201207 July/August 2012

July 5, 2012

Single- versus Dual-Frequency Precise Point Positioning

Q: What are the tradeoffs between using L1-only and L1+L2 for PPP?

A: Precise point positioning (PPP) is a technique that can compute positions with a high accuracy anywhere on the globe using a single GNSS receiver. It relies on highly accurate satellite position and clock data that can be downloaded from the International GNSS Service (IGS) or obtained in real-time from a number of service providers, using either the Internet or satellite links.

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By Inside GNSS

INS Face Off

TOP PHOTO: Antenna configurations on trials vehicle: Dual GPS antennas for the INS under test and single GPS antenna for the CIMU; BOTTOM PHOTO: Commercial IMU/DGPS system used for reference (left), FOG-based INS configuration (middle), and MEMS-based INS configuration 2 (right)

The automobile versus the horse and buggy. Cloud computing opposite desktop software. The trend is predictable, yet it is always surprising when one technology takes over the market space of another. After all, television did kill off the radio star.

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By Inside GNSS
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Drones to the Rescue!

August 1994, early morning. Spain’s Central Pyrenees Mountains still in darkness.

At the outset of an ascent to a 3,000-meter peak along the international border, one of the co-authors encounters a group of tourist hikers who have begun searching for a colleague who had left the camp the previous evening. In the pre-sunrise gloom, helicopters cannot yet operate.

A week later, the body of the hiker is found. The rescue efforts came, unfortunately, too late.

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By Inside GNSS
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