Chronos Technology’s CTL3520 GNSS Interference Locator was used to identify the source of accidental spoofing by a GNSS signal generator affecting numerous smartphones, some profoundly, at the recent ION GNSS+ 2017 conference held 25-29 September in Portland, Oregon, USA.
The GNSS Interference Locator was being exhibited on the booth of Chronos’ US partner NavtechGPS and was used to find and identify the source of the spoofing which it did within a couple of minutes.
Logan Scott of LS Consulting who used the GNSS Interference Locator and identified the source of the interference at the event said “I had no training in how to use the device but found it highly intuitive. Point it at the interference source and the power meter goes up. Point it away and the power meter goes down. Get closer and it goes up more. How hard is that? I had positive ID on the source in less than 2 minutes.”
The interference source was a GNSS simulator which was set to produce signals for 12 January 2014 at a location in Europe. This in effect turned the simulator into a spoofer which caused many mobile phones to stop working correctly in the exhibition hall. Depending on the brand of phone, there were varying degrees of impact.
The unit has been successfully used for location of GPS interference and jamming on many other instances including:
Identifying the source of disruption of a fleet tracking system in Northern Ireland:
Chronos’ customer a mobile operator was experiencing periodic holdover events with its Synchronisation Supply Unit (SSU) for periods of time ranging from a few minutes to a few hours. During one extended event there was a complete loss of satellite signals reported by the SSU. Following an analysis of the events, a Chronos GNSS Interference Locator (CTL3520) and a GNSS Interference Detector & Logger (CTL3510) was issued to a local engineer. The CTL3510 was initially used and detected the presence of an interfering signal. The CTL3520 was subsequently used to locate the source of the interference which lead to GPS jammers being found in two vehicles parked at a neighbouring company whose employees were jamming the company’s tracking system. The company had upgraded and replaced the systems hardware several times in an effort to resolve apparent reliability issues.
Successfully used to detect interfering reradiating antenna on a datacentre roof:
This was a 20 year old rogue GPS antenna. When the native GPS signal is received from the sky it is amplified in the antenna. Poor connections can cause the now relatively powerful GPS signal to be reflected back through the antenna and turn it into a local jammer. This experience also showed that the safe distance to segregate adjacent GPS antennas is considerably underestimated. Some literature suggests that 2m distance between GPS antennas is OK. However, the faulty antenna was at least 20m away from the adjacent antennas. A Chronos engineer visited the datacentre with the handheld GNSS Interference Locator and a rogue antenna was identified and decommissioned the same day. Service levels were instantly improved and therefore the quality of service the data centre offers its customers.
Detecting a reradiating antenna on a telecom switch site roof:
A telecom operator’s site had always experienced GPS signal interference based on a history of alarms and quality metrics being generated by onsite timing equipment. Detection of the issue had remained difficult due to the sporadic nature of events; either quiet periods of months or continuous streams of events for weeks at a time. A Chronos engineer visited the site with a CTL3510 which identified that GPS interference was present and a CTL3520 which pinpointed the faulty antenna within 2 minutes.
Additionally the GNSS Interference Located has successfully been used at a National mapping agency to detect interfering signals from a nearby transmitter; detected cigarette lighter GPS jammers being used for criminal privacy activity and is in use with law enforcement agencies around the world.
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