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The navigation sensors for location-based services (LBS) are complex technical systems. Modern technical science can answer most questions about the optimality of particular position determination methods, signal processing algorithms, electronic circuits or similar well-defined problems, but the rigorous answer to the questions concerning the optimal LBS positioning sensor are still a big problem.

The navigation sensors for location-based services (LBS) are complex technical systems. Modern technical science can answer most questions about the optimality of particular position determination methods, signal processing algorithms, electronic circuits or similar well-defined problems, but the rigorous answer to the questions concerning the optimal LBS positioning sensor are still a big problem.

Ivan Petrovski’s book presents not only LBS navigation sensors based mainly on satellite navigation systems (GNSS) and software radio, but also it provides valuable insight from their practical implementation. GPS, GLONASS, Galileo, and BeiDou for Mobile Devices, From Instant to Precise Positioning is written for satellite navigation experts. It summarizes the latest knowledge of mobile GNSS devices’ design and applications as well as the opinion of the author on the realization of the particular problems in the area of the GNSS signal processing and software radio, all based on his deep experience.

In contrast to Dr. Petrovski’s previous book, Digital Satellite Navigation and Geophysics, or Bernard Hoffmann-Wellenhof’s GNSS-Global Navigation Satellite Systems — GPS, GLONASS, Galileo & More, the valuable information is not placed in a wider context; so, beginners could easily lose their orientation.

The book is introduced by an inspired foreword to location-based services by Glen Gibbons. The 312 pages of the book are then organized into four parts as follows:

The first part describes advanced knowledge of navigation satellite position calculations, satellite navigation signals, and stand-alone and reference station–based GNSS positioning. The most valuable parts are modeling of the signal propagation effects and carrier phase positioning.

The second part deals with the conventional and software GNSS receivers. There is a lot of practically usable information such as advice on how to design high- or super-high–sensitivity receivers, how to optimally implement GNSS correlators to the general purpose processor and many others.

The third part addresses the essential LBS relative positioning methods including assisted-GNSS, real-time kinematic, differential GNSS, and pseudolites as well as instant BGPS (developed by Dr. Petrovski and others), precise point positioning, and snapshot methods. The presented text is not limited to describing those methods, but the author also gives practical examples of applications and provides recommendations for their implementation. Very well written is the last chapter, “Trends, Opportunities and Prospects,” in which Ivan Petrovski predicts convergence of the mobile and geodetic applications and tight integration with the Internet.

The last part deals with the GNSS receiver and LBS sensor testing. I personally use the IP-Solutions ReGen GPS simulator developed by the author for testing of LEO satellite GPS receivers. I fully agree with his attitude that the software GNSS simulators have good prospects and, thanks to the increased performance of general purpose processors, they will become a full-blown alternative to standard software-designed radio (SDR) simulators.

This book is definitely a valuable source of information for development, optimization, and testing of GNSS signals and data processing algorithms and their implementation to the software radio for mobile, indoor, and high-grade receivers.

GPS, GLONASS, Galileo, and BeiDou for Mobile Devices, From Instant to Precise Positioning
By Ivan G. Petrovski, Cambridge University Press, 2014, ISBN 978-1-107-03584-3

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1996 soccer game in the Midwest, (Rick Dikeman image)

Nouméa ground station after the flood

A pencil and a coffee cup show the size of NASA’s teeny tiny PhoneSat

Bonus Hotspot: Naro Tartaruga AUV

Pacific lamprey spawning (photo by Jeremy Monroe, Fresh Waters Illustrated)

“Return of the Bucentaurn to the Molo on Ascension Day”, by (Giovanni Antonio Canal) Canaletto

The U.S. Naval Observatory Alternate Master Clock at 2nd Space Operations Squadron, Schriever AFB in Colorado. This photo was taken in January, 2006 during the addition of a leap second. The USNO master clocks control GPS timing. They are accurate to within one second every 20 million years (Satellites are so picky! Humans, on the other hand, just want to know if we’re too late for lunch) USAF photo by A1C Jason Ridder.

