Category: GNSS

DroneDeploy offers flight logs solution to simplify regulatory compliance
DroneDeploy, a cloud-based drone software platform, is offering a flight logs solution with its partners Airnest, Drone Complier, DroneLogbook, Healthy Drones, Kitty Hawk, NVDrones and Skyward.

The logs contain highly detailed GPS positioning, drone battery life, camera activity and more, providing a vital record of flight activities often required for regulatory compliance and insurance.

Direct access to actual flight logs eliminates the tedious, manual data entry process for capturing flight data and enables drone operators to easily track and monitor their drone flights for regulatory compliance, insurance and fleet maintenance.

DroneDeploy’s more than 10,000 users in 130 countries can access logs of their DroneDeploy mapping flights. Leveraging their actual flight log data with DroneDeploy’s partners enables businesses to:
- Automate logging and recording of all drone flights for compliance and insurance purposes
- Monitor equipment performance to recommend preventative maintenance
- Explore trends in flight characteristics to define best practices
“Many large companies and enterprises are looking to scale their drone program and do it efficiently,” says Jonathan Evans, CEO of Skyward. “Now, with access to DroneDeploy flight logs, Skyward customers can manage flight information across their entire fleet.”

Other solutions on the market today typically require a high cost investment and lock businesses into working with a single drone software vendor, DroneDeploy says. DroneDeploy’s offering enables businesses to select what works best for them from a selection of industry leading drone compliance, insurance and fleet management partners. This highlights DroneDeploy’s approach to addressing the needs of the commercial drone market by developing a best-of-breed offering with ecosystem partners.
February 9, 2017
Surrey Satellite GPS receiver to navigate NASA OCO-3 mission

Colorado-based Surrey Satellite Technology US LLC has delivered an SGR-20 space GPS receiver to NASA’s Jet Propulsion Laboratory to be integrated as part of the pointing control system for NASA’s Orbiting Carbon Observatory—3 (OCO-3) mission.

OCO-3 will collect spaced-based measurements of atmospheric carbon dioxide and solar-induced fluorescence.

Once launched, OCO-3 will be installed and operated on the International Space Station (ISS) Japanese Experiment Module-Exposed Facility (JEM-EF).

Surrey’s SGR-20 is a single-frequency, multiple antenna GPS receiver designed as a spacecraft orbit determination subsystem for small satellite low-Earth orbit applications. The OCO-3 mission will use the Surrey SGR-20 for positioning information (to an accuracy of better than 20 meters) and velocity data (to an accuracy of better than 0.25 meters per second). The SGR-20 features four front ends with antennas, allowing more flexibility and redundancy for the selected mission.

According to Eugene Hockenberry, project manager at Surrey Satellite, “The SGR-20 receiver is part of a highly proven range of GPS receivers that Surrey Satellite offers. Our receivers are currently active on twenty-four Surrey satellites and have accumulated over 700 years of on-orbit experience. With this mission we will see another first for Surrey: this receiver will be our first space hardware onboard the ISS.”

Surrey Satellite delivered the receiver to JPL three months ahead of schedule. OCO-3 is scheduled to launch in 2018.

February 9, 2017
Oregon moves to tablets for no-stake 3D design

The Oregon Department of Transportation (ODOT) is embracing the growing trend in highway construction to go “stakeless” and push to full 3D design.

With more contractors using automated machine guidance applications, ODOT’s construction personnel are being asked to inspect projects with fewer stakes and visual indicators for line and grade. Employees are seeking to use the same data and information to determine line and grade when building or fixing stretches of road.

ODOT inspectors Jorge Jimenez and Mike Stennett at Multnomah Falls, preparing for a night-time paving operation. (Photo: Chris Pucci)

To address this need, rugged tablet maker DT Research worked closely with ODOT to design purpose-built Inspector Positioning Tablets that run GPS locating and 3D modeling applications, and take advantage of the Oregon Real-Time GNSS Network.

“MicroSurvey Field Genius surveying software is used to read XML files directly, allowing the inspector to work with the same files that the contractors received from the roadway designers,” said Chris Pucci, ODOT Construction Automation Surveyor.

