A few years ago, when satellites were advertised as the only aviation navigation option from takeoff to touchdown, former FAA administrator Langhorne Bond painted a picture of a dark winter night with below-limit weather conditions on the east coast. In this scenario, he explained, terrorist gps jammercould become “weapons of mass destruction”. The FAA shook it off as unsubstantiated speculation. But in a recent report on GPS-dependent ADS-B, the Inspector General of DOT took the matter very seriously and called on the FAA to “work with US intelligence agencies to assess such potential threats.”
Surprisingly, it turns out that today the most likely carriers of these weapons of mass destruction are the good boys and girls who power the country’s 18-wheel fleet. Where from? Blame the ubiquity of GPS and its ever-growing applications. Almost all large trucks now carry small GPS receivers in their cabins, along with accompanying cell phones that allow dispatchers to monitor progress without speaking to the driver.
And yes, you guessed it. If a driver wants to make an unauthorized stop for a coffee or whatever, he sticks a small GPS jammer in the cigarette lighter and floods the weak satellite signals with an interference hash. To counteract this, the developers of the tracking system found that they could roughly triangulate the location of the cell phone from three cell phone masts. In response, newer GPS tracking devices can block frequencies used. now also disrupt incoming mobile phone queries and prevent triangulation attempts. The cat-and-mouse game continues.
And these jammers are cheap. At a New Year’s sale on the Internet, a Chinese GPS / cell phone unit was offered for $ 22.65. However, the range of its jamming signals was only a little over five meters, which would likely scare off most potential buyers, although it would be sufficient to disable the GPS and associated cellphone receivers on a truck cab roof above the driver’s head. But most customers probably want more performance and opt for muscular units with a range of three miles or more. A macho thing, maybe, but that’s where the trouble starts, like at New York’s Liberty International Airport.
During the last test phase of Newark’s newly installed GPS Laas precision approach aid on runway 29, the system switched off frequently and inexplicably. The cause was eventually found as a malfunction caused by high-performance GPS jammers on trucks that drove past the nearby New Jersey Turnpike.
This has put the owners of the Laas equipment – the New York and New Jersey Port Authority (PANYNJ) – as well as Continental Airlines and the FAA in a kind of dilemma. In a December 2008 press release from PANYNJ, the agency estimated that it would spend $ 2.5 million on the purchase, installation, and maintenance of the floor system; Continental would spend about $ 1.1 million to equip 15 pilots for aircraft and training, and the FAA would commit to $ 2.5 million for technology assessment. The FAA recently reported that Continental had equipped 18 Boeing 737NGs by August 2010.
Until the risk of interference is mitigated, Newark’s Lasa installation cannot be certified for IFR approaches. AIN is aware that Honeywell – the manufacturer of the system – is planning an interference mitigation project (but not necessarily a definitive solution) that will be ready for FAA testing and certification by summer to move to Laas for the other headquarters of Continental to be scheduled in Houston and to retrofit the Newark system.
The legal questions related to GPS Jammer are not entirely clear. It is certainly illegal to intentionally disrupt state or federal agencies or public transportation and security, the deliberate use of lasers against aircraft is an obvious example. But it is one thing to show a pilot that a laser is pointing at an aircraft when it is piloting reports, and to prove in a court of law that interference to an ATC system from a particular passing vehicle is intentional rather than unintentional. It is reported that several thousand GPS / cell phone jammers are currently in use, many in vehicles other than trucks.