Here’s a panorama in broad strokes across the range of GNSSs, garnered from top system spokespersons at the Munich Satellite Navigation Summit. It’s been several years since breaking news was aired at this annual late winter/early spring event, but it’s always good for a wide-ranging update, recalibrating levels, so to speak.
GPS. With 31 operational satellites (24 is baseline) and an estimated 3 billion receivers in use worldwide, what more needs to be said about the gold standard? Its best week ever for accuracy logged a signal-in-space performance average of 45.3 centimeter. The next-generation ground control system OCX “survived quite a struggle” and has emerged from Nunn-McCurdy breach, back on track and seemingly ready for future action. Or at least for future pre-certification tests. SV1 of the GPS III generation has completed all tests and is in storage, awaiting the first GPS III launch in spring 2018. SV02 and 03 are in assembly and integration, SV04 thru 08 are in box-level assembly, and 09 and 10 are on contract. Technical challenges with payload have been resolved.
(Click to enlarge.) Galileo satellite top-level block diagram. OHB Systems AG as prime contractor and Surrey Satellite Technology (SSTL) have teamed for production of the navigation satellites. OHB is responsible for the concept, the satellite platforms and the satellite-level inegration and test. SSTL supplies the satellite payloads and supports OHB on system level. OHB also supports the customers during launch preparation and in-orbit testing. (Image courtesy OHB)
Galileo. With 18 on-orbit satellites (15 operational), the European GNSS can be termed a coming thing. Performance statistics are based on only 11 of these satellites however; the four most recently launched in November 2016 are not yet included. Nevertheless, the system is logging 80-centimeter ranging accuracy. Eight more await launch: four in 2017, and four in 2018. The constellation is broadcasting the Open Service, the Public Regulated Service, and the Search and Rescue (SAR) signal. The SAR service will officially launch in early April — on April 6, because 406 MHz is the Emergency Position Indicating Radio Beacon frequency. Galileo has improved the historic SAR location performance from 3 hours to 10 minutes. The Commercial Service is still in preparation, and will be available in 2020. Spoofing is seen as a very real threat to GNSS overall by the Galileo authorities, as exemplified by the recent bloom of amateur spoofers encouraged by Pokemon go.
GLONASS. The Russian system will undertake three or four launches this year; one of them will be a triple-satellite launch. There have been several disruptions to efforts to decrease the offset between GLONASS system time and Universal Coordinated Time but the initiative perseveres. English versions of four system interface control documents (ICDs), to include the new CDMA signal, are promised for Q2 2017; Chinese versions are coming, too. Russian-language ICDs are available at glonass.aic.ru.
BeiDou. With the addition of three new satellites in the past year, China’s system is enjoying improved system performance. Hydrogen clocks are succeeding rubidium clocks, bring an order-of-magnitude improvement in timing accuracy. A BeiDou white paper was published last June, and a revised ICD appeared in November.
In the massive Chinese mass market, 30 percent of smartphones sold in China now have BeiDou capability; that’s out of a 700–800 million total. Huawei multi-function chip LX1101 is a key driver behind this. Unistrong has released a phone with RTCM input for professional use, blurring the line between mass and professional markets.
Six to eight satellites will be launched this year, and 10 to 12 in 2018. BeiDou is in a “very ambitious and aggressive race with time to complete the global system.”
ICG. The United Nations’ International Committee on Global Navigation Satellite Systems will meet in Japan in December of this year, in China next year, and in India in 2019. This can be interpreted as vigorous international interest and “a desire to advance and promote their respective systems’ visibility” worldwide. All pertinent documents can be found at unoosa.org.
EGNOS. The European Geostationary Navigation Overlay Service has two operational geosynchronous Earth-orbit satellites (GEOs) in operation, plus one in test and one in deployment, ready to swap in. It is extending its Ranging and Integrity Monitoring Stations (RIMS) to several new countries, notably Israel and the Ukraine. EGNOS.v3 is coming and will introduce dual-frequency (L1 and L5) service, and also Galileo with GPS, for multi-constellation corrections. The new system’s qualification is planned for 2022.
QZSS. This year, Japan’s Quasi-Zenith Satellite System will launch the second and third of the figure-eight inclined geosynchronous orbit (IGSO) satellites of the Michibiki type, to become operational in 2018. A GEO bird will also be launched. A seven-satellite system is the ultimate goal.