Detail of Compass/ BeiDou2 system diagram

Hotspot 6: Beluga A300 600ST

Highest altitude fix for a GPS signal, GNSS timing signals and hacking the Grid, Eagles act as drone countermeasures and rumors of a GNSS-nano-chip contributes to cash crisis in India

Highest altitude fix for a GPS signal, GNSS timing signals and hacking the Grid, Eagles act as drone countermeasures and rumors of a GNSS-nano-chip contributes to cash crisis in India

1. GUINNESS WORLD RECORD!
Outer Space
√ NASA’s Magnetospheric Multiscale Mission (MMS) earned a Guinness World Record for the highest altitude fix of a GPS signal in November when the four satellites were on their elliptical orbit 43,500 miles from Earth. When the MMS satellites are closest to us down below, they travel up to 22,000 miles per hour, making them the fastest known operational use of a GPS receiver. The four satellites fly in a tight flying formation using precise tracking systems that depend on GNSS.

• (November 4, 2016) NASA.gov: NASA’s MMS Breaks Guinness World Record

2. HACKING THE GRID?
Redlands, California and Idaho Falls, USA
√ Those delicate GNSS timing signals crucial to the synchrophasor systems on the electrical power grid keep cybersecurity folks awake at night. But, if hackers intrude on the grid, turning the lights out could be the least of our problems. Researchers from California’s Esri and the Department of Energy’s Idaho National Laboratory are using GIS to identify the likely ripple effects — from the spread of malware to water system failure to issues for first responders. In a Christian Science Monitor article about the project, the deputy director of the National Geospatial Intelligence agency said of the intersection of digital and physical worlds: “Too many people think that cyber is its own domain and quite frankly, everything resolves to physical.”

• (November 16, 2016) The Christian Science Monitor: If hackers cause a blackout, what happens next?

3. GOTCHA!
The Hague, Netherlands
√ To the list of drone countermeasures, add “eagles” along with “shoot it” and “jam its sensors.” Law enforcement in the Netherlands has partnered with a raptor-training company to teach eagles to identify drones intruding illegally in congested or secure areas, snatch them out of the sky and fly them somewhere away from the public. In theory, it promises significantly less collateral damage than other methods. The birds are rewarded with a piece of meat to make up for the tastelessness of drone and the police say the feathered hunters succeeded 80 percent of the time during the trial period.

• Guard From Above FAQ

4. FOLLOW THE MONEY?
New Delhi, India
√ India is a cash-based economy and fake currency notes and tax avoidance run rampant. Early in November, the government withdrew two often-counterfeited high-value notes that comprise 80 percent of the cash in circulation and released a new 2000-rupee bill (that’s about US$30). This has not gone well. In addition to making it tough for people to exchange money, the move inspired rumors that the new note contained a secret mini nano-GPS chip that could reveal stashes of no-doubt undeclared cash buried as deep as 393 feet below ground. Rubbish, said the Reserve Bank of India: “Such a technology does not exist at this moment in the world.”

• (November 10, 2016) The News Minute: RBI rubbishes rumours of GPS tracking chip in Rs 2000 note
• (November 10, 2016) India.com: Rs 2000 currency notes issued by Reserve Bank of India will have no GPS tracking chip, confirms Arun Jaitley

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A national unpopularity contest. Sort of Commedia dell’arte meets Monty Python, directed by Todd Phillips, with a cameo appearance by Berlusconi.

Did we find it risible? Oh, yes, but were those tears of laughter, sorrow, or disbelief?

So, while we are collectively unpacking the meaning and nonsense from two years of political theater and telling each other our fortunes for the next four, what does it portend for GNSS?

Well, the tea leaves are a little unclear.

American Election 2016 — now that was something, wasn’t it?

A national unpopularity contest. Sort of Commedia dell’arte meets Monty Python, directed by Todd Phillips, with a cameo appearance by Berlusconi.

Did we find it risible? Oh, yes, but were those tears of laughter, sorrow, or disbelief?

So, while we are collectively unpacking the meaning and nonsense from two years of political theater and telling each other our fortunes for the next four, what does it portend for GNSS?

Well, the tea leaves are a little unclear.

The Trump-l’oeil of the president-elect’s platform to date provides few clues, although Dee Ann Divis takes a valiant stab at the implications for GPS in this issue’s Washington View column.

But consider this: Another Republican showman, Phineas Taylor Barnum, a two-term state legislator and mayor of Bridgeport, Connecticut, actually appeared to be an anti-slavery advocate toward the end.

If P. T. Barnum — better known to later generations for his traveling circuses than his political acumen — could find nobility amid his gaudy business and personal style, we should not abandon all hope. Of course, Barnum probably never thought of running for president, but if he had, could we have intuited his stance on, say, the gold standard from the content of his menagerie?

