ISS-PCsat JOINT CONSTELLATION TEST 28 Oct 2002 -------------------------------------------------------------------------- WB4APR On 10 October the ISS crew changed the ARISS packet radio system frequency from 145.800 to the PCsat frequency of 145.825 for the first experiments in the Amateur Satellite Service with two digital communications spacecraft operating in constellation with each other. Both spacecraft were configured to relay digital packets between ground users and each other to accomplish the following objectives: 1) Doubling the channel access times for all users from as low as 50 minutes (6 passes a day) with a single spacecraft to as much as 2 hours (12 passes a day) with both. 2) Operating identically and generically so that users could communicate with their same station configuration independently of which spacecraft was in view. 3) Operating as a constellation of two for satellite-to-satellite relay of user communications to extend the terrestrial range over greater distances or from continent to continent. 4) Operating in support of ech other so that one spacecraft could relay to ground stations over the horizon, the telemetry from the other. 5) Operating synergistically with dozens of worldwide fixed-tuned, no-track-omni internet linked ground stations providing near worldwide live connectivity to anyone with a browser to monitor the mutual downlinks. (www.ariss.net and pcsat.aprs.org). 6) Establishing a baseline verification of ISS antenna, transmitter and receiver performance by comparison with known ERP, antenna and sensitivity measurements on PCsat. TEST LIMITATIONS: As an experiment of opportunity, there were several limitations on the conditions of the test. First PCsat was in a maximum eclipse phase, and was only working in sunshine. Second, the phases of PCsat and ISS in their orbits were as-is, so joint periods when they wre both in line-of- sight with each other were occuring randomly and often over areas where PCsat was in the dark, or where there were no ground station observers. Third the ISS PMS was not on the 145.825 frequency of operational all the time. TEST RESULTS: (see http://www.ew.usna.edu/~bruninga/pcsat.html) Even with these limitations, the test was a great success with the following highlights: 1) On 12 October over the East coast of the USA, 6 stations relayed successful packets between both spacecraft while they were within 260 to 600 miles of each other. One station was a mobile. Multiple successful packets were captured as well into the internet linked ground station system. 2) On 22 October over the USA, another 7 stations were successful and the successful ranges between spacecraft ranged between 260 to 1880 miles. Further highlights were: * New satellite-to-satellite distance record of 1880 miles. * DX record was made by a mobile operator while driving (in motion). * Successful sat-to-sat packet from a hiker with a handheld radio. * Successes despite lack of optimization of PCsat early in the pass. * PCsat successfuly reported its telemetry over the horizon via ISS. * Packets were received by the worldwide internet linked ground stns. * Generic spacecraft operation demonstrated by identical relay of the same source packet into both satelliite footprints. 3) These tests confirm the link-budget of omni-directional satellite-to- satellite links using the installed ISS and PCsat antenna systems and nominal 2 and 5 watt ERP systems. 