Among other announcements of note made during the course of the Summit, although not by the GNSS operators’ spokespersons:
(Click to enlarge.) Key features of the Galileo satellites.
• OHB, the Galileo satellite manufacturer, said its customer has decided to refurbish the clocks on eight satellites in preparation. “Satellite navigation is nothing but comparison of very precise clocks.”
• Airbus announced a new concept for train positioning integrity: “virtual valises” to correct train position that will replace or augment current trackside valises that are very expensive to build and maintain.
• Munich Aerospace (munich-aerospace.de), a public-private non-profit venture between DLR, the German space agency, Bauhaus Luftfahrt and two technical universities, will mount a Ph.D-level education and research program for 70 individuals, with candidates from 27 nations. This will be located in “the Bavarian Silicon Valley.” It will also undertake a global effort with several other organizations.
• One of the above technical universities, the Federal Armed Forces University in Munich, announced that it is investigating Lidar for potential use in an asteroid mining project for future space exploration. It also has underway initiatives concerning Lidar + GNSS and inertial + GNSS for autonomous vehicles.
A GLONASS ground station was officially commissioned in South Africa on Feb. 27.
“Assembling and pre-commissioning work was completed on Nov. 25 to set up a measuring station on the premises of the Hartebeesthoek Radio Astronomy Observatory (HartRAO) as part of the agreement signed between Russia’s High-Precision Instrument Systems Company and South Africa’s HartRAO on Oct. 29, 2015,” said the station developer, Russia’s Precision Instrument Systems Corporation.
Sazhen-TM-BIS station in South Africa is the second station of the overseas network segment created for the GLONASS system. The first station was installed and commissioned in 2014 in Brazil.
The station will continuous monitor GLONASS and GPS satellites’ navigation signals, measurements of current navigation parameters of their travel, and receipt of navigation messages from the satellites.
New cars for the Russian market must be equipped with the automatic ERA-GLONASS emergency call system.
For certification of these in-vehicle systems, both conformance and performance tests are mandatory, in line with the Russian GOST R 55534 specification.
The Rohde & Schwarz CMW500 is being used to test the ERA-GLONASS system.
For both types of tests, the Russian Certification Center Svyaz-Certificate uses standard-compliant test solutions from Rohde & Schwarz. Manufacturers and component suppliers can use the same test solution in pre-tests to speed up certification for their products.
Now, for the newly required performance test, the center is using the GNSS simulator in the R&S SMBV100A vector signal generator.
Accuracy Requirements. During performance testing, it is verified whether the GNSS receiver of an ERA-GLONASS emergency call system fulfills the accuracy requirements of the specification.
In case of an emergency, the call system should not only correctly transmit position data according to a specified protocol to the public safety answering point, but position data must also be accurate so that the first responder can locate the accident vehicle quickly.
ERA-GLONASS module manufacturers and test houses can use the R&S SMBV100A during pre-tests to create reliable and reproducible conditions similar to those in official certification tests, according to Rohde & Schwarz, to minimize the risk of failing tests during certification.
It has been a good year for all global navigation satellite systems (GNSS), as the chief executives of each system testify here. Alternative positioning, navigation and timing (PNT) also thrives. In this roundup of the latest highlights from the past year and forecasts for the future, 2017 augurs very well indeed! Let’s look at the newest alternative-PNT offerings first, followed by forecasts from the chief executive officers (CEOs) of each of the conventional GNSS.
Alternative PNT grows and expands
Two new entrants to the positioning, navigation and timing (PNT) marketplace offer key capabilities to fill in the gaps left by GNSS. A new satellite timing and location (STL) service from low-Earth orbit satellites, provided by Satelles and Orolia, gives a strong signal capable of penetrating buildings.
Satellite Time and Location (STL) Service. Pursuant to a recent announcement of new PNT solutions independent of GPS/GNSS signals, provided via the Iridium constellation, GPS World talked with Jean-Yves Courtois, CEO of Orolia. Orolia has partnered with Satelles to bring new PNT products and services to the global market, with a focus on military, and defense, government and commercial customers worldwide.
Jean-Yves Courtois, CEO of Orolia.
