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Orbit determination

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119: 1582: 2537: 3572: 3204: 1126: 22: 4231: 2260: 3291: 2937: 3964: 1577:{\displaystyle {\begin{aligned}{\vec {e}}&={{\vec {v}}\times {\vec {h}} \over {\mu }}-{{\vec {r}} \over {\left|{\vec {r}}\right|}}=e{\vec {i}}\\&=\left({{\left|{\vec {v}}\right|}^{2} \over {\mu }}-{1 \over {\left|{\vec {r}}\right|}}\right){\vec {r}}-{{\vec {r}}\cdot {\vec {v}} \over {\mu }}{\vec {v}}\\&={\frac {1}{\mu }}\left\end{aligned}}} 2173: 2532:{\displaystyle {\begin{aligned}\cos(\Omega )&={\frac {{\vec {I}}\cdot {\vec {n}}}{n}}={\frac {n_{I}}{n}}=\cos(360-\Omega )\\\Rightarrow \Omega &=\arccos \left({\frac {{\vec {I}}\cdot {\vec {n}}}{n}}\right)=\Omega _{0},{\text{ or }}\\\Rightarrow \Omega &=360^{\circ }-\Omega _{0},{\text{ if }}n_{J}<0,\\\end{aligned}}} 3567:{\displaystyle {\begin{aligned}\cos(\nu )&={\frac {{\vec {e}}\cdot {\vec {r}}}{er}}=\cos(360-\nu )\\\Rightarrow \nu &=\arccos \left({\frac {{\vec {e}}\cdot {\vec {r}}}{er}}\right)=\nu _{0},{\text{ or }}\\\Rightarrow \nu &=360^{\circ }-\nu _{0},{\text{ if }}{\vec {r}}\cdot {\vec {v}}<0.\\\end{aligned}}} 3199:{\displaystyle {\begin{aligned}\cos(\omega )&={\frac {{\vec {n}}\cdot {\vec {e}}}{ne}}=\cos(360-\omega )\\\Rightarrow \omega &=\arccos \left({\frac {{\vec {n}}\cdot {\vec {e}}}{ne}}\right)=\omega _{0},{\text{ or }}\\\Rightarrow \omega &=360^{\circ }-\omega _{0},{\text{ if }}e_{K}<0,\\\end{aligned}}} 446:
If the position and velocity relative to the observer are available (as is the case with radar observations), these observational data can be adjusted by the known position and velocity of the observer relative to the attracting body at the times of observation. This yields the position and velocity
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calculations may use this data to calculate the probability that one orbiting object will collide with another. A satellite's operator may decide to adjust the orbit, if the risk of collision in the present orbit is unacceptable. (It is not possible to adjust the orbit for events of very low
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After orbits are determined, mathematical propagation techniques can be used to predict the future positions of orbiting objects. As time goes by, the actual path of an orbiting object tends to diverge from the predicted path (especially if the object is subject to difficult-to-predict
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of its central body. The central bodies are the sources of the gravitational forces, like the Sun, Earth, Moon and other planets. The orbiting bodies, on the other hand, include planets around the Sun, artificial satellites around the Earth, and spacecraft around planets. Newton's
4226:{\displaystyle {\begin{aligned}\cos(u)&={\frac {{\vec {n}}\cdot {\vec {r}}}{nr}}=\cos(360-u)\\\Rightarrow u&=\arccos \left({\frac {{\vec {n}}\cdot {\vec {r}}}{nr}}\right)=u_{0},{\text{ or }}\\\Rightarrow u&=360^{\circ }-u_{0},{\text{ if }}r_{K}<0,\\\end{aligned}}} 419:
Orbit determination must take into account that the apparent celestial motion of the body is influenced by the observer's own motion. For instance, an observer on Earth tracking an asteroid must take into account the motion of the Earth around the
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of the orbital plane of the orbiting body. Since the line of ascending node is the line of intersection between the orbital plane and the reference plane, it is perpendicular to both the normal vectors of the reference plane
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with respect to the attracting body. If two such observations are available, along with the time difference between them, the orbit can be determined using Lambert's method, invented in the 18th century. See
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apparatus are used, because naked-eye observations are inadequate for precise orbit determination. With more or better observations, the accuracy of the orbit determination process also improves, and fewer
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is the unit vector of the z-axis of the orbital plane. The specific angular momentum is a constant vector for an orbiting body, with its direction perpendicular to the orbital plane of the orbiting body.
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Even if no distance information is available, an orbit can still be determined if three or more observations of the body's right ascension and declination have been made.
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gathers observations of all objects in Earth orbit. The observations are used in new orbit determination calculations that maintain the overall accuracy of the
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and verify that they have not been previously discovered. The basic methods were discovered in the 17th century and have been continuously refined.
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that completely describe an orbit. The theory of orbit determination has subsequently been developed to the point where today it is applied in
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are the raw data fed into orbit determination algorithms. Observations made by a ground-based observer typically consist of time-tagged
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Diagram showing how orbit-de­ter­mi­na­tion data was handled in a 1962 NASA mission. (Of historical interest only.)
