Started by whatevah, March 31, 2005, 05:04:15 pm
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Quotewe were going to play with that in DE, in fact we were working on it with some Army MARS folks. Got pretty nice results on a preliminary test, but things got in the way from actually being able to test it air-to-ground. You can see what equipment we used at http://www.armymars.net/ArmyMARS/CAP/index.html Now, we're playing with some expensive spread-spectrum 900mhz radios from FreeWave. We got close to 15 miles out in one test before we had to turn back to work on another mission...The tech guys in my wing are really enthused about this project, and so are some people in my state government (Emergency Management and Dept of Transportation)... I'm working on a stripped down linux install (probably based on Suse 9.1 Personal) using ncftp and netpbm to process and transmit files with a minimum of user interaction. The idea is, give a mission scanner a 5 minute lesson on how to use the software and send them on their merry mission. The scanner takes pictures with a hi-res digital camera, removes the card and places it in the laptop, while he inserts another card. He opens the laptop screen and clicks on an icon, and he picks what server to transfer the files to (this way, you can transmit files to a specific mission base, or through the internet to a "customer" like FEMA or something).
QuoteAlthough it's not commonly thought of as "WiFi", it IS a form of wireless ethernet... My wing heard about a company "Freewave" that produces commercial wireless ethernet equipment, and a test a CAP member did in California. We've acquired 2 of these modems through a grant, and earlier today, we did our first true test. Piggy-backing on another mission, we put a laptop in the back seat of a 172 with an antenna for the ethernet bridge on the back window of the aircraft. Due to the angle of the antenna, we couldn't get a signal when the airplane was flying at or away from our receiving location, but at 15 miles out, the aircraft was flying perpendicular to us, and we had a strong signal around 90kpbs. The max rated speed for this equipment is around 100kbps, which we hit up to 12miles out (need to recheck distances using a better antenna setup). For the test, we had one bridge connected to a network hub, using a generic PC with FileZilla 2.2.8 on the receiving end of the connection, and another bridge connected to a laptop with FileZilla Server 0.9.2 in the aircraft. The server was set to use compression, which helps with some files, but not JPEG files, which is what we were primarily sending. A 300KB MS Word document was compressed to 25% of its original size, which is impressive, but JPEG files received less than one percent compression. Since it was just a network bridge, we technically could have just used Windows' file sharing protocols and all the network overhead that goes with it, but "we" decided to try something a little faster. After the aircrew had taken some digital pictures for their primary practice mission, they were diverted to fly away from our mobile base to see how far we could get as a test. The signal quality was excellent, but we needed to turn them back to finish their mission after they hit 15 miles. Future tests will be done to get a better judge of distance capabilities and altitude needed for good line of sight (for our terrain). The previously mentioned test in California claimed 40 nautical miles, if we can do close to that, it would be a significant boost to our Disaster Relief mission, since our state is only 90 miles long. If future tests are successful, there are chances of local agencies purchasing extra bridges for permanent installation at various locations. I realize that for larger wings, this might not be a good idea, but for our small state, it's wonderful. Our mobile command center can be from one tip of the state to the other in under 3 hours, and with 30m+ range from the aircraft, you can cover a lot of area doing post-disaster imaging. Are any other units experimenting with anything similar? Yes, there is SDIS, which has a better coverage thanks to the satelite, but it's a lot more expensive than the Freewave modems, and one (even two) per region just isn't enough, and you have to compress the files down. With the ethernet bridge, you can take as long as you want to send the file. The images we used were full-res files from the digital camera, not images compressed down to email size. More info on the ethernet bridge: http://www.freewave.com/fgr900ethernet.html
Quoteoh, I forgot to post an update... in a distance test, we managed 41 miles! Due to a software problem, we couldn't test throughput, but latency times were low, which is encouraging. We're moving ahead and making up kits and instruction guides, and software to automate the image processing... It'll be official unveiled and shown off at our wing conference at the end of January.
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