literature at PubMed from January 2000 to December 2020 were reviewed.Results:Multiple preclinical studies have demonstrated the usefulness of ICG in identifying prostate cancer by using different engineering techniques.Clinical studies have demonstrated the usefulness of ICG in guiding sentinel node dissection during radical prostatectomy,and possible better preservation of neurovascular bundle by identifying landmark prostatic arteries.New techniques such as adding fluorescein in additional to ICG were tested in a limited number of patients with encouraging result.In addition,the use of the ICG was shown to be safe.Even though there are encouraging results,it does not carry sufficient sensitivity and specificity in replacing extended pelvic lymph node dissection during radical prostatectomy.Conclusion:Multiple preclinical and clinical studies have shown the usefulness of ICG in identifying and guiding treatment for prostate cancer.Larger randomized prospective studies are warranted to further test its usefulness and find new modified approaches. | Donghua Xie Di Gu Ming Lei Cong Cai Wen Zhong Defeng Qi Wenqi Wu Guohua Zeng Yongda Liu | 2023 | Asian Journal of Urology2023，10，1： | 0 |
您所在的机构暂未开通此部分的功能，请联系管理员