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I'd like to fly drones over a, say, 100x100 meter area with centimeter precision, possibly indoors, for filmmaking. GPS is clearly not going to work, even outdoors. Time Domain sells a system with 5 cm resolution, using UWB technology -- but is there anything better than that?

Crowding Issues resolved by the AMAZING WIRELESS technology from Larry Fullerton, read this first: http://www.engology.com/eng5fullerton.htm then this http://www.timedomain.com/ This is like nothing you have ever heard of, in that it is ULTRA LOWPOWER, ULTRA WIDE BAND not in the typical sense, UNDETECTABLE, and so super scary that the military has embargoed its FULL use precisely because it is undetectable by conventional frequency scanners... Also please check out http://teaminfinity.com/robo_economy_wire for great news on ROBOTIC FRONT

This is an ultrawideband through-wall imaging system, and is an old technology that has been around for many years. Two of the many manufacturers are Time Domain [Flash!] and Camero.

Note that, while military radio emissions are regulated in the U.S. by the NTIA, U.S. civilian use of ultrawideband through-wall imaging systems is controlled by the FCC (by regulations established in April 2002 [pdf!]). 47 U.S.C. 15.510(5)(e) [pdf!] states that

Through-wall imaging systems operating under the provisions of this section shall bear thefollowing or similar statement in a conspicuous location on the device:

"Operation of this device is restricted to law enforcement, emergency rescue and firefighter personnel. Operation by any other party is a violation of 47 U.S.C. 301 and could subject the operator to serious legal penalties."

I agree that I should not have said that they were "easy to build." It has been demonstrated that it is hard. Not just the antenna design, but the software issues are significant.

Still, I recall reading in Aviation Week quite a number of years ago about a demonstration of UWB radios for the defense department. Of the four companies that presented radios, only the one from Time Domain actually worked. But it was amazing -- it had a range of about 100 miles on about 100 milliwatts of power.

thad

Ultra-wideband makes USB (and BlueTooth) irrelevant.
Check out XtremeSpectrum
and Time Domain.
The FCC approved unlicensed use of the UWB spectrum (3.1 to 10.6 Ghz) earlier this year.
This allows wireless connections of up to 500Mbps between devices (less, maybe 100Mbps for battery-powered devices).
Both companies have chipsets almost ready. They were only waiting for FCC approval.

I'm a staunch Libertarian, but I'd have to agree that divvying up the airwaves is a valid use of government. I think that the mandates should end at what's actually CARRIED on the frequencies, though. Lease it all, maybe with a lower rate for "public good" services. What's then done with that space should then be none of the government's business -- if digital becomes more economically practical, you can be it'll be adopted right quick.

On the other hand, I can't help but wonder if maybe Time Domain's technology wouldn't have been invented a few decades sooner...

Some tech recently invented by Larry Fullerton could make this feasible. It uses pulses instead of continuous sine waves, and uses 1/1000 the power of sine transcievers. Fullerton's company Time Domain is working on building commercial products. Apparently it can support "almost unlimited" bandwidth. Now if only it was available.....

Hmmm....Actually Livermore was using Time Domain technology with the microwave impulse radar, as discussed here. Also, I wouldn't envison a high powered spread spectrum transmitter reaching miles of range as tthe solution to this problem...more like a bunch of low powered ones where A can pass on to B which can pass on to C and so forth...

The real key to universal broadband is the so-called last mile - the connection to the home and thru the home into the computer there. Whatever solution you come up with will have to be duplicated tens of millions of times, just like it has been for telephone jacks and electrical outlets. A company in my hometown, Time Domain, is about to get licensed by the FCC for a revolutionary new type of wireless technology that may very well be the key to solving the last mile problem. You can read coverage about them from USA Today, The Economist, US News & World Report, Business Week, and The New York Times.

The real key to universal broadband is the so-called last mile - the connection to the home and thru the home into the computer there. Whatever solution you come up with will have to be duplicated tens of millions of times, just like it has been for telephone jacks and electrical outlets. A company in my hometown, Time Domain, is about to get licensed by the FCC for a revolutionary new type of wireless technology that may very well be the key to solving the last mile problem. You can read coverage about them from USA Today, The Economist, US News & World Report, Business Week, and The New York Times.

