Re: [討論] SpaceX日前發射Falcon 9火箭的不常見畫面

看板Military作者cppwu (肩膀痠痛 ..)時間4年前 (2019/06/15 17:25)推噓6(6推 0噓 21→)

留言27則, 5人參與討論串4/9 (看更多)

提供資料參考: SpaceX Falcon User Guide / Jan 2019 https://www.spacex.com/sites/spacex/files/falcon_users_guide_0619.pdf 2.5 AVIONICS, AND GUIDANCE, NAVIGATION AND CONTROL Falcon avionics feature a flight-proven, three-string, fault-tolerant architecture that has been designed to human-rating requirements. Avionics include flight computers, Global Positioning System (GPS) receivers, inertial measurement units, SpaceX-designed and manufactured controllers for vehicle control (propulsion, valve, pressurization, separation and payload interfaces), a network backbone, S-band transmitters and a C-band transponder for range safety tracking. The S-band transmitters are used to transmit telemetry and video to the ground, from both the first and second stages, even after stage separation. Our launch vehicles are equipped with an autonomous flight termination system to limit the potential damage caused by a launch vehicle malfunction. The system terminates the flight of the vehicle automatically if mission rules are violated. 看起來確實是 GPS / 慣性導航為主 ... 那來看看 RF 特性, 有沒有什麼可疑的: 4.3.6.1 RF SYSTEM CHARACTERISTICS Falcon launch vehicles include several radio frequency (RF) systems, which are summarized in Table 4-10 for Falcon 9 and Table 4-11 for Falcon Heavy. Part Description TX/RX Frequency 99% Bandwidth Modulation (transmitter/receiver) (MHz) (MHz) S1TX1 Telemetry Transmitter TX 2209.0 4.84 PCM/FM S1TX2 Telemetry Transmitter TX 2255.5 4.84 PCM/FM S2TX1 Telemetry Transmitter TX 2232.5 4.14 PCM/FM S2TX2 Telemetry Transmitter TX 2272.5 4.14 PCM/FM GPS Receiver RX 1575.42 20 BPSK DSSS Iridium/GPS Tracker TX 1610 - 1626.5 0.042 BPSK/QPSK Iridium/GPS Tracker RX 1610 - 1626.5 0.042 QPSK Iridium/GPS Tracker RX 1575.42 20 BPSK DSSS S-Band BPSK Receiver RX 2090 - 2093 1 BPSK Radar Altimeter TX 4235 - 4275 40 FMCW Radar Altimeter TX 4325 - 4365 40 FMCW Radar Altimeter TX 4250 - 4350 100 FMCW Radar Altimeter RX 4235 - 4275 40 FMCW Radar Altimeter RX 4325 - 4365 40 FMCW Radar Altimeter RX 4250 - 4350 40 FMCW 這個表可以證明, F9 確實有 GPS 和雷達高度計, 但可疑的是那個 S-Band BPSK Receiver, 可以從 4.3.6.3 裡查的到用途: 4.3.6.3 MAXIMUM SPACECRAFT EMISSIONS (這個章節主要是規範 Payload, 避免 Payload 發射的射頻信號干擾 F9 的 RF 接收) Table 4-14 Maximum spacecraft emissions Range (MHz) E Fi eld Limit(dBμV/m) Launch Vehicle Receive System 1.0 – 1565.42 120.0 1565.42 – 1585.42 48.0 GPS L1 1585.42 – 2090.0 1 20.0 2090.0 – 2093.0 70.0 Stage 1 Telecommand 2093.0 – 18000.0 120.0 2090 - 2093 MHz 頻率符合, 用途是 Stage 1 Telecommand, 很可疑 .. 接下來, 來找 SpaceX 過去因發射而向 FCC 申請的射頻使用許可: https://fcc.report/ELS/Space-Exploration-Technologies-Corp-SpaceX/ 1003-EX-ST-2018 https://tinyurl.com/y38suzku 果然, 有個 2090MHz / 600Kbps, 誰在用呢 ? 1. Cape Canaveral AFS 2. Autonomous Drone Ship, within 10 nautical miles 射源是 LZ-1/LZ-2 和無人船降落平台這些 Stage 1 會降落的地點 .. 但 Output Power 是小的可憐的 0.6W ... -- ※ 發信站: 批踢踢實業坊(ptt.cc), 來自: 114.32.224.67 (臺灣) ※ 文章網址: https://www.ptt.cc/bbs/Military/M.1560590704.A.68E.html ※ 編輯: cppwu (114.32.224.67 臺灣), 06/15/2019 17:28:55

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