4) This test demonstrated the viability of operating numerous 145.825 UI-Digipeating satellites in a loose constellation in the Amateur Satellite Service to provide near continuous and remote area low data rate communications from simple (mobile and handheld) stations. Using generic relay aliases and routing, all such satellites operate synergisitically to support users on the ground transparently to their individual settings. 5) The test validated the worldwide system of simple fixed frequency, omni-directional (no-track) internet linked ground stations combined with the synergy of multiple spacecraft to provide near global connectivity between the mobile/remote user and the global infrastructure. CONCLUSION: The test was a success. It demonstrated that just a few, or as many as 10 such satellite transponders can be accommodated on the single 145.825 frequency with out problem while providing near continuous global coverage to handheld, mobile, educational and other simple ground stations in the Amateur Satellite Service. Bob Bruninga, WB4APR Senior Research Engineer US Naval Academy Satellite Lab END EXECUTIVE SUMMARY-------------------------------------------------- ADDITIONAL REPORT DETAILS: DUAL HOP GEOMETRY: In general, ISS and PCsat were within range of each other about 4 hours a day. This ranges from 5400km grazing passes to 420km when PCsat is directly overhead ISS. For reliable comms, this test has validated about 2000km as the limit or about an hour a day. But with HAM activity in only about 10% of the Earth's surface, the probabiliy of good geometry for a dual hop is rare. But dual hop is not really a primary objective of a multisatellite constellation over populated areas because all packets are heard by numerous internet linked ground stations and eventually are distributed worldwide anyway. The advantage of dual hop paths are over the Oceans and Poles, where remote travelers will be able to link remote packets two hops to the nearest IGate. ISS AVAILABILITY: During this test, the ISS PMS system was occassionally moved back to the primary 145.800 freqequency for voice and also the PMS appears to have locked up twice for long periods as shown below. This PMS activity log was gathered with the help of Miles, WF1F. 8 Oct ARISS TELCOM confirmed test was still a go 10 Oct 1715z PMS heard on 145.825 2150z Was back on 145.800 voice pass over USA 12 Oct 1556z SUCCESful dual hop packets on 145.825 14 Oct 1300? last time heard on any frequency 15 Oct ..... Nothing heard 16 Oct ..... Nothing heard 17 Oct ..... Nothing Heard 18 Oct ..... Nothing heard 19 Oct ..... Nothing heard 20 Oct ..... Nothing heard 21 Oct 0735z Packet back on 145.825 22 Oct 0152z Valery heard on voice and had found PMS locked up 2001z SUCCSESSFUL dual hop tests on 145.825 2300z Valery on voice on 145.800 23 Oct 1653z Back on 145.825 24 Oct 1108z On 145.825 25 Oct 2045z Last time heard on any frequency 26 Oct ..... Nothing heard 2237z Packet back on 145.825 27 Oct 1830z Back on packet 145.825 2020z Valery on voice on 145.800 28 Oct 0000z Scheduled End of joint ISS/PCsat tests 1940z ISS still on 145.825 The Following two sections are the detail reports for the two successful opportunities... ------------------------------------------------------------------------ Date: Sat, 12 Oct 2002 18:06:24 -0400 (EDT) From: Bob Bruninga Subject: [aprssig] Dual Hop SUCCESS! (corrected copy) ISS<==>PCSAT SUCCESS: This was a pass of ISS and PCsat over USA with PCsat almost directlly overhead of ISS over Canada. To fit in 80 character Email, the first data is truncated to Header andtruncated text and the second list is just the CALLSIGN and the DATA part of the successful packets. These times are within 1 second of UTC. At 19:56:15 or so (12 Oct), PCsat passed DIRECTLY 420 km over ISS and this was about 100km NW of Natashquan, Quebec. A minute 48 seconds earlier, N4ZQ got the first successful packet and 40 seconds after the conjunction, a series of successes lasted for another minute. By that time the separation between ISS and PCsat was about 960 km. Although ISS and PCsat were in view over the entire USA, these succeses occured after most of the USA was no longer in view. The next pass was also directly over USA, but ISS had switched back to voice on 145.800 and so no packet tests were possible. But we did get to talk to Valery and thank him for the test. Here are the successful double hop packets. [19:54:24] N4ZQ>QST,W3ADO-1,RS0ISS*,SGATE,WIDE<>: [19:56:58] KB1GVR>CQ,RS0ISS*,W3ADO-1/1:=4436.18N/06826.92W-> QSL TEST [19:56:59] KB1GVR>CQ,RS0ISS,W3ADO-1*/1:=4436.18N/06826.92W-> QSL TEST [19:57:05] KB2M-3>SYQQ0W,W3ADO-1*,RS0ISS/1:'fH~l j/]www.qsl.net/kb2m [19:57:06] KB2M-3>SYQQ0W,W3ADO-1,RS0ISS*/1:'fH~l j/]www.qsl.net/kb2m [19:57:09] KB1GUE>CQ,RS0ISS*,W3ADO-1,SGATE,WIDE/1:>FN42IL/- CQ from Glenn [19:57:10] KB1GUE>CQ,RS0ISS,W3ADO-1*,SGATE,WIDE/1:>FN42IL/- CQ from Glenn [19:57:16] KB2M-5>APRSAT,RS0ISS*,W3ADO-1/1:=3911.01N/07445.00W`www.qsl... [19:57:17] KB2M-5>APRSAT,RS0ISS,W3ADO-1*/1:=3911.01N/07445.00W`www.qsl... [19:57:28] WB4APR>APRS,RS0ISS*,W3ADO-1,ARISS/1::ALL :TEST in [19:57:29] WB4APR>APRS,RS0ISS,W3ADO-1*,ARISS/1::ALL :TEST in [19:57:58] KB2M-5>APRSAT,RS0ISS*,W3ADO-1/1:=3911.01N/07445.00W`www.qsl... [19:57:58] KB2M-5>APRSAT,RS0ISS,W3ADO-1*/1:=3911.01N/07445.00W`www.qsl... Since the above were truncated to fit the 80 column format, here is the full text of those same successful packets. KB1GVR> :=4436.18N/06826.92W-> QSL TEST KB1GUE> :>FN42IL/- CQ from Glenn in Bedford Mass. - KB1GUE@amsat.org WB4APR> ::ALL :TEST in progress KB2M-5> :=3911.01N/07445.00W`www.qsl.net/kb2m Notice that packets went BOTH ways between the spacecraft. One other station, KB1EAA inadvertantly got a Triple hop, but with a ground station inbetween because he had a WIDE on the end of his path (which we have recommended for better IGate success once the packet reaches the ground). But in this case, with ISS also having the WIDE alias, it went back up via satellite! [15:54:19] KB1EAA>APK002,W3ADO-1,SGATE,RS0ISS*/1::PCSAT :HI{9 For this pass, PCsat was not commanded into optimum configuration until about the middle of the pass but it was in proper mode and fully functional with enough power by the time of the successful packets! de WB4APR@amsat.org, Bob ---------------------------------------------------------------------- Date: Tue, 22 Oct 2002 20:47:26 -0400 (EDT) Date: Tue, 22 Oct 2002 23:50:12 -0400 (EDT) <= a later update> From: Bob Bruninga Subject: [aprssig] Joint ISS/PCsat dual hop success (2) (UPDATE) On 22 October from 2001z to 2013z both ISS and PCsat were in view of the USA. Dual