“We are a manufacturer and integrator of timing equipment,” Courtois said. Orolia is the parent company of GPS/GNSS product and service providers Spectracom, McMurdo and Spectratime. “This new STL service is not fully commercialized yet, but it’s operational and it can be tested. Receivers are available and can be integrated into our equipment.
“The timing signal is very accurate and close enough to GPS for most timing applications, although the positioning accuracy is lower than what GPS users are used to. It is an augmentation for timing primarily, and secondarily for positioning.
“In terms of timing accuracy, it provides on the order of tenths of microseconds in accuracy, and this covers a lot of timing applications, very familiar to us and to our customers. This is an ideal timing backup or augmentation of GPS. As number 2 worldwide in high-precision timing, we know this market and its applications very well.”
Correlator beamforming. The Locata Corporation announced a patented correlator beamforming technology to stem multipath mitigation. The new technique’s performance under rigorous testing by the U.S. Air Force Institute of Technology will be detailed in the January 2017 issue. Look for it! Here are a series of snippets as a preview of that lengthy technical article appearing in Richard Langley’s Innovation column.
“Unlike conventional or traditional beamsteering technology, the new correlator beamforming approach combines RF signals received by any number of individual antenna elements into a single switched-RF signal. This time-multiplexed signal is then downconverted and digitized by a single RF front-end. The correlator beamforming design will should offer cost savings because the resulting data stream is processed using a single correlator channel per beam. This markedly reduces the complexity when compared to the traditional beamsteering methodology.
“The correlator beamforming technique performs antenna array signal processing to form beams as part of a receiver’s correlation process. The complete explanation of this technology can quickly get complex, even for the seasoned RF engineer. To describe this process more simply, we will assume noiseless signals and no multipath (except as noted), as well as equal noise figures for all front-end processing chains. To further simplify our explanation, modulation on the carrier and switching losses will be ignored.”
“To evaluate the performance of correlator beamforming as fairly as possible compared to traditional beamsteering and single-element processing, AFIT set up its data collection such that all three approaches could be implemented in a software receiver. Additionally, a seven-element Naval Air Systems Command GPS Antenna System 1 (GAS-1) antenna was used for this experiment. The antenna was mounted on a 51-inch (130-centimeter) diameter rolled-edge ground plane provided to the ANT Center by the MITRE Corporation.”
“The testing focused on demonstrating an easily modified GNSS receiver to potentially deliver a low-cost solution for mitigating multipath — specifically targeting short delay and carrier multipath. The results presented here show that the multipath rejection performance nearly equals that of a traditional beamsteering GNSS receiver. Applications that can significantly benefit from this technology include stationary GNSS monitoring installations such as those used in satellite-based and ground-based augmentation systems and GNSS receivers for autonomous vehicles and UAVs in high multipath areas such as urban canyons.”
GPS III ready, steady
Col. Steve Whitney, Director, U.S. Air Force GPS Directorate
“The [GPS III] program is working to solve several technical challenges as we progress to completion,” Col. Steve Whitney, director of the U.S. Air Force GPS Directorate, wrote in GPS World’s December issue. “SV-01 testing uncovered electro-magnetic interference between a payload component and a hosted payload. Testing also uncovered electron impact issues on the L-band antenna elements. In partnership with Lockheed Martin, the program developed corrective action and design mitigations for both of these issues and is implementing these steps within our production flow for all the SVs.”
“In the coming year, SV-02, the second GPS III satellite, will also be progressing towards completing production. Currently, all of the SV-02 sub-assemblies have been received by Lockheed Martin and are being integrated into the spacecraft. The next major step in the production flow for SV-02 will be to mate it with its propulsion core.
“Recently, we completed negotiations with Lockheed Martin to extend the production line with purchases of SV-09 and SV-10. These satellites will be technically equivalent to SV-01 through SV-08. This $395 million purchase of two satellites marks a significant affordability milestone for the procurement of GPS III satellites.
“Looking ahead, we are analyzing how to acquire satellites beyond SV-10. We are executing a phased strategy which starts first with determining the viability of a GPS III production design existing beyond the current contractor. We awarded an initial phase of contracts to the Boeing Company, Lockheed Martin Space Systems Company, and Northrop Grumman Aerospace Systems in May 2016 to provide a feasibility assessment of the readiness of their satellites designs. In this phase, the contractors will provide a GPS III production design, manufacturing plans and a navigation payload brassboard test report, along with manufacturing/production processes and facilities maturity.”