The tablets enable ODOT to fully use its knowledge of the Oregon Real-Time GNSS Network and expertise in survey-grade RTK GNSS to achieve accuracies of +/0.05 feet.

The model DT391GS tablets have 9-inch touchscreens. The tablets can be used as handhelds or with an external antenna and pole. ODOT purchased one of four GNSS options offered by DT Research for the DT391GS tablets. The options enable inspectors and construction crews to employ a combination of GPS locating and 3D modeling to guide construction workers.

The goal is to allow the inspectors to make the same checks they would have made if there had been traditional construction staking on a project, not to make inspectors into surveyors, Pucci noted.

A one-day training is provided to train construction personnel before they are issued a tablet. “The tablets have been very well received by our construction inspection personnel,” he said.

The tablet project is now in the pilot phase with 20 tablets deployed to eight construction offices and more than 70 construction personnel having been trained. “We also just placed an order for 22 more tablets for the upcoming 2017 construction season,” Pucci said.

February 8, 2017
Spirent highlights GNSS threats at cybersecurity conference

Spirent Communications plc will demonstrate its expanded focus on security at the cybersecurity RSA Conference 2017, held in the Moscone Center in San Francisco Feb. 13–17. In a classroom session, Spirent positioning security technologist Guy Buesnel will discuss deliberate threats to GNSS.

Focusing on deliberate attacks against GNSS at the application layer and through RF channels, Buesnel will introduce session attendees to the vulnerabilities of satellite navigation and timing systems and how they have been exploited. Based on his experience in protecting GNSS receivers from emerging threats for nearly two decades, Buesnel’s session will address the evolution of deliberate GNSS threats and present the latest evidence of deliberate jammer use from a network of detector devices.

“There are compelling parallels between the manner in which IP threats have developed on the internet and the evolution of both jamming and spoofing attacks against GNSS,” said Buesnel. “Once people understand that the evolution of GNSS threats not only has clear parallels with the way in which IP threats have evolved, but also that GNSS share many of the features of a connected network, they will see that many of the lessons learned by the information security community apply equally well to the GNSS community.”

Part of the Mobile & IoT Security track, the Guy Buesnel classroom session (Session Code MBS-F01) will take place 9–9:45 a.m. on Friday, Feb. 17, on the second floor of the Moscone West hall, room 2002.

Spirent will also preview new Cyberflood performance and security validation software at RSA.

“With our expanded focus on security, Spirent is addressing the growing need in government, industry, health care and financial services for effective products and services to assess, validate and monitor the performance and security of their networks and applications,” said John Weinschenk, general manager of applications and security at Spirent. “We look forward to demonstrating at the RSA Conference how our industry-leading product and service offerings can meet today’s need for performance and security effectiveness under a wide range of real-world threat and attack scenarios.”

Spirent representatives in the company’s booth (S2015 in the Moscone South hall) will be available during the show to speak with attendees about the Cyberflood software and many of its upcoming ease-of-use features and real-world threat and attack emulation capabilities. The new features will include a flexible advanced testing component for customized testing needs and extended fuzzing techniques that enable users to find more issues faster and understand them better than any competing product in the industry.

Attendees will also be able to learn more about the scanning, penetration testing, monitoring and source-code-analysis security services available from Spirent Security Labs for networks, wireless infrastructures, websites, mobile applications and embedded devices.

February 7, 2017
EU project to seek TREASURE in multi-GNSS positioning
A European Union (EU) project exploiting GNSS to establish the blueprint for the world’s most accurate real-time positioning service will be run at the University of Nottingham in the United Kingdom.

The service, to be developed at prototype level, will benefit safety-critical industries such as aviation and maritime navigation, as well as high-accuracy dependent applications such as offshore drilling and production operations, dredging, construction, agriculture, driverless cars and drones.

The four-year TREASURE project will take multi-GNSS to the next level. It will focus on a service that will improve on the current use of GNSS — usually based on just one or two systems — and integrate signals from GPS, GLONASS, BeiDou and Galileo to provide accuracy of a few centimeters in real time, opening up a multitude of new possibilities.

The TREASURE project is funded through the European Commission’s Horizon 2020 framework program.