If we were to elevate the theatrical aspects of the current situation to the Shakespearean level, we could consider The Winter’s Tale from which this column’s title is drawn. Recall how King Leontes of Sicily, in a sudden fit of insane jealousy, imprisons his wife. He then sends the ultimately unfortunate Antigonus to abandon Leontes’ daughter, Perdita, whom the king thinks was sired by his childhood friend, the Bohemian ruler Polixenes.

Various tragedies ensue.

By the fourth act, however, an amazing turn of events: Leontes, apparently restored to sanity through the suffering of his family and nation, frees his wife. He attends a popular festival in disguise, discovers the simple condition of common folk, and ultimately reconciles himself with Polixenes.

As metaphor of our current situation, we can hope that The Winter’s Tale might point to the end of the inutile prosecution of and threats of jail for Hillary Clinton and that the Trump era will not, as feared, worsen the inequitable distribution of wealth in society. Perhaps even that, along the way, a riven nation will find a renewed comity.

But enough of theater as politics. How about politics as politics?

Come 2017, for the first time since the second Bush administration, Republicans will have seized control of all three branches of the U.S. government. One mixed-blessing president exits the stage; another enters devoid of a majority in the popular vote. But as with George W., the Donald’s wings will probably remain unclipped despite the absence of a mandate.

Nonetheless, we should recall that it was the Bush government in 2004 that issued a (still unfulfilled) presidential directive on GPS/PNT. And another is arguably past due.

So, here’s what I think: since the 18th century, news media have often been called the Fourth Estate, implying that journalists have a seat at the table of the nation’s governance. (Of course, the election may have also underscored the passing of that notion and the rise of social media in its stead.)

But we actually have long had another de facto branch of government: the oft-maligned leaders and staff of the federal departments, agencies, and commissions. Yes, the dreaded bureaucrats — in whom resides the institutional memory of programs, policies, and practice. And therein exists a constructive inertia, the part of Newton’s First Law that asserts a body in motion will remain so absent other external forces.

Four decades into the GPS era, myriad GNSS-related initiatives — domestic and international, public and private — are under way. Every person with a cell phone getting into a car with a navigation system is a beneficiary and implicit advocate of the technology. GNSS has become an irresistible force over which the influence of any one person can only be limited, whether for good ends or poor.

For which we should be thankful.

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With the Republican Party now entirely in charge of Washington’s prime policy real estate the neighborhood is going to change. The current residents are warily watching the newcomers take measurements for a major remodel of agencies, lobbying rules, national priorities, and international relationships, and everyone is assessing the implications of the new landscape.

Although the look of the town’s ultimate layout is far from final, President-elect Donald Trump has sketched out enough of his plans to make some guesses on the shifts that could affect the GPS program — and GNSS in general — in the coming months.

In an October policy speech in Gettysburg, Pennsylvania, then-candidate Trump laid out 20+ action items for his first 100 days. Not surprisingly, changing the nation’s approach to position, navigation and timing (PNT) programs was not on the list — nor is it likely to be.

Although budget issues, spectrum conflicts, and signal jamming present escalating challenges — and a review of GPS policy has been on Obama’s long-range to-do list — the GPS program is noncontroversial, generally working well, and likely to remain the world’s PNT “gold standard” for some time.

“GPS policy updating would not be one of my priorities,” said a policy expert familiar with the program. The National Executive Committee for Space-Based Positioning, Navigation, and Timing “is largely working the way that people intended it to work,” the expert said, pointing out that the most pressing issues — consistent funding shortages impacting the Department of Transportation’s GPS obligations and disagreements with the Federal Communications Commission over spectrum and the official use of other PNT constellations — are fundamentally separation-of-powers issues.

“Those are problems with the Congress and oversight; those aren’t really subject to presidential policy,” the expert told Inside GNSS.

The new administration also appears unlikely to make immediate changes to the GPS program as part of early efforts to change the way Washington does business.

“This new administration, from what we can tell, from a space policy standpoint, they seem committed to leveraging domestic, commercial, private industry space capabilities, as much as feasible — which we, in our business, are encouraged to hear,” said Mike Tierney, vice president at Jacques & Associates, a consulting firm that specializes in defense, space/intelligence, homeland security and related industries.

