ʻŌnaehana Kamaʻilio Ukali Geostationary
ʻO nā ʻōnaehana kamaʻilio ukali geostationary kekahi o nā iwi kuamoʻo o ke kahua kamaʻilio hou, e hiki ai ke hoʻolaha kīwī, nā kelepona mamao loa, nā kamaʻilio ʻikepili, a me ka pilina pūnaewele ma nā wahi mamao. ʻAʻole e like me nā pūnaewele terrestrial e hilinaʻi nei i nā kaula fiber-optic a i ʻole nā hale kiaʻi transmitter, hoʻohana nā ʻōnaehana ukali i nā kikowaena lewa e hōʻike a hoʻouna paha i nā hōʻailona lekiō ma luna o kahi ākea ākea. Ma waena o nā ʻano o nā orbits ukali like ʻole, ʻo ka orbit geostationary (GEO) kahi koho kaulana no ka mea ke ʻano o ka ukali "kū" e pili ana i ka ʻili o ka Honua, e maʻalahi ai ka hoʻoponopono ʻana i nā antennas ma nā kikowaena honua.
Ka wehewehena a me nā ʻano o ka orbit geostationary
ʻO ka orbit geostationary he orbit pōʻai ma luna o ka equator ma kahi kiʻekiʻe o 35.786 kilomita ma luna o ka ʻili o ka Honua. Ma kēia kiʻekiʻe, ua like ka manawa hoʻohuli o ka satelite me ka manawa hoʻohuli o ka Honua (ma kahi o 23 mau hola a me 56 mau minuke), no laila ke ʻano o ka satelite ma kahi kūlana paʻa ke nānā ʻia mai kahi kiko ma ka Honua. I nā huaʻōlelo ʻē aʻe, "kau" ka satelite ma luna o kahi kikoʻī o ka longitude. ʻO kekahi ʻano koʻikoʻi ʻo ia ka liʻiliʻi o ka orbital inclination (kokoke i 0 degere), no ka mea, pono ke satelite ma luna pono o ka equator i ʻole e neʻe i luna a i lalo mai ka nānā ʻana o kahi kahua honua.
ʻO ka pōmaikaʻi nui o ke kūlana geostationary ka maʻalahi o ka hahai ʻana. ʻAʻole pono nā kīʻaha ukali ma ka home a i ʻole ma nā kahua honua i nā ʻōnaehana kuhikuhi ponoʻī paʻakikī; hiki ke kuhikuhi wale ʻia lākou i kahi kiko paʻa i ka lewa. Eia nō naʻe, he mau palena ko kēia orbit, e like me ka helu palena o nā slot orbital a me ka lohi hōʻailona kiʻekiʻe (latency) ma mua o nā satelite orbit haʻahaʻa.
Nā ʻāpana nui o ka ʻōnaehana kamaʻilio ukali GEO
ʻO ka maʻamau, aia nā ʻōnaehana kamaʻilio ukali geostationary i ʻekolu mau ʻāpana nui: ka ʻāpana lewa, ka ʻāpana honua, a me ka ʻāpana kaohi.
1. ʻĀpana ākea
ʻO kēia ʻāpana e komo pū ana me ka satelite ponoʻī a me kāna ukana kamaʻilio. ʻO ka ukana maʻamau he transponder—kahi ʻāpana e loaʻa ana nā hōʻailona mai ka Honua (uplink), hoʻonui iā lākou, hoʻololi i ko lākou alapine (frequency), a laila hoʻihoʻi iā lākou i ka Honua (downlink). Ma waho aʻe o ka transponder, loaʻa pū i ka satelite kahi antenna (beam), kahi ʻōnaehana mana (nā panela solar a me nā pila), kahi ʻōnaehana hoʻomalu ʻano, a me kahi ʻōnaehana propulsion e mālama i ke kūlana orbital (stationkeeping).
2. Nā ʻāpana honua
ʻO ka ʻāpana honua e komo pū ana me nā kikowaena honua puka komo, nā kikowaena pūnaewele, nā kikowaena Very Small Aperture Terminal (VSAT), nā kīʻaha ukali mea hoʻohana, a me nā mea hana modulation/demodulation e like me nā modem ukali. Hoʻouna nā kikowaena honua i nā hōʻailona a loaʻa nā hōʻailona mai ka ukali. Hiki i nā kikowaena mea hoʻohana ke lilo i mau mea hana hale no ke TV ukali, nā kikowaena pūnaewele ukali, a i ʻole nā kikowaena koa a me ke kai kūikawā.
