Slashdot Mirror
Communicating Via Space Dust
klieber writes: "Never mind IP over Avian Carriers, here's a company that really sends data over space dust. Transfer rates are up to 20Kbps but because the data is transferred in short, sporadic bursts, the usable transfer rate is more like 9600bps. (And it uses a proprietary protocol, not IP) The technology, called "Meteor Burst," has been around since the 1930's and was apparently first developed for the U.S. Military. It's now being targeted at vehicle positioning systems and is being used by a private ambulance company in the Pacific Northwest." This is ... really strange.
just tune any quality FM reciever to a dead area(no signal and quiet) at the lowest freq. you can; and listen close. you might hear something like this.
e r.html
for an explanation of whats going on and a link to NASA's radio meteor detection system at Marshall Space Flight Center go here: http://www.spaceweather.com/glossary/forwardscatt
- "Hear that?! The percolations are imminent! Cease your ingress!"
In principle you could use a 50bps (or even slower) signal to do GPS work, but in practice it would be too hard and expensive to nail down bit transitions accurately enough and would make initialization *very* slow. Enough so that it would be a silly thing to do.
But a couple megahertz of BW isn't bad for what GPS can do, when you think about it... but it really is a lot more than 50bps.
I hearby submit a replacement sales pitch :
Probably need a lot less technical support in the world if all companies used sales pitches like that.
You are in a twisty maze of processor lines, all alike.
There is a lot of hype here.
...anyone here tried an `Xploder` bar? Chocolate, but with `space dust` style carbon dioxide rich sugar inside. Mental!
this technology is nither new nor strange.
I have been involved in a testing run with this technology a few years back.
We set ut a 'server' that constantly transmits an idle signal. when a station recives this idle signal it establishes an 2 way comunication with the server on 2 frequencies. The link lasts for only a very short time.
Messages between stations are always sent via the 'server' making it possible to reatch half the continent with one server.
It's not so easy to eavsdrop on this system, you can easily find the idle signal, but unless you'r located very near one of the comunication stations you won't be able to eavsdrop on the databursts. This happens becouse the ionized atmosphere only creates a very limited footprint (area where you can hear the other station)
we devised our own simple protocols for the testing. We did not use IP becouse you have very short time to transmit, and in that time you need to do handshaking and conduct as much datatransfer as possible.
My experience is that the system is very stable, reliable and secure. Pity you can't get very high transferrates.
SEP
In the not-too-long-ago past the hams (I'm one myself but haven't actually tried MB) simply used tape recorders for this. No need for computers. You just record your (CW) message on the tape recorder, then play it back Real Fast on your odd (or even) minute (see another posting). Likewise, you record the received message with your tape recorder running at high speed, then you play it back at low speed. Instant compressed messaging system.
TA
Rather strange - I can see the military value but I can't really see the point in a commercial system. About the only thing going for it is the spectral bandwidth efficiency - but if you are only transmitting small bursts of information every now and then you'd probably get similar bandwidth efficiency by assigning timeslots on a reliable channel. I doubt this is really any cheaper than satellite.
I'm intreagued by the technology though. It seems to me that to take advantage of the space diversity (the small footprint) you would need a highly directional antenna. In that case, you would need to know where to point it in order to communicate. I can imagine just sending out a broadcast signal from the base station which a vehicle would hear whenever a useable meteor appeared, but how would it know in which direction to transmit the return signal? I guess you would need some way of measuring the direction the received signal is coming from. Can you do that?
If the earth were between the moon and sun so that no sunlight reached the moon (that's a lunar eclipse, right?), and you aimed the mother of all flashlights at the moon, then it probably would be brightest in the center if that's where you had the beam of light aimed. But the sun isn't aimed just at the center (from our perspective) of the moon, it floods all of it with light (and every other frequency of EM too, no doubt).
I see even classic Slashdot is now pretty much unusable on dial up anymore.
Should've called it the Internet Carrier Pigeon Protocol.
Or maybe I'm the only person juvenile enough to think ICPP would be the best acronym ever.