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representing the unit vector of the Z-axis of the reference plane, which is perpendicular to the reference plane of the central body:
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of its motion with time are required. In early modern astronomy, the only available observational data for celestial objects were the
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at epoch, which is the angle between the position vector and the periapsis at the particular time ('epoch') of observation:
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of the range to the object. This generally limits radar observations to objects relatively near the Earth, such as
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The mathematical methods for orbit determination originated with the publication in 1687 of the first edition of
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Various space agencies and commercial providers operate tracking networks to provide these observations. See
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of objects such as moons, planets, and spacecraft. One major application is to allow tracking newly observed
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at epoch, which is the angle between the position vector and the ascending line at the particular time:
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of the orbit. This direction is often defined as the x-axis of the orbital plane and has a unit vector
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for a partial listing. Space-based tracking of satellites is also regularly performed. See
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to deduce the elliptical shape of its orbit and its orientation in space, deriving his three
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drawn from the attracting body to the body at different points in time will all lie in the
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A key observation is that (to a close approximation) all objects move in orbits that are
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Orbit determination has a long history, beginning with the prehistoric discovery of the
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in 1744, whose work was in turn generalised to elliptical and hyperbolic orbits by
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The steps of orbit determination from one state vector are summarized as follows:
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The ascending node vector is a vector pointing from the central body to the
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The basic orbit determination task is to determine the classical
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of the orbit. The eccentricity vector has the magnitude of the
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One use is in the determination of asteroid masses via the
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of the orbital plane with respect to the reference plane:
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will explain the trajectory of an orbiting body, known as
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as well as the tracking and cataloguing of newly observed
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measurements (by timing of the radar echo) and relative
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In order to determine the unknown orbit of a body, some
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was able to use just three observations (in the form of
