Once all currently planned satellites have been deployed and added to those already in orbit in existing constellations, it is anticipated that positioning services, particularly in “urban canyons” and other locations where signal strength has previously been an issue, will be significantly enhanced for navigation system users around the world.

The Compass Navigation Satellite System will initially provide service to the Asia-Pacific region (public domain image courtesy of Wikimedia Commons).

The IIF satellites are part of the ongoing modernization of the GPS constellation by the United States Air Force.  The IIFs have improved atomic clocks used for timing and are therefore expected to provide more accurate navigation signals than those currently available from the rest of the GPS constellation.  The IIFs will also broadcast the civil L5 signal for safety-of-life applications, which has the potential to enhance indoor reception with its wider bandwidth and lower frequency.  The new satellites will also be compatible with the Galileo, GLONASS and QZSS constellations.  In addition, the IIFs will assist the IIRM series already in orbit with military-specific M-code, a unique encryption for military users requiring secure access. 

The new satellite, officially known as GPS IIF-1 SV-1, is expected to begin broadcasting its signal to GPS users following a three- to four-month testing period.  In addition to being the first in the new IIF satellite series, this launch was significant for another reason as well.  GPS IIF 1 SV-1 was carried into orbit on a Delta IV rocket, making it the first GPS satellite since 1985 that was not placed in orbit by an Atlas rocket.

The new IIF satellite series has finally launched. (Public domain image courtesy of http://pnt.gov/public/images/.)

The AWRA Conference covered a diverse range of subjects involving the use of GIS in the water resources industry.  There were presentations on hydrologic modeling, watershed delineation, data sharing, software interface development and land use applications, just to name a few.  The poster session added topics such as coastal management, agriculture, community water systems, education and irrigation, as well as document management.  Many of the organizations looking at Sajara to manage their infrastructure plans were also interested in using GIS for stormwater management applications, similar to what the Philadelphia Water Department is doing with phillystormwater.org.    

The opening plenary session featured Jack Dangermond with additional details on his vision for GIS in the cloud” and web services to enable data sharing.  He particularly referenced CUAHSI HIS (Consortium of Universities for the Advancement of Hydrologic Science Inc.), an organization representing over 100 United States universities.  CUAHSI has received National Science Foundation support to develop a web API and the HydroDesktop software application.  The desktop application has been released as open source and available at no cost to users to help them download and manage available water data.  But the web API and the database behind it are most interesting parts of the project.  CUAHSI harvests sensor feeds of water data from 1000’s of sites across the United States.  This data is archived and made available through a SOAP interface   Dangermond collaborated with David Maidment on a paper for the AWRA proceedings that outlined the integration of water resources data using GIS and the web more generally and the CUAHSI project specifically.  Maidment is the Director of the Center for Research in Water Resources at the University of Texas in Austin and heavily involved in the CUAHSI project.  Both of them were also part of a panel discussion on the future of water resources information. 

In addition to discussing Sajara with various organizations, one of the highlights of the conference for me was a presentation by the U.S. Army Corps of Engineers regarding GIS past, present and future for water resources applications.  Part of their vision for the future includes augmented reality applications, enabled by smart phones, special glasses or potentially car windshields, which would augment the reality experience of approaching a well or other infrastructure asset, for example, with critical descriptive information, or even diagrams and engineering plans overlaid on the reality view.  The potential for these projects is very exciting to me, particularly since the Philadelphia Department of Records recently received funding from the National Endowment for the Humanities under its Digital Humanities Startup Grant program to develop an augmented reality application for PhillyHistory.org that would enable smart phone users to view historic photographs of the city as an overlay on their camera displays by simply pointing their smart phone cameras at selected buildings. 

AWRA will be holding this year’s annual conference right here in Philadelphia beginning on November 1, 2010.  They will be addressing regional topics of interest to Mid-Atlantic water resources organizations.  Perhaps Azavea will see you there.

The Poster Session at the AWRA Conference demonstrated Sajara’s ability to organize, search and retrieve infrastructure documents in a single web interface. Azavea’s poster was one of more than forty posters showcasing various aspects of GIS for the water resources industry.

As a comparison, the current GPS constellation maintained by the United States includes 32 satellites and reached full operational capacity in 1995.  It takes a minimum of 24 operational satellites to provide complete global availability.