However, if the Trump administration looks at the military space portfolio with that commitment in mind, said Tierney, GPS would likely not be their first target for change as other military systems seem amenable to a more commercial approach that could have greater impact.

“If you’re the Trump administration and you’re looking to change the way the military does space, GPS is probably not your first candidate to look at,” Tierney said.

That doesn’t mean that PNT-related changes won’t occur under the Trump administration — perhaps, even, for the better.

Military Boost?
On that 100-day to-do list was a pledge to pump up funding for the military, including ending budget sequestration for the Department of Defense (DoD). Congressional Republicans also have been itching to boost defense spending, which could put some real momentum behind the idea.

Up to now GOP lawmakers have been wrestling with the Obama White House, which has wanted to balance any defense funding increase with more spending for non-defense programs. The situation could change, however, if a funding plan now working its way around Capitol Hill gets the go-ahead.

As of press time, the government was operating under a continuing resolution set to expire on December 9. Without a deal before midnight that day the government will shut down. Again.

Lawmakers are reportedly planning to pass another continuing resolution that would fund the government past Inauguration Day 2017 — perhaps through March. This would give the incoming Trump administration an opportunity to put its policy stamp on the 2017 spending bill and lawmakers a way to avoid further hassling with the Obama team. Higher military spending would not necessarily benefit GPS directly but it could ease some of the pressure to find new cuts.

Of course, it’s not a done deal. Obama would have to sign the new continuing resolution into law and will likely be negotiating for measures he wants included — as will lawmakers looking to shape what could be one of the last must-pass bills of this session of Congress.

PNT for Jobs?
Trump also said shortly after winning the election that, upon taking office, he intended to focus on three things: immigration, healthcare, and jobs. To generate some of those jobs quickly he proposed a $1 trillion program to update bridges, roads, and other U.S. infrastructure coast to coast. Efforts to build a backup for GPS could win support as part of Trump’s goals for job creation.

There is no question that GPS underpins the American economy. The Department of Homeland Security (DHS) has long acknowledged that the GPS service is a crosscutting capability on which 14 of the nation’s 16 critical infrastructures are critically dependent.

Despite this, the Obama administration killed a low-cost, consensus plan to create a partial backup by upgrading the Coast Guard’s existing Loran stations to enhanced Loran (eLoran) — a ground-based system that could, if something happened to GPS, provide the timing data essential to running the power grid, Internet, financial transactions, and the communications network. eLoran offers the added benefit of being nearly unjammable and available in places where GPS is not — such as under ground and under water.

“GPS signals are America’s least visible and most vulnerable infrastructure,” said Dana Goward, the president of the Resilient Navigation & Timing Foundation and a former Coast Guard executive. “Building an eLoran complement and backup for GPS will make America stronger, create jobs, and eliminate a strategic advantage that countries like China, Russia, and Iran can hold over our heads. An eLoran network should be part of any U.S. infrastructure program.”

Although the federal government long ago concluded there was indeed a need for eLoran and put the plan back on the table, it has spent more than a decade haggling over which agency would take responsibility and pay for it — dawdling to the point where it will now be far more expensive to convert the old stations.

The issue is currently being studied again, this time to set requirements for a full GPS backup, with the possibility of getting eLoran operational as an interim solution.

The new administration’s plans to update the nation’s infrastructure and boost national security could invigorate the low-energy approach taken so far towards eLoran. Not everyone in Congress is warm to the huge amount of spending Trump has proposed for infrastructure, but the Democrats seem inclined to support the plan. Moreover, there is already support among Trump-connected lawmakers for eLoran — and that might make the difference.

Connected
In a good position to bring eLoran to the forefront for consideration is Rep. Duncan Hunter, R-California, an early and vocal supporter of Trump’s candidacy who led an outreach effort to Congress for the candidate during the campaign.

Hunter served in the Marines and is a combat veteran of Iraq and Afghanistan. His name has been floated as a possible Secretary of Defense or Secretary of the Army under Trump.

Hunter is on the House Armed Services Committee and serves on the Subcommittee on Intelligence, Emerging Threats and Capabilities and the Subcommittee on Seapower and Projection Forces. It is, however, in his role as the chairman of the Subcommittee on Coast Guard and Maritime Transportation that he has been especially vocal about the need for a GPS backup.

During a 2014 hearing he blasted DHS, which is now the parent agency of the Coast Guard, for doing study after study on backing up GPS but failing to make a decision as required under a 2004 presidential directive.