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Unsourced material may be challenged and removed. 4305: 4303: 4281: 4252: 4225: 3953: 3915: 3820: 3770: 3718: 3673: 3650: 3630: 3610: 3566: 3280: 3254: 3225: 3198: 2926: 2900: 2873: 2847: 2827: 2807: 2781: 2761: 2729: 2697: 2614: 2585: 2558: 2531: 2249: 2223: 2194: 2167: 1961: 1935: 1909: 1860:{\displaystyle p={\frac {h^{2}}{\mu }}=a(1-e^{2})} 1859: 1791: 1771: 1741: 1721: 1691: 1671: 1647: 1618: 1576: 1115: 1082: 1058: 1023: 994: 965: 931: 869: 840: 811: 775: 746: 631: 579: 531: 458:, made famous in his 1801 "recovery" of the first 239:and subsequent attempts to predict their motions. 4412: 2593:are the X- and Y- coordinates, respectively, of 4300: 271:path from three observations. This was used by 4314:. Courier Corporation; 1971. Ch 2 p 51 et seq. 2698:{\displaystyle \cos(A)=\cos(-A)=\cos(360-A)=C} 290:Another milestone in orbit determination was 2231:when it is projected to the reference frame. 639:of the orbiting body from its state vector: 435:, and that the orbit lies in a fixed plane. 4349:, Chapters 7, 8; Wiley-Interscience (1985) 3658:angle, because it has the same sign as the 2769:is ambiguous in that there are two angles, 587:], of an orbiting body with respect to the 4331:Orbital Mechanics for Engineering Students 3611:{\displaystyle {\vec {r}}\cdot {\vec {v}}} 2835:value. It could actually return the angle 532:{\displaystyle a,e,i,\Omega ,\omega ,\nu } 190:and partner countries, to the extent that 1619:{\displaystyle e=\left|{\vec {e}}\right|} 106:Learn how and when to remove this message 117: 2622:, in the reference frame. Notice that 1910:{\displaystyle a={\frac {p}{1-e^{2}}},} 477:Orbit determination from a state vector 294:'s assistance in the "recovery" of the 4413: 1799:is undefined or defined as infinity): 1729:of the orbit, and its semi-major axis 376:of the radar echo) are possible using 211:probability; it would soon use up the 186:is another major application. For the 3618:can be used to check the quadrant of 580:{\displaystyle {\vec {r}},{\vec {v}}} 324: 405:List of radio telescopes#Space-based 44:adding citations to reliable sources 15: 466:, has been subsequently polished. 275:to establish the orbits of various 13: 4322: 3821:{\displaystyle h=rv\sin(90-\phi )} 2489: 2465: 2441: 2377: 2364: 2277: 2244: 514: 14: 4447: 219:.) Other countries, including 2737:is defined only in degrees. So 1701:universal gravitational constant 1657:standard gravitational parameter 227:, have similar tracking assets. 20: 4392:Statistical Orbit Determination 4310:Bate RR, Mueller DD, White JE. 3926:Optionally, we may compute the 372:measurements (by measuring the 31:needs additional citations for 4364:, Chapters 2, 5; Dover (1971) 4273: 4156: 4110: 4095: 4063: 4056: 4044: 4018: 4003: 3984: 3978: 3954:{\displaystyle u=\omega +\nu } 3910: 3904: 3889: 3877: 3856: 3841: 3815: 3803: 3765: 3739: 3713: 3694: 3602: 3587: 3548: 3533: 3483: 3437: 3422: 3390: 3383: 3371: 3345: 3330: 3311: 3305: 3246: 3129: 3083: 3068: 3036: 3029: 3017: 2991: 2976: 2957: 2951: 2908:can be used for such judgment. 2756: 2750: 2724: 2718: 2686: 2674: 2662: 2653: 2641: 2635: 2606: 2462: 2421: 2406: 2374: 2367: 2355: 2314: 2299: 2280: 2274: 2215: 2155: 2136: 2109: 2094: 2062: 2026: 2011: 1992: 1986: 1854: 1835: 1606: 1559: 1549: 1543: 1528: 1519: 1509: 1485: 1448: 1399: 1379: 1364: 1346: 1322: 1279: 1244: 1219: 1202: 1177: 1162: 1140: 1107: 1050: 1015: 986: 957: 920: 905: 890: 861: 832: 803: 767: 735: 717: 701: 682: 667: 652: 623: 571: 556: 1: 4407:, Coastal Bend College, Texas 4405:Satellite Orbit Determination 4362:Fundamentals of Astrodynamics 4334:, Chapter 5; Elsevier (2005) 4312:Fundamentals of astrodynamics 4293: 1659:for the central body of mass 200:Joint Space Operations Center 4379:, Chapter 3; Krieger (1997) 401:Category:Deep space networks 7: 2236:longitude of ascending node 247:'s careful observations of 10: 4452: 4282:{\displaystyle {\vec {r}}} 3255:{\displaystyle {\vec {e}}} 2762:{\displaystyle \arccos(C)} 2730:{\displaystyle \arccos(C)} 2615:{\displaystyle {\vec {n}}} 2224:{\displaystyle {\vec {h}}} 1116:{\displaystyle {\vec {i}}} 1059:{\displaystyle {\vec {e}}} 1024:{\displaystyle {\vec {h}}} 995:{\displaystyle {\vec {k}}} 966:{\displaystyle {\vec {K}}} 870:{\displaystyle {\vec {K}}} 841:{\displaystyle {\vec {h}}} 812:{\displaystyle {\vec {n}}} 776:{\displaystyle {\vec {k}}} 632:{\displaystyle {\vec {h}}} 414: 230: 215:the satellite carries for 973:) and the orbital plane ( 609:specific angular momentum 3771:{\displaystyle \nu \in } 3719:{\displaystyle \nu \in } 3651:{\displaystyle \arccos } 253:laws of planetary motion 4289:in the reference frame. 