Solar activity generally occurs in eleven-year cycles, with the next peak expected by 2012.  Increased solar activity is particularly troublesome for the navigation devices many drivers reference in their vehicles.  GPS blackouts may last for a number of minutes during periods of peak solar activity and may occur several times each year.  In addition to GPS blackouts, the atmospheric charge can impact the amount of time it takes for a GPS signal to make it to a GPS receiver, which causes inaccurate readings.  Positioning may be off by as much as thirty feet during these periods, which will have the greatest impact on GPS survey equipment. 

For iPhone users that want to keep track of solar activity, NASA has helped implement a new app called “3D Sun” that allows users to access a live global view of the sun.  Data is provided in near real-time fashion by NASA’s STEREO mission, a pair of satellites that provide coverage of both sides of the sun simultaneously.  More information on the app is available at http://3dsun.org/.

A high resolution 2D image of the sun taken by NASA's STEREO mission. STEREO is monitoring solar activity that may interfere with GPS and other signals. (Public domain image courtesy of NASA.)

Also known as the Beidou system, the geostationary satellites will provide free open service within the local service area.  A second level of service will provide greater accuracy to authorized users only.

On January 11, 2010, following extensive feasibility studies, the U.S. Strategic Command (USSTRATCOM) announced that three of the augmentation satellites would be moved to new locations within the GPS constellation, thus effectively increasing the number of individually positioned satellites from 24 to 27.  The main thrust of the reconfiguration is to increase coverage in previously degraded areas, such as the mountainous regions of Afghanistan, for military purposes.  However, the changes will benefit civilian and commercial users as well. 

The new “Expandable 24” configuration will take approximately two years to implement fully, but the first satellite is already on the move.  Space Vehicle Number (SVN) 24 began its journey on January 13 and should arrive in its new position sometime in January 2011.  The other two satellites have shorter journeys ahead of them.  SVN 49 will begin its journey on January 21 and is expected to be in its new position by May 2010.  SVN 26 will being its journey on February 8 and should also be in its new position sometime in May 2010. 

From the mountainous regions of Afghanistan to the urban canyons of the United States, GPS users should begin to notice gradual improvements in GPS coverage over the next two years as the number of satellites visible from any location on earth begins to increase.   I find it especially intriguing that two of the three satellites being moved are expected to be in place in May 2010, exactly 10 years after Selective Availability (SA) officially ended and GPS first became readily available to non-military users.

SVN 24, a GPS IIA satellite similar to the one in this image, is currently on the move to provide enhanced GPS coverage to users worldwide. The satellite is expected to arrive in its new location within the GPS constellation sometime in January 2011. (Public domain image courtesy of http://pnt.gov/public/images/.)

Bringing the Galileo constellation closer to reality will require the collective efforts of several nations in and beyond the European Union.  Companies in Germany (OHB System AG) and the United Kingdom (Surrey Satellite Technology Limited) will be providing the satellite components, an Italian company (Thales Alenia Space) will provide the system support services, and a French company (Arianespace) will provide launch services that will use both French Ariane-5 and Russian Soyuz launchers.

The announcement was made on January 7, 2010, and contracts are expected to be signed within the next few weeks.  The European Commission anticipates initial navigation system services by early 2014.  The final completion date of the 30-satellite constellation has not been announced.

The Galileo constellation, sponsored by the European Union (EU) and European Space Agency (ESA), was originally slated for full operation by the end of 2009.  Though test satellites have been launched to verify orbits and time synchronization for the new constellation, delays in planning and lack of funds have postponed the first operational satellites from being launched until sometime in late 2010.  The projected number of satellites in the Galileo constellation has already been reduced from 28 to 22 initially, due to cost overruns.

Russia’s GLONASS was fully operational back in 1995, but lack of funding due to the collapse of the Soviet Union eventually caused the system to fall into disrepair.  A new commitment in 2001, including the announcement of a partnership with India, has put the program back on track, though still far behind its target date of restoring full world coverage by the end of 2009.  Even after placing 3 new satellites in orbit in December 2009, GLONASS has only 19 working satellites in its constellation, which guarantees coverage only within Russian territory.  A total of 24 satellites are needed to provide global coverage. 

