TAG: Frank van Diggelen

Letters: Galileo Sync, GLONASS Scoop, an Open Letter

June 23, 2014By

June Cover Story In the June issue’s cover story, “Interchangeability Accomplished,” is a paragraph headed, “Satellite Intersystem Biases,” which appears to assert that Galileo System Time (GST) is 3 seconds ahead of UTC. However, in the version of the Galileo Signal In Space Interface Control Document posted at: http://ec.europa.eu/enterprise/policies/satnav/galileo/files/galileo-os-sis-icd-issue1-revision1_en.pdf, paragraph 5.1.2 appears to indicate that Galileo System Time (GST) was synchronized, at... read more

Predicted Ephemeris: Waste of Time or an Untapped Resource?

September 18, 2013By
This map of Portland by Geoloqi has 2.5 million data points.

GPS World contributing editor Eric Gakstatter gave a talk on predicted ephemeris at the Civil GPS Service Interface Committee (CGSIC) on Tuesday. The talk was invited and the topic was suggested by CGSIC coordinators. The 53rd meeting of the CGSIC was held Monday and Tuesday before the Institute of Navigation GNSS+ 2013 Conference. Here is Eric’s talk: Whenever I point... read more

This article is tagged with , , , , , and posted in Featured Stories

Single-Shot Position: Cell-Phone Location without Ephemeris

February 1, 2011By

A new method enables the mobile phone to compute its own position using acquisition assistance data with increased resolution in some of the fields. It benefits network operators as they can deliver the best performance with minimum bandwidth requirements, making this especially relevant in emergency-call situations. read more

This article is tagged with , and posted in Mobile Devices, Wireless Infrastructure

Down and Deep

December 1, 2010By
Figure 1. In Shinjuku, Japan, a receiver tracks nine GPS satellites, but only three (white lines) with direct line of sight, giving an HDOP of 58. Add two QZSS satellites (green) for an HDOP of 3.

As we all know, GPS is practically perfect in every way — as long as it’s outside and unobstructed. Even cell phones can now produce meter-level accuracy under open sky. There are still many deficiencies in state-of-the-art location, particularly in deep urban canyons and inside large buildings. Which technologies will lead personal navigation into the future? read more

This article is tagged with , , and posted in Mobile Devices, Personal Navigation

Expert Advice: Are We There Yet?

March 1, 2010By

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 far, we can ask that most famous of all navigation questions: Are we there yet? read more

The Smartphone Revolution

December 1, 2009By

Seven technologies put GPS in mobile phones around the world. Here is the how and why of location’s entry into modern consumer mobile communications. read more

This article is tagged with , and posted in LBS/Wireless, Mobile Devices, Receiver Design