1、I-SWEAT Micro-Satellite Mission: Ionospheric Space Weather Effects in Auroral ThermosphereAndrew Yau , D.D. Wallis University of Calgary Yunlong Lin , J. McConnell, M. Shepherd, B. SolheimYork University P. Harrison1, R.B. Langley2，W. Lunscher3, J.M. Noel41Magellan Bristol 2UNB 3COM DEV 4RMC Support

2、ed by Canadian Space Agency 電離層及熱層空間天氣研究微小衛(wèi)星：I-SWEAT1Outline 報告內容Focus of talk: Science 報告焦點: 科學Scientific Motivation 科學動機 Scientific Objective 科學目標Mission Concept 科學任務的概念研究Results from Mission Concept Study 初步結果和結論我的國語不太行, 用英語作這個報告, 希望各位多多原諒 2Scientific Motivation 科學動機 (1) Understand physics of ion

3、osphere-thermosphere response to space weather: magnetic storms and substorms 研究空間天氣(磁暴和亞暴)對電離層以及熱層的影響 Advance prediction capability of space weather effects 改進有關空間天氣影響電離層以及熱層的預測,預報,監(jiān)測和預警Ionosphere: Total Electron Content (TEC) increase at mid/high latitude 電離層：在中，高緯區(qū)域“電子濃度總含量”的增長 Scintillation: dis

4、rupt radio communications and GPS navigation 對無線電信號閃爍的影響： 擾亂無線電通訊和GPS導航Thermosphere: Heating, density increase, expansion at high latitude 熱層： 加熱過程，密度增長，在高緯的擴張Anomalous orbit drag to low-Earth-orbit (LEO) satellites 對低地球軌道衛(wèi)星軌道保持的影響：產(chǎn)生不規(guī)則軌道拖曳3Space Weather Effects in Ionosphere磁暴期間電子濃度總含量(TEC) 增加及 GP

5、S 信號閃爍TEC increase and GPS signal scintillation in magnetic stormStorm electron density (SED) increase over North America in Oct. 2003 “super-storm” Foster 2005 2003年10月北美地區(qū)磁暴期間電子密度增長GPS scintillation at Ithaca, NY, in minor magnetic storm Kintner 20072001年9月小磁暴期間同樣也有GPS信號閃爍4Scientific Motivation 科學

6、動機 (2) Understand physics of ionosphere-thermosphere response to space weather: magnetic storms and substorms 研究空間天氣(磁暴和亞暴)對電離層以及熱層的影響 Advance prediction capability of space weather effects 改進有關空間天氣影響電離層以及熱層的預測,預報,監(jiān)測和預警Ionosphere: Total Electron Content (TEC) increase at mid/high latitude 電離層：在中，高緯區(qū)

7、域“電子濃度總含量”的增長 Scintillation: disrupt radio communications and GPS navigation 對無線電信號閃爍的影響： 擾亂無線電通訊和GPS導航Thermosphere: Heating, density increase, expansion at high latitude 熱層： 加熱過程，密度增長，在高緯的擴張Anomalous orbit drag to low-Earth-orbit (LEO) satellites 對低地球軌道衛(wèi)星軌道保持的影響：產(chǎn)生不正常軌道拖曳下降5Space Weather Effects in

8、 Thermosphere 磁暴期間高層大氣擴張, 導致低地球軌道衛(wèi)星不正常軌道下降Atmospheric expansion & anomalous orbit drag in magnetic stormAnomalous drag of CHAMP orbit by 500 m (SMA) in Oct. 2003 storm at 410 km altitude2003年10月的磁暴對410公里高度的CHAMP衛(wèi)星產(chǎn)生500米的軌道下降2 increase in atmospheric mass density at 410 km inferred on CHAMP Sutton 20

9、052003年超過2倍的大氣密度增長對410公里高度的CHAMP衛(wèi)星的影響6Space Weather & Anomalous Orbit Drag 空間天氣對人造衛(wèi)星軌道的影響Spacecraft collision avoidance:Effective avoidance strategy requires orbit prediction to within 3-5 km“State-of-the-art” orbit prediction:Ap and F10.7 based (e.g. STK) Has large uncertainty: up to 20 kmOrbit Err