In principle you could use a 50bps (or even slower) signal to do GPS work, but in practice it would be too hard and expensive to nail down bit transitions accurately enough
In the early 1960's, scientists at The Johns Hopkins Applied Physics Lab in beautiful Laurel, Maryland, determined the orbit of Sputnik from listening to the doppler shift of the radio signal as it passed. APL's chairman came up with the neat concept that if you knew the orbit of the satellite, you could determine the position of the receiver from the doppler shift as well.
This was the birth of TRANSIT, the first satellite based navigation system. It transmitted orbit ephemeris every 2 minutes, and the receivers used the doppler shift curve to figure out location.
TRANSIT also had satellites called "Oscar" long before OSCAR (i.e. Orbiting Satellites Carrying Amateur Radio), which lead to many confusing conversations when I first worked at Johns Hopkins APL.
Hmm... Think I've heard of a company that does shit like that for a living... They've got this product they call NT... New Technology my ass...
.sig today
Geirlk
--
Sorry, no
That's pretty scary, considering how fragile those planes' electrical systems are..
Your Working Boy,
In Europe there is the company Meteor Data
Communications, in the Netherlands that uses the same technology in
Europe for lowcost (relatively) vehicle tracking and other
not-really-time-critical data transport. There is also a rather good
explanation of how things work on their site.
My 2 cents.
Merijn
---- Boring sig.
When stopped, my clock doesn't display anything
is it that it's never wrong then ?
Not really, considering the Radar systems that 'paint' these aircraft every few seconds are MUCH more powerfull than the Puny amateur transmitters.
Obviously, there is way too much VC money out there.
Someone you trust is one of us.
This is mostly used in the arctic/antarctic regions. Why? Because the ionosphere is not usable there. In the rest of the world, you just bounce off the ionosphere...in the pole regions, you must await the odd meteor.
Errata: I once told a National Security Agency computer science intern about this. A few months later it was on an NSA test she took. Now, THAT'S strange!
READ the US Constitution, the Bill of Rights and the other amendments! http://lcweb2.loc.gov/const/const.html
Truckers using 11M CB radios do this all the time, but by using the ionized atmosphere during daylight hours. Similar effect--bouncing off of ionized layers. However, that's a significantly more reliable communication medium. Oh, and BTW, hams discovered ionosphere bounce, back when they were relegated to the "useless" frequencies "below 200m" (above 1.5 MHz).
Kinda. Meteorologists have put up remote weather stations all over the place, and they transmit data this way. That's how they know how much snow fell in BFE Utah last night. Find out how much snow fell in BFE Utah last night. http://utdmp.utsnow.nrcs.usda.gov/
There are 01 kinds of cars in the world. The General Lee, and everything else.
What I don't understand is how the signal is reliably recievable, due to the limitations of the elliptical footprint (see section 1.5.2 of this link) and the sporadicness (Is that a word? Doubt it...) of the meteors.
Looking at the chart they have on the site showing meteor frequency, it seems as if all of the ground stations would have to constantly broadcast to catch the next meteor.
And with the elliptical footprint, wouldn't that exacerbate problems of the RF reflecting off of buildings if the mobile transmitters were on vehicles?
Of course, we didn't cover this in my General ham radio classes.
--Brant
the fewer declarative statements a man makes, the less likely he is to look like a fool.
Brant
Argle. Bargle.
This "News" was reported by Tommorows World (UK science and tech TV magazine programme) about 10 years ago and I had a bit of a rant about it then.
Radio Amateurs have been doing this since Methuselah was a youngster. Meteor scatter transmissions have been going on around the world since at least the early sixties. Probably earlier, I'm not a radio historian
And while we're at it has anyone heard of packet radio? It's principles formed the basis of that little used and now largely irrelevant protocal know as IP.
It's even more strongly linked with the much hyped "new generation" of mobile phone services known as General Packet Radio Services (GPRS) which promises (but will not likely deliver) so much.
End of semi rant. Sorry folks.
Ian
Golf 1 Charlie Foxtrot Tango - If it means anything.
