A growing awareness of the limitations and vulnerabilities of GNSS — along with advances in inertial designs and manufacturing — has opened a new era in which these admirably complementary technologies are converging ever more often into integrated products.

A growing awareness of the limitations and vulnerabilities of GNSS — along with advances in inertial designs and manufacturing — has opened a new era in which these admirably complementary technologies are converging ever more often into integrated products.

Two key devices are associated with inertial navigation: gyroscopes and accelerometers, which measure, respectively, the angular velocity and the linear acceleration of a platform. Integration with GNSS is typically realized in an IMU comprised of three gyros, three accelerometers, and a computer. Most accelerometers are based on similar sensor technologies, and thus the significant differences among IMUs usually stem from the type of gyroscopes used.

Modern inertial navigation arose during the 1930s and was originally applied to guidance of rockets. Consequently, the technology has long been associated with military endeavors, and export controls continue to impose constraints on some inertial products.

OLD & NEW TECHNOLOGIES
In the past, expansion of civil and commercial applications have been limited by the high unit costs associated with optical-based gyroscope technologies, such as ring laser gyros (RLGs) and fiber-optic gyros (FOGs), able to meet requirements for precision navigation. Such systems typically weigh about 25 pounds, use 50 watts of power, are in boxes of about 0.5 cubic feet, and cost between $50,000 and $100,000.

Since their introduction in the early 1990s, silicon micro-machined gyroscopes have been steadily improving. Consequently, micro-electromechanical (MEMS) inertial measurement units (IMUs) based on this manufacturing method are approaching the level of RLGs and FOGs. These IMUs may weigh 0.1 pound, use 0.1 watt, come packaged in boxes of about two cubic centimeters, with bias stability in the range of 1 to 10 degrees per hour, and cost less than $2,000.

A 2011 report by Yole Développement sees the overall IMU market growing at a 9 percent annual growth rate, reaching $2.6 billion by 2015 and still dominated by defense and aerospace applications. Unlike the historical trend, however, MEMS industrial and tactical-grade types of sensors comprise the most dynamic technology. Yole sees the high-performance MEMS IMU market growing from $361.8 million in 2009 to $604.6 million in 2015.

The availability of MEMS IMUs now promises to open up a range of potential applications markets for which traditional precision IMU technologies are practically unaffordable.

EXPERT ADVICE
Mike Perlmutter has worked in the inertial navigation field for more than 30 years and was a key contributor to Yole Développement’s IMU & High Performance Inertial MEMS 2011 Report. He was the Navigation Systems Division director of strategy and planning at Northrop Grumman in 2007 when he retired from the company and established Skylight Navigation to consult in the area of inertial systems, navigation, corporate planning, and strategy.

A co-founder of Fibersense Technology, Perlmutter holds three degrees from MIT and has authored 10 U.S. patents on inertial sensors, GPS, and navigation technology. We asked him to comment on the evolution of inertial technology, applications, and markets.

IGM: In which ways are the boundaries among inertial technologies changing in terms of cost, performance, and applications?

PERLMUTTER: Because they have been in high volume production for so long — almost 35 years, RLGs are changing the least. Both RLGs and FOGs have their “sweet spot” from the high tactical grade (less than 1 degree/hour) up to navigation-grade (0.005 degree/hour) performance class.

FOGs are also fairly mature, and producers are no longer able to reduce costs through to improvements in components from the telecom industry, manufacturing efficiency resulting from higher volume production, or breakthroughs in basic technology.

MEMS are making the most significant improvements in performance. In addition to the expected technological advances, (smaller, less power, lower cost), two significant breakthroughs will affect these sensors: complete MEMS IMUs can now be fabricated on planar substrates (three orthogonal axes of gyros and accelerometers), greatly reducing the manufacturing and assembly costs; and the ability to eliminate long-term bias drift by periodically applying a reference stimulus (and later extracting it) is greatly improving the long term performance of MEMS IMUs.

IGM: What are the motivating factors to use MEMS-based IMUs over older/non-MEMs technology?

