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Russian GPS Alternative Near Completion 177

Posted by ScuttleMonkey
from the better-late-than-never dept.
Russia has successfully launched another round of GLONASS satellites bringing the grand total to 18 of the navigational units online. "The GPS competitor -- first begun in the Soviet era and only recently revived after years of post-collapse neglect -- is now theoretically capable of providing coverage to the entire Russian territory, with First Deputy Prime Minister Sergei Ivanov claiming that the first compatible consumer devices will be available in the middle of next year. By 2010 Russia plans to open the system up to outside nations as well, contributing to an eventual three- or even four-system global market"
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Russian GPS Alternative Near Completion

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  • by PktLoss (647983) on Wednesday December 26, 2007 @03:19PM (#21823842) Homepage Journal
    In Soviet Russia, Satelite tracks you!
  • So... (Score:3, Insightful)

    by milsoRgen (1016505) on Wednesday December 26, 2007 @03:19PM (#21823850) Homepage
    ...we're going to have more choice in satellite positioning systems then we do with satellite radio?
  • What was the saying? "A man with one clock always knows what time it is -- a man with two clocks is never sure"?

    I suppose if every one of these systems provides a precise enough location, for most purposes it won't matter if they all conflict with one another by a meter or so.
    • by willgps (939538) on Wednesday December 26, 2007 @04:14PM (#21824332)
      Firstly, with regular GPS you already have more than one clock - one on your receiver, and one on each of the satellites. You can directly solve for the receiver clock bias by taking measurements to an extra satellite, hence the need to track 4 satellites for a three-dimensional position fix because of the four unknowns ( X, Y, Z, and time.)

      Secondly, while GPS and GLONASS use different terrestrial reference frames, there exists a well defined transform between the WGS-84 used by GPS and the PZ-90 used in GLONASS.

      Finally, in a combined GPS/GLONASS receiver it is not optimal to calculate a separate position solution for each constellation. If you track a few more satellites, you can solve directly for the clock offset between the two navigation systems and treat the range measurements as if they were all from one giant 60 satellite constellation. This actually gives you much better satellite geometry, and is often more accurate than any single navigation system on its own.

      There is much research being done on the effects of combined constellations with GPS,GLONASS, Galileo and the Chinese Compass system.
      • by hey! (33014) on Wednesday December 26, 2007 @04:49PM (#21824620) Homepage Journal
        My own experiments with GPS would bear this out.

        When I was doing more of this stuff, clients would sometimes take several GPS points, and find to their delite that nearly always the three points were much closer than the supposed precision of plain old non-differential GPS. As a result, they began to assume the system had more precision than rated.

        Intrigued by this I set up a fixed station that tracked all the fixes coming out of the receiver over several hour period. What I found is that sequential readings tended to be strongly correlated to their immediate predecessors but weakly correlated to fixes taken much earlier. Essentially the receiver would report all the points as being in a smallish bucket a couple of meters wide, but every fifteen or twenty minutes it would pick up the bucket and put it a different place five or even ten meters away. Then there'd be a run for fifteen minutes or so at the new "bucket position", after which the bucket would move once again.

        The way I interpret this is that the various sources of error change as a satellite's position changes. Perhaps a mountain range gives a strong reflection in one position or not another, or perhaps a new satellite rises (or an old one sets), leading to a whole new set of data.

        So, it stands to reason that having more than twice the number of satellites means that the various random sources of error would tend to be averaged out more, provided any difference between the old and new system could be accounted for systematically.
        • by C. Alan (623148)
          Back when we were purchasing land surveying grade recievers for our company, the sales man explained to us that 10-15 feet was the best that was avalible due to the signal getting distorted by passing through the atmosphere. This is why RTK or DGPS is used in land surveying with multiple recievers.
        • by joggle (594025) on Wednesday December 26, 2007 @06:57PM (#21825536) Homepage Journal

          Hmmm, that's odd. I would expect to see this behavior if the GPS was trying to resolve the integeter ambiguity of the phase measurement. Survey-quality receivers do this by using both GPS frequencies in combination with corrections from a reference GPS receiver at a previously surveyed position. Any GPS can trivially determine the fraction of the phase cycle between it and the satellite but must determine the number of cycles via statistical methods using good quality measurements and initial guesses. If this number is estimated correctly, the distance between the satellite and receiver is known to within a couple of centimeters instantaneously.