Do you have time for "good crypto" if you're at about 9600 baud? That could slow things down even further.
________________________________________________
suwain_2
In certain parts of the UK, the water authorities use MS to transmit sensor readings from remote sites. The transmitters are often solar or wind powered, and work with maybe a couple of watts on 49MHz.
They make a distinctive "burp burp burp" noise. Each packet is coded so it can be identified as part of a set so multiple copies aren't logged.
Moonbounce, on the other hand, does indeed use the moon as a passive reflector. You need *HUGE* antennae for this, and a very powerful transmitter. This is because the signal is largely scattered by the convex reflector. If you send a quick burst of morse (say your callsign), you can hear it come back about 3 seconds later...
As a previous poster mentioned, it is indeed very, very strange...
I have been a Ham for quite awhile. One of the things we do out of necessity (to keep costs down, since it is a hobby) is bounce signals off of things, such as buildings, mountains, the moon, and even meteors. Another naturally occuring phenomenon we use is the Aurora (makes a good mirror!)
Also, "Soft hit = binary" should have a zero after it. Don't know what happened there...
My karma's bigger than yours!
SIG: HUP
Completely potshot, completely random, and yet reliable enough for some pretty high-level stuff, neat. I've heard that the US Military has for some time been using microwave transmitters to heat large sections of the upper atmosphere in order to achieve the same radio-reflective effect with less guesswork.
~ The Irony is, The only reason I'm not at Berkeley right now is because I was on acid during my SAT's..
I read a ham radio book this morning on this subject. It was written in the late 50s.
The reflecting surface lasts a few seconds. Because it's not suitable for voice, hams usually use very high speed Morse code, much faster than you could send by hand, sent by computer and read off a video display. Two way communications work this way: one party sends their message repeatedly over one minute on the odd minutes, the other party sends on the even minutes. The odds are that during that minute there's a meteor where you want one and the message gets through.
Thanks
Bruce
Bruce Perens.
Yes, this is an old trick. Whenever there's a meteor shower (a few days of increased activity, when Earth passes near the residue of a comet; this happens a few times a year on schedule) a lot of ham operators point their VHF (2 meter or 70 cm CW, typically) antennas at it and bounce signals off of the tails. Not exactly the meat of long conversations, but a nice way to get some well-beyond-the-horizon contacts into the logbook (think "radiosport"; we do it for the challenge, often competitively).
I suppose if you throw enough at it, you can find enough tiny meteors to make it a fairly regular means of communications. But it's rarely the medium of choice, what with dirt-cheap geostationary satellite bandwidth for the sites that can't get to the fiber networks.
If the antennas are pointed up at space, and if they are directional enough, they can use the same spectrum as other ground-to-ground systems and not interfere.
This will make more money than Ginger in five years.
Well, not really. Back in the olden days when I was a lad, long before commsats and optical fibers, we used to use High Frequency radio for long-distance communications. The signals bounce off of the ionosphere. Meteor Burst is essentially the same thing, except that you're waiting for that momentary ionization trail created by a descending meteor to bounce the signal. I worked on a military project that was using MB. The trail lasts a brief time and is random, but there are so many meteors hitting the atmosphere in a day, that it was seldom more than a few minutes before we got an open path to burst our data. The challenge was, we were doing this at the dawn of the microprocessor age and it was quite the software triumph to set up our little beacon/burster program in 2048 bytes.
"If I have seen further than other men, it is by stepping on their glasses." - Michael Swaine
"Comrad, lets hold off untill the kids go to sleep"
eather way, theres always iridim
Broadband Pr0n for all!
________
Does anyone actually have a Java program designed to control air traffic, or for the operation of a nuclear facility?
Magic dust man! Magic dust! (please don't mod this up---i'm kapped out. go play whack-a-troll instead.)
----
----
Am I the only one who thinks Microsoft is a misnomer? Perhaps Macrosoft would be a better fit?
Finally! A quality use for those Iridium satellites...
Drinking will help us plan!