“They did a study and now they are going to do more studies and that’s the circle loop, the endless loop of stupidity we have in Congress instead of just getting something done,” Hunter said.

Hunter also signed a letter with Rep. Garamendi, D-California, pressuring the three government agencies responsible for leading PNT policy and publishing the Federal Radionavigation Plan — the departments of defense, transportation, and homeland security — to get moving on a backup system.

“America’s Global Positioning System (GPS) is an essential element of nearly every infrastructure upon which our economy and security depend,” they wrote. “While GPS is superbly maintained and operated, its signals are necessarily faint and can be easily disrupted. This has become a well-recognized and unacceptable risk for our nation.”

In addition Hunter backed at least two bills this congressional session aimed at sorting out the agency responsibilities for a backup. He co-sponsored Garamendi’s bill, the National Positioning, Navigation, and Timing Resilience and Security Act of 2015 (HR 1678) along with Peter DeFazio, D-Oregon, Frank LoBiondo, R-New Jersey, and Bill Shuster, R-Pennsylvania.

HR 1678 would have fixed the funding issue by mandating that DoD “provide for the establishment, sustainment, and operation of a reliable land-based positioning, navigation, and timing system.” DoD would have to work with the Coast Guard, the secretary of transportation, and the private sector to move things along.

The fact that Shuster became involved with HR 1678 is also a boost for eLoran supporters. Shuster endorsed Trump in April and his name has come up as a possible nominee to head the Department of Transportation — though he told Politico that he is not interested in the job.

Garamendi’s bill did not make it out of the House, but a bill sponsored by Hunter did. The Coast Guard and Maritime Transportation Amendments Act of 2016 (H.R. 5978) would mandate that the Coast Guard “provide for the establishment, sustainment, and operation of a reliable land-based enhanced LORAN, or eLORAN.”

Garamendi co-sponsored Hunter’s legislation as did (in alphabetical order) Representatives Henry Cuellar, D-Texas; Blake Farenthold, R-Texas; David Rouzer, R-North Carolina; Don Young, R-Alaska; and Lee Zeldin, R-New York. Farenthold, Rouzer, and Zeldin all endorsed Trump; all three won re-election this fall.

Space-Based Influence
Rep. Jim Bridenstine, R-Oklahoma, could also be a voice for GPS.

A former Navy pilot, Bridenstine has been mentioned as a possible choice for secretary of the Air Force or NASA administrator. A strong supporter of Trump, he sharply criticized Speaker Paul Ryan for his lackluster backing of the GOP candidate during the campaign.

Bridenstine serves on the House Armed Services Committee including two subcommittees, the first being Sea Power and Projection Forces and the second Strategic Forces. He is also on the House Science, Space, and Technology Subcommittee for which he chairs the Environment Subcommittee and serves on the Oversight Subcommittee.

More to the point, Bridenstine has taken an interest in all things space-related, including GPS and the new PNT constellations coming online. He proposed the American Space Renaissance Act (HR 4945), which includes a forward-looking mandate for GNSS.

Under Section 103 of the bill, DoD would be required to report on its strategy to “best leverage” signals from other systems including Galileo and commercial PNT systems “that use commercial satellite constellations.”

That strategy is to include at least these three elements:

• issues associated with monitoring and verification of the accuracy, integrity, availability, and security of foreign and commercial positioning, aviation, and timing signals
• mechanisms for timely notification to military users of the current and projected reliability of such foreign and commercial systems
• methods for sharing information across the Global Positioning System, the Galileo system, and other positioning, navigation, and timing systems to improve the interoperability and effectiveness of the systems for military users.

The mention of commercial systems in the context of PNT services brings to mind eLoran, which has been discussed as a public private partnership, and a PNT service now being offered by Iridium and Satelles. At least one other private sector PNT service with a space component is under discussion.

The commercial element Bridenstine included in his legislation is particularly interesting in light of the incoming administration’s emphasis on supporting domestic, commercial space capability.

Although his bill has not progressed, Bridenstine has said, according to Space News, that he sees it more as providing a collection of ideas that can be incorporated into other legislation. “This bill will serve as a repository for the best space reform ideas,” he said in a speech at the 31st Space Symposium in Colorado Springs, Colorado, in April. “Many of its policies can be inserted into other bills that will pass.”

