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The System: New Math for GPS

February 1, 2010 - By

The U.S. Air Force GPS Wing and 50th Space Wing have begun repositioning GPS satellites in space to fly what they call the 24+3 or Expandable 24 constellation plan. The initiative will take up to 24 months to fully implement. Benefits to users will be slowly realized during that time, as the number of GPS satellites in view will increase, potentially increasing GPS receiver accuracy. Plus: Penny-Wise, Pound-Foolish U.S. Coast Guard to Pull Loran Plug; Galileo Satellites Awarded to OHB; Compass at Three read more

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Expert Advice: Integrity: Lessons from the 2008 Financial Collapse

February 1, 2010 - By

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 led to models that dramatically accentuate its flaws, which in turn led to absurd but eagerly accepted conclusions for loan-default risk. These models proved dramatically vulnerable to changes in the housing market in 2007–2008 and led directly to the ensuing crash. read more

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Out in Front: Rocky Road to Robustness

February 1, 2010 - By

The system’s command and control operational software update uploaded in late 2009 (see page 10) has started wreaking some havoc with installed military receivers across many fielded platforms, as well as with some civil receivers. Whether major or minor havoc, I don’t pretend to know yet. The concept of selective availability anti-spoofing module (SAASM) figures in it, though now I’m toeing classified turf. read more

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