3. ʻĀpana hoʻomalu
ʻO kēia ʻāpana e komo pū ana me ke kikowaena hoʻomalu ukali, ka mea e nānā i ke olakino ukali, hoʻokele i ka telemetry, hoʻokō i nā telecommands, a hana i nā hoʻoponopono orbit a me ke kuhikuhi. Me ka ʻole o ka ʻāpana hoʻomalu, pilikia kahi ukali e heleleʻi ana mai kona orbit a i ʻole e ʻike i nā hoʻopilikia hana.
Kumu hana kamaʻilio: uplink a me downlink
Hana nā kamaʻilio ukali geostationary ma ke kumumanaʻo o ka relay radio. Hoʻouna ʻia nā hōʻailona mai kahi kahua honua i ka ukali ma o kahi uplink. Ke loaʻa, hoʻonui ka transponder ukali a hana i ke alapine, a laila hoʻouna hou i ka hōʻailona i ka wahi uhi ma o kahi downlink. He mea nui ka hoʻokaʻawale ʻana o nā alapine uplink a me downlink e pale aku i ka hoʻopilikia ʻana o ka hōʻailona. No ka laʻana, ma ka hui Ku, hiki i ka uplink ma kahi o 14 GHz a me ka downlink ma kahi o 12 GHz.
Ma waho aʻe o nā kamaʻilio ala hoʻokahi (e.g., nā hoʻolaha kīwī), kākoʻo pū nā ʻōnaehana GEO i nā kamaʻilio ala ʻelua, e like me ka pūnaewele a me ke kelepona. Ma kahi ʻōnaehana ala ʻelua, hoʻouna kahi kikowaena mea kākau inoa i kahi noi ʻikepili i ka satelite a loaʻa kahi pane ma o ke kahawai like e hele ana ma o ka satelite.
Nā kaula alapine i hoʻohana pinepine ʻia
Hana nā ʻōnaehana kamaʻilio ukali GEO ma nā ʻano alapine like ʻole, kēlā me kēia me nā ʻano kikoʻī:
– C band (ma kahi o 4–8 GHz): ʻoi aku ka paʻa i ka ua (ua mae), kūpono no nā wahi wela, akā koi ʻia kahi antenna nui aʻe.
– Ku band (ma kahi o 12–18 GHz): nā antennas liʻiliʻi a kaulana no ke TV ukali a me VSAT, akā ʻoi aku ka maʻalahi i ka emi ʻana o ke aniau.
– Ka band (ma kahi o 26–40 GHz): hāʻawi i ka bandwidth nui aʻe no nā lawelawe pūnaewele wikiwiki, akā ʻoi aku ka maʻalahi i ka hoʻopilikia ʻana o ka lewa.
Ke koho ʻana i nā kaula alapine (frequency) e noʻonoʻo ana i nā koi o ka mana, nā kūlana o ke aniau, nā kumukūʻai o nā lako, a me nā hoʻoponopono spectrum ma kēlā me kēia ʻāina.
Nā Pōmaikaʻi o nā satelite geostationary
Aia kekahi mau pono koʻikoʻi e pili pono ai nā satelite GEO:
1. Uhi ākea
Hiki i kahi satelite GEO hoʻokahi ke uhi i kahi ākea, a hiki i ka hapakolu o ka ʻili o ka Honua. Me ʻekolu mau satelite i hoʻonoho pono ʻia, hiki ke lawelawe ʻia ka ʻili o ka Honua holoʻokoʻa (koe naʻe nā wahi polar loa).
2. Antenna mea hoʻohana maʻalahi
Ma muli o ke ʻano o ka satelite e kū nei, ʻaʻole pono ka antenna i ka hahai ʻana i ka dynamic. Hoʻemi kēia i ka paʻakikī o ke kikowaena a me ke kumukūʻai.
3. Kūpono no ka hoʻolaha ʻana
No nā hoʻolaha TV a me nā lekiō, he kūpono loa ʻo GEO no ka mea hiki i nā miliona o nā mea hoʻohana ke loaʻa i hoʻokahi hoʻoili ʻana ma kahi like.
4. ʻO ke kahua wikiwiki ma nā wahi mamao
Ma nā wahi i paʻakikī ai ke kiʻi ʻana i nā pūnaewele uwea, he hopena kūpono nā satelite no ka hāʻawi ʻana i nā kamaʻilio maʻamau.
