基于分段常值的全电推进GEO卫星制导策略

电推进技术因其比冲高的技术特点在GEO轨道转移中应用可大大减少燃料质量,提高有效载荷质量比,延长任务寿命等。针对全电推进GEO卫星入轨的轨迹优化和制导问题,首先利用间接法获得小推力燃料最优GEO轨道转移的数值解,提出一种多项式曲线拟合最优轨迹的方法,多项式曲线形式简单,可作为参考轨道在星上存储和使用。在多项式参考轨道的基础上,建立了一种分段常值推力跟踪参考轨道的闭环制导策略,在常值推力条件下,轨道要素控制量与控制力有解析关系,简化了制导律设计;将多圈轨道转移问题分解为多个单圈轨道优化问题。结果显示,本文提出的分段常值跟踪制导策略跟踪精度高,和最优轨道相比多消耗7%的燃料。本制导策略控制结构简单,易于工程实施。     

航天器轨道交会迭代制导算法

针对航天器轨道交会的脉冲推力模型与实际发动机连续推力模型不相符的问题,研究一种脉冲变轨策略的工程实现方法,使脉冲变轨策略可应用于工程实际.基于Lambert飞行时间定理和遗传算法,研究航天器最优脉冲变轨策略.根据脉冲变轨优化的结果,采用迭代制导算法研究脉冲变轨工程化问题.仿真结果验证了迭代制导算法在航天器轨道交会中的有效性.     

单个航天器对Walker星座中多卫星的近距离接近

通过设计航天器轨道,可使航天器发射入轨后无需机动即实现对Walker星座中非共轨的多颗卫星的快速、近距离接近.给出了该轨道的搜索方法以及基于星座特性的代换法,并给出了仿真示例.      

探空火箭定时定点入轨的一种制导控制规律

针对特定探测天体,给出了特殊用途的探空火箭与其实现空间交会的时刻与地点的计算方法.根据特定天体的运行轨道,发射前算出标称交会飞行轨道,装订在箭载计算机内.火箭发射后,利用箭载惯性导航系统确定自身当前的位置与速度,比对标称飞行轨道参数得出飞行偏差,通过控制火箭推力偏斜调整飞行轨道,使探空火箭在交会时刻到达交会点,并在交会时刻相对与惯性空间的速度为0.定义了研究所用的各种坐标系,建立了火箭飞行动力学方程.研究了标称飞行轨道最优交会点选取,交会时间与发射时间计算等问题.给出了发射后动力飞行段的制导控制规律,核心思想是将控制信号分解为时间控制、当地水平面上的海拔高度控制、南北控制与东西控制,通过设置偏置量减小关机后轨道摄动因素引起的漂移.利用计算机数值仿真验证了这种制导控制规律的可行性.     

北斗卫星导航系统第二星成功定点

4月20日17点06分,北斗卫星导航系统第二颗卫星成功定点于预定轨道。4月15日,中国航天科技集团公司从西昌卫星发射中心成功发射了北斗卫星导航系统第二颗卫星。该卫星是北斗卫星导航系统首颗地球静止轨道卫星。经过4次远地点变轨和4个批次定点捕获,该卫星于4月20日成功定点。从今年起,北斗卫星导航系统进入组网高峰期。预计2010年左右,北斗卫星导航系统建设覆盖亚太地区,2020年前建成全球卫星导航系统。     

地球静止轨道卫星电推进位保策略研究

研究了利用电推进系统进行GEO卫星轨道保持问题,给出了一种基于日预报的位置保持策略。首先,根据GEO卫星轨道漂移规律,分析了小推力推进系统每日进行位保的可行性;然后,针对四电推力器配置构型,给出了每日轨道误差、各推力器工作时间与区间的预测方法;进一步,针对给定的定点位置,根据位保效果对电推进安装角进行了优化选择,并研究了推力变化对位保效果和燃料消耗的影响。以东经100°定点为例对所给方法进行了仿真验证,数值结果表明:所给策略可有效用于GEO卫星位置保持。     