PERLMUTTER: The main motivating factor is that in many cases MEMS IMUs offer nearly the same performance (or adequate performance given their extremely small size and cost) while using 1 to 2 orders of magnitude less power, weighing an order of magnitude less, occupying 1 to 2 orders of magnitude less space, and costing an order of magnitude less than traditional optical-based IMUs.

IGM: What markets/applications are driving the use of MEMs IMUs?

PERLMUTTER: During Q2 of 2011 Apple alone sold over 30 million IMUs in their iPhones and iPads alone! (every iPhone and iPad has three gyros and three accelerometers — so, only a slight stretch). Thus these types of consumer applications are the strongest drivers for the MEMS IMUs.

Will MEMS-based IMUs ever replace all other technologies in all market places? I do not think so! Some significant physical limitations (large surface to volume ratios makes MEMS devices very sensitive to surface effects such as charging, contamination, out-gassing and trapping) will prevent small sensors (less than one square centimeter) from being able to have performances of slightly larger optical sensors. Nevertheless continued progress in MEMS-based IMUs will continue to make them ubiquitous in virtually all applications where some type of motion is involved — to analyze it, control it, or perhaps stabilize it.

The post Inertial technology, MEMS, and GNSS appeared first on Inside GNSS - Global Navigation Satellite Systems Engineering, Policy, and Design.

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

1. AQUARIUS
Buenos Aires, Argentina and Vandenberg AFB, California, USA

1. AQUARIUS
Buenos Aires, Argentina and Vandenberg AFB, California, USA
√ Aquarius/Sac-D earth observatory, a joint project of NASA and Argentina’s space agency, CONAE, launched from Vandenberg AFB on June 10. Its science instruments include Italy’s ROSA GPS receiver and the U.S. TDP, a GPS navigation and inertial guidance technology demonstration. Ocean salinity measuring is the satellite’s main mission.

Aquarius mission Argentina (United Launch Alliance)

2. DOG HIS PREY
Washington D.C., USA
√ On June 27, The U.S. Supreme Court agreed to untangle legal confusion on GPS-aided surveillance and privacy rights. In United States v. Jones, police secretly tracked a suspect for weeks. D.C. Circuit judge Douglas Ginsburg said it’s not ok “for a stranger to dog his prey” until he knows everything about you. We’ll see next fall.

(June 28 2011 Inside GNSS) U.S. Supreme Court to Weigh In on GPS Surveillance and the Fourth Amendment

3. FOLLOWING ON
Cape Canaveral, Florida USA
√ SVN-63, the second of 12 planned GPS IIF satellites launched successfully from Cape Canaveral on July 16. The first IIF boasts a boffo atomic clock, but earlier had trouble with L1, L2 and L5 signals; its M-code signal was switched off in April.

(July 22 2010 Inside GNSS) Air Force Investigating Residuals in GPS IIF Signals

(July 19, 2010 Air Force Space Command) SMC Update on Next Generation GPSS IIF-1 Satellite On-orbit Checkout

GPS.GOV space segment page

United Launch Alliance

4. NATALIA
Varna, Bulgaria
√ Natalia is Europe’s first Galileo IOV satellite, scheduled for lift off from Kourou, French Guiana on October 20, 2011. It’s named for a nine-year old Bulgarian girl who won an EC-sponsored drawing contest with her colorful rendition of two astronauts meeting on Mars. All 30 planned satellites will be named after EU children.

(June 16 2011 European Commission) Bulgarian Natalia on Galileo’s Satellite

5. RICKSHAW WARS
New Delhi, India
√ Commuters depend on New Delhi’s 55,000 auto-rickshaws, called tut-tuts, but it’s a wild ride. This summer, the state transportation authority mandates GPS-assisted tracking devices, using SatNav Technologies maps, on the three-wheelers to control fraud and reduce harassment of customers. Low-wage drivers walked off the job in May, demanding help with installation costs.

