浅谈企业科研课题的组织与管理

论述企业科研课题及其成果的组织管理工作。     

论航空产品质量改进

航空产品质量改进针对旧的质量标准．建立新的质量标准，可以不断提高产品技术水平，克服存在的缺陷,改善使用性能。为保证质量改进取得预期效果，应从程序、方法和管理控制等多方面着手。     

简单二体引力模型用于空间目标轨道面交线确定的效果分析

在空间目标碰撞预警分析中，准确地计算出空间目标的轨道面交线是进行地心距筛选、时间差筛选的前提，目前较多使用的快速确定轨道面交线的方法为简单二体引力模型。深入分析该模型，比较了其计算的空间目标轨道面交线与STK计算结果的差异，指出了简单二体引力模型在计算空间目标轨道面交线时的局限性，认为轨道摄动是影响轨道面交线计算准确性的主要原因，应该采用更能反映空间目标实际运动规律的改进的二体引力模型的方法。     

以先进的制造技术和管理取得竞争优势

针对如何提高机械加工的生产效率,改进生产管理结合实际工作做了论述,提出了自己的观点。     

First results from the LUCID-Timepix spacecraft payload onboard the TechDemoSat-1 satellite in Low Earth Orbit

The Langton Ultimate Cosmic ray Intensity Detector (LUCID) is a payload onboard the satellite TechDemoSat-1, used to study the radiation environment in Low Earth Orbit ($～$635?km). LUCID operated from 2014 to 2017, collecting over 2.1 million frames of radiation data from its five Timepix detectors on board. LUCID is one of the first uses of the Timepix detector technology in open space, with the data providing useful insight into the performance of this technology in new environments. It provides high-sensitivity imaging measurements of the mixed radiation field, with a wide dynamic range in terms of spectral response, particle type and direction. The data has been analysed using computing resources provided by GridPP, with a new machine learning algorithm that uses the Tensorflow framework. This algorithm provides a new approach to processing Medipix data, using a training set of human labelled tracks, providing greater particle classification accuracy than other algorithms. For managing the LUCID data, we have developed an online platform called Timepix Analysis Platform at School (TAPAS). This provides a swift and simple way for users to analyse data that they collect using Timepix detectors from both LUCID and other experiments. We also present some possible future uses of the LUCID data and Medipix detectors in space.     

An empirical solar radiation pressure model for satellites moving in the orbit-normal mode

We present a family of empirical solar radiation pressure (SRP) models suited for satellites orbiting the Earth in the orbit normal (ON) mode. The proposed ECOM-TB model describes the SRP accelerations in the so-called terminator coordinate system. The choice of the coordinate system and the SRP parametrization is based on theoretical assumptions and on simulation results with a QZS-1-like box-wing model, where the SRP accelerations acting on the solar panels and on the box are assessed separately. The new SRP model takes into account that in ON-mode the incident angle of the solar radiation on the solar panels is not constant like in the yaw-steering (YS) attitude mode. It depends on the elevation angle of the Sun above the satellite’s orbital plane. The resulting SRP vector acts, therefore, not only in the Sun-satellite direction, but has also a component normal to it. Both components are changing as a function of the incident angle. ECOM-TB has been used for precise orbit determination (POD) for QZS-1 and BeiDou2 (BDS2) satellites in medium (MEO) and inclined geosynchronous Earth orbits (IGSO) based on IGS MGEX data from 2014 and 2015. The resulting orbits have been validated with SLR, long-arc orbit fits, orbit misclosures, and by the satellite clock corrections based on the orbits. The validation results confirm that—compared to ECOM2—ECOM-TB significantly (factor 3–4) improves the POD of QZS-1 in ON-mode for orbits with different arc lengths (one, three, and five days). Moderate orbit improvements are achieved for BDS2 MEO satellites—especially if ECOM-TB is supported by pseudo-stochastic pulses (the model is then called ECOM-TBP). For BDS2 IGSOs, ECOM-TB with its 9 SRP parameters appears to be over-parameterized. For use with BDS2 IGSO spacecraft we therefore developed a minimized model version called ECOM-TBMP, which is based on the same axis decomposition as ECOM-TB, but has only 2 SRP parameters and is supported by pseudo-stochastic parameters, as well. This model shows a similar performance as ECOM-TB with short arcs, but an improved performance with (3-day) long-arcs. The new SRP models have been activated in CODE’s IGS MGEX solution in Summer 2018. Like the other ECOM models the ECOM-TB derivatives might be used together with an a priori model.     

Orbit determination and prediction of GEO satellite of BeiDou during repositioning maneuver

In order to establish a continuous GEO satellite orbit during repositioning maneuvers, a suitable maneuver force model has been established associated with an optimal orbit determination method and strategy. A continuous increasing acceleration is established by constructing a constant force that is equivalent to the pulse force, with the mass of the satellite decreasing throughout maneuver. This acceleration can be added to other accelerations, such as solar radiation, to obtain the continuous acceleration of the satellite. The orbit determination method and strategy are illuminated, with subsequent assessment of the orbit being determined and predicted accordingly. The orbit of the GEO satellite during repositioning maneuver can be determined and predicted by using C-Band pseudo-range observations of the BeiDou GEO satellite with COSPAR ID 2010-001A in 2011 and 2012. The results indicate that observations before maneuver do affect orbit determination and prediction, and should therefore be selected appropriately. A more precise orbit and prediction can be obtained compared to common short arc methods when observations starting 1 day prior the maneuver and 2 h after the maneuver are adopted in POD (Precise Orbit Determination). The achieved URE (User Range Error) under non-consideration of satellite clock errors is better than 2 m within the first 2 h after maneuver, and less than 3 m for further 2 h of orbit prediction.     

用两颗GPS卫星确定低轨卫星轨道的初值方法

研究了用两颗全球定位系统（ＧＰＳ）卫星粗略确定低轨卫星轨道的问题,并着重讨论了其中的初值问题,给出了一种有效的初值方法。实验结果证明：这种方法能给出一个确定的、实用的初值,大大减少了初轨计算的计算量,并使得算法收敛更加有保障。在工程实用方面比传统的猜测方法具有较大的优势。     

GPS在卫星精密测轨中的应用

自从美国全球定位系统(GPS)试验系统建立以来,发展了各种各样的方法,利用GPS 测量来精密确定卫星轨道。在1984年,LANDSAT-5上装载一个GPSPAC 的仪器进行了飞行,以验证用GPS 定轨的精确度。1982年在美国喷气推进试验室((?)PL),为TOPEX 卫星研究了一种GPS 距离和距离变化率的双差分法,以满足其厘米级的精度要求。除GPS 对低轨地球卫星定轨应用外,有人也提出了用GPS 测量对高轨地球卫星甚至同步卫星的定轨方法及精度分析。文章对上述各种方法给以简要的介绍和评述。     

数据中继卫星的频率和轨道

描述了典型数据中继卫星系统的通信链路;给出了这些系统在用的和计划使用的无线电频谱;讨论了影响数据中继卫星频段选择的因素。为了防止其他中继卫星系统对一个中继卫星系统的有害干扰,可以使用如频率错开、极化分辨、经度分离,甚至采用伪码分辨的方法。