Tag: JPL

NASA’s GUARDIAN Tsunami Detection catches wave in real time

News from NASA

A massive earthquake and subsequent tsunami off Russia in late July tested an experimental detection system that had deployed a critical component just the day before.

A recent tsunami triggered by a magnitude 8.8 earthquake off Russia’s Kamchatka Peninsula sent pressure waves to the upper layer of the atmosphere, NASA scientists have reported. While the tsunami did not wreak widespread damage, it was an early test for a detection system being developed at the agency’s Jet Propulsion Laboratory in Southern California.

Called GUARDIAN (GNSS Upper Atmospheric Real-time Disaster Information and Alert Network), the experimental technology “functioned to its full extent,” said Camille Martire, one of its developers at JPL. The system flagged distortions in the atmosphere and issued notifications to subscribed subject matter experts in as little as 20 minutes after the quake. It confirmed signs of the approaching tsunami about 30 to 40 minutes before waves made landfall in Hawaii and sites across the Pacific on July 29 (local time).

“Those extra minutes of knowing something is coming could make a real difference when it comes to warning communities in the path,” said JPL scientist Siddharth Krishnamoorthy.

Near-real-time outputs from GUARDIAN must be interpreted by experts trained to identify the signs of tsunamis. But already it’s one of the fastest monitoring tools of its kind: Within about 10 minutes of receiving data, it can produce a snapshot of a tsunami’s rumble reaching the upper atmosphere.

The dots in this graph indicate wave disturbances in the ionosphere as measured between ground stations and navigation satellites. The initial spike shows the acoustic wave coming from the epicenter of the July 29 quake that caused the tsunami; the red squiggle shows the gravity wave the tsunami generated. (Image: NASA/JPL-Caltech)

The dots in this graph indicate wave disturbances in the ionosphere as measured between ground stations and navigation satellites. The initial spike shows the acoustic wave coming from the epicenter of the July 29 quake that caused the tsunami; the red squiggle shows the gravity wave the tsunami generated.

The goal of GUARDIAN is to augment existing early warning systems. A key question after a major undersea earthquake is whether a tsunami was generated. Today, forecasters use seismic data as a proxy to predict if and where a tsunami could occur, and they rely on sea-based instruments to confirm that a tsunami is passing by. Deep-ocean pressure sensors remain the gold standard when it comes to sizing up waves, but they are expensive and sparse in locations.

“NASA’s GUARDIAN can help fill the gaps,” said Christopher Moore, director of the National Oceanic and Atmospheric Administration Center for Tsunami Research. “It provides one more piece of information, one more valuable data point, that can help us determine, yes, we need to make the call to evacuate.”

Moore noted that GUARDIAN adds a unique perspective: It’s able to sense sea surface motion from high above Earth, globally and in near-real-time.

Bill Fry, chair of the United Nations technical working group responsible for tsunami early warning in the Pacific, said GUARDIAN is part of a technological “paradigm shift.” By directly observing ocean dynamics from space, “GUARDIAN is absolutely something that we in the early warning community are looking for to help underpin next generation forecasting.”

How GUARDIAN works

GUARDIAN takes advantage of tsunami physics. During a tsunami, many square miles of the ocean surface can rise and fall nearly in unison. This displaces a significant amount of air above it, sending low-frequency sound and gravity waves speeding upwards toward space. The waves interact with the charged particles of the upper atmosphere — the ionosphere — where they slightly distort the radio signals coming down to scientific ground stations of GPS and other positioning and timing satellites. These satellites are known collectively as the Global Navigation Satellite System (GNSS).

While GNSS processing methods on Earth correct for such distortions, GUARDIAN uses them as clues. The software scours a trove of data transmitted to more than 350 continuously operating GNSS ground stations around the world. It can potentially identify evidence of a tsunami up to about 745 miles (1,200 kilometers) from a given station. In ideal situations, vulnerable coastal communities near a GNSS station could know when a tsunami was heading their way and authorities would have as much as 1 hour and 20 minutes to evacuate the low-lying areas, thereby saving countless lives and property.

Key to this effort is the network of GNSS stations around the world supported by NASA’s Space Geodesy Project and Global GNSS Network, as well as JPL’s Global Differential GPS network that transmits the data in real time.

The Kamchatka event offered a timely case study for GUARDIAN. A day before the quake off Russia’s northeast coast, the team had deployed two new elements that were years in the making: an artificial intelligence to mine signals of interest and an accompanying prototype messaging system.

Both were put to the test when one of the strongest earthquakes ever recorded spawned a tsunami traveling hundreds of miles per hour across the Pacific Ocean. Having been trained to spot the kinds of atmospheric distortions caused by a tsunami, GUARDIAN flagged the signals for human review and notified subscribed subject matter experts.