Galileo coming on strong
Director of the Galileo Programme Paul Verhoef of the European Commission wrote in that same issue of the magazine, “The production of the satellites continues to maintain a steady rhythm, with a production line stretching from suppliers across Europe to OHB and SSTL and then to ESA’s ESTEC Test Centre in the Netherlands for acceptance testing, based on a wide range of simulated space tests.”
Paul Verhoef, director of the Galileo Programme and Navigation-related Activities, European Space Agency.
“The acceptance of the next satellites to launch is scheduled for this year’s end,” continued Verhoef. “Along with the two more Ariane 5 launches to come — one in the second half of 2017 and another in 2018 — the current plan is to commission further launch services as well as additional satellites in order to have Galileo fully operational by 2020. For these launches, Galileo may be the first customer of the new Ariane-6 launch vehicle.
“2017 will see the upgrade of various elements of the Galileo Ground Segment to reinforce its robustness, including updated releases to the Galileo Control Segment overseeing the satellites and the Galileo Mission Segment, overseeing the navigation signals. A new release of elements of the Galileo Security Facility, for security monitoring of the system, as well as the secure Public Regulated Service, will be deployed at the two Galileo Security Monitoring Centres.
“The Galileo Ground Segment will gain a sixth tracking telemetry and control facility, for monitoring the satellite platforms in Papeete, Tahiti, and additional processing chains for increased redundancy will be deployed across the Uplink Stations in Kourou, Reunion and Noumea used to update the navigation message information. Similar redundant chains will be finalized for all 15 current Galileo Sensor Stations, which perform continuous collection of Galileo signals to identify the tiniest clock error or satellite drift.”
EGNOS. “Along with the progress of Galileo, contracts are planned to cater for the further development of the ESA-designed European Geostationary Navigation Overlay Service, Europe’s first navigation system. EGNOS was certified for safety-of-life aviation use in 2011, and is managed by the European Commission through a contract with operator the European Satellite Services Provider, based in France. ESA will support the technical evolution of EGNOS version 3, intended as multi-constellation in nature, again through the Horizon 2020 framework.”
GLONASS looks forward to a new signal: CDMA!
Sergey Karutin, GLONASS Chief Designer, wrote “On the threshold of the first GLONASS-K2 launch, new GLONASS reference documents were published in October 2016, describing the family of code-division multiple-access (CDMA) radionavigation signals. The draft GLONASS Open Service Performance Standard has been developed. The GLONASS User Information Support System continues to evolve.”
From left: Sergey Karutin, GLONASS designer general; Nicolay Testoedov, director general, SC Information Satellite Systems; and Andrey Tulin, director general, SC Russian Space Systems.
“The system transmitting CDMA navigation signals is referred to in four interrelated interface control documents containing general information on signals and the detailed description of signal structures and digital message data. The new signals make it possible to include 63 satellites in the constellation, not only in circular medium-Earth orbit but also on geostationary and high-Earth orbits.
“The transition to the flexible string-type structure of the message data produces 2-second periodicity of integrity information delivery to users. The increased number of digits occupied by the ephemeris and clock parameters contributes to a better orbit and clock broadcast accuracy. The ephemeris broadcast precision improves from 0.4 to 0.001 meters. Time-stamp length in CDMA signal has increased to 30 bits, compared to 12 bits of frequency-division multiple-access signals.”
BeiDou approaches full regional services
Li Wang
“In 2017, three to four launches of BeiDou satellites will occur,” wrote Li Wang, Director of the International Cooperation Center in China’s Satellite Navigation Office. “BDS will provide basic services to the countries along the Belt and Road region by 2018, and possess global service capability by 2020.”
“BDS will keep improving its nationwide reference station network and steadily enhance its service performance. The dense reference stations for the nationwide frame network will be constructed by 2018, providing meter and decimeter level real-time location services for users in China, even centimeter level service in some areas.
“BDS will carry out the design, validation and construction of SBAS in accordance with international civil aviation standards. The first GEO satellite of BDSBAS will be launched in around 2018. The satellite-based augmentation services covering China and surrounding regions will be provided from 2020, to provide CAT-I services to civil aviation users.