The real key to universal broadband is the so-called last mile - the connection to the home and thru the home into the computer there. Whatever solution you come up with will have to be duplicated tens of millions of times, just like it has been for telephone jacks and electrical outlets. A company in my hometown, Time Domain, is about to get licensed by the FCC for a revolutionary new type of wireless technology that may very well be the key to solving the last mile problem. You can read coverage about them from USA Today, The Economist, US News & World Report, Business Week, and The New York Times.

The real key to universal broadband is the so-called last mile - the connection to the home and thru the home into the computer there. Whatever solution you come up with will have to be duplicated tens of millions of times, just like it has been for telephone jacks and electrical outlets. A company in my hometown, Time Domain, is about to get licensed by the FCC for a revolutionary new type of wireless technology that may very well be the key to solving the last mile problem. You can read coverage about them from USA Today, The Economist, US News & World Report, Business Week, and The New York Times.

The real key to universal broadband is the so-called last mile - the connection to the home and thru the home into the computer there. Whatever solution you come up with will have to be duplicated tens of millions of times, just like it has been for telephone jacks and electrical outlets. A company in my hometown, Time Domain, is about to get licensed by the FCC for a revolutionary new type of wireless technology that may very well be the key to solving the last mile problem. You can read coverage about them from USA Today, The Economist, US News & World Report, Business Week, and The New York Times.

The real key to universal broadband is the so-called last mile - the connection to the home and thru the home into the computer there. Whatever solution you come up with will have to be duplicated tens of millions of times, just like it has been for telephone jacks and electrical outlets. A company in my hometown, Time Domain, is about to get licensed by the FCC for a revolutionary new type of wireless technology that may very well be the key to solving the last mile problem. You can read coverage about them from USA Today, The Economist, US News & World Report, Business Week, and The New York Times.

The FCC is being very cautious about mass-market UWB products. Since these things blither over a gigahertz or so of spectrum, they overlap with other services. At low power, a few of these things are probably OK, but in bulk, there could be trouble. The concern is that mass deployment could wipe out other services in congested areas.

It gets worse.

While you can at least hear SS signals on a conventional receiver (they sound like more- or less-random noise), there are technologies coming down the pike that are completely undetectable without a time-correlated receiver.

See, for example, Time Domain's technology. Ultra-wideband radio is fundamentally different from both DSSS/FHSS and conventional modulation technologies, and it may very well prove to be the Right Way to send and receive wireless signals in the long run.

If time-domain radio turns out to be the natural direction of evolution for wireless systems, we don't have a chance in hell of listening in on ET's phone conversations. :(

This is my biggest problem with SETI -- the assumptions they are making about the nature of an advanced civilization's communications traffic are almost all entirely unwarranted. I don't think we're going to find anything interesting by staring at frequency-domain FFT displays all day.

Actually, the U.S. Department of Defense has clearly outlined scenarios in which GPS would be locally shut down and/or jammed; Space.com had an interesting story about it earlier this month.
Another reason is the available of ultrawideband technology (UWB). It's really interesting, relatively inexpensive, and can provide tremendously accurate (1 centimeter) positioning.
No, I don't own stock in it or anything like that (although, as a U.S. citizen, I should).

• A full duplex 1.3 GHz system with an average output power of 250 microWatts, and a variable data rate of either 39 kbps or 156 kbps. The radio has been tested to beyond 16 kilometers (10 miles).
• A full duplex 1.7 GHz walkie-talkie with an average output power of 2 milliWatts, a data rate of 32 kbps and a range of 900 meters. The unit was also capable of measuring the distance between radios with an accuracy of 3 cm (0.1 ft).
• A simplex 2.0 GHz data link with an effective average output power of 50 microWatts, a data rate of 5 Mbps at bit error rate (BER) of 0 with no forward error correction (FEC) and a range of 10 meters (32 ft) through two walls inside an office building.

Another plausable advantage is that since they don't use continious waves, multi-pathing isn't a big problem. The wave packets from the two paths are completely distinguishable, and therefore do not interfere. However, this makes each path look like a seperate transmitter on a different channel. So you sacrifice total bandwidth (by reducing the number of channels availbable) in exchange for reducing fade-out from point of destructive interference.

In any case, anyone interested should check out this whitepaper more info. I doubt this is a scalable as they claim, but they do have some interesting ideas, and the single-chip positioning and radar sounds cool, too.

