From the Magazine

Innovation: Orbit determination of LEO satellites with real-time corrections

Precision on board
Described are the results of realistic simulations carried out to precisely position a low-Earth-orbit satellite using a source of real-time GPS corrections actually transmitted by a network of geostationary satellites. Even accounting for data outages, 3D positioning accuracies better than a decimeter have been obtained. Precision on board? Not right now but likely coming real soon. read more

Backpacks for enhanced work travel, efficiency

April 12, 2017By

It’s conference season again. Every year I struggle with the best way to tote my MacBook Pro, DSLR camera and all the acoutrements I haul around as part of my job. No doubt you, too, need to travel with expensive electronics you want to protect from damage or theft. Determined to find the best solution for my trip in May... read more

Report: UAV sector on the upsurge

April 5, 2017By

Where It’s At, Where It’s Heading Assessing the health of an entire industry is not an easy task, but talking with industry leaders and looking for examples of growth and investment can help. My inquiries have led to discussions with General Atomics, Association for Unmanned Vehicle Systems International (AUVSI), Aeryon Labs and SensoFusion. Further viewpoints welcome; see the conclusion of... read more

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LTE cellular steers UAV: Signals of opportunity work in challenged environments

No GPS? No Problem! Long-term evolution (LTE) cellular signals can be exploited for accurate and resilient autonomous vehicle navigation in the absence of clear GNSS signals. Simulation and experimental results demonstrate that GPS-like performance can be achieved in the absence of GPS signals when cellular pseudoranges aid an inertial navigation system. By Zaher M. Kassas, Joshua J. Morales, Kimia Shamaei,... read more

U.S. Air Force puts more power into GPS Block IIR-M C/A-code

April 1, 2017By

By Peter Steigenberger, André Hauschild, Steffen Thoelert and Richard B. Langley Between Feb. 7, 05:02 UTC and Feb. 8, 12:30 UTC, 2017, all seven operational GPS Block IIR-M satellites were consecutively subject to short periods of unavailability. These official outage periods, when the satellite signals were set unhealthy and deemed unusable, were announced ahead of time through Notice Advisories to... read more

Research: Assessment evaluates GNSS receivers’ tolerance of adjacent band

March 22, 2017By

By Stephen Mackey, Hadi Wassaf, Karen Van Dyke, Christopher Hegarty, Karl Shallberg, John Flake and Terence Johnson. The Adjacent Band Compatibility Assessment evaluated the adjacent radiofrequency band power levels that can be tolerated by GPS and GNSS receivers, to advance the U.S. Department of Transportation’s understanding of the extent to which such power levels impact devices used for transportation safety... read more

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2017 Simulator Buyers Guide

March 21, 2017By

Cast Navigation iP-Solutions Racelogic Skydel Spectracom Spirent Federal Systems Syntony-GNSS Talen-x Cast-5000 GPS wavefront generator CRPA and Attitude Determination Receiver Testing The CAST-5000 produces a single coherent wavefront of GPS RF signals to provide repeatable testing in the laboratory environment or anechoic chamber. The basic system generates four independent, coherent simulations that reference a single point and is upgradeable to... read more

Innovation: Position estimation using non-line-of-sight GPS signals

March 15, 2017By and

Reflected Blessings.
A technique developed by researchers at the University of Illinois at Urbana-Champaign distinguishes a reflected non-line-of-sight (NLOS) signal of a particular satellite from the LOS signal and characterizes the NLOS signal as coming from a virtual mirror-image satellite in the direction of the signal reflection point. By using information on the position and orientation of the reflector, the NLOS signal can be treated as an additional LOS signal. read more