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A homemade receiver for GPS and GLONASS satellites
- iaw 10y agoFYI, The technology detailed on that page is governed by ITAR for US citizens. You can end up facing some serious penalties if you are a US citizen and build a GPS receiver (capable of operating > 10,000 feet) for someone in another country.
- mikeyouse 10y agoThey relaxed the ITAR restrictions on GPS quite a bit a few years ago. The new rules only involve decryption of the precise positioning signals, steerable antennas designed to avoid jamming, and GPS designed as missile guidance technology (ability to deliver 500kg payload at least 300km). http://www.insidegnss.com/node/4051 http://www.insidegnss.com/node/4051
- LeifCarrotson 10y agoAdditionally, the previous restrictions specified they were to be inoperable when BOTH above 18,000m altitude (not 10,000 ft) AND 515 m/s velocity. Many manufacturers accomplished this by restricting operation when either condition was sensed, but you could find some that could be used in applications that only violated one condition, like high-altitude balloons.
- ams6110 10y agoSo does that mean my phone's GPS won't work in flight on a commercial jetliner? (never tried it).
- fnj 10y agoCommercial jetliners never fly at 18,000 m (nor at 515 m/s). Max is about 11,000 m or so, and about 250 m/s. It would be interesting to know if consumer GPS ever worked aboard the Concorde.
- knz 10y agoIf you're going to use the Concorde for a speed test then you might as well also test the SR-71. For..er... science!
- DiabloD3 10y agoThe story: http://oppositelock.kinja.com/favorite-sr-71-story-1079127041 http://oppositelock.kinja.com/favorite-sr-71-story-107912704... Merry Christmas to everyone who hasn't read it yet.
- sitic 10y agoThis one is my favorite story from the same Blackbird pilot (Brian Shul): https://www.reddit.com/r/todayilearned/comments/2q2ctc/til_that_the_sr71_blackbird_was_so_fast_that_a/cn26i0z/ https://www.reddit.com/r/todayilearned/comments/2q2ctc/til_t... Bonus story, also from Brian Shul: https://www.reddit.com/r/MilitaryPorn/comments/1mimvu/80000_ft_where_the_wild_blue_yonder_meets_the/cc9ze0p/ https://www.reddit.com/r/MilitaryPorn/comments/1mimvu/80000_...
- 13of40 10y agoA couple of years back my kid got the GPS working on his Windows phone, using some 3rd party app that cut through all of the other location detection crap. We were able to track our speed and location in a passenger jet flying out of Maui.
- anticodon 10y agoYou can use offline GPS navigation software on a plane. I did it several times, just as my friends. I use LG G3 and OsmAnd app. LG G3 has very poor GPS antenna so you have to press the phone against the plane window and wait for 4-5 minutes before it finds sufficient number of sattelites.
- 4ad 10y agoIf you take pictures from the air with an iPhone, they will be geotagged. When you land and you get internet back, they will be labeled correctly in Photos.app. Other phones had trouble finding GPS signal in airplanes, but I never had a problem with my iPhone 6s or iPhone 7.
- toomuchtodo 10y ago> The new rules only involve decryption of the precise positioning signals, steerable antennas designed to avoid jamming, and GPS designed as missile guidance technology (ability to deliver 500kg payload at least 300km). Now I want to publish all of that info in a book and distribute it world wide, a la PGP Philip Zimmerman style. ITAR...Pssssha!
- brian-armstrong 10y agoSomehow the potential repercussions for this feel worse - your information could be used to guide actual missiles against people. I know you can make similar arguments with encryption but at least that can't deliver explosive payloads by itself
- toomuchtodo 10y agoI doubt that's going to be a vector compared to driving a truck into a Christmas market. Encryption is far more dangerous than precision positioning, but it should still be freely available.
- avar 10y agoDo these ITAR restrictions only apply to GPS, or also GLONASS / Galileo etc.?
- nradov 10y agoThe ITAR regulations apply to any type of satellite navigation. The speed and altitude restrictions were removed in 2014. https://www.regulations.gov/document?D=DOS_FRDOC_0001-3863 https://www.regulations.gov/document?D=DOS_FRDOC_0001-3863 https://www.regulations.gov/document?D=DOS-2014-0017-0001 https://www.regulations.gov/document?D=DOS-2014-0017-0001
- jrockway 10y agoIs there any case law on this subject? Instructions for building a GPS receiver (which is what source code is) seems like a logical extension of Bernstein v. US.
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- ohazi 10y agoThat helical antenna is gorgeous. There's a similar project that used an FPGA here: http://www.aholme.co.uk/GPS/Main.htm http://www.aholme.co.uk/GPS/Main.htm
- nateguchi 10y agoThat must be one of the most professional looking electronics DIY project I've seen for a while.