Atmospheric disruption

One of the key aspects of the research is to mitigate the effects of the atmosphere, in particular related to space weather, which can often create impairing conditions that vastly reduce satellite communication and positioning accuracy.

Controlled by the interaction of the sun with the Earth’s magnetic field, the ionosphere (the upper layer of Earth’s atmosphere) is characterized by the presence of free electrons, which interfere with a satellite’s signal passing through it.

Mainly, but not only when solar activity is high, electron density irregularities may form in the ionosphere, which can cause signal diffraction and lead to scintillation — a scattering of the satellite signal that makes it difficult for a GNSS receiver to lock onto the satellite and calculate its position.

This has a particularly disruptive effect on positioning technology especially at high latitude or equatorial regions, such as in Northern Europe or in Brazil, respectively.

Similarly, the troposphere, a lower layer of the atmosphere, also interferes with the signals. The presence of water vapor in this neutral part of the atmosphere can create an additional disruptive effect on the satellite signals, also affecting GNSS accuracy.

Correcting all intervening errors

The project aims to develop new error models, positioning algorithms and data assimilation techniques to monitor, predict and correct not only the effects of the atmosphere but also signal degradation due to manmade sources of interference, which can also limit positioning accuracy.

Signal processing techniques — tailored to the features of the interfering signals — will be used to improve the quality of the measurements and ultimately to generate reliable position solutions.

Moreover, TREASURE researchers will also develop new multi-GNSS real-time precise orbit and clock products, specifically for use with the new Galileo system.

Industry potential for multi-GNSS service

All these problems pose significant risks to the many public and industrial sectors that now rely on GNSS or aim to use it to overcome growing humanitarian challenges such as food or energy production.

“A highly-accurate multi-GNSS service could, for instance, assist demanding terrestrial applications like precision agriculture, giving farmers access to real-time precisely located data gathering and analysis to maximize food production, reduce costs and minimize pesticide use,” said project lead Marcio Aquino, Nottingham Geospatial Institute.

“On the other side of the spectrum, a deep-sea drilling platform that experiences any temporary degradation of positioning accuracy could lead to phenomenal losses right at a time when, due to the current oil production climate, companies are striving to increase operational efficiency,” Aquino said. “This industry would also benefit from such an accurate multi-GNSS service.”

The study will focus on two existing GNSS techniques known as PPP (precise point positioning) and NRTK (network real-time kinematic). Both use GPS and GLONASS, but could potentially meet future real-time high-accuracy positioning demands when Galileo is fully integrated, and if TREASURE is successful.

Benefits and limitations of PPP and NRTK

The NRTK technique uses fixed reference stations operating high-grade GNSS receivers at carefully surveyed reference locations to secure accurate GNSS positioning data.

The transmission of corrections from reference locations to users is at the core of NRTK. The technique’s effectiveness relies on the spatial correlation of errors between user and reference, which must be situated less than 20-30km apart – a short enough distance to allow potential signal errors to “cancel out.”

If atmospheric variations between reference and user are strong, a greater number of reference stations may be necessary, rendering the technique less cost-effective.

Contrary to NRTK, PPP does not rely on errors cancelling out between the user and a known reference station. The user operates their receiver independently of the existence of nearby stations with known coordinates.

This is achieved by incorporating external information in the solution, in the form of highly-precise satellite clocks and orbit products derived from global networks and available either for free or commercially.

However, the accurate prediction of the state of the atmosphere, also crucial for PPP, is not normally available from these global networks — overcoming this situation is one of the main objectives of TREASURE.

Creating a critical mass and testing market potential

TREASURE brings together four top universities, one research institute and four leading European companies to provide the research that will result in the ultimate high-accuracy EGNSS solution.

The project team will train and work alongside 13 Marie Skłodowska-Curie Fellows who will be earmarked as high-flying candidates for future employment in the burgeoning GNSS industry or as specialist researchers.

The Fellows will build a prototype tool to support the different PPP and NRTK needs and test what commercial interest there is to bring the future service to market.