          These integer ambiguities are solved for at least 4 satellites simultaneously. There are always several combination of cycle counts that will result in a good position. However, these candidates may be several meters apart. If the initial guess is wrong, it may be several minutes before a new candidate is chosen and then the switch is instantaneous (hence the jump you observed).

          I didn't think a consumer single-frequency receiver could do this, even with WAAS. I would expect a single-frequency receiver to simply drift around the true position without any sudden jumps (assuming there are at least 5 satellites visible at any given point in time and there aren't any strong reflectors nearby--such as a tall building). I know consumer units take phase measurements, but all of the ones I've seen have had rather poor measurement quality due mainly to the cheap antennas they use (survey quality GPS antennas are at least 8 inches in diameter and cost hundreds, even thousands of dollars if they use a choke ring to mitigate multipath).

      • Basically you need one satellite to resolve each variable in the solution. Thus if you hook up GPS and GLONASS it costs you one saltellite. THus, adding 5 GLONASS satellites to the solution is the same as more or less equivalent to adding 4 GPS satellites. There are many top-end GPS receivers that do this to great effect.
    • I suppose if every one of these systems provides a precise enough location, for most purposes it won't matter if they all conflict with one another by a meter or so.
      For your curiosity, one can use GPS signal to get a precision of 2mm. No this isn't an error or bullshit (and it is not DGPS [wikipedia.org]), it's "phase resolution". In short, you use the GPS signal's phase from multiple GPS satellites to get a 2mm spatial resolution. Whether Selective Availability is on or not doesn't matter, but you can do this only in post-processing mode however, not real-time (afaik). A friend was doing his PhD on this. There are a few great applications, such as doing GPS phase-resolution for bridges, thus knowing by how much they move due to traffic, temperature, lateral wind, etc. The funny thing is we don't even know the position of the satellite at such a precision, but it does not matter, we're using the phase of multiple satellites here, not the content of the signal. (I'm not a professional of GPS phase resolution myself, anyone with more knowledge is welcomed to correct me, I'll appreciate :-)

      A little more related to GLONASS, there's COMPASS, the global positioning system of China. It's first satellite was successfully launched last February [computing.co.uk].

      Here I provided (shameless but informative plug) news on Europe's Galileo, which somehow solved their important funding problems [slashgeo.org]. As for GLONASS, Putin himself clearly stated he wants GLONASS back to full speed [blogspot.com].

      Anyone avid of GPS-related news is welcomed here [slashgeo.org] (this is the GPS topic on Slashgeo, yeah, a plug, but hey, it's right on topic no? And there's no ads whatsoever ;-). Happy holiday time.
      • by C. Alan (623148) on Wednesday December 26, 2007 @06:18PM (#21825198)

        You can already do this with the US based GPS system using OPUS. Forgive my bad html, but here is the link:

        http://www.ngs.noaa.gov/OPUS/ [noaa.gov]

        You have to set up your reciever to log satilite observations over at least 2 hours, and take a reading at least every 5 minutes. Opus uses precises satilite orbital information to post process point information. The accuracy of your results depend upon how long you run your observations, and how many observations you log. I typicall run mine over 4 hours, and get an accuracy of around 4mm horizontal. Opus is a great tool when you need to tie your land survey to WGS84 coordinates, or State plane coordinates.

    • What was the saying? "A man with one clock always knows what time it is -- a man with two clocks is never sure"?


      On the other hand a man with two clocks who averages them can know better than a man with one clock.
      • Re: (Score:3, Funny)

        by Binestar (28861)
        On the other hand a man with two clocks who averages them can know better than a man with one clock.

        I don't know about that. I'd rather have a clock that said 3:15 when it was actually 3:10, than 2 clocks that said 2:20 and 1:45 when it was actually 3:10.
  • better article (Score:5, Informative)

    by Takichi (1053302) on Wednesday December 26, 2007 @03:45PM (#21824096)
    The linked article in the summary doesn't have much more info, but here's a good one. [itar-tass.com]

    They say it can theoretically cover all of Russia because only 13 of the 18 are operational. Here's an interesting quote from the article:

    "The main point is to avoid the 1997 situation, when 24 sputniks were on the orbit, but only the military were making use of the system. However, it is now feared that a similar situation is apt to re-occur, since there are some problems with the development of navigation equipment for the consumers at large, although the constructor-general is trying to cope with them"
    • One thing that would bug me about depending on this system, if I were Russian, is that the Russians are notoriously inept at ensuring long life for their satellites. They tend to just launch a lot of them and accept a short lifespan as they wig out. The US, by contrast, tends to go for gold-plated satellites that live a very long time, and launch far fewer. Is the Russian "shotgun" scheme going to work out for a navigation satellite system? I don't know, but it's a question I'd be asking myself before s
    • by N8F8 (4562)
      I'm pretty sure those clever Chinese engineers will find a way if they think there is a market.
  • by inicom (81356) <aem@ i n i c o m . c om> on Wednesday December 26, 2007 @03:45PM (#21824098) Homepage
    Here's one [iht.com] from the International Herald Tribune.