Notably, tsunamis are most often caused by large undersea earthquakes, but not always. Volcanic eruptions, underwater landslides, and certain weather conditions in some geographic locations can all produce dangerous waves. An advantage of GUARDIAN is that it doesn’t require information on what caused a tsunami; rather, it can detect that one was generated and then can alert the authorities to help minimize the loss of life and property.

While there’s no silver bullet to stop a tsunami from making landfall, “GUARDIAN has real potential to help by providing open access to this data,” said Adrienne Moseley, co-director of the Joint Australian Tsunami Warning Centre. “Tsunamis don’t respect national boundaries. We need to be able to share data around the whole region to be able to make assessments about the threat for all exposed coastlines.

September 16, 2025
Final grounding for Ingenuity?

NASA’s Ingenuity took this picture on Jan. 18, 2024. The sand-dune, rock-less area where Ingenuity last
showing the shadow of its damaged rotor blade. (Image: NASA)

It appears that the little extraterrestrial drone that could has come a cropper on Mars and now will not be flying again – it is permanently grounded. The Jet Propulsion Lab (JPL) crew managing Ingenuity was running a regular scouting trip over a featureless sand-dune area on Dec. 22, 2023. Suddenly, the UAV’s visual navigation system malfunctioned, which led to a hard emergency landing.

When the autonomous navigation system did not have any landmarks to match its digital reference map, it reverted to an emergency landing. Maybe the poor guy should have had a few moments to gather its airborne wits and to come down softly, but alas at the same time the connection with the rover was lost, he dove for cover and broke a chunk off at least one of the counter-rotating blades. This now apparently prevents further take-offs. Mars’ atmosphere is only 1% as dense as Earth’s, so those rotors need all their designed lift capabilities to grab enough ‘air’ and get the 4 lb helicopter airborne. The flight control system may be unable to cope with the resulting compromised lift profile. Either way Ingenuity’s flying days are over, according to NASA.

Conceptual design for the Sample Recovery Helicopters
(Image: Aerovironment/ NASA/ JPL)

Ingenuity completed 72 flights over the course of three years, surpassing its original 30-day mission to prove the possibility of a miniature, autonomous helicopter flight on Mars. After its initial four flights, NASA and JPL chose the UAV to scout out safe paths for the Perseverance rover from an airborne perspective.

All is not lost for Ingenuity, however. AeroVironment, the UAV manufacturer that co-developed Ingenuity with NASA/JPL, has been awarded another contract to design and develop two prototype ‘sample-return’ helicopters for NASA’s next major Mars expedition.

Building on Ingenuity’s design, the new UAV will have wheels and a grappling contraption to pick up sample tubes, which could assist in the Mars sample recovery mission. Perseverance is currently expected to be the lead in transferring cached sample tubes to the new Sample Retrieval Lander for return to Earth, but the new helicopters provide a different backup option on Mars for pick-up and transport of the tubes.

Back here on Earth, the latest tragic news from the Middle East — the UAV attack on the US Tower 22 military outpost in Jordan which cost three soldiers their lives and injured at least 34 others — appears to have been due to a lack of defensive capability. Earlier news releases indicated that the kamikaze UAV had arrived at the same time as the expected return of a U.S. UAV from the base, implying that defenses may have been taken down temporarily. It now seems that there was little active defense to prevent the attack.

The attacking UAV reportedly came in very low, and the base was unable to track its approach. The base is said to have defensive signal jamming capabilities, but without radar visibility of the UAV and knowing an attack was in progress, the jammers may have been ineffective or inactive.

Tower 22 was thought of as a low-risk-of-attack U.S. base, perhaps supporting another U.S. base in Syria with logistics, so no active drone suppression system had been provisioned. This assessment, and those for similar bases in the area and around the world, may perhaps have to be revised and sufficient active defenses may need to be installed.

While U.S. and Ukrainian forces deal with attacking drones, Iran has unveiled its latest addition to its arsenal of one-way killer unmanned aircraft.

Image: Iranian Military Media

Iran displayed the Shahed-238 in public in November 2023, so there may have already been enough time to get some of these very fast-flying vehicles through the manufacturing process and begin deliveries to Russia and Iranian proxy agents. The advantage of jet-power is of course significant speed over propeller-driven variants, while the range may be significantly less for the same fuel capacity. The disadvantage for the United States and Ukraine is that most fielded conventional UAV detection radars have difficulty seeing fast targets in time to activate and aim defensive weapons.