“China will promote construction of a national comprehensive positioning, navigation and timing (PNT) system based on BDS, and strive to establish such a national PNT system with a united benchmark, no-gap coverage, security and effectiveness by 2030, as well as to upgrade capabilities to provide time and space information.”
Q: What significant new developments in positioning, navigation or timing can we anticipate in 2017?
Dan Conway, Executive VP, Guidance & Stabilization, KVH Industries
A: With increasing focus on robust and resilient positioning, navigation and timing (PNT), the industry must respond with improved access to accurate and trusted position and timing, particularly for the warfighter. For military vehicles, this translates to a requirement for improved navigation systems that will provide commanders and onboard vehicle electronic systems with resilient PNT in contested environments. Secure and more robust navigation systems must now, more than ever, assure position and timing regardless of access to satellites.
Jeff Martin, VP of Business Development & Sales, Spirent Federal
A: Global navigation satellite systems have continually evolved, and 2017 should be no exception. With the scheduled launch of GPS III satellites, the world will see two new signals: M-code from a directional antenna and L1C (new civil signal). The European Galileo system may become operational. Russia is not expected to launch the new GLONASS K-2 satellites in 2017, but it’s not far off. Developers, integrators and users will have lots of options in 2017!
A: With approximately 65 percent of mass-market receiver chipsets already capable of multi-constellation tracking — and with this figure set to rise significantly in the near future — the demand for cost-effective but highly capable consumer goods with GNSS capabilities is clearly growing at an exponential rate. The forthcoming civilian signals offer huge opportunity to many sectors, but also present a challenge in the test and validation of new products, which will require highly capable and flexible simulation equipment.
A: Next year will bring huge strides in autonomous navigation. Multi-band high-precision GNSS will be a key enabler for robotics applications. Customers are demanding navigation solutions that are accurate, fast, robust and affordable. Multi-band enables convergence times measured in seconds, not minutes. Rapid time to first fix and reacquiring fix quickly after passing under obstructions will be essential for autonomous driving applications. Low-cost L1/L2 RTK GNSS will help bring these autonomous robotic applications to life.
From left: Sergey Karutin, GLONASS designer general; Nicolay Testoedov, director general, SC Information Satellite Systems; and Andrey Tulin, director general, SC Russian Space Systems.
In October 2017 we will celebrate the 35th anniversary of the first GLONASS satellite launch. Since 1982, the capabilities provided by GLONASS satellites have multiplied and the system’s ground infrastructure has expanded beyond the Russian Federation.
Growing demand for satellite navigation services and increasing user requirements call for continuing modernization, which is only possible if advanced, technically complex solutions are employed, thorough efforts on design and in-orbit validation are made, and continuing dialogue with users is maintained to promptly react to their needs.
The stable operation of the third generation GLONASS-M satellites, the core of the today’s constellation, means more satellites are working beyond their design lifetime. In 2016, two single-satellite launches occurred, in February and May. Seven more satellites of this type remain in ground storage.
The reliability of on-orbit satellites forces us to develop new ground storage technologies since some satellites were manufactured more than three years ago, while the need for their launch may not arise until 2018. Therefore in the next two years the constellation will be sustained with this type of satellite.
The performance of the on-board atomic frequency standards (AFS) carried by the latest GLONASS-M satellites is considerably better than that of those carried by the first GLONASS-M satellites (see Figure 1). Their relative one-day stability has improved from 10-13 to 2.4× 10-14, contributing to smaller signal-in-space range errors (SISREs).
FIGURE 1. Estimation of the Allan Variation versus GLONASS System Timescale.
In February 2016, flight testing of the fourth generation GLONASS-K satellite was completed. It carries not only a cesium atomic-beam tube but a rubidium AFS for the first time in GLONASS history. The relative daily stability of this rubidium AFS is 4×10-14. As a result the SISRE for this satellite is about 1 meter.
We are also proud of the success of the passive hydrogen maser (PHM), which we have been building for almost 7 years (Figure 2). Multiyear ground tests displayed its excellent reliability and one-day stability of 5×10-15. It is expected to contribute to 0.3-meter SISRE. The PHM for flight tests measures 360×180×630 millimeters and weighs 25 kilos. Its power consumption is 54 watts. The PHM will be validated onboard the GLONASS-K2 satellite set for launch in 2018.
