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Simulations of the tracking station. Astro-G link coverage simulation by FAKESAT (1/2). 1 tracking station coverage is 20 - 40 % which is highly depends on small-omega value. Most possible 3 tracking station network (Usuda, Greenbank and Yebes), gives, 55 - 90 % coverage.
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Astro-G link coverage simulation by FAKESAT (1/2) 1 tracking station coverage is 20 - 40 % which is highly depends on small-omega value. Most possible 3 tracking station network (Usuda, Greenbank and Yebes), gives, 55 - 90 % coverage. Missing the tracking station in southern hemisphere (SH), drops the coverage to 50 % time. If we have 3 tracking stations including one SH tracking station, coverage will be 60-80 %, and we can have ideal location of 3 tracking station (2 northern, 1 southern), we can have 80 % coverage for all time.
Astro-G link coverage simulation by FAKESAT (2/2) If we can use the Usuda tracking pass with the elevation angle of more than 10, or 15 degree, (because of its low margin of link budget). Coverage is less than 40 % in some period. (If we can use Tid, the results may be changed.) GTO (higher apogee height) gives better coverage. But the link budget become worse. El limit is critical to decide the coverage, when apogee is in southern hemisphere, if we have only northern tracking station. Tracking station in southern hemisphere is required if we need to keep more then 75-80 % observing time.
Simulation conditions Nominal orbit Apogee 1000km, Perigee 25000km, I = 31 deg Elevation limit Use > 5, 10, 15 for Usuda and > 5 deg (for other tracking station) GTO Apogee 1000km , Perigee 36000km, I = 31 deg Elevation limit Use > 5, 10, 15 for Usuda and > 5 deg (for other tracking station) Elevation limit Use > 10, 15 for Usuda and > 10 deg (for other tracking station) Calculate (small-omega) – (link coverage in 14 days) dependence Assume Usuda, Green Bank, Madrid (Yebes) are basic 3 station Add one southern hemisphere station from Hartebeesthoek, Tidbinbilla, and Santiago Value of Small-omega is defined by initial of 14 days
Coverage of the single tracking station • Nominal orbit (Apogee: 25,000 km, Perigee: 1,000 km I=31) • Usuda with EL limit of (5, 10, 15 degree) • Coverage by Usuda, Gbank, Madrid, • Hart, Santiago, Tidbinbira • El limit = 5 deg
Coverage by 3 stations • Nominalorbit Usuda + Greenband +Madrid (with changing Usuda El limit) All EL > 5 All EL > 5 Usuda + Greenbank + (Southern TS or Madrid) Usuda + Madrid + (Southern TS or Greenbank)
Four stations • Nominal orbit • Usuda+Greenbank+Madrid (+ Southern TS) • El > 5 for TS, except for Usuda Usuda EL < 5 Usuda EL < 10 Usuda EL < 15
GTO (Geo-stationally orbit Transfer Orbit) • GTO • (Apogee: 36,000 km, • Perigee: 1,000 km I=31) Red: Normal, U+G+M (EL > 5) Red: Normal, U+G+M (EL > 5) Red: Normal, U+G+M (EL > 5) GTO: Usuda EL < 5 GTO: Usuda EL < 15
GTO • Usuda EL>10,15deg • Others EL>10deg Red: Normal, U+G+M (EL > 5) GTO: Usuda EL < 10 GTO: Usuda EL < 15