小卫星三轴稳定模式下的有限推力轨道转移

由搭载方式发射的小卫星,通常需要变轨才能进入自己的工作轨道。这种变轨一般由小推力发动机执行,传统的冲量变轨方法存在较大局限性。文章研究了在小推力作用下,小卫星由椭圆停泊轨道进入共面圆工作轨道的点火信息求解方法;给出对地定向三轴稳定模式下和俯仰角偏置三轴稳定模式下的变轨控制仿真结果;提供了对任务设计有参考价值的结论。     

最大全电卫星完成最快定点

<正>今年6月1日发射的欧洲通信卫星公司的"欧洲通信卫星172B"全电推进卫星在发射了4个月之后成功完成定点,创下了全电卫星最快定点纪录。该卫星是首颗发射入轨的空客造全电卫星。在此之前,波音建造的4颗较小卫星已经采用过电推进轨道提升技术。这4颗卫星用了6     

北斗“双胞胎”入网很关键

随着第12、13颗北斗卫星成功入轨,北斗卫星首次"落户"中圆轨道(MEO轨道),我国的北斗区域卫星导航系统日趋成型。在此次双星发射之前,太空中已有5颗地球静止轨道(GEO轨道)北斗卫星和5颗倾斜地球同步轨道(IGSO轨道)北斗卫星,按照"5+5+4"的组网计划,会有4颗MEO轨道卫星上天。而此次发射     

北斗-1卫星定点成功

在西安卫星测控中心的精确控制下,我国于5月25日成功发射的第3颗北斗-1导航定位卫星,于北京时间6月3日5时零分成功定点,顺利进入地球同步轨道。 北斗-1卫星发射升空后,成功进入地球静止转移轨道,按计划运行了220h,在此期间,西安卫星测控中心采用国际先进的中心遥控模式,组织所属地面测控站对卫星进行了持续跟踪与精确控制,使卫星完成了地球捕获、太阳能帆板展开和星上发动机多次点火、调姿变轨等数十个动作,准确地进入了地球准同步轨道。之后,又经过位置保持等多项复杂测量控制,最终成功定点于地球赤道上空。 北斗-1导航卫星定点后,西安卫星…     

星载GNSS确定GEO卫星轨道的积分滤波方法

采用星载全球导航卫星系统（GNSS）确定地球静止轨道（GEO）,以解决目前应用星载全球定位系统(GPS)时导航卫星可见性差的问题。以风云卫星为例,分析了未来的GNSS相对于GEO卫星的可见性,针对GEO轨道上导航接收机采样间隔较长的问题,综合轨道积分和卡尔曼滤波方法的优点,提出了确定GEO卫星轨道的积分滤波方法。并利用STK软件仿真产生所需数据,用MATLAB对提出的算法编程并进行仿真验证,结果表明,提出的方法性能优越,定轨精度较高。     

高分四号卫星控制方案设计特点及在轨实现

高分四号(GF 4)是首颗地球静止轨道光学面阵遥感卫星.简要综述了国外该领域发展情况,重点介绍了高分四号卫星控制系统方案设计的主要特点,包括全星敏转移轨道技术、姿态小角度步进机动与快速稳定、以及阳光规避技术,并结合实际飞行情况介绍了上述技术的在轨验证情况,最后对后续该领域技术发展提出了展望     

Near real-time BDS GEO satellite orbit determination and maneuver analysis with reversed point positioning

