May 17, 2012

Extending The GNSS Simulator In The R&S®SMBV100A With 24 Satellites For GNSS Hybrid Constellations

Rohde & Schwarz has launched the R&S®SMBV-K96 option, extending the global navigation satellite system (GNSS) simulator in the R&S®SMBV100A vector signal generator for up to 24 satellites . This extension offers a perfect fit for hybrid receivers that support more than one GNSS system.

The new R&S®SMBV-K96 extension for up to 24 satellites meets the requirements of state-of-the-art receiver technology, where it is possible to switch from a single system receiver (typically GPS) to a dual-mode receiver supporting GPS and Glonass.

  • Simulation of GPS C/A and Glonass signals from up to 24 GNSS satellites
  • Increase in the multipath budget of GPS C/A and Glonass signals to 24 if R&S®SMBV K92 is additionally installed
  • The extension requires the R&S®SMBV-K91 option

Why are 24 satellites needed?
With GPS, a receiver can see a maximum of 12 satellites from one position on earth. The same is true for Glonass, which is the second worldwide GNSS system. So to simulate the complete maximum set, a dual-mode receiver for GPS and Glonass can see a maximum of 12 + 12 = 24 satellites. Glonass coverage is preferential in Russia but also used worldwide, enabling users to globally benefit from Glonass.

In an open environment such as on a highway, the receiver can see many satellites distributed across the horizon, even if only one system (e.g. GPS) is supported, and this works very well. But in a dense city with many skyscrapers, only a limited number of satellites can be seen, since signals are often blocked by buildings. If the receiver is able to look for not only GPS but also Glonass satellites, it can still see enough satellites to provide a stable location fix, which may not be possible if only GPS is supported.