Inside GNSS Media & Research

MAR-APR 2018

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M A R C H / A P R I L 2 0 1 8 InsideGNSS 37 TYPES OF INTERFERENCE Poss, whose storied track record with the military makes him a leading expert on Unmanned Aircraft Systems (UAS), talked about both intentional and unintentional interference. In a real-time survey of attendees, seven in 10 indicated that they had experienced interference, a f igure that was a little higher than Poss had anticipated. There are a lot of folks out there that think they've got interference, but are not quite sure," Poss said when the poll question results were delivered. "But I'll tell you what my experience in the Air Force is that there are all types of interferences that you just never knew in a lot of cases because [back then] we didn't have advanced software and techniques that we're going to be talking about today." He said the Air Force conducted extensive tests and training sessions in the 1990s to combat jam- ming and to learn how to make GPS as secure and robust as possible. Some of the findings included a bigger dependence on GPS than expected at that time, and also some unexpected interferers, namely a cigarette charger that can double up as an effec- tive GPS jammer. "I guarantee that if you have some kind of emit- ting device that puts out RF energy you're going to take out a chunk of that GPS. So, it turned out to be a really big problem both nationally and inter- nationally. Unintentional GPS interference was a big deal around the world and is a big deal in the Air Force." INTERFERENCE TOOLKIT During the Munich Satellite Navigation Summit, Kennedy wa s a pa nelist of a session titled: "Authentication for GNSS: A Real Need for New Applications." In the webinar she stated that the time has come for a product like the Interference Toolkit. "When we were planning our OEM7 generation of precise GNSS receivers we knew it was time to introduce interference detection and mitigation ca- pability," she said. "Interference effects can be dif- ficult to diagnose and complicated to track down. We learned this in our own developments and from ADDITIONAL SUPPORT •  Contact if further assistance is required to l ocate previous publications on mitigation. •  V isit to w atch Interference Mitigation videos and find related product i nformation. •  V isit to s ign u p fo r fe ature a nd P C software updates on NovAtel's Interference Toolkit. THE PANELISTS Paul Alves, Principal Research Engineer, Applied Research Team, NovAtel Sandy Kennedy, Chief Engineer of Receiver Cards, NovAtel James Poss, Maj Gen (Ret) CEO of ISR Ideas John Schleppe, Engineering Fellow and Manager of Research NovAtel HAT ATTENDEE ANTED TO KNO Participants had the chance to ask questions during the webinar. Here are a few of those questions: •  Do the filters in the ITK preserve phase? •  C an you detect out of band interference and what would that l ook like on a spectrum plot? •  C an the ITK identify the type of jammer I am encountering? •  D o we have a way to notch out certain bands in the receiver tracking aside from using external notch filters? •  I s it possible to find the direction and the distance of your i nterference source using these techniques? •  D oes Loran still have a role when providing backup to GPS, o r is it completely shut down? •  In the Calgary case study, was the video transmitter perfor- mance strong enough to affect the positioning performance o f the receiver? •  I n a UAV application can the PwrPak7 internal memory be u sed for logging data during flight to enable you to do post- processing to evaluate any interference? •  C an the Interference Toolkit be used at GLONASS frequencies? •  I s RAIM a good option for mitigation interference? TO WATCH THE FULL WEBINAR, GO TO: https://register.

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