{"id":144,"date":"2024-07-02T13:58:50","date_gmt":"2024-07-02T11:58:50","guid":{"rendered":"https:\/\/csut-new.preprod.lamp.cnrs.fr\/?page_id=122"},"modified":"2025-08-08T13:26:42","modified_gmt":"2025-08-08T11:26:42","slug":"recevoir-entrysat","status":"publish","type":"page","link":"http:\/\/csut.org\/en\/recevoir-entrysat\/","title":{"rendered":"To receive Entrysat"},"content":{"rendered":"<h1 class=\"western\">To Receive EntrySat<\/h1>\n<h2 class=\"western\">The beacon :<\/h2>\n<p align=\"left\">Entrysat plans to remain in orbit for at least six months before launching its scientific mission to study the re-entry environment into the atmosphere. During its operation in orbital mode, Entrysat will emit a beacon every minute. This 50-byte message contains basic information such as the satellite&#8217;s operating mode, supply voltages and currents, and platform temperatures (see below). As it approaches the ground station (Toulouse, France), additional information about the cubesat&#8217;s sensors will be sent to the ground.<\/p>\n<h2 class=\"western\">The radio link :<\/h2>\n<p>The link to the ground uses a BPSK modulation at 9600 baud on the frequency 436.95 MHz in the amateur radio bands. Moreover, Entrysat has an amateur radio call sign ON2FR which is essential for transmitting on this band. There are several ways to receive and demodulate its signal. This is left to each individual&#8217;s discretion to experiment with receiving digital data. However, we propose a solution through an SDR receiver with its software. (<a href=\"http:\/\/gqrx.dk\/\">Gqrx<\/a> of OZ9AEC for inatance) and a demodulation software like <a href=\"http:\/\/uz7.ho.ua\/packetradio.htm\">SoundModem<\/a> of UZ7HO (version G3RUH-BPSK-9K6). The SDR receiver must be in USB mode, with a bandwidth of at least 24kHz and a frequency offset of -12kHz to compensate for the USB offset (or +12kHz if you choose LSB mode)<\/p>\n<p>&nbsp;<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-305 size-full\" src=\"http:\/\/csut.org\/wp-content\/uploads\/2024\/07\/Gqrx.png\" alt=\"\" width=\"941\" height=\"495\" srcset=\"http:\/\/csut.org\/wp-content\/uploads\/2024\/07\/Gqrx.png 941w, http:\/\/csut.org\/wp-content\/uploads\/2024\/07\/Gqrx-300x158.png 300w, http:\/\/csut.org\/wp-content\/uploads\/2024\/07\/Gqrx-768x404.png 768w\" sizes=\"auto, (max-width: 941px) 100vw, 941px\" \/><\/p>\n<h2 class=\"western\">The decoding of the :<\/h2>\n<p>The beacon uses an AX25 frame to deliver a PUS packet according to the ECSS standard. Here is an example of a received frame:<\/p>\n<p>8c 6c 96 a8 82 40 e0 : F6KTA-0 (ASCII&lt;&lt;1)<br \/>\n9e 9c 60 64 8c a4 61: ON02FR-0 (ASCII&lt;&lt;1)<br \/>\n03 f0 : Control Bit \/ Protocol Identifier (fixed)<br \/>\n\u2014\u2014\u2014\u2014\u2014\u2013Information Field \u2014\u2014-<br \/>\n00 00 00 00 : Time not used<br \/>\n\u2014\u2014\u2014\u2014\u2014 TM PACKET\u2014\u2014\u2014\u2014\u2013<br \/>\n08 01 : packet ID<br \/>\nc7 29 : packet sequence control<br \/>\n00 12 : packet length<br \/>\n10 : Spare\/TM source packet number\/ Space (fixed)<br \/>\n03 19 : service \/ service sub_type (3,25)<br \/>\n23 fe bd cd 17 : time (0x23<em>256^3 + 0xfe<\/em>256^2 + 0xbd<em>256 + 0xcd + 0x17<\/em>256^-1) = 2019\/02\/19 @ 13:14:53<br \/>\ntime since 2000\/1\/1 @ 00:00:00<br \/>\n\u2014\u2014\u2014\u2014\u2013SOURCE DATA\u2014\u2014\u2014\u2014\u2014\u2014<br \/>\n06 : SID (6)<br \/>\n00 : Mode Safe<br \/>\nf1 : EPS_VBATT ( 3+0.05\u00d7241 = 15.05V ) Battery Voltage<br \/>\n6b : EPS_BATT_VCURRENT ( -1+0.0078740\u00d7107 = -157.48mA ) Battery consumption<br \/>\n00 : EPS_3.3V Current (0.025\u00d70 = 0A) 3.3V current sink<br \/>\n00 : EPS_5V Current (0.025\u00d70 = 0A) 5V current sink<br \/>\n9e : TRX_TEMP (-15+0.25\u00d7158 = 24.5\u00b0C) Radio Transceiver temperature<br \/>\na0 : EPS_TEMP ( 25 \u00b0C) Power Management module temperature<br \/>\n98 : BATT_TEMP ( 23\u00b0C ) Battery temperature<br \/>\n1f c6 : Packet CRC<br \/>\nb0 : Frame status, AX.25 transfer frame information field (fixed)<br \/>\n09 be fe 23 : Time, AX.25 transfer frame information field, Coded in Little Endian (last packet sent)<\/p>\n<p>In this example, the cubesat is in survival mode. Therefore, it does not consume current on its 3.3V and 5V power lines for the payloads (EPS 3.3V and 5V), Current=0A.<\/p>\n<p>A decoding software has been written by AMSAT-FR and is available for download. It interfaces with the demodulation software through its KISS server.<\/p>\n<p align=\"center\"><a href=\"http:\/\/site.amsat-f.org\/entrysat\/\">Link to the EntrySat Decoder<\/a> (thank you Xtof)<\/p>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>To Receive EntrySat The beacon : Entrysat plans to remain in orbit for at least six months before launching its scientific mission to study the re-entry environment into the atmosphere. During its operation in orbital mode, Entrysat will emit a beacon every minute. This 50-byte message contains basic information such as the satellite&#8217;s operating mode, [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-144","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"http:\/\/csut.org\/en\/wp-json\/wp\/v2\/pages\/144","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/csut.org\/en\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"http:\/\/csut.org\/en\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"http:\/\/csut.org\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/csut.org\/en\/wp-json\/wp\/v2\/comments?post=144"}],"version-history":[{"count":1,"href":"http:\/\/csut.org\/en\/wp-json\/wp\/v2\/pages\/144\/revisions"}],"predecessor-version":[{"id":663,"href":"http:\/\/csut.org\/en\/wp-json\/wp\/v2\/pages\/144\/revisions\/663"}],"wp:attachment":[{"href":"http:\/\/csut.org\/en\/wp-json\/wp\/v2\/media?parent=144"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}