Innovation

Innovation: A Better Way

March 1, 2013By
In-opener

Monitoring the Ionosphere with Integer-Leveled GPS Measurements
II am joined by two of my graduate students, who report on an advance in the signal processing procedure for better monitoring of the ionosphere, potentially allowing scientists to get an even better handle on what’s going on above our heads. read more

This article is tagged with and posted in From the Magazine, Innovation

Innovation: Getting Control

February 1, 2013By
I-opener2

Off-the-Shelf Antennas for Controlled-Reception-Pattern Antenna Arrays
The antenna is a critical component of any GNSS receiving equipment. It must be carefully designed for the frequencies and structures of the signals to be acquired and tracked. Important antenna properties include polarization, frequency coverage, phase-center stability, multipath suppression, the antenna’s impact on receiver sensitivity, reception or gain pattern, and interference handling. While all of these affect an antenna’s performance, let’s just look at the last two here. read more

This article is tagged with , and posted in From the Magazine, GNSS, Innovation

Innovation: Getting at the Truth

January 1, 2013By
Inn-opener

A Civilian GPS Position Authentication System
When a GPS receiver reports its position to a monitoring center using a radio signal of some kind, how do we know that the receiver or its associated communications unit is telling the truth? It’s not that difficult to generate false position reports and mislead the monitoring center into believing the receiver is located elsewhere — unless an authentication procedure is used. In this month’s column, we look at the development of a clever system that uses the concept of supplicant and authenticator to assess the truthfulness of position reports. read more

This article is tagged with and posted in Algorithms & Methods, From the Magazine, GNSS, Innovation

Innovation: Getting Along

November 1, 2012By
Thumb

Collaborative Navigation in Transitional Environments
In this month’s article, a team of researchers at The Ohio State University discusses a system under development for collaborative navigation in transitional environments — environments in which GPS alone is insufficient for continuous and accurate navigation. Their prototype system involves a land-based deployment vehicle and a human operator carrying a personal navigator sensor assembly, which initially navigate together before the personal navigator transitions to an indoor environment. This system will have multiple applications including helping first responders to emergencies. Read on. read more

This article is tagged with and posted in Algorithms & Methods, From the Magazine, Innovation

Innovation: Easy Peasy, Lemon Squeezy

October 1, 2012By
FIGURE 2. Illustration of the isolines of constant Doppler for one and two GNSS satellites. Sv and Uv are the satellite and receiver velocity vectors, respectively. ϴ is the angle between the velocity difference vector and the vector pointing from the satellite to the receiver. The figure on the right shows the intersection of Doppler ellipses for the two satellites.

Satellite Navigation Using Doppler and Partial Pseudorange Measurements
Have we outgrown the use of Doppler measurements for position fixing? It seems not. In this month’s column, we’ll take a look at a GNSS positioning technique that uses admittedly inaccurate Doppler-based position fixes as a first step in producing an accurate fix using just a snapshot of recorded Doppler frequency and code-phase data with no need to decode the navigation message. Old dog, new tricks. read more

This article is tagged with and posted in From the Magazine, Innovation

Innovation: Software GNSS Receiver

September 1, 2012By
Fig9

An Answer for Precise Positioning Research
In this month’s “Innovation,” we look into the development and capabilities of one modern software GNSS receiver in an effort to answer the question “What is the ideal GNSS receiver for precise positioning research?” read more

This article is tagged with and posted in From the Magazine, Innovation, Manufacturing, Receiver Design

Innovation: The Devil Is in the Details

July 1, 2012By
FIGURE 4. A CPSE observed on SVN48 (PRN07) on September 15, 2010, at 19:21:42 GPS Time. (Click to enlarge.)

Looking Closely at Received GPS Carrier Phase
The stability of a received GPS signal determines how well the receiver can track the signal and the accuracy of the positioning results it provides. While the satellites use a very stable oscillator and modulation system to generate their signals, just how stable are the resulting phase-modulated carriers? In particular, do received signals always conform to the published system specifications? In this month’s column we take a look at a specially designed receiver for analyzing GPS carrier phase and some of the interesting results that have been obtained. read more

This article is tagged with and posted in From the Magazine, GNSS, Innovation, Signal Processing

Innovation: Coming Soon

June 1, 2012By
FIGURE 1. GNSS tracking stations in the IGS real-time network.

The International GNSS Real-Time Service
The International GNSS Service has embarked on a project to provide a high-accuracy GPS satellite orbit and clock data service in real time. The service will also provide 1-Hz data streams of GPS and GLONASS data from a network of global continuously operating reference stations. The IGS real-time data and orbit and clock products will be of immense benefit for geoscience studies and a host of other science and engineering applications. A team of authors associated with this project discusses the genesis and status of the real-time service and the plans to provide an initial operating capability. read more

This article is tagged with and posted in Augmentation & Assistance, From the Magazine, GNSS, Innovation