4260:is the Z-coordinate of 3262:in the reference frame. 3233:is the Z-coordinate of 2927:{\displaystyle \omega } 2815:in , who have the same 2250:{\displaystyle \Omega } 2202:is the Z-coordinate of 1936:{\displaystyle e\neq 1} 1648:{\displaystyle \mu =GM} 217:orbital station-keeping 159:values. Telescopes or 4426:Spaceflight technology 4390:Schutz, Tapley, Born; 4360:Bate, Mueller, White; 4283: 4254: 4227: 3955: 3917: 3822: 3778:. Both are related by 3772: 3720: 3675: 3652: 3632: 3612: 3568: 3282: 3256: 3227: 3200: 2928: 2902: 2875: 2849: 2829: 2809: 2783: 2763: 2731: 2699: 2616: 2587: 2560: 2533: 2251: 2225: 2196: 2169: 1963: 1937: 1911: 1861: 1793: 1773: 1743: 1723: 1693: 1673: 1649: 1620: 1578: 1117: 1084: 1060: 1025: 996: 967: 933: 871: 842: 813: 777: 748: 633: 581: 533: 123: 4284: 4255: 4253:{\displaystyle r_{K}} 4228: 3956: 3918: 3823: 3773: 3721: 3676: 3674:{\displaystyle \phi } 3653: 3633: 3613: 3569: 3283: 3257: 3228: 3226:{\displaystyle e_{K}} 3201: 2929: 2913:argument of periapsis 2903: 2901:{\displaystyle n_{J}} 2876: 2874:{\displaystyle 360-A} 2850: 2830: 2828:{\displaystyle \cos } 2810: 2808:{\displaystyle 360-A} 2784: 2764: 2732: 2700: 2617: 2588: 2586:{\displaystyle n_{J}} 2561: 2559:{\displaystyle n_{I}} 2534: 2252: 2226: 2197: 2195:{\displaystyle h_{K}} 2170: 1964: 1938: 1912: 1862: 1794: 1774: 1744: 1724: 1694: 1674: 1650: 1621: 1579: 1118: 1085: 1061: 1026: 997: 968: 934: 872: 843: 814: 778: 749: 634: 582: 541:orbital state vectors 534: 386:artificial satellites 307:celestial coordinates 198:resources allow, the 129:is the estimation of 121: 55:"Orbit determination" 4264: 4237: 3965: 3933: 3928:argument of latitude 3832: 3782: 3730: 3726:, and negative when 3685: 3665: 3642: 3631:{\displaystyle \nu } 3622: 3578: 3292: 3281:{\displaystyle \nu } 3272: 3237: 3210: 2938: 2918: 2885: 2859: 2839: 2819: 2793: 2773: 2741: 2709: 2626: 2597: 2570: 2543: 2261: 2241: 2206: 2179: 1973: 1953: 1921: 1870: 1803: 1783: 1757: 1733: 1713: 1683: 1663: 1630: 1587: 1127: 1098: 1074: 1041: 1006: 977: 948: 881: 852: 823: 794: 758: 643: 614: 547: 493: 351:an optical telescope 292:Carl Friedrich Gauss 40:improve this article 4347:Celestial Mechanics 1772:{\displaystyle e=1} 1036:eccentricity vector 396:of natural bodies. 208:Collision avoidance 127:Orbit determination 4394:, Academic Press. 4279: 4250: 4223: 4221: 3951: 3913: 3818: 3768: 3716: 3671: 3648: 3628: 3608: 3564: 3562: 3278: 3252: 3223: 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697: 687: 686: 678: 672: 671: 663: 657: 656: 648: 638: 636: 635: 630: 628: 627: 619: 586: 584: 583: 578: 576: 575: 567: 561: 560: 552: 538: 536: 535: 530: 483:orbital elements 378:radio telescopes 311:orbital elements 255:in the process. 178:atmospheric drag 111: 104: 100: 97: 91: 89: 48: 24: 16: 4451: 4450: 4446: 4445: 4444: 4442: 4441: 4440: 4411: 4410: 4325: 4323:Further reading 4320: 4319: 4308: 4301: 4296: 4268: 4267: 4265: 4262: 4261: 4244: 4240: 4238: 4235: 4234: 4220: 4219: 4204: 4200: 4195: 4186: 4182: 4173: 4169: 4162: 4153: 4152: 4147: 4138: 4134: 4117: 4105: 4104: 4090: 4089: 4088: 4086: 4082: 4069: 4060: 4059: 4025: 4013: 4012: 3998: 3997: 3996: 3994: 3987: 3968: 3966: 3963: 3962: 3934: 3931: 3930: 3851: 3850: 3836: 3835: 3833: 3830: 3829: 3783: 3780: 3779: 3759: 3755: 3746: 3742: 3731: 3728: 3727: 3707: 3703: 3686: 3683: 3682: 3666: 3663: 3662: 3643: 3640: 3639: 3623: 3620: 3619: 3597: 3596: 3582: 3581: 3579: 3576: 3575: 3561: 3560: 3543: 3542: 3528: 3527: 3522: 3513: 3509: 3500: 3496: 3489: 3480: 3479: 3474: 3465: 3461: 3444: 3432: 3431: 3417: 3416: 3415: 3413: 3409: 3396: 3387: 3386: 3352: 3340: 3339: 3325: 3324: 3323: 3321: 3314: 3295: 3293: 3290: 3289: 3273: 3270: 3269: 3241: 3240: 3238: 3235: 3234: 3217: 3213: 3211: 3208: 3207: 3193: 3192: 3177: 3173: 3168: 3159: 3155: 3146: 3142: 3135: 3126: 3125: 3120: 3111: 3107: 3090: 3078: 3077: 3063: 3062: 3061: 3059: 3055: 3042: 3033: 3032: 2998: 2986: 2985: 2971: 2970: 2969: 2967: 2960: 2941: 2939: 2936: 2935: 2919: 2916: 2915: 2892: 2888: 2886: 2883: 2882: 2860: 2857: 2856: 