TREASURE project partners are:
- University of Nottingham
- University of Bath
- Politecnico di Torino
- Technische Universiteit Delft
- Istituto Nazionale di Geofisica e Vulcanologia
- Fugro Intersite BV
- Geo++GmbH
- Noveltis SAS
- Deimos Engenharia SA
February 7, 2017
Spirent security experts predict greater risk to GNSS in 2017
Spirent Communications plc, provider of mobile network, application, services and device-test solutions, is warning of the increased likelihood of disruptions this year to a wide variety of civil and military applications relying on GNSS.

The prediction of greater risk from hacking and location spoofing attacks by criminal, state-sponsored, and other adversaries is part of Spirent’s annual security forecast for 2017. The forecast also highlights the continued risk of distributed denial of service (DDoS) attacks on Internet of things (IoT) devices and industries, including health care and automotive, that Spirent believes are the prime targets for security threats in the near future.

In 2016, Spirent’s predictions led off with a prescient warning about the increased risk of cyber espionage, which has since been borne out, most notably by news reports of suspected activities by the Russian government to influence the 2016 U.S. presidential election.

Also as predicted, in 2016 threats from ransomware, malicious insiders and compromised IoT devices increased, as did attacks on industrial control systems. For example, FBI sources reported on CNN that losses attributed to ransomware in the U.S. were set to exceed $1 billion by the end of 2016. That number is expected to grow in 2017.

In addition to an increased likelihood of GNSS interference, Spirent’s annual security forecast for 2017 predicts an expansion of risks from:
- More frequent DDoS attacks against IoT devices, as evidenced in the last quarter of 2016, when multiple major DDoS attacks surfaced worldwide. The most disruptive attack employed Mirai malware covertly installed on a large number of IoT devices. A number of high-profile websites such as Netflix, AirBnB, Twitter, GitHub and others were rendered inaccessible. Spirent believes that perpetrators will continue to innovate and find new methods for improving and broadening these type of attacks.
- Threats to IoT security, which are increasing as everything that is connected becomes a potential attack vector, including embedded devices, mobile devices, consumer electronics, connected medical devices, industrial control systems, smart home devices, and more.
- Threats to medical applications, networks, and devices in the health care industry, both the back-office systems on which these facilities run and the medical instruments that provide care to patients. A ransomware infection or data breach could adversely affect patient health and privacy.
- Threats to connected vehicles by malicious attackers, as a greater number of attack vectors are inadvertently created that enable remotely gaining control of critical operational components of the vehicle, including engine, steering, and braking functions in addition to other vehicle systems that communicate through the relatively insecure CAN bus infrastructure.
“With the greater drive towards use of autonomous vehicles, which rely heavily on precision GPS positioning and timing, threats posed by signal spoofing, jamming, time tinkering, and more could result in serious disruptions and worse,” said Sameer Dixit, senior director of security consulting at Spirent. “The transportation industry is taking this very seriously and already looking at various ways to protect against these threats. Because of this, we see momentum towards improving GNSS security in 2017.”

According to an article in Defense One, Timothy Bennett, a science-and-technology program manager at the Department of Homeland Security, has already reported the use of GPS spoofing and jamming equipment by Mexican drug cartels along the border to interfere with the U.S. Customs and Border Protection agency’s use of drones to patrol the area. Unlike the larger drones designed to military specifications, the smaller drones used for this purpose are more vulnerable to these kinds of attacks.

Spirent’s global network of GPS interference detectors has recorded more than 15,000 interference events since it was deployed in 2015, including a surprisingly high number of unintentional events caused by various forms of interference in the GPS L1 frequency band. A significant number of these unintentional events, which often correlate with transmissions from nearby RF transmitters and telecom equipment, have the potential to interfere with GPS signal reception.

Dixon noted one bright spot on the horizon: the increasing awareness up and down the technology food chain of the importance of security in these systems, and the entry of large, experienced, and security-conscious players into the IoT arena.

For information on Spirent’s security solutions, visit https://www.spirent.com/Solutions/Security-Applications.
February 6, 2017
Boeing, US Air Force extend partnership to sustain GPS IIA, IIF

Boeing and the U.S. Air Force have signed a GPS sustainment agreement to ensure the health of current satellites on orbit. The agreement enables persistent GPS capability for civilians and the military as Boeing works on next-generation GPS satellites.