hop packets reported are below: Long packets are truncated to make them fit an 80 column Email format: [20:01:16] K7FZO-1>4W3YVV,RS0ISS,W3ADO-1*,SGATE,WIDE:'2^Al#1k/]"41}@arrl.net [20:01:30] K7FZO-1>4W3YVV,RS0ISS,W3ADO-1*,SGATE,WIDE:'2^Al#1k/]"41}@arrl.net [20:02:11] K7FZO-1>4W3YVV,RS0ISS,W3ADO-1*,SGATE,WIDE:'2^Al#1k/]"4/}@arrl.net [20:02:53] K7FZO-1>4W3YVV,RS0ISS,W3ADO-1*,SGATE,WIDE:'2^Al#1k/]"40}@arrl.net [20:03:06] K7FZO-1>4W3YVV,RS0ISS,W3ADO-1*,SGATE,WIDE:'2^Al#1k/]"41}@arrl.net [20:03:36] K7FZO-1>4W3YVV,RS0ISS,W3ADO-1*,SGATE,WIDE:'2^Al#1k/]"40}@arrl.net [20:05:12] K7FZO-1>4W3YVV,RS0ISS,W3ADO-1*,SGATE,WIDE:'2^Al#1k/]"42}@arrl.net [20:05:42] COMAND-1*>WB4APR-3 prompt:OUTPUT was 11111111,0111,1) [20:06:21] W3ADO-1*>BEACON,SGATE:T#020,165,165,067,219,213,00111111,0111,1 [20:06:25] COMAND-1*>WB4APR-3:TELEMTRY was WAIT 6/WAIT 18 [20:07:43] WB6OLA]CM99GK,W3ADO-1,RS0ISS*,qAR,WB0WNX:Hi WD5EEV [20:08:09] WD5EEV>CQ,W3ADO-1>RS0ISS*:] de John [20:08:09] K7FZO-7>TWRWYS,W3ADO-1,RS0ISS*,WIDE3-3:'1Dol [/> [20:08:18] WB6OLA>CM99GK,W3ADO-1,RS0ISS*: [20:08:22] K7FZO-7>TWRWYS,W3ADO-1,RS0ISS*,WIDE3-3:'1Dol [/>Thom's D7 v146.52 [20:08:25] W3ADO-1>BEACON,RS0ISS*:T#022,079,067,077,101,213,00111111,0101,1 [20:08:31] K7FZO-1>4W3YVV,W3ADO-1,RS0ISS*,WIDE:'2^Al#1k/]"4.}k7fzo@arrl.net [20:08:33] N4ZQ>QST,W3ADO-1,RS0ISS*: [20:08:36] N8IGJ>CQ,RS0ISS,W3ADO-1*,WIDE: [20:08:40] K7FZO-7>TWRWYS,W3ADO-1,RS0ISS*,WIDE3-3:'1Dol [/> [20:08:40] W3ADO-1>ID,RS0ISS*:W3ADO-1/R XBAUD/G MAIL-1/B [20:08:49] K7FZO-1>4W3YVV,W3ADO-1,RS0ISS*,WIDE:'2^Bl#1k/]"4/}k7fzo@arrl.net [20:08:52] RS0ISS*>CQ,SGATE:>ARISS - International Space Station [20:09:02] N8IGJ>RS0ISS>W3ADO-1*>WIDE>CQ: [20:09:20] WB4APR-3>APRS,W3ADO-1,RS0ISS*,ARISS: Ping...# 2 [20:09:20] WF1F>MILES,W3ADO-1,RS0ISS*: [20:09:37] N8IGJ>CQ,RS0ISS,W3ADO-1*,WIDE/1: [20:09:39] WF1F>MILES-3,W3ADO-1,RS0ISS*: I got a doble ping [20:09:43] WB6OLA>CM99GK,W3ADO-1,RS0ISS*:Hello de Carl in Chico,Ca [20:09:39] WF1F>MILES,W3ADO-1,RS0ISS*/1:I got a doble ping [20:09:43] WB6OLA>CM99GK,W3ADO-1,RS0ISS*/1:Hello de Carl in Chico, Ca [20:09:52] WB4APR-3>APRS,W3ADO-1,RS0ISS*,ARISS/1:Lets try OPS NORMAL for a while [20:09:52] WB4APR-3>APRS,W3ADO-1,RS0ISS*,ARISS/1:Ping...# 3 [20:13:59] KB1GVR>CQ,RS0ISS,W3ADO-1*/1:=4436.18N/06826.92W-> Ellsworth ME6 The first packet was a DX record for satellite-to-satellite packet of 1880 miles between spacecraft. To see the geometries involved, see the maps on the PCsat web page below. http://www.ew.usna.edu/~bruninga/pcsat.html In the above dual-hop packets between ISS and PCsat, there are a few packets of special interest that deserve comment: The first packets were when ISS was out over the pacific with only the west coast in view, thus there was little interference for the numerous (7) easy DX successes (the first was over 1880 mi): This packet decodes as a packet from a mobile IN MOTION in Seattle, WA: > [20:01:16] K7FZO-1>4W3YVV,RS0ISS,W3ADO-1*,SGATE,WIDE:'2^Al#1k/]"41}@arrl The next packet below documents when the USNA Ground station set PCsat to optimum power mode (after those initial packets). The 7 previous successful packets shows us that PCsat can support dual hop packets even without command station support (placing it in best power mode). > [20:05:42] COMAND-1*>WB4APR-3 prompt:OUTPUT was 11111111... The next packet shows the Batterys almost fully charged at 16.5 volts