2840: 2837: 2836: 2820: 2817: 2816: 2794: 2791: 2790: 2774: 2771: 2770: 2742: 2739: 2738: 2710: 2707: 2706: 2627: 2624: 2623: 2601: 2600: 2598: 2595: 2594: 2577: 2573: 2571: 2568: 2567: 2550: 2546: 2544: 2541: 2540: 2526: 2525: 2510: 2506: 2501: 2492: 2488: 2479: 2475: 2468: 2459: 2458: 2453: 2444: 2440: 2416: 2415: 2401: 2400: 2399: 2397: 2393: 2380: 2371: 2370: 2335: 2331: 2329: 2309: 2308: 2294: 2293: 2292: 2290: 2283: 2264: 2262: 2259: 2258: 2242: 2239: 2238: 2210: 2209: 2207: 2204: 2203: 2186: 2182: 2180: 2177: 2176: 2162: 2161: 2149: 2145: 2128: 2104: 2103: 2089: 2088: 2087: 2085: 2081: 2068: 2059: 2058: 2047: 2043: 2041: 2021: 2020: 2006: 2005: 2004: 2002: 1995: 1976: 1974: 1971: 1970: 1954: 1951: 1950: 1922: 1919: 1918: 1895: 1891: 1884: 1879: 1871: 1868: 1867: 1848: 1844: 1818: 1814: 1812: 1804: 1801: 1800: 1784: 1781: 1780: 1758: 1755: 1754: 1751:parabolic orbit 1734: 1731: 1730: 1714: 1711: 1710: 1684: 1681: 1680: 1664: 1661: 1660: 1631: 1628: 1627: 1601: 1600: 1596: 1588: 1585: 1584: 1571: 1570: 1554: 1553: 1538: 1537: 1523: 1522: 1518: 1504: 1503: 1480: 1479: 1475: 1474: 1469: 1459: 1443: 1442: 1438: 1437: 1436: 1435: 1434: 1430: 1429: 1425: 1415: 1406: 1405: 1394: 1393: 1386: 1374: 1373: 1359: 1358: 1357: 1355: 1341: 1340: 1317: 1316: 1312: 1311: 1306: 1296: 1290: 1274: 1273: 1269: 1268: 1267: 1265: 1264: 1260: 1251: 1250: 1239: 1238: 1214: 1213: 1209: 1208: 1197: 1196: 1194: 1184: 1172: 1171: 1157: 1156: 1155: 1153: 1146: 1135: 1134: 1130: 1128: 1125: 1124: 1102: 1101: 1099: 1096: 1095: 1075: 1072: 1071: 1045: 1044: 1042: 1039: 1038: 1010: 1009: 1007: 1004: 1003: 981: 980: 978: 975: 974: 952: 951: 949: 946: 945: 915: 914: 900: 899: 885: 884: 882: 879: 878: 856: 855: 853: 850: 849: 827: 826: 824: 821: 820: 798: 797: 795: 792: 791: 762: 761: 759: 756: 755: 730: 729: 712: 711: 696: 695: 691: 677: 676: 662: 661: 647: 646: 644: 641: 640: 618: 617: 615: 612: 611: 598:Keplerian orbit 589:reference frame 566: 565: 551: 550: 548: 545: 544: 494: 491: 490: 479: 417: 394:radar astronomy 343:observation arc 335:right ascension 327: 241:Johannes Kepler 233: 112: 101: 95: 92: 49: 47: 37: 25: 12: 11: 5: 4449: 4439: 4438: 4433: 4428: 4423: 4409: 4408: 4402: 4400:978-0126836301 4388: 4373: 4358: 4343: 4324: 4321: 4318: 4317: 4298: 4297: 4295: 4292: 4291: 4290: 4275: 4272: 4247: 4243: 4218: 4215: 4212: 4207: 4203: 4197: if  4194: 4189: 4185: 4181: 4176: 4172: 4168: 4165: 4163: 4161: 4158: 4155: 4154: 4149: or  4146: 4141: 4137: 4133: 4129: 4123: 4120: 4112: 4109: 4103: 4097: 4094: 4085: 4081: 4078: 4075: 4072: 4070: 4068: 4065: 4062: 4061: 4058: 4055: 4052: 4049: 4046: 4043: 4040: 4037: 4031: 4028: 4020: 4017: 4011: 4005: 4002: 3993: 3990: 3988: 3986: 3983: 3980: 3977: 3974: 3971: 3970: 3950: 3947: 3944: 3941: 3938: 3924: 3912: 3909: 3906: 3903: 3900: 3897: 3894: 3891: 3888: 3885: 3882: 3879: 3876: 3873: 3870: 3867: 3864: 3858: 3855: 3849: 3843: 3840: 3817: 3814: 3811: 3808: 3805: 3802: 3799: 3796: 3793: 3790: 3787: 3767: 3762: 3758: 3754: 3749: 3745: 3741: 3738: 3735: 3715: 3710: 3706: 3702: 3699: 3696: 3693: 3690: 3670: 3660:fly-path angle 3647: 3627: 3604: 3601: 3595: 3589: 3586: 3559: 3556: 3550: 3547: 3541: 3535: 3532: 3524: if  3521: 3516: 3512: 3508: 3503: 3499: 3495: 3492: 3490: 3488: 3485: 3482: 3481: 3476: or  3473: 3468: 3464: 3460: 3456: 3450: 3447: 3439: 3436: 3430: 3424: 3421: 3412: 3408: 3405: 3402: 3399: 3397: 3395: 3392: 3389: 3388: 3385: 3382: 3379: 3376: 3373: 3370: 3367: 3364: 3358: 3355: 3347: 3344: 3338: 3332: 3329: 3320: 3317: 3315: 3313: 3310: 3307: 3304: 3301: 3298: 3297: 3277: 3263: 3248: 3245: 3220: 3216: 3191: 3188: 3185: 3180: 3176: 3170: if  3167: 3162: 3158: 3154: 3149: 3145: 3141: 3138: 3136: 3134: 3131: 3128: 3127: 3122: or  3119: 3114: 3110: 3106: 3102: 3096: 3093: 3085: 3082: 3076: 3070: 3067: 3058: 3054: 3051: 3048: 3045: 3043: 3041: 3038: 3035: 3034: 3031: 3028: 3025: 3022: 3019: 3016: 3013: 3010: 3004: 3001: 2993: 2990: 2984: 2978: 2975: 2966: 2963: 2961: 2959: 2956: 2953: 2950: 2947: 2944: 2943: 2923: 2909: 2895: 2891: 2870: 2867: 2864: 2844: 2824: 2804: 2801: 2798: 2778: 2758: 2755: 2752: 2749: 2746: 2726: 2723: 