Few outside the position, navigation, and timing (PNT) community will also recall that the day before the 9/11 attacks, the U.S. government released a landmark document that described the vulnerabilities of services provided by GPS to disruption, whether by attack or inadvertent interference. The...More>>

I started my relationship with GNSS and Moore’s Law in 1985, writing software for GPS tracking loops on the Advanced Range Instrumentation Aircraft program at the Applied Physics Laboratory of Johns Hopkins University for the U.S. Air Force. The project’s purpose was to navigate a large jet to...More>>

Defense editor Don Jewell is a retired Air Force officer who served for 30 years; many of his former peers and contemporaries are currently senior officers in today’s U.S. Air Force. Don sat down recently with General C. Robert Kehler, Commander of the U.S. Air Force Space Command, whom he has...More>>

A packed audience attended the National Physical Laboratory in the United Kingdom for a February 23 meeting titled, “GPS Jamming and Interference: A Clear and Present Danger,” organized by the Digital Systems Knowledge Transfer Network. In his keynote address, David Last described a dark,...More>>

At the start of a new decade, let’s examine the state of the GNSS consumer market and technology. In the December 2009 issue of GPS World, I described the developments that put GPS in cell phones over the last decade. That technology revolution has brought GPS a very long way. Having come this...More>>

Deterministic risk modeling, the basis of the Efficient Market Hypothesis (EMH) at the core of modern quantitative finance, is known to be fundamentally flawed, but its elegance and convenience has blinded researchers to growing evidence of its weaknesses. The near-complete acceptance of the EMH...More>>

Recent attention given to aging GPS satellites and availability gaps from lagging constellation replenishment have provoked deep concern, particularly within the aviation community. Available remedies include exploitation of well known but unused methods plus new techniques; those discussed here...More>>

It appears that the GPS satellite constellation has a glass ceiling, so to speak. GPS was designed as a 24-satellite constellation, with four satellites in six orbital planes arranged to provide maximum observability around the globe. According to the government’s Space-Based Positioning,...More>>

The most widely used of all GPS devices are in-car navigators. When vehicles carrying navigators are used for criminal purposes, records contained in the devices may be examined. Such investigations rely on newly developed forensic techniques that employ a combination of computer expertise and...More>>

The GPS Wing and its contractors have traced the cause of pseudorange errors on L1 and L2 broadcast by the newest GPS satellite, SVN-49, to the manner in which the L5 signal demonstration payload was added to the satellite. Signal leakage between the two input ports of the antenna coupler network...More>>