Satellite Navigation current status

The situation with the Global Navigation Satellite Systems is not easy to predict so for now just explaining the current situation may illuminate what could happen in the near future.

We currently have only free signals. This is sometimes lost on regular users, the two flying constellations GPS and GLONASS offer services that are essentially free. I say essentially because obviously you have to buy a receiver, but there is a huge range of GNSS receivers so the good news is that there is a receiver out there for everyone! In any case the signals any receiver uses to calculate position and to ‘navigate’ are completely free.

The only difference between services in GPS and GLONASS is ‘open’ or ‘restricted’, the latter is only available to authorised users which can buy athorised receivers (military users, etc) so they will not be discussed further. In any case both services are free as the signals emmitted from the satellites can be received by any GNSS receiver.

For the future we assume that Galileo (Europe) and Compass (China) will also fly satellite constellations to provide navigation services. All of these systems should be interoperable but so far only GPS and Galileo have done the difficult work of properly coordinating the signals so as to provide interoperability.

Such interoperability is difficult at the moment since GPS and GLONASS do not interoperate very well. Of course the systems were designed during the Cold War so interoperability was never considered, but the decision of GLONASS to continue using FDMA instead of CDMA as GPS and Galileo use means that GLONASS could be relegated. The complexity of including FDMA and CDMA technology in a receiver would not be cost effective for the mass market. For high accuracy applications, where more signals means increased accuracy, as soon as an option exists most high-end receivers will use only the CDMA systems.

Therefore I predict that multiple system receivers (GPS, GLONASS, Galileo, Compass) will be very limited. On the other hand if GLONASS and Compass agree to interoperability terms with GPS and Galileo more 4-system receivers will be available in the future, otherwise GPS+Galileo receivers will dominate the high-end market and GLONASS receivers will become even more difficult to find!

Of course I could be wrong, what do you think?

2 Responses to “Satellite Navigation current status”

  1. Springinhetveld Says:

    Well the internal Chinese market is really huge. So compass/Beidou receivers will certainly be available and extremely cheap. Will be interesting to see if GPS and/or Galileo can compete with that.

    In case the systems are truely interoperable the cost for multi system reciever will really be limited. There are already 48 channel chips available today and they can track any system as long as they are truely interoperable.

    I have little knowledge about the Beidou/Compass signals. But for GLONASS it seems that they are heading towards a CDMA system as well. And if the Russians put their mind to something they are usually quite successful. They came to the moon first (not with people but much more effictively with a robot) and GLONASS was in service before GPS was….

    So, I think the GNSS future looks bright and 2008 (and 2009) will be really interesting!

  2. nacho Says:

    Agreed!! it looks very bright as competition usually makes things better for sure

    But the hard work is making all of them truly interoperable so that any new navigation message on L1 does not interfere with the GPS/Galileo ones, we will see. otherwise we could get terrible interference and then the situation would actually be worse!! but i doubt they (US and Europe) will let that happen.

    On the russian/chinese capabilities I do not doubt that they are capable but as their internal markets tend to be very limited usually their high-technology, high-precision applications are not top of the world! I think that only when your internal markets are very developed then you produce very high quality precision technology for sustained periods of time. I obviously have a bias in this comment being european!! … For consumer goods we all buy chinese made merchandise, but the features and inventions inside your iPod did not come from China even if was made there! and the same for aircraft, super-computers, brain scanners, mri scanners, high end cars, atomic clocks, etc, etc. But again I have my biases since I live here!!

    in any case I wish everyone all the best and I agree we have a great future in the Satellite Navigation field!

    all the best,

    Nacho

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