2720: 2717: 2714: 2694: 2691: 2688: 2685: 2682: 2679: 2676: 2673: 2670: 2667: 2664: 2661: 2658: 2655: 2652: 2649: 2646: 2643: 2640: 2637: 2634: 2631: 2608: 2605: 2580: 2576: 2553: 2549: 2524: 2521: 2518: 2513: 2509: 2503: if  2500: 2495: 2491: 2487: 2482: 2478: 2474: 2471: 2469: 2467: 2464: 2461: 2460: 2455: or  2452: 2447: 2443: 2439: 2435: 2430: 2423: 2420: 2414: 2408: 2405: 2396: 2392: 2389: 2386: 2383: 2381: 2379: 2376: 2373: 2372: 2369: 2366: 2363: 2360: 2357: 2354: 2351: 2348: 2343: 2338: 2334: 2328: 2323: 2316: 2313: 2307: 2301: 2298: 2289: 2286: 2284: 2282: 2279: 2276: 2273: 2270: 2267: 2266: 2246: 2232: 2217: 2214: 2189: 2185: 2160: 2157: 2152: 2148: 2144: 2141: 2138: 2135: 2132: 2129: 2127: 2123: 2118: 2111: 2108: 2102: 2096: 2093: 2084: 2080: 2077: 2074: 2071: 2069: 2067: 2064: 2061: 2060: 2055: 2050: 2046: 2040: 2035: 2028: 2025: 2019: 2013: 2010: 2001: 1998: 1996: 1994: 1991: 1988: 1985: 1982: 1979: 1978: 1958: 1944: 1932: 1929: 1926: 1906: 1898: 1894: 1890: 1887: 1883: 1878: 1875: 1856: 1851: 1847: 1843: 1840: 1837: 1834: 1831: 1826: 1821: 1817: 1811: 1808: 1788: 1768: 1765: 1762: 1738: 1718: 1704: 1688: 1668: 1644: 1641: 1638: 1635: 1614: 1608: 1605: 1599: 1595: 1592: 1568: 1561: 1558: 1551: 1545: 1542: 1536: 1530: 1527: 1521: 1517: 1511: 1508: 1501: 1493: 1487: 1484: 1478: 1473: 1468: 1462: 1456: 1450: 1447: 1441: 1433: 1428: 1422: 1419: 1414: 1411: 1409: 1407: 1401: 1398: 1389: 1381: 1378: 1372: 1366: 1363: 1354: 1348: 1345: 1338: 1330: 1324: 1321: 1315: 1310: 1305: 1299: 1293: 1287: 1281: 1278: 1272: 1263: 1259: 1256: 1254: 1252: 1246: 1243: 1237: 1234: 1227: 1221: 1218: 1212: 1204: 1201: 1193: 1187: 1179: 1176: 1170: 1164: 1161: 1152: 1149: 1147: 1142: 1139: 1133: 1132: 1109: 1106: 1079: 1052: 1049: 1032: 1017: 1014: 988: 985: 959: 956: 941:ascending node 928: 922: 919: 913: 907: 904: 898: 892: 889: 863: 860: 834: 831: 805: 802: 788:ascending node 784: 769: 766: 743: 737: 734: 728: 725: 719: 716: 709: 703: 700: 694: 690: 684: 681: 675: 669: 666: 660: 654: 651: 625: 622: 594:laws of motion 573: 570: 564: 558: 555: 528: 525: 522: 519: 516: 513: 510: 507: 504: 501: 498: 478: 475: 471:dynamic method 456:Gauss's method 429:conic sections 416: 413: 374:Doppler effect 326: 323: 303:Gauss's method 287:in 1761–1777. 232: 229: 114: 113: 28: 26: 19: 9: 6: 4: 3: 2: 4448: 4437: 4436:Astrodynamics 4434: 4432: 4429: 4427: 4424: 4422: 4419: 4418: 4416: 4406: 4403: 4401: 4397: 4393: 4389: 4386: 4385:0-89464-010-0 4382: 4378: 4375:Madonna, R.; 4374: 4371: 4370:0-486-60061-0 4367: 4363: 4359: 4356: 4355:0-471-89316-1 4352: 4348: 4344: 4341: 4340:0-7506-6169-0 4337: 4333: 4332: 4327: 4326: 4315: 4313: 4306: 4304: 4299: 4270: 4245: 4241: 4216: 4213: 4210: 4205: 4201: 4192: 4187: 4183: 4179: 4174: 4170: 4166: 4164: 4159: 4144: 4139: 4135: 4131: 4127: 4121: 4118: 4107: 4101: 4092: 4083: 4079: 4076: 4073: 4071: 4066: 4053: 4050: 4047: 4041: 4038: 4035: 4029: 4026: 4015: 4009: 4000: 3991: 3989: 3981: 3975: 3972: 3948: 3945: 3942: 3939: 3936: 3929: 3925: 3907: 3901: 3898: 3895: 3892: 3886: 3883: 3880: 3874: 3871: 3868: 3865: 3862: 3853: 3847: 3838: 3812: 3809: 3806: 3800: 3797: 3794: 3791: 3788: 3785: 3760: 3756: 3752: 3747: 3743: 3736: 3733: 3708: 3704: 3700: 3697: 3691: 3688: 3668: 3661: 3645: 3625: 3599: 3593: 3584: 3557: 3554: 3545: 3539: 3530: 3519: 3514: 3510: 3506: 3501: 3497: 3493: 3491: 3486: 3471: 3466: 3462: 3458: 3454: 3448: 3445: 3434: 3428: 3419: 3410: 3406: 3403: 3400: 3398: 3393: 3380: 3377: 3374: 3368: 3365: 3362: 3356: 3353: 3342: 3336: 3327: 3318: 3316: 3308: 3302: 3299: 3275: 3268: 3264: 3243: 3218: 3214: 3189: 3186: 3183: 3178: 3174: 3165: 3160: 3156: 3152: 3147: 3143: 3139: 3137: 3132: 3117: 3112: 3108: 3104: 3100: 3094: 3091: 3080: 3074: 3065: 3056: 3052: 3049: 3046: 3044: 3039: 3026: 3023: 3020: 3014: 3011: 3008: 3002: 2999: 2988: 2982: 2973: 2964: 2962: 2954: 2948: 2945: 2921: 2914: 2910: 2893: 2889: 2868: 2865: 2862: 2842: 2822: 2802: 2799: 2796: 2776: 2753: 2747: 2744: 2721: 2715: 2712: 2692: 2689: 2683: 2680: 2677: 2671: 2668: 2665: 2659: 2656: 2650: 2647: 2644: 2638: 2632: 2629: 2603: 2578: 2574: 2551: 2547: 2522: 2519: 2516: 