The Geostationary Earth Orbit (GEO) satellite is a crucial part of the BeiDou Navigation Satellite System (BDS) constellation. However, due to various perturbation forces acting on the GEO satellite, it drifts gradually over time. Thus, frequent orbit maneuvers are required to maintain the satellite at its designed position. During the orbit maneuver and recovery periods, the orbit quality of the maneuvered satellite computed with broadcast navigation ephemeris will be significantly degraded. Furthermore, the conventional dynamic Precise Orbit Determination (POD) approach may not work well, because of a lack of publicly available satellite information for modeling the thrust forces. In this paper, a near real-time approach free of thrust forces modeling is proposed for BDS GEO satellite orbit determination and maneuver analysis based on the Reversed Point Positioning (RPP). First, the station coordinates and receiver clock offsets are estimated by GPS/BDS combined Single Point Positioning (SPP) with single-frequency phase-smoothed pseudorange observations. Then, with the fixed station coordinates and receiver clock offsets, the RPP method can be conducted to determine the GEO satellite orbits. When no orbit maneuvers occur, the proposed method can obtain orbit accuracies of 0.92, 2.74, and 8.30?m in the radial, along-track, and cross-track directions, respectively. The average orbit-only Signal-In-Space Range Error (SISRE) is 1.23?m, which is slightly poorer than that of the broadcast navigation ephemeris. Using four days of GEO maneuvered datasets, it is further demonstrated that the derived orbits can be employed to characterize the behaviors of GEO satellite maneuvers, such as the time span of the maneuver as well as the satellite thrusting accelerations. These results prove the efficiency of the proposed method for near real-time GEO satellite orbit determination during maneuvers.     

单星导航HEO卫星初轨确定算法

HEO(Highly Elliptical Orbit)轨道卫星利用星载GPS(Global Positioning System)进行自主定轨面临的主要难题之一就是解决在单颗导航卫星条件下的初轨确定问题.从理论上分析了利用单颗导航卫星的观测量确定HEO卫星轨道初值的所需满足的条件,指出了利用F.G级数法求解初值存在的问题,提出了一种基于轨道根数约束的迭代批处理算法,该算法无需复杂的数学运算,避免了F.G级数法用短弧资料定初轨时系数矩阵秩亏的影响.仿真结果表明,当先验轨道根数误差在允许范围内取值时,在考虑轨道射入误差的情况下,初值的位置偏差在10⁴ m量级,速度偏差在10⁰ m/s量级,能够根据单颗导航卫星的短弧观测值可靠地完成轨道初值的确定.     

Application of CCD drift-scan photoelectric technique on monitoring GEO satellites

Geosynchronous Earth Orbit (GEO) satellites are widely used because of their unique characteristics of high-orbit and remaining permanently in the same area of the sky. Precise monitoring of GEO satellites can provide a key reference for the judgment of satellite operation status, the capture and identification of targets, and the analysis of collision warning. The observation using ground-based optical telescopes plays an important role in the field of monitoring GEO targets. Different from distant celestial bodies, there is a relative movement between the GEO target and the background reference stars, which makes the conventional observation method limited for long focal length telescopes. CCD drift-scan photoelectric technique is applied on monitoring GEO targets. In the case of parking the telescope, the good round images of the background reference stars and the GEO target at the same sky region can be obtained through the alternating observation of CCD drift-scan mode and CCD stare mode, so as to improve the precision of celestial positioning for the GEO target. Observation experiments of GEO targets were carried out with 1.56-meter telescope of Shanghai Astronomical Observatory. The results show that the application of CCD drift-scan photoelectric technique makes the precision of observing the GEO target reach the level of 0.2″, which gives full play to the advantage of the long focal length of the telescope. The effect of orbit improvement based on multi-pass of observations is obvious and the prediction precision of extrapolating to 72-h is in the order of several arc seconds in azimuth and elevation.     