After initially expressing interest in assisting the EU with its Galileo constellation, the Chinese government is planning its own Compass constellation that will expand the existing Beidou Navigation System from regional China-only coverage to worldwide coverage.  The target completion date is 2015.  However, there were positioning issues with the first 2 satellites in 2009 that may ultimately delay or even prevent the Compass constellation from becoming a reality.  

The Quasi-Zenith Satellite System (QZSS) is a proposed three-satellite system that would provide enhanced GPS coverage within Japan.  The first satellite is scheduled for launch sometime in mid-2010.  Full operation is anticipated by 2013.  However, funding for the second and third satellites in the system is not expected until 2011 at the earliest, since it is contingent on the successful launch and operation of the first satellite.  QZSS is intended to enhance rather than replace GPS, and is expected to provide improved reliability and usability to the entire South East Asian region. 

The Indian Regional Navigational Satellite System (IRNSS) is a regional satellite system being developed by the Indian Space Research Organisation.  A seven-satellite system is scheduled for completion by 2012, and will provide accurate coverage of India and a 2,000-kilometer perimeter around its borders.  All space, ground and user components will be made in India. 

As the United States moves to modernize its own aging GPS constellation in 2010 and beyond, interoperability with one or more of the new constellations will ultimately become possible.  GPS receivers with dual capabilities will be able to get more accurate readings, and the addition of new satellites to any of these alternate constellations will provide needed back-up to the United States as its older satellites fail.  I will be looking skyward in 2010 to monitor these conditions and providing periodic updates on each constellation as news becomes available.

Artist’s rendering of a GPS III-A satellite, part of the U.S. modernization of the existing GPS constellation. (Public domain image courtesy of http://pnt.gov/public/images/.)

However, a report on GPS issued in May 2009 by the Government Accountability Office (GAO) was much less favorable.  The GAO concluded that if significant action was not taken by the Air Force to meet critical goals for modernizing the system, the older satellites in the GPS constellation will begin to fail in 2010, and it is likely that the total number of operational satellites will fall below the minimum number of 24 needed to provide the level of GPS service that the world has grown accustomed to.  Currently, about half of the existing GPS constellation is approaching “single thread” operation status, where a critical system error could render could render a satellite inoperative. 

It is possible this assessment is overly pessimistic, at least in the short term.  The constellation is currently at its maximum number of 30 active satellites and has another five deactivated spares as well as satellites that are “in the barn” on the ground, ready to launch on short notice.  However, the GPS III upgrade has been repeatedly delayed and further delays could endanger the integrity of the system.  Colonel Brad Parkinson, the original architect of the GPS, recently testified to substantial concerns regarding the risk of a GPS “brownout” that could arise from reduced satellite numbers. 

A reduction in operational satellites would cause performance degradations and a decline in positioning accuracy that would do more than simply reduce the accuracy of your car navigation systems or impact the ability of your GPS-enabled smart phone to find the nearest public transit station.  For example, many Enhanced-9-1-1 emergency calls, particularly from mobile carriers, rely on GPS technology to determine and transmit caller location data to emergency dispatch centers.  Power companies also use the precision timing of GPS to synchronize power plants and substations.  Without it, they will lose the vital ability to trace back failures in the power grid in the event of a major blackout, and restoration of power could be significantly hampered.  In addition, the airline industry may need to delay, cancel or reroute flights to allow for projected gaps in GPS coverage.  Military operations would be impacted as well. 

The United States controls the GPS constellation, and although civilian access has been allowed on a global scale since selective availability (SA) was discontinued in May 2000, there has been growing concern in other nations that some level of selective availability could be re-established in the event of another terrorist attack or hostile military actions against the United States.  While the GPS III system will not include any SA capabilities, these fears, along with a desire for independence and concerns about the aging satellite infrastructure, have spawned the development of alternate Global Navigation Satellite Systems (GNSS) that would compete with and/or complement the existing GPS constellation.  Unfortunately, these systems will not be operational in time to provide any back-up to the United States in the event of one or more satellite failures within the next couple of years.  

I’ll have more information about the alternate GNSS in my next blog post. 

A diagram of the existing GPS constellation showing 24 healthy satellites in orbit around the earth. Failure of any of these satellites could cause some level of performance degradation and a decline in positioning accuracy for GPS users worldwide. (Public domain image courtesy of http://pnt.gov/public/images/.)