Aether Wire on the other hand was the exact opposite in my experience. Not only was I able to talk to someone, but that someone was one of the head engineers. At the time they were planning on having prototype kits available for testing this summer, but I don't know if that date has changed. Aether Wire is focusing on positioning and tracking applications of UWB, and these products could have many important uses for warehouses, hospitals, emergency services, and the military. That is, if the products ever exist and live up to everyone's claims.

The Time Domain's website is timedomain.com (flash plugin required, tho).

At 5GHz, walls attentuate the signal even more than at 2.4GHz, the 802.11b standard, so it remains to be seen how close you will get to the 54MBs signalling rate. With the MAC protocol overhead, even in the best enviroment, you'll loose between 30-50%. This is not just a wireless feature, 100 MBs Ethernet also gets a MAC penalty, just not as much as wireless.

What will really impress the geek in all of us is a new wireless products utilizing Ultra Wide Band (UWB) techniques. A UWB radio tranmits its signal using gaussian monocycles instead of sine waves. With ultra-low power emmisions and over 2GHz of spectrum, conventional narrow-band systems are not disturbed and UWB signals appear as white noise making UWB very hard to detect. Highspeed bandwith, precise precision and location, and RADAR capabilities are being demonstrated today. A leader in the field is Time Domain. The FCC is expected to rule on legalizing UWB this fall.

Current CDMA/TDMA cellphones pump out 0.6 watts (carphones/bag phones use 3.0 watts). As the power decreases the health risks will decrease aswell, even if they are minute to begin with.

Solution? Move to the next generation of Cellular Phones, ala Time Domain's Time Modulated UltraWideband Impulse tech, or what ever they are calling it these days. From what I understand, phones built upon this tech would only produce 0.0025watts... Hell I make more power belching.

(To avoid some confusion, I'm going to use one definition of bandwidth: How many bits you can squeeze into a certain amount of time. The concept of a frequency band becomes somewhat moot...)

This technology could be used to create sort of an ultra-high-bandwidth wireless world wide web. There would really be no need for any other form of radio transmission, since other formats are less efficient by nature. Once fully developed, the bandwidth would be astonishing. (But then, when is anything really fully developed?) Think of it -- instead of hogging up one whole frequency band (or more), your transmitter only uses nanoseconds of time to transmit bits into a local area, only when it needs it. Transmitters share the space. This is a lot like how a LAN works, but with much more bandwidth.

Here's the kicker: Unlike a LAN, collisions become near impossible, because receivers use the transmitter's location to weed the signal out from the noise of other sources. Even if two transmitters send a pulse at the exact same time, the receiver only pays attention to the portion of the signal that is coming from the transmitter that it is listening to. Of course, sometimes another signal will overwhelm everything else, (like a lightning strike nearby) but these are rare.

This is like listening to a person talking on a subway. You can hear them clearly over the noise because your brain singles out not only the sound but the location of the speaker. You can selectively ignore other sounds coming from different locations, even if many people are talking.

This technology covers a local area -- one transmitter can't send a signal across the world. It's great for low-power transmissions between two nearby devices (feet or miles). To move data further, a repeater could pick up the signals and send them where necessary. Nobody will need to license anything, just get a box to hook up or a device with it built-in, and either join some local connections or pay a service provider for access to the global net. Heck, the devices themselves could act as repeaters, who needs ISP's?

This is scary technology to many because a lot of people will lose money if it becomes established. It has the potential to place wireless technology directly into the hands of the people, cutting out the middleman.

On a lighter note... This type of transmission is indistinguishable from noise, if you don't have the right receiver that "knows" the transmitter that it's listening to. I have a good idea why SETI hasn't been able to hear anything... :>8-)

The future of wireless is in TM-UWB (Time Modulated - Ultra Wide Band). Follow this link for details. Basically, TM-UWB involves the transmission of precisely timed pulses which can be decoded by a receiver and compared to a standard pulse stream. The only thing that matters so far as data transfer is concerned is how much the actual pulse differs in time from the standard stream. There is no carrier frequency. With the ability to place pulses a trillionth of a second apart...the bandwidth is huge. There are a lot of details/issues that I don't yet comprehend, but it sounds fascinating.