References
If you're interested in learning more about aspects of the engineering behind some
of the satellite constellations I've introduced, here are some relevant
academic papers and patents that I've come across as part of my PhD work.
It should be enough to get you started; do note my networking and
intersatellite-link bias.
An informal alphabetical list of people who have published academic papers on aspects
of satellite
constellations, where
online copies of publications are available. Additions are welcome. A number of interesting
papers on satellite networking can be found by looking through Research Index.
The schemes
If you're really interested in the specific details of
a U.S. satellite constellation that may exist only on paper, your best bet
is the set of public Federal Communications Commission (FCC) filings for that scheme. These documents are
public, but difficult to obtain; either you deal with
International Transcription Services,
the FCC's duplicating contractor, with FCCFilings.com, or you try telephoning the lawyers who
made the application on behalf of the filing company, and ask them to send
you a copy. The filings are not written by FCC staff, so they're not on the FCC webserver, unfortunately.
FCC applications can be interesting, and they can be useful. As they're
legal documents, lots of attention is paid to financial aspects, frequencies,
the ground-space interface, and coexisting with other systems. As they're
US legal documents, the world outside North America is often effectively
ignored. As they're describing not-yet-implemented systems using not-quite-ready
technology, they can also be outmoded by events.
If you want satellite design
specifics or networking details, you're generally fresh out of luck -
there's generally enough technical detail to make them convincing to lawyers, but
not enough to tell you anything useful. In other words, they're just like
patents...
Enough about FCC filings and patents. What is out there that might be
useful? Here's a very incomplete list to get you going.
- Iridium
-
Read:
- Granted Motorola patents related to Iridium
- and therefore worth a read, although there's no guarantee that the
Iridium implementation is exactly like these. I note these as I stumble across them;
there are likely to be far more that I haven't found yet.
- Satellite cellular telephone and data communication system
(US patent 5604920)
- Packet routing system and method for achieving uniform link usage and minimizing link load
(US patent 5596722)
- Method and apparatus for adaptive directed route randomization and distribution in a richly connected communication network
(US patent 5430729)
- Communications system employing spectrum reuse on a spherical surface
(US patent 5268694)
- Satellite system cell management
(US patent 5227802)
- Low-earth orbit global cellular communications network
- Leopold, R. J., Proceedings of ICC '91, pp.
1108-1111.
A short paper introducing the original 77-satellite Iridium
scheme.
- The Iridium system: a new paradigm in personal communications
- Leopold, R. J.,
Applied Microwave and Wireless, vol. 5 no. 4 pp. 68-78.
More system details.
There are lots of FCC applications to look at too - more than for any other scheme,
in fact, since Iridium
was first to file. They contain a lot of technical information on the ground/space interface.
- Globalstar
-
I don't pay much attention to Globalstar, simply because it's not a satellite
network constellation in that the satellites are not network nodes, while I'm a networks geek and lower layers interest me less. Having said that, Globalstar
does have a complex ground network.
- Some granted Globalstar patents
-
courtesy of what was the free-to-access IBM patents server.
There are no guarantees that the Globalstar
system embodies the concepts detailed here:
- Low earth orbit communication satellite gateway-to-gateway relay system (US patent 5758261)
- Satellite beam steering reference using terrestrial beam steering terminals (US patent 5758260)
- Radio relay method, radio relay system using the method and radio unit (US patent 5697050)
- Low earth orbit communication satellite gateway-to-gateway relay system (US patent 5634190)
- Teledesic
-
I'm not aware of much public information on the 288 active-satellite Boeing
redesign or any current design; I don't even know the exact orbital parameters of
current plans. However, the original
design was advertised widely back when Teledesic started up.