The bill is co-sponsored by Rep. Doug Lamborn, R-Colorado, who maintained his support for Trump after the emergence of a damaging recording of Trump making remarks about groping women. Colorado was a battleground state, this election and it’s likely to get some extra GOP attention going forward.

Just how important is these lawmakers’ early support of Trump’s candidacy? Pretty important it appears. Trump, so far, has chosen his advisors and cabinet officials from among his loyal supporters.

The lawmakers mentioned don’t necessarily have to get the administration jobs they are being considered for in order to have influence on the new administration. They made their bones during the heat of one of the country’s most intense elections. Wherever they wind up, it’s a decent bet they will be able to at least get a call back from the Trump team when it comes to PNT policy.

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GPS seems to have come out of nowhere. There was no progression like eight-track tape to cassette to CD to MP3 player. One day we were driving around clueless of where we were, struggling with roadmaps bought as gas stations that couldn’t be folded back neatly once opened and — suddenly — there was an amiable female voice coming out of the dashboard offering directions to our destination and showing no signs of impatience when we made wrong turns.
From the author’s introduction to GPS for Everyone

GPS seems to have come out of nowhere. There was no progression like eight-track tape to cassette to CD to MP3 player. One day we were driving around clueless of where we were, struggling with roadmaps bought as gas stations that couldn’t be folded back neatly once opened and — suddenly — there was an amiable female voice coming out of the dashboard offering directions to our destination and showing no signs of impatience when we made wrong turns.
From the author’s introduction to GPS for Everyone

The book is motivated by a taxi driver asking GPS expert Pratap Misra how the system works. As GPS experts, we should be capable of passing an under¬standing of GPS to the non-technical individual and Pratap’s book does that. The average person views GPS as the little box that gives location and direction. Pratap discusses GPS history, example operations, and antidotes so that the lay person can bet¬ter understand the system.

GPS for Everyone covers the basic principles of operation, the GPS sig¬nals and how the receiver processes the signals, the technology involved, many of the civil and military operations, and the story of how GPS came to be developed. Pratap has a nice variety of pictures and illustrations significantly enhancing an individual’s understand¬ing. He also discusses what is ahead in satellite navigation with the new systems coming on line.

I was so impressed with this book, that when I gave a talk to my former high school, I took a copy and left it with them.

GPS for Everyone: You are Here
By Pratap Misra, Ganga-Jamuna Press, 2016, ISBN-13: 978-0-9709544-3-5

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A United Launch Alliance (ULA) Atlas V rocket carrying the Geostationary Operational Environmental Satellite R-series (GOES-R) for National Aeronautics and Space Administration (NASA) and National Oceanic Atmospheric Administration (NOAA) lifted off from Cape Canaveral Air Force Station, Florida, yesterday (November 19, 2016) headed for geosynchronous orbit.

A United Launch Alliance (ULA) Atlas V rocket carrying the Geostationary Operational Environmental Satellite R-series (GOES-R) for National Aeronautics and Space Administration (NASA) and National Oceanic Atmospheric Administration (NOAA) lifted off from Cape Canaveral Air Force Station, Florida, yesterday (November 19, 2016) headed for geosynchronous orbit.

As the first in the next generation of U.S. weather satellites, GOES-R will produce images of weather patterns and severe storms as frequently as every 30 seconds, with improved timeliness and accuracy as a result of onboard GPS receivers optimized for high-altitude space missions.

A feature article in the forthcoming November/December issue of Inside GNSS describes how improved positioning, navigation, and timing (PNT) provided by advanced GNSS receivers is transforming the effectiveness of space missions at altitudes even higher than the orbits of the navigation satellites themselves.

ULA’s Atlas and Delta vehicles have successfully launched every operational GOES satellite, beginning with the launch of GOES-A in 1975, according to Laura Maginnis, ULA vice president of Custom Services.

In about two weeks, once GOES-R is situated in orbit 22,300 miles above Earth, it will be known as GOES-16. Within a year, after undergoing a checkout and validation of its six instruments, the new satellite will become operational.

In comparison, GPS satellites operate at about 12,550 miles altitude. At these higher altitudes, the “spillover” energy radiating over the limb of the Earth has come to define the utility and access of GPS. As the authors of the Inside GNSS article explain, this more challenging signal processing environment has been designated as the GPS Space Service Volume (SSV), defined as the region of space between 3,000 kilometers and GEO altitudes of about 36,000 kilometers.