Artist’s impression of a GPS Block II/IIA satellite in orbit. (Credit: U.S. government)

Under the agreement, Boeing will support GPS IIA and IIF satellites on orbit for the next five years. Boeing, which has been the prime GPS contractor for more than 40 years, is now part of the Air Force effort that may lead to the next generation of GPS satellites.

“This agreement continues Boeing’s strong legacy of GPS innovation and mission support,” said Dan Hart, vice president, Government Satellite Systems. “We are focused on delivering reliable, affordable and resilient GPS capability now and for generations to come.”

Collectively, Boeing GPS satellites have accrued more than 550 years of on-orbit operation. In March 2016, the company delivered its 50th GPS satellite on orbit to the Air Force and has built more than two-thirds of the GPS satellites that have entered service since 1978.

February 6, 2017
ION announces executive committee and council for 2017-19
The Institute of Navigation (ION) has announced its Executive Committee and Council for 2017-19. The ION Executive Committee and Council consists of a wide range of professionals in the field of positioning, navigation and timing.

“ION is excited with the talented and distinguished group of professionals that hail from all segments of the PNT community who are giving their time to serve on the ION Executive Committee and Council,” said Lisa Beaty, executive director of ION.

ION Executive Committee
- President: John Raquet, Air Force Institute of Technology
- Executive Vice President: Jade Morton, Colorado State University
- Treasurer: Frank van Graas, Ohio University
- Eastern Region Vice President: Anthea Coster, MIT Haystack Observator
- Western Region Vice President: Gary McGraw, Rockwell Collins
- Satellite Division Chair: Frank van Diggelen, Google
- Military Division Chair: Elliott Kaplan, The MITRE Corporation
- Immediate Past President: Dorota Grejner-Brzezinska, The Ohio State University
2017–19 Council Members
- Eastern Council Member-at-Large: Francine Vannicola, U.S. Naval Research Laboratory
- Eastern Council Member-at Large: Keith McDonald, The MITRE Corporation
- Western Council Member-at-Large: Neil Gerein, NovAtel Inc., Canada
- Western Council Member-at-Large: Paul Benshoof, Locata Corporation
Technical Representatives
- José Ángel Ávila Rodríguez, European Space Agency, The Netherlands
- Sunil Bisnath, York University, Canada
- Mathieu Joerger, The University of Arizona
- Olivier Julien, ENAC, France
- Allison Kealy, The University of Melbourne, Australia
- Di Qiu, Polaris Wireless, Inc.
- Andrey Soloviev, QuNa
- Terry Moore, University of Nottingham, UK
February 6, 2017
System of Systems: FCC seeks comments on Galileo use in US
FCC seeks comments on Galileo use in US

Galileo satellites 15–18 being deployed from their dispenser, two at a time. (Artist’s rendering: ESA)

The Federal Communications Commission (FCC) is inviting public comments on the European Commission’s request for a waiver of licensing requirements applicable to Galileo receivers in the United States.

Comments are due Feb. 21. Read the notice here.

If the waiver is approved, Galileo-capable receivers won’t need to be licensed in the U.S. At present, FCC rules require that receivers operating with non-U.S.-licensed space stations obtain a license.

In a letter dated Jan. 30, 2015, the National Telecommunications and Information Administration submitted a request by the European Commission (EC) for a waiver of the FCC licensing requirements to permit non-federal receive-only Earth stations — receivers — within the U.S. to operate with Galileo signals.

Interested parties can file comments on or before Feb. 21, and reply to comments on or before March 23. All comments should reference IB Docket No. 17-16. Go to https://www.fcc.gov/ecfs/ to file comments.

The Commerce Department has played a major role in supporting the European Commission’s waiver request. As co-chair of the GPS-Galileo Working Group on Trade and Civil Applications, the Office of Space Commerce has been discussing the FCC licensing requirement with the European Commission and assisting it with the waiver request for several years. The waiver, if granted, would allow use of Galileo in official government systems such as Enhanced 911.

Previously, the National Telecommunications and Information Administration (NTIA) assessed federal users’ perspectives on the EC request and did not find any interference issues. The FCC stated that it agrees with the NTIA, but wants confirmation and public input.