10、or Simulation/Analysis: Storm/substorm related anomalous orbit drag contributes significantly to errors in orbit prediction. 避免衛(wèi)星在軌碰撞； 提高軌道預報能力； 軌道預報偏差的模擬和分析； 磁暴和亞暴對低地球軌道衛(wèi)星的軌道預報的正確性具有重要影響February 11, 2009U.S. And Russian Satellites Collide “Two communications satellites one Russian, one American cra

11、cked up in silent destruction The American satellite was an Iridium, ” 紐約時報（2009年2月11日）對美蘇衛(wèi)星相撞的報道：美國衛(wèi)星是提供衛(wèi)星電話服務的銥星7Scientific Objective 科學目標Scientific Objective 科學目標Measurements探測需求Instruments測儀器Investigation Objectives 研究目標8Mission Concept 衛(wèi)星計劃和概念Micro-satellite: 3 instruments on “QuickSat” BusOrbi

12、t:Polar LEO: 300-700 kmSun- or non-Sun-syncScience operations: Operation in selected orbits / orbit segments 衛(wèi)星: “快捷”微小衛(wèi)星儀器: 中性粒子質量及速度分析器, 雙頻GPS接收機, 磁強計軌道: 高傾角軌道，或者極軌；高度: 300-700 公里9System Architecture 衛(wèi)星系統(tǒng)和空間任構成Instrument Payload:ANA: Atmospheric Neutral AnalyzerDGR: Dual-frequency GPS ReceiverFMG:

13、 Fluxgate Magnetometer中性粒子質量及速度分析器 雙頻GPS接收機 磁強計Ground System:Amateur-radio type ground stationMission Operations CenterMulti Science Operation Center (SOC)多元化分布式地面站Uplink/downlink: VHF/UHFVHF/UHF通訊10I-SWEAT QuickSat Spacecraft 加拿大“快捷”微小衛(wèi)星平臺FMG deployedon boom磁強計DGR side-facing antenna雙頻GPS接收機VHF Upl

14、ink AntennaX (ram)Z (nadir)ANA ram-facing entrance slit中性粒分析儀Solar panels deployment11Atmospheric Neutral Analyzer (ANA) 中性粒子質量及速度分析儀探測原理1. Entrance aperture accepts neutrals; deflects ions2. Electron beam ionizes a fraction of neutral; retains incident velocity3. Accelerate ions to same perpendicul

15、ar energy/charge6. CCD images ion positions (hence neutral velocities)5. Accept only resonant ions4. RF Analyzer energizes ions of “resonant” velocity (M/q)12Dual-Frequency GPS Receiver (DGR) 雙頻GPS接收機設計HeritageSimplified version of e-POP GAP GAP co-developed by UNB and Magellan BristolGAP has array

16、of 5 GPS receivers networked to 4 patch antennas and 1 occultation antennaDesign2 GPS receivers networked to 2 antennasRe-use GAP interface, power, GPS cardsModified GAP implementationCASSIOPE/e-POP GAP electronics CASSIOPE/e-POP GAP electronics13Fluxgate Magnetometer (FMG) 磁通門磁強計的設計Measurement Goal

17、: field-aligned currents 1 A/m2 along 1 km pathSampling: 32 samples/sec 500 m/sample; resolution: 1 nTFluxgate magnetometer: measures magnetic field vector components by modulating permeability of ferro-magnetic rings inside detection coilsNon-zero magnetic flux inside coils induces voltage at 2 mod

18、ulation freq.Low-freq. feedback current through coil ambient magnetic flux componentDesign: Based on CASSIOPE/e-POP MagneticField Instrument (MGF)Resolution: 1/16 nT; Range: 65,536 nTCASSIOPE/e-POP MGF sensor assembly14I-SWEAT Summary 初步研究結果和結論Mission Concept:QuickSat bus in low-Earth polar orbitInstruments: Atmospheric Neutral Analyzer, Dual-frequency GPS Receivers, Fluxgate MagnetometerLow-cost science operation