“The next generation of weather satellites is finally here. GOES-R is one of the most sophisticated Earth-observing platforms ever devised,” said NOAA Administrator Kathryn Sullivan. “GOES-R’s instruments will be capable of scanning the planet five times faster and with four times more resolution than any other satellite in our fleet. With these new instruments and powerful new capabilities, GOES-R will strengthen NOAA’s ability to issue life-saving forecasts and warnings and make the United States an even stronger, more resilient Weather-Ready Nation.”

GOES-R will scan the skies five times faster than today’s GOES spacecraft, with four times greater image resolution and three times the spectral channels. It will provide high-resolution, rapid-refresh satellite imagery as often as every 30 seconds, allowing for a more detailed look at a storm to determine whether it is growing or decaying.

The Role of GPS in GOES-R
GOES-R’s two key innovations — an improved imaging instrument coupled with GPS PNT — provide “game-changing science products to substantially improve weather prediction capabilities and public safety situational awareness of fast-moving events,” according to the Inside GNSS article.

The feature article is authored by James J. Miller, deputy director of the Policy & Strategic Communications Division with the Space Communications and Navigation Program at NASA Headquarters, along with NASA colleagues and key technical experts supporting the development of high-altitude space navigation.

“GOES-R illustrates the class of applications in which navigation performance must be maintained during, and subsequent to, propulsive maneuvers,” they write. “On the legacy GOES satellites without GPS, station-keeping maneuvers mandated relaxing requirements for up to six hours post-maneuver, directly affecting the geolocation accuracy for tracking time-critical events such as tornadoes, flash floods, and forest fires.”

“By effectively tracking the aggregate GPS signals already radiating over the Earth’s limb, signal availability is vastly improved, leading directly to precise rapid recovery from station-keeping maneuvers to accelerated data collection and processing during potential disaster scenarios. Without GPS services in space, such improved products would simply not be available.”

GOES-R data will help improve hurricane tracking and intensity forecasts, the prediction and warnings of severe weather, including tornadoes and thunderstorms. Additionally, GOES-R’s improved rainfall estimates will lead to more timely and accurate flood warnings.

According to Miller and his coauthors, scientists expect that reliable extended forecasting will stretch from three to five days now to five to seven days with GOES-R data, enabled by the nearly continuous availability of GPS at GEO.

Advanced Sensing Technologies
GOES-R is flying six new instruments, including the first operational lightning mapper in geostationary orbit. This new technology will enable scientists to observe lightning, an important indicator of where and when a storm is likely to intensify. Forecasters will use the mapper to hone in on storms that represent the biggest threat. Improved space weather sensors on GOES-R will monitor the sun and relay crucial information to forecasters so they can issue space weather alerts and warnings. Data from GOES-R will result in 34 new, or improved, meteorological, solar and space weather products.

NOAA manages the GOES-R Series Program through an integrated NOAA-NASA office. NASA’s Goddard Space Flight Center oversees the acquisition of the GOES-R series spacecraft and instruments. Lockheed Martin is responsible for the design, creation, and testing of the satellites and for spacecraft processing along with developing the Geostationary Lightning Mapper and Solar Ultraviolet Imager instruments.

Harris Corporation provided the GOES-R’s main instrument payload, the Advanced Baseline Imager, the antenna system for data receipt and the ground segment. The Laboratory for Atmospheric and Space Physics provided the Extreme Ultraviolet and X-Ray Irradiance Sensor, and Assurance Technology Corporation provided the Space Environment In-Situ Suite.


“We are ready to receive and process GOES-R data into our forecasts as soon as it is available,” said NOAA National Weather Service Director Louis W. Uccellini. “Forecasters will not only have sharper, more detailed views of evolving weather systems, they will have more data — better data — ingested into our weather models to help us predict the weather tomorrow, this weekend and next week. This is a major advancement for weather forecasting.”

For the aviation sector, GOES-R will deliver clearer views of clouds at different atmospheric levels, generating better estimates of wind speed and direction and improved detection of fog, ice and lightning. This will improve aviation forecasts and flight route planning to avoid hazardous conditions such as turbulence.

Beyond weather forecasting, GOES-R will be part of SARSAT, an international satellite-based search and rescue network. The satellite is carrying a special transponder that can detect distress signals from emergency beacons.

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