    Somebody please stomp out myminicity. It's seriously polluting /.
  • Hey, I have a great idea! Aperture Science should launch a GLaDOS satellite!

    Then we can all be test subjects and enjoy delicious and moist cake!
  • by fahrbot-bot (874524) on Wednesday December 26, 2007 @03:54PM (#21824170)
    Hmmm...

    A man with one GPS knows where he is; a man with two is never quite sure.

    [Apologies to Lee Segall.]

  • Yeah! More GPS sat's (Score:5, Informative)

    by C. Alan (623148) on Wednesday December 26, 2007 @04:00PM (#21824216)

    This is good news for land surveyors everywhere. Most all surveyors have switched over to GPS based equipment in the last 10 years. I have been out in the field with GPS equipment, and watched my accuracy go to hell because there were not enough satilites above the horizon. Being able to pull signals from both systems means less downtime for land surveyors, and better field accuracy.

    Engaget does not have one fact correct. Topcon has been offering surveying grade GPS units that can pull signals from both the US based system, and the GLONASS system for at least 3 years.

    http://www.topconpositioning.com/uploads/tx_tttopconproducts/HiPerPro_Broch_REVB.pdf [topconpositioning.com]

    BTW, if you are wondering how land surveyors get the accuracy down to 1cm for gps, it involves using two GPS recievers and a process called RTK. In RTK one reciever (the base) is placed over a known point, and equipped with a radio transmitter. This station transmitts a correction for the GPS signal to the other reciever (the rover). The results are very accurate, and our firm has pretty much stopped using conventional total station, except where vertical accuracy is an issue (gps is only good to 10cm in vertical accuracy).

    • RTK is pretty much the same as DGPS. If you're a land surveyor and within 200-400 miles of a coast guard station transmitting DGPS correction signals, you have no need to have the "base" system at a known point.

      Also, can you provide some geographic reference to where you haven't had enough satellites above the horizon?

      • by LWATCDR (28044)
        I would think that RTK would be more accurate than DGPS.
        If the Base system is at a known point only a few hundred feet from the rover then it should be a little more accurate than DGPS. From the Wikipedia.
        "The United States Federal Radionavigation Plan and the IALA Recommendation on the Performance and Monitoring of DGNSS Services in the Band 283.5-325 kHz cite the United States Department of Transportation's 1993 estimated error growth of 0.67 m per 100 km from the broadcast site but measurements of accura
      • by C. Alan (623148)

        RTK is pretty much the same as DGPS. If you're a land surveyor and within 200-400 miles of a coast guard station transmitting DGPS correction signals, you have no need to have the "base" system at a known point.

        Also, can you provide some geographic reference to where you haven't had enough satellites above the horizon?

        Not exactly. DGPS requires post processing after you get back into the office in order to download the correction files from your reference station. In RTK the correction is done in real

    • Re: (Score:3, Informative)

      by Neil Jansen (955182)

      I have been out in the field with GPS equipment, and watched my accuracy go to hell because there were not enough satilites above the horizon.

      Maybe that was the case 10-15 years ago, but definitely not today. Not only do they have 31 out of 32 possible satellites in use, but there are even a few backup satellites up there in case something happens. On average you can expect 10+ satellites visible at any given time. Don't take my word for it though, you can easily load the current almanac [uscg.gov] into a viewer program and see for yourself.

      If you're still having problems with your GPS receiver, maybe it's time to get a new one..