The best sources for descriptions of the documented 840-active-satellite design and
for what Teledesic might have been thinking some years ago are:
- granted Teledesic patents
-
courtesy of what was the free-to-access IBM patents server. Again, no guarantees that the eventually-implemented
system will embody the concepts included here:
- Low-earth orbit satellite acquisition and synchronization system using a beacon signal (US patent 5936570)
- Non-blocking dynamic fast packet switch for satellite communication system (US patent 5930254)
- System and method for the acquisition of a non-geosynchronous satellite signal (US patent 5929808)
- Terrestrial antennas for satellite communication system
(US patent 5905466)
- Frequency sharing for satellite communication system
(US patent 5822680)
- Non-blocking dynamic fast packet switch for satellite communication system
(US patent 5796715)
- Traffic routing for satellite communication system - Moshe Liron's 127-page routing patent
(US patent 5740164)
- Earth-fixed cell beam management for satellite communication system using dielectic lens-focused scanning beam antennas
(US patent 5736959)
- Terrestrial antennas for satellite communication system
(US patent 5650788)
- Spacecraft antennas and beam steering methods for satellite communication system
(US patent 5642122)
- Inflatable torus and collapsible hinged disc spacecraft designs for satellite communication system
(US patent 5641135)
- Linear cell satellite system
(US patent 5621415)
- Dielectric lens focused scanning beam antenna for satellite communication system
(US patent 5548294)
- Modular communication satellite
(US patent 5527001)
- Earth-fixed cell beam management for satellite communication system
(US patent 5408237)
- The Teledesic satellite system
- Sturza, Mark A. and
Ghazvinian, F.
Fourth Budapest International Conference on Up-to-Date Satellite Communications,
September 1996
Presentation slides covering the 840-active-satellite design.
- The wireless communications and small satellite revolutions:
next generation communications concepts
- Stuart, J. R.
presentation at the Space Horizons Summit, Boston, 4 May 1996
An overview of the various FCC filing, schemes and markets, with a series of
terse slides describing what Teledesic is and how it will work.
- Architecture of the Teledesic satellite system
- Sturza, Mark A.
Proceedings of the International Mobile Satellite Conference '95, Ottawa, pp. 214-218.
A summary of much of the information presented in the Calling paper, with
a description of the final 840 active-satellite design, subsystems and communications
payloads.
- The Calling network: a global wireless communications system
- Lawrence, M. H.,
Patterson, D. P., Stuart, J. R., Tuck, E. F.
International Journal of Satellite Communications. Vol. 12, No. 1, Jan-Feb 1994,
pp.45-61.
A very readable, non-too-technical introduction to the original scheme that we now know
as Teledesic, with a
whole page devoted to the biographies and careers of the writers to establish
their credentials, get the scheme taken seriously, and presumably attract funding,
which it eventually did - from one Bill Gates.
Ignore figure 5, which is misleading.
- Patent for a satellite communication system
- Calling Corporation, US Patent application WO 93/09613
PCT/US92/08966.
The original Calling patent application. A complete mixed grab-bag of every idea that ever came out of the
abandoned Strategic Defence Initiative, ranging from the sublime to the
ridiculous, from mechanical engineering to traffic algorithms, with a number
of silly, not-so-silly and completely dissimilar satellite designs. Very,
very large.
Granted Calling Corporation patents:
- Celestri
-
Their FCC filing
of June 1997 is your best starting point.
- Spaceway/Galaxy
-
Take a look at:
- Spaceway system summary
- Fitzpatrick, Edward J. of Hughes Communications,
Space Communications Vol. 13, pp. 7-23, 1995.
Intersatellite links, spot cell positioning, link budgets and more for
this geostationary network.
There's a very similar online version,
giving much the same information, although Figure 3 is in error.
A geostationary satellite at 101 degrees north?
See the paper for a more convincing diagram of the scheme.
The paper described phase 1 of the scheme. Given the competition, they've
skipped that and network has been redesigned with more
satellites - see their FCC submission details for more. To request filings, the lawyers for Hughes Communications are Latham and Watkins.
Further information
Textbooks
Satellite Communications Systems: Systems, Techniques and
Technology, fourth edition, is worth looking at. I used the second edition heavily when I took one of
Surrey's Masters courses.
Although that edition predated most commercial constellation proposals, it
provided
a good introduction to much of the maths and engineering behind
satellite design, including link budgets. I should
note that I know and have been taught by the authors; Gérard Maral supervised my masters thesis. Browse for a book.
Lloyd Wood
(L.Wood@society.surrey.ac.uk)
this page last updated 23 May 2004