2511: 2507: 2498: 2493: 2485: 2480: 2476: 2472: 2470: 2450: 2445: 2437: 2433: 2428: 2418: 2412: 2403: 2394: 2390: 2387: 2384: 2382: 2361: 2358: 2352: 2349: 2346: 2341: 2336: 2332: 2326: 2321: 2311: 2305: 2296: 2287: 2285: 2271: 2268: 2237: 2233: 2212: 2187: 2183: 2158: 2150: 2146: 2142: 2139: 2133: 2130: 2125: 2121: 2116: 2106: 2100: 2091: 2082: 2078: 2075: 2072: 2070: 2065: 2053: 2048: 2044: 2038: 2033: 2023: 2017: 2008: 1999: 1997: 1989: 1983: 1980: 1956: 1949: 1945: 1930: 1927: 1924: 1904: 1896: 1892: 1888: 1885: 1881: 1876: 1873: 1849: 1845: 1841: 1838: 1832: 1829: 1824: 1819: 1815: 1809: 1806: 1786: 1766: 1763: 1760: 1752: 1736: 1716: 1709: 1705: 1702: 1686: 1666: 1658: 1642: 1639: 1636: 1633: 1612: 1603: 1597: 1593: 1590: 1566: 1556: 1540: 1534: 1525: 1515: 1506: 1499: 1491: 1482: 1476: 1471: 1466: 1460: 1454: 1445: 1439: 1431: 1426: 1420: 1417: 1412: 1410: 1396: 1387: 1376: 1370: 1361: 1352: 1343: 1336: 1328: 1319: 1313: 1308: 1303: 1297: 1291: 1285: 1276: 1270: 1261: 1257: 1255: 1241: 1235: 1232: 1225: 1216: 1210: 1199: 1191: 1185: 1174: 1168: 1159: 1150: 1148: 1137: 1104: 1093: 1077: 1069: 1047: 1037: 1033: 1012: 983: 954: 942: 926: 917: 911: 902: 896: 887: 858: 829: 800: 789: 785: 764: 741: 732: 726: 723: 714: 707: 698: 692: 688: 679: 673: 664: 658: 649: 620: 610: 606: 605: 604: 601: 599: 595: 590: 568: 562: 553: 542: 526: 523: 520: 517: 511: 508: 505: 502: 499: 496: 488: 484: 474: 472: 467: 465: 461: 457: 452: 451:for details. 450: 444: 442: 441:orbital plane 438: 434: 430: 425: 423: 412: 410: 409:Space Network 406: 402: 397: 395: 391: 387: 383: 379: 375: 371: 367: 363: 358: 356: 352: 348: 344: 340: 336: 332: 322: 320: 319:minor planets 316: 315:GPS receivers 312: 308: 304: 300: 297: 293: 288: 286: 282: 278: 274: 273:Edmund Halley 270: 266: 265: 261: 256: 254: 250: 246: 242: 238: 228: 226: 222: 218: 214: 209: 205: 201: 197: 193: 189: 188:United States 185: 181: 179: 175: 174:perturbations 169: 167: 162: 158: 154: 150: 146: 142: 138: 136: 132: 128: 120: 110: 107: 99: 88: 85: 81: 78: 74: 71: 67: 64: 60: 57: –  56: 52: 51:Find sources: 45: 41: 35: 34: 29:This article 27: 23: 18: 17: 4391: 4376: 4361: 4346: 4329: 4328:Curtis, H.; 4311: 3574:The sign of 3267:true anomaly 3265:Compute the 2911:Compute the 2234:Compute the 1946:Compute the 1706:Compute the 1068:eccentricity 1034:Compute the 786:Compute the 607:Compute the 602: 480: 468: 453: 445: 426: 418: 398: 382:fourth power 359: 331:observations 328: 296:dwarf planet 289: 262: 257: 234: 182: 170: 166:false alarms 141:Observations 140: 139: 126: 125: 102: 93: 83: 76: 69: 62: 50: 38:Please help 33:verification 30: 1948:inclination 539:, from the 433:prime focus 364:, relative 355:unit vector 347:fixed stars 339:declination 245:Tycho Brahe 96:August 2009 4421:Astrometry 4415:Categories 4345:Taff, L.; 4294:References 301:in 1801. 213:propellant 168:" result. 157:range rate 66:newspapers 4274:→ 4180:− 4175:∘ 4157:⇒ 4111:→ 4102:⋅ 4096:→ 4080:⁡ 4064:⇒ 4051:− 4042:⁡ 4019:→ 4010:⋅ 4004:→ 3976:⁡ 3949:ν 3943:ω 3908:ϕ 3902:⁡ 3887:ϕ 3884:− 3875:⁡ 3857:→ 3848:⋅ 3842:→ 3813:ϕ 3810:− 3801:⁡ 3761:∘ 3748:∘ 3737:∈ 3734:ν 3709:∘ 3692:∈ 3689:ν 3669:ϕ 3626:ν 3603:→ 3594:⋅ 3588:→ 3549:→ 3540:⋅ 3534:→ 3511:ν 3507:− 3502:∘ 3487:ν 3484:⇒ 3463:ν 3438:→ 3429:⋅ 3423:→ 3407:⁡ 3394:ν 3391:⇒ 3381:ν 3378:− 3369:⁡ 3346:→ 3337:⋅ 3331:→ 3309:ν 3303:⁡ 3276:ν 3247:→ 3157:ω 3153:− 3148:∘ 3133:ω 3130:⇒ 3109:ω 3084:→ 3075:⋅ 3069:→ 3053:⁡ 3040:ω 3037:⇒ 3027:ω 3024:− 3015:⁡ 2992:→ 2983:⋅ 2977:→ 2955:ω 2949:⁡ 2922:ω 2866:− 2800:− 2748:⁡ 2716:⁡ 2681:− 2672:⁡ 2657:− 2651:⁡ 2633:⁡ 2607:→ 2490:Ω 2486:− 2481:∘ 2466:Ω 2463:⇒ 2442:Ω 2422:→ 2413:⋅ 2407:→ 2391:⁡ 2378:Ω 2375:⇒ 2365:Ω 2362:− 2353:⁡ 2315:→ 2306:⋅ 2300:→ 2278:Ω 2272:⁡ 2245:Ω 2216:→ 2151:∘ 2134:∈ 2110:→ 2101:⋅ 2095:→ 2079:⁡ 2063:⇒ 2027:→ 2018:⋅ 2012:→ 1984:⁡ 1928:≠ 1889:− 1842:− 1825:μ 1634:μ 1607:→ 1560:→ 1544:→ 1535:⋅ 1529:→ 1516:− 1510:→ 1486:→ 1472:μ 1467:− 1449:→ 1421:μ 1400:→ 1388:μ 1380:→ 1371:⋅ 1365:→ 1353:− 1347:→ 1323:→ 1304:− 1298:μ 1280:→ 1245:→ 1220:→ 1203:→ 1192:− 1186:μ 1178:→ 1169:× 1163:→ 1141:→ 1108:→ 1092:periapsis 1051:→ 1016:→ 987:→ 958:→ 921:→ 912:× 906:→ 