      • Re: (Score:3, Interesting)

        by maeka (518272)
        If you are getting 10 satellites with strong L2 signals you are lucky. At 40 degrees north I rarely have eight satellites with decent L2 SNRs, and really appreciate the extra 1 to 3 sats GLONASS gives me. I'm talking about a Trimble R8 model 2, arguably the best GPS antenna and receiver on the market today.
  • Why alternatives? (Score:3, Insightful)

    by loonicks (807801) on Wednesday December 26, 2007 @04:22PM (#21824400)
    One of the most compelling reasons for deploying alternatives is that the US controls Navstar GPS. The US government can introduce random errors into the CA (civilian) codes, decreasing the accuracy of GPS receivers. This is called selective availability. US Military receivers can, of course, get the "correct" signal by being loaded with crypto keys to access P(Y) codes. Additionally, CA code (and even P-code), is susceptible to spoofing by the enemy. Obviously, without the right keys, GPS is hardly acceptable as a positioning system for non-US militaries.
    • Re:Why alternatives? (Score:5, Interesting)

      by Local Land Surveyor (1208154) on Wednesday December 26, 2007 @04:50PM (#21824626)
      For those of us in land surveying, having another few satelites is very important if your in a hurry. My current equipment (Topcon Hiper-lite) can obtain accuracy of less than 1 cm in less than 2 minutes just using the US GPS satelites and more accurate in less time using both US GPS and Russian GLONASS. Also, here are a few other interesting facts associated with GPS for Surveyors (who need sub-centimeter accuracy) 1) The more satelites the better (and my equipment which happens to be rebadged JAVAD) has been getting signals from GPS and GLONASS for a few years already, 2) The US stopped encoding the GPS signals under executive directive a year or more ago, and 3) The Eurpoean Union is working to put up their own GPS network which the latest generation of commercial survey grade receivers are already prepared for. So, for those of us whose business requires GPS, the article seems to be more about political posturing and less about anything new system-wise.
      • Re: (Score:3, Funny)

        by C. Alan (623148)
        So you want to start a Leica VS Topcon flame war? No one here but us would understand the references.

        I admit Leica has been behind the ball on adopting GLONASS, but I still like their post processing better. Multiple observations on a single point work out much better in Leica.
      • For those of us in land surveying, having another few satelites is very important if your in a hurry.

        Land surveyors shouldn't be in a hurry in the first place - because their measurements can affect people for generations.
    • The two problems with that that immediately come to mind is: A) the US uses GPS for everything now. For example, aircraft navigation uses the civilian GPS bits. That's why the FAA begged Clinton to permanantly turn off SA.

      B) All the stories you hear about US Military troops using OTS GPS receivers because the Military versions are a) unavailable, b) break more easily, and c) don't work as well.

  • I wonder if the Russian system will have the equivalent offsets that the US system has, you know... to keep terrorists and other miscreants from using them to accurately call in artillery on the local police stations from home made, butane powered potato mortars.
  • Dupe (of a sort) (Score:3, Interesting)

    by joggle (594025) on Wednesday December 26, 2007 @05:18PM (#21824826) Homepage Journal
    This is actually the second time GLONASS has become fully operational. The first time was back on February of 1996 (see 'Understanding GPS Principles and Applications [amazon.com]' for details). However, older satellites started failing soon after and they weren't able to replace them quickly enough so the constellation quickly degraded in functionality.
  • by CFD339 (795926) <<moc.htroneht> <ta> <pwerdna>> on Wednesday December 26, 2007 @05:32PM (#21824910) Homepage Journal

    In Soviet Russia, You give GPS directions!
  • There is a big market for a "free* GPS system. That market is basically "the entire world".

    It gets quite a bit smaller when there's a subscription fee involved. And even that market is quite small when there's a free alternative.

  • So what improvement can be achieved by combining GLONASS & GPS? Another 10 satellites should improve accuracy, but the media isn't covering this.
  • No matter how much petro wealth is created, a nation conceived from a lie can not do great things. At best, they can copy. Even then, poorly.

    I had always hoped that when George Bush looked into Vladimir Putin's eyes, and found someone he could trust, he would force a copy of a biography of George Washington into his hands. It would have given him a recipe to follow.

    Sadly, it was not to be. The Russians are beyond salvation.

    I wish them the best (really, I do).
    • a nation conceived from a lie can not do great things

      Maybe ... but Russia certainly has done some big things!
  • This is going to help.

    If you've ever worked with high-precision GPS gear, you know how frustrating it is. I've used such gear on robot vehicles. Three satellites give you approximate latitude and longitude, but not elevation. With four, you get elevation. With five, Omnistar corrections work and you can get 15cm accuracy. There are many times when you can't see five satellites on land; some may be too low in the sky and blocked by terrain. Plus, some GPS satellites may be down. They're not always opera

  • It's comptetion - it's good for you. Free markets, remember?
  • by tsa (15680)
    And as always, Europe talks about striving to be the forerunner in science and technology, talks some more, makes a halfhearted attempt of achieving the goal, gets into fights with the different parties involved, and is now surpassed by Russia of all countries. I'm ashamed of my continent.

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