GPSでどのようにして現在地が分かるのか

iOSDC2024 Day0
https://fortee.jp/iosdc-japan-2024/proposal/d9070852-4d5c-4af3-a8de-ee7050fe36ea

Transcript

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11. ߤ๏ϝοηʔδ 1 C/A ʜ 20 C/A 1 Bit ʜ 300 Bit 1 Subframe ʜ 5 Subframe 20ms 6s يಓΤϨϝϯτ 30s ൃ৴࣌ࠁ
12. Ґஔ͕ܾ·Βͳ͍ͱ͖ wి೾ͷ୳ࡧ
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13. ݱࡏ஍ΛٻΊ͍ͯ͘ 🛰 SvID: 12 🛰 SvID: 15 🛰 SvID: 23 🛰 SvID: 24 ػͷαϒϑϨʔϜΛ ϩά͔Βऩू͢Δ
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17. Жඵ୯Ґͷܭଌ $"ίʔυͷλΠϛϯάͰЖඵ୯Ґͷ͕࣌ࠩΘ͔Δ
18. يಓΤϨϝϯτ e ཭৺཰ 㲋A يಓ௕൒ܘ 🛰 i0 يಓ܏ࣼ֯ Ω0 ঢަ఺੺ܘ ω ۙ஍఺Ҿ਺ ۙ஍఺ 🌎 M0 ฏۉۙ఺֯
19. 🛰 SvID: 12 √A = 5153.6 e = 0.0086532 i0 = 0.96156 Ω0 = -1.3823 ω = 1.4596 M0 = -2.4836 🛰 SvID: 15 √A = 5153.7 e = 0.015987 i0 = 0.93637 Ω0 = 2.5828 ω = 1.3401 M0 = 0.10739 🛰 SvID: 23 √A = 5153.6 e = 0.0045318 i0 = 0.98011 Ω0 = 1.6629 ω = -2.9633 M0 = -2.0696 🛰 SvID: 24 √A = 5153.7 e = 0.015681 i0 = 0.9342 Ω0 = -2.5968 ω = 0.9968 M0 = -0.78405
20. 🛰 🛰 🛰 🛰 SvID: 12 SvID: 24 SvID: 23 SvID: 15 22,297km 20,198km 20,424km 21,415km