(July 6 2011 Techcircle.in) SatNav’s Maps to be Installed in Autos; Govt Authorises Tracking

(June 28 2011 Times of India) July Deadline for GPS in Autos, Trials Next Week

(May 20 2011 Indo Asian News Service | IANS) Auto strike cripples Delhi; unions refuse to budge

(May 20 2011 The Hindu) Auto-rickshaws set to go on strike from today

(May 14 2011 Delhi Information) GPS row: Autos to go off roads from May 20

The post GNSS Hotspots | July 2011 appeared first on Inside GNSS - Global Navigation Satellite Systems Engineering, Policy, and Design.

Aside from the fact that someone gambling with other people’s money, with friends in high places benefiting from his largesse, can make the law stand on its head and our hair stand on end.

But then, we already knew that.

Just because the forces behind the broadband cellular company, Philip Falcone and Harbinger Investments, made their money by betting against the housing bubble doesn’t take away from the fact that they represent the same crew who helped take down the world economy in 2007.

What have we learned from the LightSquared fiasco?

Aside from the fact that someone gambling with other people’s money, with friends in high places benefiting from his largesse, can make the law stand on its head and our hair stand on end.

But then, we already knew that.

Just because the forces behind the broadband cellular company, Philip Falcone and Harbinger Investments, made their money by betting against the housing bubble doesn’t take away from the fact that they represent the same crew who helped take down the world economy in 2007.

People who use other people’s money to get rich off of enterprises founded on real innovation, hard work, competition, and marketplace risk are not in the same business as the latter. They aren’t even in the same economy.

It’s also not news that the Federal Communications Commission is filled with political cronies prepositioning themselves for lucrative returns to the industry they regulate.

So, have we learned anything useful from the slow-motion car wreck that is LightSquared and it’s encroachment into L-band frequencies long allocated for other purposes? What can the GPS and wider GNSS community do to increase our preparedness for the next attack on the hard-won equities of this wonderful public utility?

Well, the need for more effective, continuing organization and representation of the GNSS community — manufacturers, service providers, and users — seems pretty clear.

Despite the commercial availability of the GPS resource for more than 20 years, there has never been a strong awareness of the community as one involved in a mutually interdependent, on-going common enterprise.

Indeed, companies in the GNSS business often appear to consider themselves a subset of other industries — perhaps information technology, telecommunications, electronics, or mobile devices. The confusion is not surprising, given the strong vertical application markets into which GNSS products and services are sold.

But GNSS has unique characteristics that mark it as a something apart: a space-based infrastructure that is publicly owned, dual-use, and therefore possessing certain requirements regarding export of technology.

Common interests abound, and I’m not just referring to the RF issues that fuel the present furor. Already, some in Congress seem to be toying with the idea of requiring receiver standards that could include GPS products. In the great national deficit debate, program budgets are often laid waste — this year congressional committees have already whacked FY12 funds for GPS III and OCX space and ground segment modernization.

Multiple agencies and overlapping regulations control the export of products in any global market such as ours. The emergence of other GNSS systems raise issues of fair trade and common technical standards that promote compatibility and interoperability.

The list goes on and on.

Despite its high profile in the contest before the FCC, the U.S. GPS Industry Council (USGIC) has never represented a true industrywide entity, although many besides its members have benefitted from the council’s efforts. Over the years, the USGIC has lobbied effectively for GPS-related trade policies and helped transform multiple presidential policy directives into law.

But for all its good work, the USGIC’s self-defined mandate has limited its reach. We still need a broad-based industry association.

Such an organization would look more like the ad hoc Coalition to Save Our GPS that formed in a hurry around the LightSquared issue. The coalition claims to represent more than 100,000 companies and millions of employees, either independently or through their trade associations.

The coalition’s reach clearly extends further than its grasp, at least until now. Many of the individuals and companies included in its claim probably don’t even know of the coalition’s existence.

But the coalition has awakened and gathered a far greater number of companies and organizations with vested interests in GPS than ever before. And its role in the second or third act of the LightSquared drama could transform it from a single-issue entity into a full-fledged, permanent advocate for GPS.

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