GPS World

Tag: Tracy Cozzens

  • How GPS was affected by the solar eclipse

    How GPS was affected by the solar eclipse

    I had my special ISO-certified glasses ready. Living in Oregon, I wasn’t about to miss the once-in-a-lifetime chance to see a total eclipse of the sun.

    On Aug. 21, my family drove a few miles north to get into the path of totality, which for us lasted about a minute. It was definitely worth the field trip.

    Besides regular folk like me, experts in numerous fields turned their eyes — and their instruments — to the eclipse.

    The National Center for Atmospheric Research took to the air with a Gulfstream V fitted out with sensors and equipment for atmospheric research. The flight gathered data about the sun that can’t be collected from the ground.

    With better instruments than ever before, for the first time scientists had the chance to observe the corona in the infrared spectrum, which may provide insight into the sun’s magnetic fields.

    Back on terra firma, atmospheric scientists closely monitored changes in temperature and other weather effects. The temperature dropped as much as 7 degrees in Crossville, Tennessee, reports the National Weather Service.

    Scientists at zoos and aquariums across the country closely watched animal behavior during totality. Species exhibiting unusual behavior included elephants, hippos, crocodiles and penguins.

    As for GPS, experts from the NASA Jet Propulsion Laboratory, NASA HQ Earth Science Division and the University of New Brunswick kept a close eye on the event, collecting data from GPS receivers and other ionospheric monitoring tools to better understand exactly how the ionosphere reacts to a total eclipse of the sun.

    The scientists found a “decrease in the number of free electrons in the part of the Earth’s ionosphere along the eclipse path where sunlight was temporarily blocked by the moon…

    “TEC [total electron content] time series from two continuously operating GPS monitoring stations near the path of totality…show a small dip of about 2 TECU [TEC units] or so around 18:00 UTC on Aug. 21, coincident with the timing of the eclipse.”

    The eclipse also affected WAAS real-time correction data from geostationary satellites.

    While study of the data continues, it’s clear that GPS easily withstood the eclipse. Learn more here.

  • What to expect from ION GNSS+ and Intergeo 2017

    What to expect from ION GNSS+ and Intergeo 2017

    Intergeo 2016

    It’s almost September. For the GPS World staff, this means scramble time. We have two important industry events to attend: The venerable ION GNSS+ conference and the huge Intergeo trade show.

    ION GNSS+ is the Institute of Navigation’s largest technical meeting and showcase of GNSS technology, products and services. Hundreds of papers are shared by experts in the field, in presentations and panels.

    The show has changed over the years to broaden its focus to applications, and added a “+” to its name to incorporate all the positioning, navigation and timing (PNT) technology that aids GNSS in location, much as we have also done in providing a new subtitle to our magazine.

    New this year are Short Courses, aimed at bringing your non-technical staff up to speed on the technology behind the industry, no matter their background. For instance, one course is “GNSS 101: An Introduction.”

    Intergeo, which is held each year in different city in Germany, comes to Berlin. The huge show, attended by about 17,000 people, is a conference and trade fair (emphasis on trade fair) for the fields of geodesy, spatial data, surveying, UAVs and land management.

    A hot topic at Intergeo continues to be Geospatial 4.0, the massive transformation where big data, mobility and cloud solutions are driving a new global digital economy.

    Other buzzed-about topics include photogrammetry, building information modeling (BIM) and smart cities.

    One important and timely topic is the need for infrastructure that ensures data security and protection. Once again, the Interaerial Solutions show for UAVs will take place as part of Intergeo.

  • Backpacks for enhanced work travel, efficiency

    Backpacks for enhanced work travel, efficiency

    Udee backpack
    Udee backpack

    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 to the European Navigation Conference (ENC), I researched several options. Instead of the roller bag I’ve been using, (and accidentally rolled over people’s feet — I apologize if I ever bumped you!), I opted for a backpack.

    The TLS Mother Lode Weekender travel backpack includes nifty organizational details and a laptop compartment. It has an expansion zipper — nice, because I always come home with more than I leave with, thanks to all the literature and hand-outs at the booths I visit. It looks like a backpack, but opens like a suitcase.

    The Kenneth Cole Reaction backpack has a “checkpoint-friendly” laptop compartment — always a handy feature. The middle compartment features an organization panel, and it has an iPad/tablet pocket.

    These are both nice choices, but I found a backpack that has a home for my bigger camera as well as my laptop. The Udee backpack, a new product developed through a kickstarter campaign, is designed not just for office folk like me, but field workers. It has 19 features, including a few unusual ones — a portable cooler, an earphone port, pockets for passpports and glasses, and a USB port for charging electronics using a battery stored within the bag (battery not included).

    It also has an anti-theft feature (important to me in case I fall asleep on a train).

    If you’re attending ENC, look for me — the one with the backpack pictured above.

  • New book explains GPS for the rest of us

    I’ve absorbed the basics of how GPS works in the decade since I joined the staff of GPS World magazine, when I barely gave the positioning system a thought. But in those first few months, this is the book I wish I’d had.

    Terms I needed to learn back then included pseudorange (nothing to do with juicy fruit), geodesy (not an undiscovered work by Homer) and multipath (not a forking trail in a park).

    All of these and more are described in the new book GPS for Everyone: You Are Here by Pratap Misra. Pratap is Professor of the Practice, Department of Mechanical Engineering at Tufts University, and he sent me his new book for review. As a non-engineer, I have found it a great resource — Pratap explains complex subjects in an entertaining, highly readable narrative, accompanied by photos, illustrations and even a few cartoons.

    Even if I’m not looking for a little background, I find myself engaged in the story of GPS: its history, its uses today (location-based services, defense, UAVs), privacy concerns and more.

    For instance, I hadn’t given much thought to how general relativity had to be taken into account in designing the clocks for GPS satellites. If the clocks hadn’t been designed with an offset, GPS would lose 38 milliseconds a day. So much for an accurate timing reference.

    Aother interesting story was the rescue of U.S. pilot Captain O’Grady, downed during the Bosnian conflict in the 1990s and quickly rescued because he was able to provide his coordinates from his handheld Flightmate GPS receiver. Today, of course, military receivers would automatically provide the location, and rescue would be even faster.

    Pratap also co-authored with Per Enge of Stanford a graduate-level engineering textbook on GNSS. But for the rest of us, GPS for Everyone: You Are Here is available through bookstores everywhere.