Power increase tested on 19 GPS II satellites

On Jan. 25, Air Force Space Command (AFSPC) began a limited-duration test implementing an increase of the Ll C/A power level on the GPS Block IIR-M and llF satellites — a total of 19 satellites.

Launch of GPS IIF-12. (Photo: ULA)

The C/A power was set to remain within IS-GPS-200-H specifications, and the power increase was not expected to increase the noise floor by more than 0.3 signal-to-noise ratio in the worst case.

“We assess that there will be no adverse impacts to civil, commercial or military GPS users, but anyone who experiences issues during this test should address them through established reporting channels,” said Gen. John W. Raymond, U.S. Air Force commander, in a Memorandum for Distribution.

Military users can contact the GPS Operations Center at DSN 560-2541, while civilian users can contact the U.S. Coast Guard Navigation Center at 703-313-5900.

In the event of unexpected critical impacts, a process to cease testing operations has been put in place.

OCX passes qualification tests

Raytheon completed factory qualification testing of the Launch and Checkout System (LCS) of the GPS Next-Generation Operational Control System, known as GPS OCX.

The company tested 74 OCX segment requirements at its Aurora, Colorado, factory in a cyber-hardened environment, verifying that the LCS is on its way to meeting U.S. Air Force requirements.

Next, the remaining OCX segment requirements will be qualified in a retest period.

Those requiring external interfaces will be qualified onsite at Schreiver Air Force Base before delivery of the overall OCX LCS in 2017.

Clocks fail on 5 Galileo satellites: All have backup

The European Space Agency (ESA) issued a statement on Jan. 19 addressing Galileo clock failures. GPS World Innovation editor Richard Langley provided the following summary of the satellites and clocks involved, based on information received to date.
- 5 satellites affected: 3 IOVs, 2 FOCs
- Total of 10 failures; 1 fixed; so 9 continuing failures
- 5 masers on IOV satellites
- 2 masers on FOC satellites but 1 of these fixed
- 3 rubidiums on FOC satellites
- No satellite currently has fewer than 2 working clocks
An ESA press release provides additional details on the failures and actions being taken to address the problem. Read more here.
February 4, 2017
Wildwood eLoran transmitter starts broadcasting Feb. 6

Update (2/9/17):

The Wildwood transmitter is back on the air after a presumed lightning strike affected transmissions.

The transmitter stopped broadcasting at 5:35 a.m. EST on Feb. 9. Testing took place 5:35 a.m. to 8:19 EST, after which it came back on the air, reports Steve Bartlett, vice president of operations for UrsaNav Inc.

The transmitter will be taken off the air tomorrow morning (Feb. 10) so that engineers can assess and repair any damage.

The Wildwood, New Jersey, eLoran transmitter will be continuously broadcasting from 9 a.m. EST on Feb. 6 through 12 p.m. EST on March 31, announced Steve Bartlett, vice president of operations for UrsaNav Inc.

“Wildwood will be broadcasting as 8970 Master and Secondary most of the time, but occasionally may operate at other rates,” Barlett said.

The Loran Data Channel (LDC) will be undergoing testing and may be unavailable or unreliable for short periods of time Feb. 6-10, he said.

February 2, 2017
US Coast Guard adds security to website

The Coast Guard Navigation Center has implemented a small but important change to its website address. It is now https://www.navcen.uscg.gov, instead of http://www.navcen.uscg.gov.

The change provides a secure, encrypted connection between browsers or other tools connecting to the Navigation Center website. It also provides authentication that you are unquestionably connecting to the Navigation Center website.

This change is a result of Office of Management and Budget (OMB) Memorandum M-15-13, Policy to Require Secure Connections across Federal Websites and Web Services, which requires that all publicly accessible federal websites and web services only provide service through a secure connection (HTTPS instead of HTTP).

Address any questions to the Navigation Center’s Web Services team via the Contact Us page.

January 31, 2017
Interference mitigated with CRP and dual-polarized antennas: Free webinar

Two new topic areas and presentations have been added to this Thursday’s free webinar on Signal Interference: Detection and Mitigation.

