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The authors present a new scientific space mission consisting of a satellite carrying a receiving- only SAR which receives the signal transmitted by the ENVISAT-1 SAR. The integration of ENVISAT-1 SAR and bistatic radar data offers an improved potentiality of surface classification, three-dimensional observation, and the opportunity of advanced scientific experiments in the field of bistatic scattering. The small satellite nominal orbit and the attitude manoeuvres are designed in order to maintain an adequate overlap between the two radar swaths along the whole orbit, taking into account the ENVISAT-1 attitude and pointing. A preliminary satellite design (2-year lifetime) is then performed to evaluate the orbit decay and to determine the appropriate orbit manoeuvres (every 4 days) to control the satellites relative phase. The numerical simulation shows that a spacecraft of about 584kg is able to meet the mission requirements. 相似文献
103.
In this report, the specifications and some results of the China multimode microwave remote sensor (CMMRS) onboard China's SZ-4 spaceship are described. Technical details and initial processing results of the CMMRS measurement data are reported. 相似文献
104.
基于LabVIEW设计曲线拟合仪 总被引:1,自引:0,他引:1
张爱平 《华北航天工业学院学报》2004,14(3):5-7
基于LabVIEW图形化编程环境和软件分析库函数设计的曲线拟合仪,界面友好,功能齐全,操作简便,在科学研究和工程应用中具有较强的实用价值。文中简要介绍利用NI虚拟仪器技术设计曲线拟合仪的方法,给出软件设计思想与实现方案,对主要软件功能模块进行了分析。 相似文献
105.
In extension to common applications such as groundtrack displays and antenna steering, the SGP4 orbit model is proposed for operational orbit determination in small satellite missions. SGP4 is an analytical orbit model for Low-Earth orbiting satellites that is widely used for the propagation of NORAD twoline elements. Twoline elements may hence be generated completely independent of NORAD. Their use as exclusive source of orbital information simplifies the operations concept and reduces mission costs through the extensive use of existing low-cost mission support software. Due to small computer resource requirements of 8–10kByte, the SGP4 model may also be applied for onboard orbit computations making use of e.g. a 80186 processor, thus ensuring full compatibility of ground-based and onboard operations. The proposed approach is particularly suited in combination with a space-borne GPS receiver, were the C/A-code navigation solutions are treated as measurements that are adjusted in a least-squares sense using the SGP4 model. As consequence, inherent drawbacks of the pure navigation solutions such as data gaps and scatter as well as limited velocity accuracy are avoided, while the operational navigation activities are kept at a minimum. The feasibility of the concept is illustrated based on real GPS navigation data from the TOPEX/Poseidon and the MIR space station with an inherent data quality of 50–100 m. It is shown that 3 hours of data within a 4 day period are sufficient to keep the position error within 4 km, that is considered sufficient for most applications. 相似文献
106.
以经营者人力资本效用价值为主导的激励模型研究 总被引:1,自引:0,他引:1
张永国 《郑州航空工业管理学院学报(管理科学版)》2001,19(1):23-26
对经营者激励机制的研究在我国已有多年,但一直未形成良好的激励体系。本文提出的以经营者人力资本效用价值为主导的激励模型是在企业效益分离的基础上,以股票期权和股票期股的组合方式设计的激励模式。 相似文献
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陕西省复合型人才奇缺,尤其是特色经济和支柱产业人才奇缺,造成人才缺口原因虽然是多方面的,但是市场经济决定了人才走势。根据今年市场对人才的需求,向在校毕业生们提出了几点就业的建议。 相似文献
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