SEPTENTRIO PolaRx5S, User Manual

Page: 63 / 107

6.2. A I M+: DETECT I NG AND M I T I GAT I NG I NTERFERENCE
6.2 AIM+: Detecting and mitigating
interference
The PolaRx5S is equipped with a sophisticated RF interference monitoring and mitigation
system (A
I M+). To mitigate the e ff ects of narrow-band interference, three notch fi lters can
be con fi gured in either auto or manual mode. These notch fi lters e ff ectively 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 e
ff ects of wideband
interference both intentional and unintentional can be mitigated by turning on the WB I
mitigation system. The WB I system also reduces, more e ff ectively than traditionally used
pulse-blanking methods, the e ff ects of pulsed interferers.
The spectrum view plot
I n 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 MHz indicated. Di ff erent 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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