To make the dust layer reflection more reliable, there was in the 1960's a military program to put needles (well, dipoles) in low Earth orbit to form an artificial reflecting layer. I forget the name, but it was run by MIT Lincoln Labs. After a huge controversy (about polluting outer space!), it flew and... nothing happened. Not enough needles, I guess.
Of course, this was at a time when they were (in Project Starfish) exploding nukes 600 km up to see what it would do to the ionosphere...
I wasn't aware that DGPS was capable of getting down into the cm positioning accuracy area. Is that cm range achieved by using DGPS in conjunction with carrier tracking? I led an engineering team that did some early work on DGPS for NASA and the Army back in the '80s for precision approaches and we didn't see accuracies like that using straight differential (but it was good enough to meet CAT II requirements when you used P-code). Carrier tracking was pretty much out of the question at the time (cost = outrageous). Having been out of the GPS field for a number of years now, I have to ask: Is carrier tracking common in today's receivers?
--
CUR ALLOC 20195.....5804M
I've seen a lot of people say "why would you do this if you can get really cheap satellite bandwidth". Well, because this method uses FREE bandwidth.
It's a niche application certainly, but there is a place for this technology. Rural areas, mountainous areas that can't get LOS to the geosynchronous ring, etc.
In fact, here's an article that talks about an ambulance company that is using the technology right now. (The article mentions a further niche use for their technology as a sort of Lojack system.)
Gentoo Linux http://gentoo.org/
Why would you consider moonbounce strange? That's what moonlight is. Light's just electromagnetic radiation of a particular frequency range.
I see even classic Slashdot is now pretty much unusable on dial up anymore.
So do you mean trying moonbounce during an eclipse, to see if the signal-to-noise ratio is higher? Might not be a bad idea. I know that solar noise is very broad band.
You can actually pick up solar EM radiation using an analogue satellite TV receiver. Set the dish up pointing south. When the sun passes the line-of-sight of the dish, you can see the signal strength increase. This is due to solar noise. I've got the circuit for connecting a plotter to the AGC line to draw a graph of this somewhere.
While Meteor Scatter is an interesting mode, I think that Airplane Scanner is even more interesting. Recently Hams have been bouncing Signals in the 10Ghz range off the metal skins of high flying Aircraft. Communication ranges of up to 500 miles have been recorded. A recent (last few months) article in QST had the details...
Don't know what on Earth happened to the company since then (I think it was the same company anyway) but at the time there was much info on the web site about how it was used to do periodic downloads of results from many very remote automated data collectors, like atmospheric stations and so on. There was something about shipping too. But the data rate was extremely short, and it seemed only useful to communications that could be accomplished with a handful of bytes each signal.
I remember at the time worrying about security, since antennas and signals might draw fire from military on innocent villages etc. There still is hardly any phone infrastructure, and any really good solution (like the phone system in the sky one satellite company built for Thailand) seemed prey to a rapacious telecom ministry. Well that's a few years ago. I think I suggested more research into either a store and forward to satellites, or a line of site ham network using a specialized linux type distribution.
Anyway, I said "Amateur Scientist meteor radio" to Google and Google showed me some very nice links!
Meteorscatter Links--Make More Miles on VHF
A link on this page ( Meteor Burst Communication) mentions the noise floor is limited to the noise emitted by the galaxy, which changes through the day as you scan different parts of it. Cool! It says you really ought to be away from cities and highways to keep the floor as low as possible.
The American Meteor Society Radiometeor Project
(a reprint posted last summer of a 1997 article from the Society of Amateur Radio Astronomers)
I talked to these people two years ago, and they had a functinal system, mostly used to communicate with trucks in unknown odd territoria, such as Russia. The guy also told me they had lots and lots of interference from the NATO bombing on Serbia Paul
No ionosphere in the arctic regions? Nonsense. Where did you get that from? FYI, I'm a ham and I live in the arctic (70N), and the ionosphere works just fine, thank you. No different from the time I spent in more southern latitudes.
It's indeed a lot of radio noise coming from the Sun. If you have e.g. an L-band autotracking satellite dish available (you may need to go find a satellite ground station for this :-) then you'll find that you can easily get the antenna system to auto-track the Sun.