FIGURE 2. Passive hydrogen maser.
Passive hydrogen maser plot.
User Needs. On the threshold of the first GLONASS-K2 launch, new GLONASS reference documents were published in October 2016, describing the family of code-division multiple-access (CDMA) radionavigation signals. The draft GLONASS Open Service Performance Standard has been developed. The GLONASS User Information Support System continues to evolve.
The system transmitting CDMA navigation signals is referred to in four interrelated interface control documents containing general information on signals and the detailed description of signal structures and digital message data. The new signals make it possible to include 63 satellites in the constellation, not only in circular medium-Earth orbit but also on geostationary and high-Earth orbits.
The transition to the flexible string-type structure of the message data produces 2-second periodicity of integrity information delivery to users. The increased number of digits occupied by the ephemeris and clock parameters contributes to a better orbit and clock broadcast accuracy. The ephemeris broadcast precision improves from 0.4 to 0.001 meters. Time-stamp length in CDMA signal has increased to 30 bits, compared to 12 bits of frequency-division multiple-access signals.
The GLONASS Open Service Performance Standard, being drafted according to recommendations of the International Committee on Global Satellite Navigation Systems (ICG), is harmonized with the Performance Standard Template elaborated by the Working Group on Systems, Signals and Services of ICG with the active involvement of the Russian Federation.
As a result, it is also harmonized with the GPS, Galileo and BeiDou performance documents — in addition to international parameters like the horizontal and vertical availability, user positioning error (average and worst over Earth’s surface) and UTC broadcast error. The Draft Standard also includes:
PDOP availability (PDOP availability for the worst point on the Earth’s Surface, global average);
User Equivalent Range Error for the worst point of a satellite visibility cone (95%);
UTC(SU)-GLONASS Time offset broadcast error (global average 95%);
21 healthy satellites availability;
Per-slot availability;
24 healthy satellites availability;
Continuity (probability that a healthy satellite becomes unhealthy without notification 48 hours in advance);
Major failure probability (SIS URE of >75 meters).
GLONASS User Information Support infrastructure development is a complex program that covers establishing User Information Centers to raise awareness of all categories of users of the capabilities GLONASS provides and its guaranteed performance through www.glonass-iac.ru in Russian, English and Chinese languages.
The network of GLONASS-based navigation and information service providers is being developed. Services include satellite navigation activities, from emergency response to control of autonomous unmanned vehicles.
Sponsored by: Hemisphere GNSS Broadcast Date: Thursday, May 16, 2013 Moderator:Alan Cameron, Editor & Publisher, GPS World Speakers: Mark Sampson, LabSat Product Manager, RaceLogic; John Fischer, Chief Technology Officer, Spectracom; Markus Lörner, Product Manager, Rohde & Schwarz; Steve Hickling, Lead Product Manager, Spirent Communications; Mark Wilson, Vice President of Sales, IfEN GmbH Summary: Simulation and testing experts offer key technical insights on the intricacies and importance of product and signal testing, whether by simulator, record-and-replay, or in the field, in the increasingly complex environment of multiple modernizing and expanding GNSS signals, from GPS III to BeiDou, with Galileo coming on strong and GLONASS a perennial standby.
Purchase Decisions in the Evolving Landscape of GPS, Multi-GNSS and Alternative PNT Sponsored by:NavCom Broadcast Date: Thursday, June 5, 2014
Moderator: Alan Cameron, Group Publisher, GPS World & Geospatial Solutions
Speakers: Steve Ault, Product Manager, NavCom Technology Inc.; John Pottle, Fellow, Institute of Engineering Technology and Royal Institute of Navigation; Philip Mattos, R&D scientist for several GNSS companies; Paul Benshoof, Global Business Development Manager, Locata Corporation Summary: Last month’s two GLONASS stumbles prompted some industry leaders to resume their calls for multi-GNSS and for redundant PNT. But neither concept yet exists, truly and pervasively, that is to say effectively for all users. When will reliable, robust, consistent and continuous positioning, navigation, and timing become a reality? Should we rely on whatever technology we currently possess until the perfect system comes available, or should we continuously upgrade at each iterative step along the way?
