engineering

SAM_0387.JPG
May 20, 2015

Thinking Small

Equations 2, 7, 8, 9, 10 & 11

Unmanned aerial vehicles (UAV) are finding increased application in both domestic and governmental applications. Small UAVs (maximum take off weight less than 20 kilograms) comprise the category of the smallest and lightest platforms that also fly at lower altitudes (under less than 150 meters).

Designs for this class of device have focused on creating UAVs that can operate in urban canyons or even inside buildings, fly along hallways, and carry listening and recording devices, transmitters, or miniature TV cameras.

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By Inside GNSS
Why are carrier phase ambiguities integer?
January 16, 2015

Why are carrier phase ambiguities integer?

It is well known that carrier phase ambiguities are integer values. Intuitively, this is hard to understand with a common counter-argument progressing along these lines: even if the receiver measures the instantaneous phase of the incoming signal (thus removing any fractional cycle component at the receiver end), the phase of the signal at the satellite cannot be guaranteed to be zero, so how can the ambiguity be integer?

In this article we explain why the carrier phase ambiguities are indeed integer.

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By Inside GNSS
Frank van Diggelen: Riding the GNSS Wave

Frank van Diggelen: Riding the GNSS Wave

Running San Francisco Marathon, with daughter, Tanera. Note GPS watch.

SIDEBAR: Frank van Diggelen’s Compass Points

“It all traces back to my parents,” says Frank van Diggelen. “My father, Tromp van Diggelen, was a surfer. He taught me to surf and swim, in that order, when I was five. I was racing sailboats before I was 10, and there’s a lot of navigation there. Even when you’re just on a lake, the racing is all about reading the wind, understanding angles of convergence, velocity-made-good, and so on.”

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By Inside GNSS
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A Universal GNSS Software Receiver Toolbox
July 21, 2014

A Universal GNSS Software Receiver Toolbox

In recent years, numerous, relatively inexpensive hardware platforms for conducting scientific research using the software defined radio (SDR) paradigm have become commercially available. The Manufacturers section near the end of this article lists examples of several of these. In turn, this has spurred universities and research groups around the world to adopt this technology for advanced GNSS signals-based research and development.

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By Inside GNSS
NavtechGPS Winter GNSS Training (Courses 123, 346 & 546)
June 9, 2014

NavtechGPS Winter GNSS Training (Courses 123, 346 & 546)

NavtechGPS Winter GNSS Training 2014 will take place at the Bay Club Hotel and Marina in San Diego, California, December 8-11, 2014.

Register by October 15, 2014 and get a $100 Discount for 4-Day Courses.

Course 346: In-Depth GPS/GNSS Operation for Engineers & Technical Professionals: Principles, Technology, Applications and an Introduction to Basic DGPS Concepts. (4-day course)
Taught by Dr. Chris Hegarty, MITRE

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By Inside GNSS
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AUVSI Unmanned Systems 2014
January 23, 2014

AUVSI Unmanned Systems 2014

The 2014 Unmanned Systems conference and trade show sponsored by AUVSI will be held from May 15 – 19 at the Orange County Convention Center in Orlando, Florida, USA.

The call for papers has closed. The early registration deadline is March 15, regular registration through May 10, with onsite registration starting May 11.

The conference features technical panels and presentations, workshops and poster sessions on the state of the unmanned systems market. It covers military, civil and commercial applications for air, ground and maritime vehicles.

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By Inside GNSS
Ionospheric Scintillation
January 19, 2014

Ionospheric Scintillation

Ionospheric scintillations are rapid temporal fluctuations in both amplitude and phase of trans-ionospheric GNSS signals caused by the scattering of irregularities in the distribution of electrons encountered along the radio propagation path. The occurrence of scintillation has large day-to-day variability. The most severe scintillations are observed near the poles (at auroral latitudes) and near the equator (within ± 20 degrees of geomagnetic equator).

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By Inside GNSS
Reaching for the STARx

Reaching for the STARx

Equation 1

GNSS modernization includes not only the global coverage capabilities of GPS, GLONASS, Galileo, and BeiDou, but also regional GNSS enhancement systems such as Japan’s Quasi-Zenith Satellite System (QZSS), the Indian Regional Navigation Satellite System (IRNSS), and the European Geostationary Navigation Overlay Service (EGNOS).

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By Inside GNSS
London Conference Beats Drum for Galileo Acceptance
December 11, 2012

London Conference Beats Drum for Galileo Acceptance

The accompanying figure shows the acquisition results of the FM3 Galileo satellite (PRN 11) E1b data channel, as computed by the NAVigation Signal Analysis and Simulation (NavSAS) group of the Politecnico di Torino/Istituto Superiore Mario Boella (ISMB) in Italy. The upper plot shows the search space along ±7 kHz Doppler frequency, while the lower one shows the search space along 4 millisecond code delay. The coherent integration time used to obtain this search space was 4 milliseconds, coupled with 11 noncoherent accumulations.

The third Galileo in-orbit validation (IOV) satellite, also known as Flight Model 3 (FM), began transmitting signals last week, and the FM4 spacecraft, like the FM3 launched on October 12, is expected to come on-line soon — providing the theoretical capability of 3D positioning using solely satellites of Europe’s GNSS system.

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By Inside GNSS
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