Yes, this is real-time DGPS using carrier tracking. Carrier tracking is common on high-end survey class receivers. On consumer grade / lower-end stuff where you're not doing DGPS, there's not much point in tracking carrier because atmospheric fluctuations overwhelm any gain you might make.
Not susceptible to unauthorized listeners? Huh?! It's just standard broadcast.
The rest of the page talks about a mixed-mode (line-of-sight + meteor burst) operation. I bet they never implement the meteor burst aspect: it's just a hook for customers and investors. Ordinary phone technology would do as well or better.
What interesting things, besides positioning, can be done with low bit-rate channels?
-- Stanislav Shalunov
Truckers using 11M CB radios do this all the time, but by using the ionized atmosphere during daylight hours.
Man, if ET had this technology, things sure would have been different...
I can definately see the military's reasons for this technology, but I see no value in it for civilian communications at all. Even if it is advanced to transfer at greater speeds, it's not any jiant leap of technology... We have typical radio for most modern applications, and satelite communication for any long-distance communications. If our satelities are bombarded by missles from China, the last thing you need to worry about is wether or not you can read the latest slashdot news. ;-)
This is ... really strange.
Meteor scatter isn't that strange, since the space dust ionizes the atmosphere. Moonbounce on the other hand is ... really strange.
In moonbounce you use the moon as a passive reflector. Google has more info.
RFC1925
Altavista sides with me here, giving 306 hits for Line-Of-Site versus 4557 hits for Line-Of-Sight.
On the other hand, I wouldn't be surprised if someone came up with facts that said Line-Of-Site had been common use since 1800 A.D. .
I'm still trying to figure out what people mean by 'social skills' here.
I agree that the article is somewhat optimistic about the security of the beam. The bounced signal widens into a 30km by 15km ellipse. While that's better than broadcasting with an omnidirectional antennae, it doesn't quite add up to the pinpoint precision you could get with lasers. If you were within that ellipse, then you could easily listen to one side of the message traffic, and you might be able to mess with the communications by responding to the "probe" signal. Good crypto, however, would get rid of these problems.
The article also mentions that they handle the case where multiple remote sites reply to the base station's "probe" signal. Thus, while the system works best with a large, sparse network, they can have some level of density.
Check out Chad's News
(DUCK)
OK, OK, but it was pretty lame to begin with. The only advantage of this thing is its operability without satellites, and if anything happens that would wipe out all the satellites (hint, it would probably involve lots and lots of uncontrolled nuclear fission and fusion reactions) would probably also wipe out MB propagation too. I think.
OTOH if it didn't wipe out MB comms it would almost certainly have the opposite effect of making them redundant by creating a huge ionospheric mirror so that all VHF comms would propagate. Hard to say, given the test history, which way it would go. It's a bit late and I'm a bit too drunk to look it up.
Either way, this silly system is redundant.
Brackets contain world's first nanosig, highly magnified:[.]
"Hey Bob! Lets bounce radio waves off space dust burning up in the atmosphere!"
[alien #1] Hey, someone on this planet is trying to talk to us with VHF radio waves.
[alien #2] Maybe they want to help us.
[alien #1] In fact they are trying to communicate with our dust tail?!??!
Soft hit = binary
Of course, everything in nature is basically analog, so hard and soft hits have to be defined in analog terms just like bits in computers - but if it really hurts it's a 1.
My karma's bigger than yours!
SIG: HUP
significantly on the news that they will be offering an additional service at the the begining of March.
This new service will be called "Mir Burst". A spokesman for the company said that while meteor burst gives only milliseconds to send data packets, it's expected that the burning trail of the russian space station Mir will give them as much as an half of an hour of reliable highspeed data capability.
When asked about the temporary nature of Mir Burst, the spokesperson said that they were in negotiations with other satellite companies to move obsolete communications equipment into lower earth orbit so that they too could re-enter the atmosphere and provide fleet communications.
Take the cheese to sickbay, the doctor should see it as soon as possible - B'Elanna Torres, "Learning Curve"