The situation for Ukraine and the United States in the Middle East appears to be worsening as large numbers of Iranian-supplied and locally manufactured kamikaze UAVs are pumped into the war zone and ‘hot spots’ in the Middle East.

It is sad that Mars aerial views may be limited as Ingenuity seems to be permanently grounded, and the Middle East doesn’t sound too safe to be hanging around in either! Further escalation of prices might be expected, too, as a good part of the volume of cargo ships settle into sailing around Africa. Let’s look for better news in the coming months.

February 21, 2024
Seen & Heard: Lighthouses no more, GPS mitigates natural disasters

“Seen & Heard” is a monthly feature of GPS World magazine, traveling the world to capture interesting and unusual news stories involving the GNSS/PNT industry.

Bikes get tricked out

Image: Snik Bike

Snik Bike is a new app-paired tracking device designed to help users track their bikes if they are lost or stolen, reported North Shore News. Snik Bike Security Co-founder Fraser Vaage developed Snik Bike after having two of his bikes stolen. Snik equips any bike with a rechargeable location device that can be installed in five minutes or less. After pairing the device, the bike is automatically registered with Project 529, which is an online bike registration service. Vaage emphasized that while this device is not a ride-tracking software, such as Strava, it acts as an odometer, tracking overall mileage. The battery is only activated when a bike is stolen, Vaage said, therefore, it’s unlikely Snik will run out of battery. However, if it does, the device diverts to AirTag technology as a backup.

Lighthouses no more

Image: Wiltser/E+/Getty Images

With the wide adoption of GNSS, lighthouses on U.S. shorelines are no longer needed for navigation. To preserve these properties, the General Services Administration has been transferring ownership of the lighthouses to anyone willing to preserve them, reported The Guardian. This year, six lighthouses are being offered to federal, state or local government agencies, non-profits, educational organizations or anyone willing to make them publicly available for educational, cultural, or recreational purposes.

Location data ad weather resiliency

Image: DenisTangneyJr/E+/Getty Images

A Southern Methodist University research team, led by Nicos Markris, measured Dallas’ resilience by recording anonymous cell phone location data among residents in the Dallas metroplex before, during, and after the February 2021 North American winter storm. Measuring a city’s resilience is critical for planning responses to future events and uncovering potential vulnerabilities. By averaging location data, Makris and his team outlined the movement patterns of Dallas residents during a typical week. They compared the normal movement patterns to those during and after the week of the winter storm to determine when Dallas started getting back to normal.

GPS mitigates natural disasters

Image: Philip Thurston/E+/Getty Images

NASA’s Jet Propulsion Lab (JPL) is testing new ways to detect tsunami-like ocean waves before they cause catastrophic damage. The GNSS Upper Atmospheric Real-Time Disaster Information and Alert Network (GUARDIAN) is a new experimental monitoring system that can use data from clusters of GPS and other satellites to detect deadly waves triggered on Earth. Radio signals from GNSS are examined by scientific ground stations around the world. That data is then reviewed by the JPL’s Global Differential GPS network to help mitigate disasters. The GUARDIAN is still evolving and may be used in the future to develop early warning strategies, according to the United Nations’ International Committee on GNSS.

August 7, 2023
GNSS shows how volcanic eruptions cause ionospheric disruptions

On Jan. 15, Hunga-Tonga-Hunga-Ha’apai, an uninhabited volcanic island on the Tongan archipelago in the South Pacific Ocean, erupted with spectacular force, churning ocean waters halfway across the globe.

GNSS engineers also detected its effects hundreds of miles above, in the ionosphere. The GNSS community is now moving from such after-the-fact detection to real-time monitoring using NASA’s Global Differential GPS (GDGPS) system, according to a team with the Tracking Systems and Application Section at NASA’s Jet Propulsion Laboratory (JPL) in Southern California.

“We monitored, in real time, four GNSS satellite constellations from numerous stations around the world using the GDGPS network. In particular, the three stations closest to the volcano, in Samoa, Fiji and Tahiti,” said postdoctoral associate Leo Martire. “We could see extremely high and strong signals in the ionosphere, which is very unusual. As a function of radial distance from the eruption, the first detected ionospheric perturbation likely originated directly from the explosion. Then we see patterns propagating at increasing distances at different radial propagation speeds.”

Monitoring such events adds information to the catalog of signals from natural hazards, pointed out Siddharth Krishnamoorthy, a research technologist who manages JPL’s GUARDIAN near-real-time tsunami warning system, currently under development. “That is useful because, in the future, if you want to be able to spot natural hazards and issue alerts, you need to know what the signal looks like. There have been reports of a tsunami in Tonga due to this event, so we will look at potential tsunami-induced signatures in the ionosphere. We are trying to get to a place where we pick up a signal like this and we are able to say, ‘This is a tsunami propagating at this speed and in this direction.’”