- brian-armstrong 10y agoThat article is where I found the link to this one, actually. The FPGA one is more sophisticated for sure but the article doesn't explain how the GPS signals work quite as well, while the older one does a good job of putting GPS into context. I think my favorite part of GPS is that it uses CDMA to set all of the transmissions on top of each other on the same frequency channel. It's incredible that this technique can recover signals under the termal noise floor.
- prashnts 10y agoCan anyone suggest a good textbook for Radio, Antenna theory, Ham radio in general? I'm quite interested in learning these but most books I've come across either seem too basic, or too advanced. I am a math major so mathematics isn't a problem for me if it is supported with enough text. Thanks!
- brian-armstrong 10y agoThose are pretty wildly different topics For "radio" I'd recommend reading on Analog and Digital Signal Processing. Antenna theory is an entirely separate field which you'd want to reference specifically. Ham is more of of the culture/context surrounding ham radio, and for that I'd recommend one of the ARRL exam study books from http://www.arrl.org/shop/What-s-New http://www.arrl.org/shop/What-s-New though for the easier tests these are pretty light on technicals and are more about policy and good radio operator behavior
- deleted 10y ago[deleted]
- prashnts 10y agoAh, you're right -- I meant that if there's some reference covering the relevant topics that'd be great. Thanks for the clarification! The ARRL study books look good too.
- b_emery 10y agoThe Radar Handbook by Merrill Skolnik often comes up as a basic reference covering some of these topics, radar and radio being intimately related. Plus the pdf is usually around: http://airspot.ru/book/file/961/radar_handbook.pdf http://airspot.ru/book/file/961/radar_handbook.pdf
- NelsonMinar 10y agoArchive link: http://archive.is/AMNvJ http://archive.is/AMNvJ
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- aw3c2 10y agoThis is the internet I know and love. Pure content created by someone loving what they are doing. No bullshit blingbling, no ads, no tracking, just sharing experiences and knowledge. Wonderful and inspiring!
- brian-armstrong 10y agoWell, to be fair, this article is from the 90s. It's probably just a reflection of the times it was made in.
- sasas 10y agoAlso a possible reflection on this fact; the site may not have been designed to handle the influx of traffic we just sent it from HN as it's now unreachable. Here is the archive.org mirror: https://web-beta.archive.org/web/20161109161053/http://lea.hamradio.si/~s53mv/navsats/theory.html https://web-beta.archive.org/web/20161109161053/http://lea.h...
- rckclmbr 10y agoThere's no Under Construction gif, definitely not a reflection of the times. http://www.netanimations.net/fire-under-construction-animation.gif http://www.netanimations.net/fire-under-construction-animati...
- fapjacks 10y agoThe websites of ham radio operators often are like this. It seems to be a common thread, for whatever reason. It's nice.
- wwkeyboard 10y agoIf you want to view a site over an amateur radio link it can't include advertisements, and the link will be slow compared to any of the 802.11 modes. Plus lots of hams learned web design in the 90's. edit: not an hour later I land on this site http://www.phonestack.com/farhan/bitx.html http://www.phonestack.com/farhan/bitx.html
- imperialdroid88 10y agoGLONASS wasn't even around in the 90s what are you smoking because you gotta pass it and not bogart the weed
- rlanday 10y agoYes it was… https://en.wikipedia.org/wiki/History_of_GLONASS https://en.wikipedia.org/wiki/History_of_GLONASS “The first launch took place in 1982. Until its dissolution in 1991, the Soviet Union launched 43 GLONASS-related satellites. Work on the system was continued by the Russian Federation which brought it its full operational capability in 1995. In the following years, the system fell into disrepair due to the economic crisis in the country and diminished space funding.”
- Stratoscope 10y agoIf you read the article, you will see Table 5 which lists the launch dates of a couple dozen GLONASS satellites from 1988 through 1993. (If the site is not responding, try the archive link listed elsewhere on this HN page.)
- dang 10y agoPlease don't do this here. We detached this subthread from https://news.ycombinator.com/item?id=13247447 https://news.ycombinator.com/item?id=13247447 and marked it off-topic.
- Sephr 10y agoDoes anyone have a mirror including http://lea.hamradio.si/~s53mv/navsats/software.zip http://lea.hamradio.si/~s53mv/navsats/software.zip ?
- jakeogh 10y agohttps://web-beta.archive.org/web/20160322050334/http://lea.hamradio.si/~s53mv/navsats/software.zip https://web-beta.archive.org/web/20160322050334/http://lea.h...
- drmpeg 10y agoModern day technique with SDR. https://www.youtube.com/watch?v=uf2vatqek_o https://www.youtube.com/watch?v=uf2vatqek_o
- the_duke 10y agoPft, no Galileo support? Just pathethic... (Kidding of course. Awesome write-up.)
- dharma1 10y agoFor affordable and small high precision (centimeter level) GNSS, I really like this https://emlid.com/reach/ https://emlid.com/reach/