Within any GNSS receiver, an operator is looking to balance available signals with potential interference by selectively applying filtering protection.
ITK incorporates a spectrum analyzer specific for GNSS frequencies that auto detects in-band and out-of-band interference and allows users to see the RF spectrum levels using NovAtel Connect™ 2.0, a GUI that lets operators communicate and configure receivers via serial port, USB or Ethernet connection.
The analyzer displays a 100 MHz wide frequency spectrum—far more bandwidth than a typical receiver would have or need, which is 25 MHz.
Patrick Marvin Casiano, Applied Technology Group Lead at NovAtel, explains, “The Interference Toolkit allows operators to identify distinct features in the interspectrum displays and then adjust the spectrum for easier viewing. It’s a bigger picture view because of the wider bandwidth. For instance, we can detect if there is a spike in the frequency satellite-based communication systems such as Globalstar or Inmarsat, which might be affecting performance. Other onboard frequency spectrum analyzers don’t offer that; they only offer the bandwidth that the receiver needs.”
The frequency spectrum map produced by the analyzer clearly shows the shape of the spectrum (in the data plot) and the changes due to interference.
Before ITK, Casiano recalls one customer who was in the validation phase of the development of an integrated smart antenna receiver, but he kept getting interference on one of the bands. After considerable time and money trying to determine the interference, the team called in an RF consultant to determine the source of the interference.
“It turns out, the PCs that were used for performance validation were the cause of the performance deficiency. If the development team had the Interference Toolkit, they would have pinpointed the 1.6 GHz signal interference frequency, which would have led them to DDR memory on the laptop that was sitting beside the antenna.”
Mitigation of the interference, in this case, was to simply move the PCs further away from the receiver.