Chart: Jet Propulsion Laboratory

Before being detected in the ionosphere, signals from natural hazards must travel all the way from the surface. For tsunamis, this usually takes more than 10 to 20 minutes, but the volcanic eruption only took a couple of minutes to reach the ionosphere because it shot straight up. “We do not know yet, based on observations, how exactly different events on the surface caused by natural hazards couple with the atmosphere,” said research technologist Panagiotis Vergados. “Every event is unique in its spectral properties.”

The event did not affect the quality of GDGPS’s GNSS positions or orbits, because dual-frequency measurements remove significant ionospheric effects. “Instead of looking at the direct effects on the position of our available reference stations, which is what our traditional real-time monitoring does and which was basically negligible, imagine the links from each of those stations to a dozen or more satellites,” said Larry Romans, GDGPS chief technologist. “Every time one of those many links pierces the ionosphere, we can monitor that signal for ripples as waves go by. So, this is an incredibly powerful method for seeing disturbances, just in terms of the density of data. It is very complementary to position-based natural-hazards monitoring because the data is much richer.”

In addition to volcanoes and tsunamis, several other natural events, such as earthquakes and very large thunderstorms, also produce these effects. “These natural forcings cause large-scale, low-frequency pressure perturbations that tend to travel up and be visible in the ionosphere,” Krishnamoorthy said. “There are also perturbations of the ionosphere due to events from outside the Earth, such as solar flares or bolide impacts.”

Many of these perturbations start from the troposphere, which ranges between 10 km and 15 km in altitude — including hurricanes, which overshoot gravity waves all the way to the ionosphere, and thermal tides that have been observed to go all the way up to 600 km, said Vergados. “There are also geomagnetic storms and sub-storms that, during electron precipitation, can change the ionization of the ionosphere. So, the coupling can happen from either below or above or simultaneously, and then the effect can be dramatically enhanced.”

Most of the perturbations that come from below are of a pressure nature — that is, they start out as mechanical waves — while most of those that come from above are electromagnetic. “Aside from nuclear explosions, very large chemical ones, such as the 2020 Beirut explosion, also cause a signature on the ionosphere because they create very large pressure waves,” Krishnamoorthy said.

Photo: Tonga Meteorological Services, Government of Tonga

February 14, 2022
Sentinel-6 sea-level mission to use GNSS-RO for weather and climate monitoring

To get the best measurements of Earth’s atmosphere, you sometimes have to leave it. This November, the Sentinel-6 Michael Freilich spacecraft will do just that.

News from the Jet Propulsion Laboratory

When a satellite by the name of Sentinel-6 Michael Freilich launches this November, its primary focus will be to monitor sea-level rise with extreme precision. But an instrument aboard the spacecraft will also provide atmospheric data that will improve weather forecasts, track hurricanes and bolster climate models.

“Our fundamental goal with Sentinel-6 is to measure the oceans, but the more value we can add, the better,” said Josh Willis, the mission’s project scientist at NASA’s Jet Propulsion Laboratory in Southern California. “It’s not every day that we get to launch a satellite, so collecting more useful data about our oceans and atmosphere is a bonus.”

A U.S.-European collaboration, Sentinel-6 Michael Freilich is one of two satellites that compose the Copernicus Sentinel-6/Jason-CS (Continuity of Service) mission. The satellite’s twin, Sentinel-6B, will launch in 2025 to take over for its predecessor. Together, the spacecraft will join TOPEX/Poseidon and the Jason series of satellites, which have been gathering precise sea-level measurements for nearly three decades. Once in orbit, each Sentinel-6 satellite will collect sea-level measurements down to the centimeter for 90% of the world’s oceans.

JPL-developed instrument

Meanwhile, they’ll also peer deep into Earth’s atmosphere with GNSS-RO to collect highly accurate global temperature and humidity information. Developed by JPL, the spacecraft’s GNSS-RO instrument tracks radio signals from navigation satellites to measure the physical properties of Earth’s atmosphere. As a radio signal passes through the atmosphere, it slows, its frequency changes, and its path bends. Called refraction, this effect can be used by scientists to measure minute changes in atmospheric physical properties, such as density, temperature, and moisture content.

The precise global atmospheric measurements made by Sentinel-6 Michael Freilich will complement atmospheric observations by other GNSS-RO instruments already in space. Specifically, the National Oceanic and Atmospheric Administration’s National Weather Service meteorologists will use insights from Sentinel 6’s GNSS-RO to improve weather forecasts.