Orbit determination of BeiDou navigation satellite system maneuvered satellites based on instantaneous velocity pulses parameters

The BeiDou navigation satellite system (BDS) comprises geostationary earth orbit (GEO) satellites as well as inclined geosynchronous orbit (IGSO) and medium earth orbit (MEO) satellites. Owing to their special orbital characteristics, GEO satellites require frequent orbital maneuvers to ensure that they operate in a specific orbital window. The availability of the entire system is affected during the maneuver period because service cannot be provided before the ephemeris is restored. In this study, based on the conventional dynamic orbit determination method for navigation satellites, multiple sets of instantaneous velocity pulses parameters which belong to one of pseudo-stochastic parameters were used to simulate the orbital maneuver process in the orbital maneuver arc and establish the observed and predicted orbits of the maneuvered and non-maneuvered satellites of BeiDou regional navigation satellite system (BDS-2) and BeiDou global navigation satellite system (BDS-3). Finally, the single point positioning (SPP) technology was used to verify the accuracy of the observed and predicted orbits. The orbit determination accuracy of maneuvered satellites can be greatly improved by using the orbit determination method proposed in this paper. The overlapping orbit determination accuracy of maneuvered GEO satellites of BDS-2 and BDS-3 can improve 2–3 orders of magnitude. Among them, the radial orbit determination accuracy of each maneuvered satellite is basically better than 1 m. simultaneously, the combined orbit determination of the maneuvered and non-maneuvered satellites does not have a great impact on the orbit determination accuracy of the non-maneuvered satellites. Compared with the multi GNSS products (indicated by GBM) from the German Research Centre for Geosciences (GFZ), the impact of adding the maneuvered satellites on the orbit determination accuracy of BDS-2 satellites is less than 9 %. Furthermore, the orbital recovery time and the service availability period are significantly improved. When the node of the predicted orbit is traversed approximately 3 h after the maneuver, the accuracy of the predicted orbit of the maneuvered satellite can reach that of the observed orbit. The SPP results for the BDS reached a normal level when the node of the predicted orbit was 2 h after the maneuver.     

对异面椭圆轨道目标航天器的长期绕飞轨迹设计与控制

研究了绕飞卫星对异面椭圆轨道目标航天器进行长时间绕飞观测的轨道设计与控制问题。首先建立了适用于目标航天器运行在椭圆轨道上的长期绕飞轨迹设计模型;得到了绕飞轨迹以目标航天器为中心且保持封闭的条件。然后,考虑绕飞轨迹安全性和完成任务的相对距离需求,针对具体目标设计了长期绕飞观测轨道。绕飞过程中存在的摄动和误差影响会使绕飞轨迹不能保持封闭,不满足任务需求,为此采用双脉冲方法对绕飞轨迹进行控制。仿真结果表明,对运行在异面椭圆轨道上的目标航天器,所建立的绕飞轨迹设计模型和轨迹控制方法可以用于长期绕飞轨迹设计与控制中。     

V型轮控系统卫星东西位置保持策略优化方法研究

以某在轨GEO卫星为研究对象,探讨了适用于V型轮控系统特点的东西位置保持策略．首先分析了V型轮控系统的工作原理,提出了轮控过程中推力器效率的标定方法和喷气卸载对轨道影响的数学模型;然后深入分析了轮控过程中姿态控制对卫星东西位置保持环及偏心率的影响,提出了延长位保周期的控制策略,并在实际任务中获得了较好的效果．     

卫星姿态大角度机动的轨迹规划和模型预测与反演控制

空间科学观测、态势感知、对地遥感、操控服务等应用对卫星提出了高精度、高稳定度、平稳柔顺大角度姿态机动的需求。采用欧拉角形式,对时变、非线性卫星姿态动力学系统进行了分析与建模,将每一个测控周期视为一个姿态机动过程。基于动力学系统受控运动的规律,在每一个姿态跟踪机动过程中,预测姿态偏差,通过卫星姿态演化的反演得到控制指令。以三角函数为基础,设计了一种卫星姿态大角度机动的运动轨迹规划方法。本文所述的轨迹规划及控制方法具有轨迹跟踪精度高、稳定性好,跟踪和机动过程平稳柔顺的特点。数学仿真验证了该方法的可行性和有效性。 关键词：轨迹规划; 模型预测与反演控制; 卫星姿态; 大角度机动