GPS World, February 2016

TAKING POSITION Unsung Heroes of the Industry FEBRUARY 2016 WWW GPSWORLD COM GPS WORLD 7 BY Tracy Cozzens MANAGING EDITOR A ntennas When I was a kid antennas meant the pair of rabbit ears sitting on top of the family TV set We had to constantly adjust the angles to get the best reception using aluminum foil to improve the signal Wow how things have changed Today consumer users of smartphones Fitbits smartwatches tablets and a hundred other electronic devices dont even think about antennas Most consumers probably havent given a thought to the fact that their favorite device contains an antenna Unlike broadcast antennas back in the day modern GNSS antennas in consumer devices are invisible to the consumer but perform even in lessthan ideal conditions Every year brings new improvements and smaller sizes Then there are the external antennas which grow more rugged to withstand the elements while receiving more signals from more constellations such as BeiDou and Galileo GPS World has traditional ly published its Antenna Survey in February following the Receiver Survey in January The first antenna survey appeared in 2001 nine years after we published our first receiver survey Perhaps it took a few years to realize how critical antennas are in GNSS systems As usual the Antenna Survey encapsulates the important specifications on dozens of antennas from stand alone designs for high precision commercial defense and timing applications to micro antennas for integration into a variety of smartphones UAVs and automobiles This year 30 antenna manufacturers provide all the details on their products Check out the 20 page survey supplement sponsored this year by NovAtel following page 18 Q What is the optimum number of GNSS signals to include process in a consumer grade PNT device A The cost for including additional silicon to a receiver for processing more signals is low thanks to multiplexing hardware and high clock speeds Having more satellite measurements allows the receiver to be selective about which ones it actually uses for PVT calculations so a number of 30 or higher is desirable Such a high number and especially if the signals come from multiple constellations enables the receiver to have a good view on integrity too A The answer depends on application and environment where the device will be used With the increasing need for ubiquitous positioning in difficult environments like urban canyons the minimum number of satellites from one constellation is not sufficient The technology makes it possible today to achieve better performance using multiple constellations with low impact on power consumption and this is where we see the future A Demand for more accuracy availability and reliability will drive design evolution Sensor map augmentations will likely drive system availability while depending on GNSS for better accuracy and reliability As accuracy is a function of measurement quality and sky view with the latter fixed for most use cases placing more emphasis on minimizing errors appears ideal Therefore I see dual constellation dualfrequency GNSS as the optimal combination and the right balance between complexity versus performance DANIEL AMMANN EXECUTIVE VICE PRESIDENT U BLOX GROUP GIAN GHERARDO CALINI HEAD OF MARKET DEVELOPMENT EUROPEAN GNSS AGENCY CHAMINDA BASNYAKE PRINCIPAL ENGINEER RENESAS ELECTRONICS