SEPTENTRIO AsteRx-U3, User Manual

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6.2. AIM+: USING THE SPECTRUM ANALYZER TO
DETECT AND MITIGATE INTERFERENCE
6.2 AIM+: Using the spectrum analyzer to
detect and mitigate interference
The AsteRx-U3 is equipped with a sophisticated RF interference monitoring and mitigation
system (AIM+). To mitigate the effects of narrow-band interference, 3 notch
fi lters can be
con fi gured either in auto or manual mode. These notch fi lters effectively remove a narrow
part of the RF spectrum around the interfering signal. The L2 band being open for use by
radio amateurs is particularly vulnerable to this type of interference. The effects of wideband
interference both intentional and unintentional can be mitigated by turning on the WBI
mitigation system. The WBI system also reduces, more effectively than traditionally used
pulse-blanking methods, the effects of pulsed interferers.
The spectrum view plot
In the Spectrum window of the GNSS menu, you can monitor the RF spectrum and con fi gure
three separate notch fi lters to cancel out narrowband interference. Figure 6-2 shows the L2
frequency band with the GPS L2P signal at 1227.60 indicated. Different bands can be viewed
by clicking on the
‘ Show table ’ button as shown. The spectrum is computed from baseband
samples taken at the output of the receiver ’ s analog to digital converters.
Figure 6-2: The RF spectrum of the L2 Band
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