Archive for 2007

Selective Availability OFF forever

Saturday, December 15th, 2007

Galileo has the money!!

Wednesday, December 12th, 2007

GGTO – an interesting correction

Thursday, November 8th, 2007

GPS Control Center updated!

Tuesday, October 16th, 2007

Where is GNSS heading

Sunday, September 9th, 2007

RealTrack football (I mean soccer!)

Wednesday, August 15th, 2007

what GNSS signals do we have …

Wednesday, June 13th, 2007

  • C1 ; Ranging to the satellite based on the Civil message.
  • P1 ; Ranging to the satellite based on the Encrypted (high-security) message.
  • L1 ; Number of cycles since satellite acquisition.

  • P2 ; Ranging to the satellite based on the Encrypted (high-security) message.
  • L2 ; Number of cycles since satellite acquisition.

On the real Galileo benefits

Monday, June 4th, 2007

  1. It reduces the pressure on GPS and promotes healthy competition.
  2. It helps to push GPS stakeholders “to stay ahead” of Galileo developments, otherwise we would live in a C1, L1, L2, P2, P1 world for how much longer?
  3. It allows others to develop capabilities complementary to the ones in the US. In the long run having both continents with competent professionals and capable companies helps the overall climate of cooperation and understanding. Pretending GPS can solve all future problems leads us to a terrible state monopoly situation.
  4. Galileo will provide integrity for ALL constellations, after the EGNOS project Europe is a key player in both GPS and GLONASS integrity algorithms so we can get integrity for all from one signal. I doubt GPS or GLONASS would do the same now or in the future.
  5. We have already done it in Europe! following the models of INMARSAT, EUTELSAT and EUMETSAT we have already created large multi-national satellite operators at first fully dependant on ESA for technology and national governments for funding and control and later independent and even completely private. Galileo will follow this same model and all the better for it.

GLONASS and GPS differences

Saturday, April 14th, 2007

  1. GLONASS is not complete. Whereas GPS has 32 satellites transmitting signals GLONASS only has 14 which does not guarantee world-wide coverage.
  2. GLONASS uses FDMA for its transmissions whereas GPS uses CDMA. in FDMA each satellite uses a different frequecy to transmit the same ranging code. in CDMA each satellite uses the same frequency with different ranging codes per satellite.
  3. GLONASS is providing a second Civilian signal on L2 which helps civilian users to properly eliminate the ionospheric error.
  4. GLONASS satellites are upgraded more often. This is due to a russian satellite design constraint or due to cost-saving measures but the GLONASS satellites have to be replaced much more often than GPS ones (every 5 to 7 yrs). This appears as a problem but it allows GLONASS to introduce new capabilities much faster than GPS.

Semana Geomatica

Wednesday, February 28th, 2007