891:→ 862:→ 833:→ 804:→ 768:→ 736:→ 718:→ 702:→ 683:→ 674:× 668:→ 653:→ 624:→ 572:→ 557:→ 527:ν 521:ω 515:Ω 269:parabolic 264:Principia 155:, and/or 149:elevation 135:asteroids 1753:, where 370:velocity 366:distance 349:, using 260:Newton's 176:such as 1699:is the 1655:is the 848:, with 790:vector 437:Vectors 415:Methods 285:Lambert 237:planets 231:History 192:optical 145:azimuth 80:scholar 4431:Orbits 4398:  4383:  4368:  4353:  4338:  4233:where 4077:arccos 3646:arccos 3404:arccos 3206:where 3050:arccos 2745:arccos 2713:arccos 2705:, but 2539:where 2388:arccos 2175:where 2076:arccos 1679:, and 1626:where 754:where 277:comets 221:Russia 131:orbits 82:  75:  68:  61:  53:  819:from 464:Ceres 362:radar 360:With 299:Ceres 281:Euler 243:used 225:China 196:radar 161:radar 153:range 87:JSTOR 73:books 4396:ISBN 4381:ISBN 4366:ISBN 4351:ISBN 4336:ISBN 4211:< 3828:and 3555:< 3184:< 2789:and 2566:and 2517:< 1917:(if 1779:and 407:and 388:and 337:and 249:Mars 223:and 194:and 59:news 4171:360 4048:360 4039:cos 3973:cos 3899:tan 3872:cos 3798:sin 3757:360 3744:180 3705:180 3498:360 3375:360 3366:cos 3300:cos 3144:360 3021:360 3012:cos 2946:cos 2863:360 2855:or 2823:cos 2797:360 2678:360 2669:cos 2648:cos 2630:cos 2477:360 2359:360 2350:cos 2269:cos 2147:180 1981:cos 1002:or 485:or 422:Sun 206:. 42:by 4417:: 4302:^ 3881:90 3807:90 3558:0. 1943:). 1070:, 600:. 489:, 462:, 443:. 411:. 357:. 321:. 151:, 147:, 4387:. 4372:. 4357:. 4342:. 4271:r 4246:K 4242:r 4217:, 4214:0 4206:K 4202:r 4193:, 4188:0 4184:u 4167:= 4160:u 4145:, 4140:0 4136:u 4132:= 4128:) 4122:r 4119:n 4108:r 4093:n 4084:( 4074:= 4067:u 4057:) 4054:u 4045:( 4036:= 4030:r 4027:n 4016:r 4001:n 3992:= 3985:) 3982:u 3979:( 3946:+ 3940:= 3937:u 3923:. 3911:) 3905:( 3896:h 3893:= 3890:) 3878:( 3869:v 3866:r 3863:= 3854:v 3839:r 3816:) 3804:( 3795:v 3792:r 3789:= 3786:h 3766:] 3753:, 3740:[ 3714:] 3701:, 3698:0 3695:[ 3600:v 3585:r 3546:v 3531:r 3520:, 3515:0 3494:= 3472:, 3467:0 3459:= 3455:) 3449:r 3446:e 3435:r 3420:e 3411:( 3401:= 3384:) 3372:( 3363:= 3357:r 3354:e 3343:r 3328:e 3319:= 3312:) 3306:( 3244:e 3219:K 3215:e 3190:, 3187:0 3179:K 3175:e 3166:, 3161:0 3140:= 3118:, 3113:0 3105:= 3101:) 3095:e 3092:n 3081:e 3066:n 3057:( 3047:= 3030:) 3018:( 3009:= 3003:e 3000:n 2989:e 2974:n 2965:= 2958:) 2952:( 2894:J 2890:n 2869:A 2843:A 2803:A 2777:A 2757:) 2754:C 2751:( 2725:) 2722:C 2719:( 2693:C 2690:= 2687:) 2684:A 2675:( 2666:= 2663:) 2660:A 2654:( 2645:= 2642:) 2639:A 2636:( 2604:n 2579:J 2575:n 2552:I 2548:n 2523:, 2520:0 2512:J 2508:n 2499:, 2494:0 2473:= 2451:, 2446:0 2438:= 2434:) 2429:n 2419:n 2404:I 2395:( 2385:= 2368:) 2356:( 2347:= 2342:n 2337:I 2333:n 2327:= 2322:n 2312:n 2297:I 2288:= 2281:) 2275:( 2213:h 2188:K 2184:h 2159:, 2156:] 2143:, 2140:0 2137:[ 2131:i 2126:, 2122:) 2117:h 2107:h 2092:K 2083:( 2073:= 2066:i 2054:h 2049:K 2045:h 2039:= 2034:h 2024:h 2009:K 2000:= 1993:) 1990:i 1987:( 1957:i 1931:1 1925:e 1905:, 1897:2 1893:e 1886:1 1882:p 1877:= 1874:a 1855:) 1850:2 1846:e 1839:1 1836:( 1833:a 1830:= 1820:2 1816:h 1810:= 1807:p 1787:a 1767:1 1764:= 1761:e 1737:a 1717:p 1703:. 1687:G 1667:M 1643:M 1640:G 1637:= 1613:| 1604:e 1598:| 1594:= 1591:e 1567:] 1557:v 1550:) 1541:v 1526:r 1520:( 1507:r 1500:) 1492:| 1483:r 1477:| 1461:2 1455:| 1446:v 1440:| 1432:( 1427:[ 1418:1 1413:= 1397:v 1377:v 1362:r 1344:r 1337:) 1329:| 1320:r 1314:| 1309:1 1292:2 1286:| 1277:v 1271:| 1262:( 1258:= 1242:i 1236:e 1233:= 1226:| 1217:r 1211:| 1200:r 1175:h 1160:v 1151:= 1138:e 1105:i 1078:e 1048:e 1013:h 984:k 955:K 944:( 927:. 918:h 903:K 897:= 888:n 859:K 830:h 801:n 765:k 742:, 733:k 727:h 724:= 715:k 708:| 699:h 693:| 689:= 680:v 665:r 659:= 650:h 621:h 569:v 563:, 554:r 543:[ 524:, 518:, 512:, 509:i 506:, 503:e 500:, 497:a 164:" 109:) 103:( 98:) 94:( 84:· 77:· 70:· 63:· 36:.

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orbits
asteroids
azimuth
elevation
range
range rate
radar
false alarms
perturbations
atmospheric drag
Satellite tracking
United States
optical
radar
Joint Space Operations Center
satellite catalog
Collision avoidance
propellant

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