each! But these are very weak NiCd's that are "soft" and near the end of their life, so a high voltage under charge doesnt really mean things are all that great... and the telemetry counter of #020 shows us it has only been alive for 20 minutes even though it has been in the sun almost 40. > [20:06:21] W3ADO-1*>BEACON,SGATE:T#020,165,165,067,219,213,00111111,0111,1 The next packet is another first, from a Handheld in the hands of a hiker in the mountains of Washington State: > [20:08:09] K7FZO-7>TWRWYS,W3ADO-1,RS0ISS*,WIDE3-3:'1Dol [/> The next two packets are another first. it is the first time a satellite has reported its own telemetry and ID via another satellite. > [20:08:25] W3ADO-1>BEACON,RS0ISS*:T#022,079,067,077,101,213,00111111,0101,1 > [20:08:40] W3ADO-1>ID,RS0ISS*:W3ADO-1/R XBAUD/G MAIL-1/B The next packet shows that ISS is now configured to also digipeat its own packets via another satellite or ground station with the alias of SGate. I was supposed to add SGATE as a UI-DIGI alias on PCsat so that PCsat would do the same for ISS. That is, it would relay the ISS beacons when ISS was normally out of range of any other ground stations. (The SGATE alias was not configured on PCsat for this pass). > [20:08:52] RS0ISS*>CQ,SGATE:>ARISS - International Space Station The next two packets show a single original packet picked up by both spacecraft and then both spacecraft relay it successfully via the other. This is the normal APRS generic routing method where the packet was generically transmitted using the path of via WIDE,WIDE, and then each satellite recognizes the alias of WIDE and then digipeats the packet while substituting its callsign in place of the generic WIDE so that the actual path taken is shown. (This only works when PCsat is commanded to enable its WIDE alias DURING the pass. THus it worked here, but don't plan on it, because PCsat now forgets all settings every 100 minutes due to eclipses). [20:09:51] WB4APR-3>APRS,RS0ISS,W3ADO-1*,ARISS/1:Lets try OPS NORMAL [20:09:52] WB4APR-3>APRS,W3ADO-1,RS0ISS*,ARISS/1:Lets try OPS NORMAL And the last packet was again excellent DX as both satellites passed over the East coast and yielded a 1340 mi path between spacecraft. > [20:13:59] KB1GVR>CQ,RS0ISS,W3ADO-1*/1:=4436.18N/06826.92W-> Ellsworth ME6 Again, the purpose of this test was to show the utility of a simple UI digipeating TNC on orbit especially if we have multiple such TNCs and satellites on the same frequency. Remember, ANY satellite can do this if it just has a TNC on 145.825. That's all PCsat is, a TNC and a 555 timer to reset it every now and then. PCsats RESET problems are not related to that design, but only to the loss of one solar panel on launch and subsequent negative power budget during periods of eclipse. We hope to see more satellite launches in the future with digipeating TNC's to expand this comunications capability into a constellation of UI digipeating satellites on 145.825 with one always in view of the most remotest of travelers or portable operators. de WB4APR@amsat.org, Bob PCsat WEB page http://www.ew.usna.edu/~bruninga/pcsat.html ISS-APRS FAQ: http://www.ew.usna.edu/~bruninga/iss-faq.html CUBESAT Designs http://www.ew.usna.edu/~bruninga/cubesat.html APRS LIVE pages http://www.ew.usna.edu/~bruninga/aprs.html APRS SATELLITES http://www.ew.usna.edu/~bruninga/astars.html