The speakers will explore anti-jamming protection with controlled radiation pattern antennas (CRPAs) and with dual-polarized antennas. The latter topic is also the cover story for the February issue, which demonstrated a significant improvement in positioning accuracy and robustness against interference with a dual-polarization approach: a gain in terms of C/N₀, particularly for low-elevation angle satellites and valuable in urban environments.

Headshot: Kirk Burnell

Kirk Burnell from NovAtel joins the Feb. 2 panel to present “How to deliver assured positioning, navigation and timing in GNSS-compromised environments.”

He will look at applications that stress the importance of high-reliability PNT. Compromised GNSS signals due to unintentional interference is of great concern, but intentional interference due to jamming is much more insidious. Anti-jamming protection via controlled reception pattern antenna (CRPA) technology is now available to a wide range of users. A brief explanation of the technology will be followed by a few use-cases where CRPAs have been deployed in a variety of applications.

Burnell, Core Cards Product Manager for NovAtel, has worked at the company since 2015. With an education in survey engineering, Kirk has been working with precision GNSS system designers and integrators in both support and product management capacities for more than 20 years.

Headshot: Matteo Sgammini

Matteo Sgammini of the German Aerospace Center (DLR) will talk about work with dual-polarized antennas: the principles of operation of such an antenna array and how one performed in real-world jamming and non-jamming scenarios. This ION GNSS+ 2016 presentation became the cover story for GPS World’s February issue.

Innovation editor Richard Langley writes in his introduction to the February column, “All GNSS satellites transmit RHCP [right-hand circularly polarized] signals and therefore most GNSS receiving antennas are designed for such signals. However, a funny thing can happen to a satellite signal on the way to a receiving antenna. If the signal bounces off a nearby structure or the ground or the sea surface, its polarization is modified and it will become LHCP [left-hand circularly polarized] or a combination of the two polarizations.

“A primarily LHCP antenna can capture a significant portion of the energy in such a RHCP signal and could provide a strong response to a reflected signal when the line-of-sight signal is missing or very weak. So, there could be a benefit in having a dual-polarized antenna to improve positioning capability in marginal situations. Furthermore, jamming signals can be of arbitrary polarization and a dual-polarized antenna array with beamforming capability could better separate and mitigate such interference.”

February cover story. Photo: GNSS

Researchers at the DLR equipped a GNSS receiver with a diversely polarized antenna array to combine signal processing in the spatial and in the polarization domain. Tests show a significant improvement in receiver robustness against interference compared with the general single-polarization case.

The carrier-to-noise-density ratios of the line-of-sight components are improved since the receiver can use the power present on the left-hand circularly polarized channels, particularly for satellites with low elevation. Interference mitigation improves due to the possibility of filtering in the polarization domain and the additional number of available degrees of freedom.

Sgammini received a Masters degree in electrical engineering from the University of Perugia, Italy and now works at the Institute of Communications and Navigation, DLR. He is currently pursuing a Ph.D. in electrical engineering with research interests in interference mitigation techniques for GNSS. His research activity includes adaptive filtering, array signal processing and estimation theory for GNSS.

Sign up for this Thursday’s free webinar here.

Webinar Summary:

As the number of GNSS signals being tracked increases, so does the potential for interference to dismiss the performance gains of using those additional signals.

To maximize performance and efficiency, prepared PNT users need their equipment to be able to detect when interference is present and mitigate it.

Developers, integrators and users need mitigation tools to protect and preserve GNSS measurement quality, maintaining high-quality multi-frequency multi-constellation positioning performance, even in challenging RF environments. This is essential particularly on the integration journey, especially during prototyping and when encountering unforeseen interference events in field testing, in order to produce fully successful integrated products.

The one-hour webinar also will include a follow-up Q&A session with the speakers. Burnell and Sgammini join Patrick Casiano of NovAtel and Rick Hamilton of CGSIC on the speaker panel. Casiano will present an Interference Toolkit that measures RF spectrum levels and allows the user to apply mitigation tools to protect and preserve GNSS measurement quality. Hamilton will explain the proliferation of jammers, aspects of illegal use, coordinated government response to interference events, and regulations to prohibit manufacture, import, export, sale and use of jammers.

January 30, 2017