[amsat-bb] Community Survey Request -- crosslinks, multi-hop packet, and satellite DX
zleffke at vt.edu
Mon Apr 3 00:16:33 UTC 2017
Oh and I should also mention that for #1 there, I'm really really
pushing that 'providing a service to the Amateur Radio Community' be an
actual project goal. Like, they can't declare mission success unless
hams are also using the constellation. So 'distance records' per say
aren't a requirement, but if I get my way, 'Providing Amateur Service'
will be on the Mission Goals list along with the science goals.
Aerospace Systems Lab
Ted & Karyn Hume Center for National Security & Technology
Virginia Polytechnic Institute & State University
Work Phone: 540-231-4174
Cell Phone: 540-808-6305
On 4/2/2017 8:13 PM, Zach Leffke wrote:
> Thanks again for the responses both on and off list, keep 'em coming!
> 1. No, not really a an academic goal. But cross linking is a
> requirement. And pseudo-range determination is a requirement. So,
> 'distance records' or at least multi-hop comms are a natural extension.
> 2. 3 1Us in a single P-POD. But, different drag profiles and
> different masses. One has a drag brake that will be deployed shortly
> after deployment from the PPOD and after initial checkout. The other
> two have the same profile but different masses.
> 3. Aiming for an ISS deployment. Overall science goal is to generate
> data for atmospheric density models at LEO and low LEO altitudes. So
> higher would be better for the crosslinking/distance, but would be
> worse for the science. So it will be a relatively short mission,
> current estimates on the order of 6 months or so.
> 4. We're still sorting out the exact operating details. Earlier I
> gave a two satellite example, simplest case. We'll see how
> complicated we can make it as we move forward. One options is up to
> one, across to the other two, and down from both. Another is the
> triple hop (the really desirable one), where each time it hits a new
> bird, it gets sent on the crosslink and on the downlink. We don't
> have a specific plan yet, which is part of why I sent out the survey
> request, to see what people would be interested in, if at all, so we
> can try to incorporate it into the design.
> 5. yesss!!! different modes, different options, different ways to
> reconfigure, either from the ground or with built in 'fallback'
> operating modes. All the kind of things we're discussing and working
> through, but are leaving to the students to decide / figure out. I'm
> only a faculty advisor on the project, so can lob recommendations at
> my team, but I'm not in charge. We know for a fact (or are at least
> really really sure) that we will almost certainly lose one of them
> (the one with the drag brake) faster than the others. So the comms
> will need to be able to adapt.
> 6. Thats all the money we could drum up for the mission. But we'll
> take it, and are grateful for the chance here! I'm just hoping we can
> balance power budgets appropriately, cause yeah, its tight.
> -Zach, KJ4QLP
> Research Associate
> Aerospace Systems Lab
> Ted & Karyn Hume Center for National Security & Technology
> Virginia Polytechnic Institute & State University
> Work Phone: 540-231-4174
> Cell Phone: 540-808-6305
> On 4/2/2017 7:12 PM, Stefan Wagener wrote:
>> A few quick thoughts:
>> 1. Is the "long distance record" truly an academic goal? I hope that
>> is just a side effect of a more scientific endeavour :-)
>> 2. How will the deployment of the satellites being scheduled? Too close
>> together means long time for separation to make it useful but longer
>> lifetime for use. Too much initially separation and the satellites won't
>> see each other for too long.
>> 3. How about the deployment altitude. The higher the better?
>> 4. What happens to the sat in the middle, just a link between the other
>> ones and no direct contact/use?
>> 5. How can the system be programmed that if one satellites fails it
>> 6. Why 1Us and not bigger for better power budget and redundancies?
>> Have fun,
>> 73, Stefan VE4NSA
>> On Sun, Apr 2, 2017 at 5:54 PM, KO6TZ Bob <my.callsign at verizon.net>
>>> I like what I see so far on your initial proposal.
>>> In the past, I have been involved with 2-HOP and 3-HOP packet attempts
>>> using various combinations of the ISS, NO-44 and NO-84 when they
>>> were all
>>> working on 145.825MHz.
>>> Your proposal of using a 9K6 FSK 2-port_digi's on board three
>>> in the same orbital track resolves what I believe to be the main
>>> we faced in our 1200 baud experiment. If the footprints overlap, the
>>> satellites should be able to talk to each other.
>>> 1) Since the satellites were in different orbits, there was Doppler
>>> in the signal between them. In your proposal, doppler is minimal
>>> for FM
>>> 2) With your 2-port digi, the repeated packets between satellites will
>>> not be interfered with by multiple up link signals. Improving the
>>> 3) I find that 9K6_FSK is as easy to copy as 1200baud, so
>>> efficiency in
>>> channel usage is gained.
>>> Once the operators acquire confidence in establishing basic 2 & 3 Hop
>>> packet contacts, the other experiments and distance records you
>>> will follow.
>>> I'm in.....
>>> Sent via AMSAT-BB at amsat.org. AMSAT-NA makes this open forum available
>>> to all interested persons worldwide without requiring membership.
>>> are solely those of the author, and do not reflect the official
>>> views of
>>> Not an AMSAT-NA member? Join now to support the amateur satellite
>>> Subscription settings: http://www.amsat.org/mailman/listinfo/amsat-bb
>> Sent via AMSAT-BB at amsat.org. AMSAT-NA makes this open forum available
>> to all interested persons worldwide without requiring membership.
>> Opinions expressed
>> are solely those of the author, and do not reflect the official views
>> of AMSAT-NA.
>> Not an AMSAT-NA member? Join now to support the amateur satellite
>> Subscription settings: http://www.amsat.org/mailman/listinfo/amsat-bb
> Sent via AMSAT-BB at amsat.org. AMSAT-NA makes this open forum available
> to all interested persons worldwide without requiring membership.
> Opinions expressed
> are solely those of the author, and do not reflect the official views
> of AMSAT-NA.
> Not an AMSAT-NA member? Join now to support the amateur satellite
> Subscription settings: http://www.amsat.org/mailman/listinfo/amsat-bb
More information about the AMSAT-BB