On May 29 a Soyuz-2.1b with upper stage Fregat and a GLONASS-M satellite (No. 53) successfully lifted off from Plesetsk Space Center. The satellite was placed into its preprogrammed orbit and registered by the facilities of the Titov Main Test and Space Systems Control Centre. Ground control established communications with it. The stable telemetry link shows that onboard satellite systems are functioning normally.
According to Russian officials, an unexpected issue with the Fregat upper stage caused it to burn longer than planned to inject the satellite into its planed orbit. No further details were provided.
The satellite is destined for a replenishment mission of the GLONASS constellation, currently at 25 operational satellites. Russian plans call for as many as eight satellites to be launched by the end of 2017 to replenish the constellation. As part of that strategy, a Proton-M heavy carrier rocket with three GLONASS satellites aboard may take place by the end of this year.
Iridium Communications Inc. has introduced its Satellite Time and Location (STL) service, an alternative or complement to traditional indoor and outdoor location-based technologies, and declared it ready for use. STL’s position, navigation and timing (PNT) technology is deployed through Iridium’s 66 cross-linked, low-earth orbit satellite constellation.
Through Iridium satellites and in GNSS receivers, STL technology can work to verify GPS, GLONASS, Galileo and other navigation services, and also can serve as an alternative for those services when GPS signals are degraded or unavailable. STL also can provide an alternative source of time when testing GPS signals.
Iridium is working with Satelles, a division of iKare Corporation, as its primary technology partner. Satelles enables Iridium’s paging channels to reach small, low-cost receivers in nearly any environment, the company says in a news release.
“We think STL can help solve an important and growing problem for governments and businesses, and serve as a platform for continued innovation,” says Matt Desch, chief executive officer at Iridium. “With STL, we are introducing a global capability that is already in space, technologically ready for use and is independent of any particular location technology. The team at Satelles has been able to leverage the unique capabilities that our network offers to create a solution that can ultimately be integrated into almost any kind of platform, including other Iridium machine-to-machine devices, heavy machinery, automobiles and even the power grid, to name a few. Once implemented, STL could revolutionize the way the world’s largest, global companies and governments operate and manage cyber security.”
In a chipset about the size of a postage stamp, the technology can be embedded into many devices. STL’s signal strength may make spoofing GPS systems more difficult, the company says. STL transmits its signals through Iridium’s satellite constellation to deliver a unique code to each position on the ground that can be independently authenticated, which allows operation or access only if the user is in the location expected.
“Commercial users are now able to use STL to deliver trustworthy timing solutions for critical infrastructure, such as LTE networks, transactional data centers and the power grid,” says Greg Gutt, president and chief technology officer of Satelles. “Military and government users can also acquire these commercial off-the-shelf solutions for the Department of Defense and other government applications. In addition to enhancing the security and resiliency of GPS, STL technology can be embedded into servers anywhere in the world to geo-fence data and applications, providing trusted time and location data as an independent factor for end-point authentication.”
The STL solution has been successfully demonstrated across multiple sectors, including military, academia and commercial applications. The technology is available today and will be supported by Iridium NEXT, the Iridium’s next-generation global satellite constellation, which is scheduled for completion by late 2017, the company says.
“Even the best technology has a bad day,” Charles Schue told the New York Stock Exchange (NYSE), which relies very heavily on the best technology to keep the world’s financial edifice afloat. Vulnerabilities in the stock market were pointed up during a demonstration on April 19, showcasing how one positioning, navigation and timing (PNT) system can cover the chinks in another. Respectively, eLoran and GPS in this case.
Schue is CEO of UrsaNav, a company that has been developing complementary PNT solutions, specifically the high-power, low-frequency (LF), ground-wave technology that is eLoran, which UrsaNav calls “the most reliable, scalable, and future-proof available.” Schue spoke at the NYSE along with representatives from the Department of Homeland Security (DHS), the U.S. Coast Guard, Juniper Networks and Harris Corporation.
“2014 was a very bad year for GNSS,” Schue continued, citing the GLONASS full-system outage for 11 hours and Galileo’s wrong-orbit launch of two satellites. “This year, GPS, the gold standard, had an ‘oops’ and slipped from gold to silver, when one satellite kind of wigged out, a 13.7 microsecond error that contaminated 15 other satellites.” He ran a simulation that showed how, at one point, six GPS satellites were communicating bad timing to the Eastern seaboard, where the NYSE is located.