Nā palena a me nā pilikia
ʻOiai kona uhi ʻoi aku ka maikaʻi, he nui nā pilikia o nā ʻōnaehana GEO:
1. Ka lohi kiʻekiʻe
Ma muli o nā mamao lōʻihi, pono nā hōʻailona i ka manawa huakaʻi lōʻihi. Hiki i kahi huakaʻi hele a hoʻi ma kahi o 500-700 milliseconds, kahi mea i ʻike ʻia ma nā noi manawa maoli e like me nā pāʻani pūnaewele a i ʻole nā kelepona wikiō inā ʻaʻole i hoʻonohonoho pono ʻia.
2. Nā haunaele o ke aniau
Hiki i ka ua nui, ʻoiai ma nā hui Ku a me Ka, ke hoʻohaʻahaʻa i ka maikaʻi o ka hōʻailona. No ka hoʻoponopono ʻana i kēia, hoʻohana ʻia nā ʻano hana e like me ke adaptive coding a me ka modulation, ka hoʻonui ʻana i ka mana, a me ka hoʻolālā hoʻolālā loulou kūpono.
3. Nā wahi hoʻohele palena ʻia
He kumuwaiwai palena ʻia ke kūlana geostationary. Mālama ʻia kona hoʻoponopono ʻana e ka ITU (International Telecommunication Union) a me nā mea hoʻoponopono aupuni e pale aku i ka hoʻopilikia ʻana ma waena o nā satelite.
4. Nā kumukūʻai hoʻokuʻu a me ka hana ʻana kiʻekiʻe
He nui nā satelite GEO, he lōʻihi ko lākou ola hana (ʻo 15 mau makahiki maʻamau), a koi i nā kaʻa hoʻokuʻu ikaika. ʻO kēia ka mea e nui ai ka hoʻopukapuka mua, ʻoiai hiki ke kūpono ke kumukūʻai no kēlā me kēia mea hoʻohana no ka lawelawe nui.
Nā noi nui o nā ʻōnaehana kamaʻilio ukali GEO
He ākea loa ka hoʻohana ʻana o nā satelite geostationary, me:
– Nā hoʻolaha kīwī a me nā lekiō (DTH/Direct-to-Home)
– Nā pūnaewele VSAT no ka panakō, kūʻai liʻiliʻi a me ka ʻoihana
– Hoʻihoʻi kelepona ma nā wahi mamao a mokupuni paha
– Nā kamaʻilio moana a me nā mokulele
– Nā kamaʻilio ulia pōpilikia i ka wā o nā pōpilikia ke hōʻino ʻia nā ʻōnaehana honua
– ʻO ka lawelawe pūnaewele ukali kiʻekiʻe (HTS)
ʻO ka ʻenehana Satellite Throughput High e ʻae i ka hoʻonui ʻana i ka mana ʻikepili ma o ka hoʻohana ʻana i nā kukuna kiko a me ka hoʻohana hou ʻana i ke alapine (frequency), e ʻae ana i nā lawelawe pūnaewele GEO e hoʻokūkū no nā pono kikoʻī, ʻoiai ma nā wahi i loaʻa ʻole ai ka fiber.
Pani
He ʻenehana koʻikoʻi nā ʻōnaehana kamaʻilio ukali geostationary no ka hoʻopili pono ʻana i nā wahi ākea. Me nā satelite e kū nei i ka lewa, hoʻomaʻalahi kēia mau ʻōnaehana i ka ʻike mea hoʻohana a hiki i nā lawelawe hoʻolaha a me ka pilina ma waena o nā ʻāpana. ʻOiai nā pilikia e like me ka latency kiʻekiʻe, ka hoʻopilikia ʻana o ke aniau, a me nā kumukūʻai hoʻopukapuka kālā kiʻekiʻe, ʻo nā hana hou e like me nā satelite hiki ke kiʻekiʻe, nā ʻano hana modulation adaptive, a me ka hoʻokele spectrum i hoʻomaikaʻi ʻia e hoʻomau i ka hoʻoikaika ʻana i ke kuleana o GEO i loko o ka ʻōnaehana kamaʻilio honua. I ka wā e hiki mai ana, e noho mau nā satelite GEO i kahi hopena hoʻolālā, me nā satelite orbit haʻahaʻa (LEO) a me nā pūnaewele terrestrial e hana i nā lawelawe kamaʻilio ākea a hilinaʻi hoʻi.