2016 has also seen renewed GPS jamming from North Korea.
The stock exchange, along with other global financial markets, relies on microsecond timing to properly execute all transactions. The U.S. air traffic management system likewise relies on high-precision aspects of GPS that are vulnerable to interference, jamming, and even occasional system failure. Many other industries, telecommunications principally among them, are also building infrastructures and applications that rely on GPS for precise timing, thus making them vulnerable as well.
One Back-Up Transmitter in Place
An eLoran transmitter in Wildwood, New Jersey, relies on three primary reference standards, three atomic clocks, just as each GPS satellite carries three or four atomic clocks. “The signals coming from space, the signals coming from ground, they’re very similar.” ELoran also has monitoring and control sites on the ground, just like the satellite system; it has differential reference stations, and of course eLoran receivers, playing the same role as GPS receivers.
Schue asserted that the cost of launching one GPS satellite into space would fund an eLoran system for the continental United States for 20 years. Also, that a lot of industries in addition to the financial community are building infrastructures and applications that rely on GPS for precise timing, and so are equally vulnerable.
The eLoran demonstration showed how the Wildwood station sent a timing signal 130 miles to the NYSE, deep within several urban canyons and enveloped in several layers of concrete, steel and glass. A GPS receiver in the room did not pick up anything. The eLoran receiver showed precise time, to the standard of NYSE requirements.
Equipment utilized included a Spectracom SecureSync providing time to the network, once it received it from eLoran.
On a screen display showing plus or minus 500 nanoseconds relative to Coordinated Universal Time, “that red line is us receiving eLoran timing at that antenna, 130 miles away, through the urban canyons, inside this building, right now at minus 14 nanoseconds.” The eLoran equipment transmitted and received two signals, with a data channel on one of the signals. “We could put the data channel on both signals, and we could put multiple data channels on both on there as well.”
Schue said another demo inside a downtown Boston hotel, 305 miles from the New Jersey transmitter, obtained 83-nanosecond accuracy. A 2015 test to an outdoor receiver in Bangor, Maine, 500 miles from the transmitter, logged 68-nanosecond accuracy.
Plus or minus 100 nanoseconds is the typical GPS performance. “We can do far better, and GPS often does far better than that.”
Initial operating capability for a wide-area eLoran service providing precise time for the continental United States would require four transmitter sites across the middle of the country. The corporate and government partners hope to use some repurposed Loran-C assets and turn them into eLoran stations. Wildwood is transmitting at 360 kilowatts; if transmitting at 1 million watts, or 1 megawatt, the signal could penetrate even further inside buildings. The cost difference between the two powers of transmitter is not significant.
Bringing six more continental eLoran transmitter sites online, for a total of ten, would add a back-up positioning capability in addition to timing. “This is very important, because with positioning, you get mobile time — a co-primary solution for position, navigation, and timing.”
Using a differential receiver would yield even better local-area accuracy for about 35 miles around a selected site, for high-priority locations. Such a higher-precision system for the nation’s top 50 metropolitan areas, top 50 airports, and top 50 harbors could be accomplished with 71 differential sites.
Concurrence from Government and Other Industry Partners
Spokespersons from the DHS, Coast Guard, Juniper Networks and Harris Corporation preceded Schue at the NYSE presentation, all giving similar perspectives on U.S. vulnerability in many aspects, due to reliance on GPS as a sole, unsupported source of precision PNT. “Of the 16 critical infrastructure / key resource sectors in the United States, 15 use GPS for timing. GPS timing is deemed essential for 11 of these sectors,” stressed DHS.
Another GLONASS-M satellite, designed and built by a team of Information Satellite Systems – Reshetnev Company, has been delivered to the Plesetsk cosmodrome.
Accompanied by the company’s technical team and housed in a dedicated high-technology container, it was shipped to the Yemelyanovo Airport of Krasnoyarsk and then flew to the Plesetsk cosmodrome aboard a cargo aircraft IL-76.
At the cosmodrome, ISS-Reshetnev technicians will begin preparing the satellite for its launch, which is expected to take place in late May.