Also, the GNSS-RO information will provide long-term data that can be used both to monitor how our atmosphere is changing and to refine models used for making projections of future climate. Data from this mission will help track the formation of hurricanes and support models to predict the direction storms may travel. The more data we gather about hurricane formation (and where a storm might make landfall), the better in terms of helping local efforts to mitigate damage and support evacuation plans.

The Sentinel-6 Michael Freilich spacecraft undergoes tests at its manufacturer Airbus in Friedrichshafen, Germany, in 2019. The white GNSS-RO instrument can be seen attached to the upper left portion of the front of the spacecraft. (Photo: Airbus)

A brief history of radio occultation

Radio occultation was first used by NASA’s Mariner 4 mission in 1965 when the spacecraft flew past Mars. As it passed behind the Red Planet from our perspective, scientists on Earth detected slight delays in its radio transmissions as they traveled through atmospheric gases. By measuring these radio signal delays, they were able to gain the first measurements of the Martian atmosphere and discover just how thin it was compared to Earth’s.

By the 1980s, scientists had started to measure the slight delays in radio signals from Earth-orbiting navigation satellites to better understand our planet’s atmosphere. Since then, many radio occultation instruments have been launched; Sentinel-6 Michael Freilich will join the six COSMIC-2 satellites as the most advanced GNSS-RO instruments among them.

“The Sentinel-6 instrument is essentially the same as COSMIC-2’s. Compared to other radio occultation instruments, they have higher measurement precision and greater atmospheric penetration depth,” said Chi Ao, the instrument scientist for GNSS-RO at JPL.

GNSS-RO basics

The GNSS-RO instrument’s receivers track navigation satellite radio signals as they dip below, or rise from, the horizon. They can detect these signals through the vertical extent of the atmosphere — through thick clouds — from the very top and almost all the way to the ground. This is important, because weather phenomena emerge from all layers of the atmosphere, not just from near Earth’s surface where we experience their effects.

“Tiny changes in the radio signal can be measured by the instrument, which relate to the density of the atmosphere,” said Ao. “We can then precisely determine the temperature, pressure, and humidity through the layers of the atmosphere, which give us incredible insights to our planet’s dynamic climate and weather.”

With the help of JPL’s GNSS-RO principal investigator Chi Ao and NOAA’s National Weather Service meteorologist Mark Jackson, this video explains how the GNSS-RO instrument aboard Sentinel-6 Michael Freilich will be used by meteorologists to improve weather forecasting predictions. (Credit: NASA/JPL-Caltech)

But there’s another reason why probing the entire vertical profile of the atmosphere from orbit is so important: accuracy. Meteorologists typically gather information from a variety of sources – from weather balloons to instruments aboard aircraft. But sometimes scientists need to compensate for biases in the data. For example, air temperature readings from a thermometer on an airplane can be skewed by heat radiating from parts of the aircraft.

GNSS-RO data is different. The instrument collects navigation satellite signals at the top of the atmosphere, in what is close to a vacuum. Although there are sources of error in every scientific measurement, at that altitude, there’s no refraction of the signal, which means there’s an almost bias-free baseline to which atmospheric measurements can be compared in order to minimize noise in data collection.

And as one of the most advanced GNSS radio occultation instruments in orbit, said Ao, it will also be one of the most accurate atmospheric thermometers in space.

More on the mission

Copernicus Sentinel-6/Jason-CS is being jointly developed by the European Space Agency (ESA), the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT), NASA, and the National Oceanic and Atmospheric Administration (NOAA), with funding support from the European Commission and support from France’s National Centre for Space Studies (CNES).

The first Sentinel-6/Jason-CS satellite that will launch was named after the former director of NASA’s Earth Science Division, Michael Freilich. It will follow the most recent U.S.-European sea-level observation satellite, Jason-3, which launched in 2016 and is currently providing data.

NASA’s contributions to the Sentinel-6/Jason-CS mission are three science instruments for each of the two Sentinel-6 satellites: the Advanced Microwave Radiometer, the GNSS-RO, and the Laser Retroreflector Array. NASA is also contributing launch services, ground systems supporting operation of the NASA science instruments, the science data processors for two of these instruments, and support for the international Ocean Surface Topography Science Team.

September 4, 2020
UCAR system boosts GNSS data for weather forecasting

Atmospheric and Environmental Research Inc. (AER), a Verisk business, will license a satellite-data-processing system from the University Corporation for Atmospheric Research (UCAR), building on UCAR’s commitment to improve weather forecasting.

The agreement will enable AER to process satellite data for commercial companies that sell their Earth observation data products to government agencies and other organizations that provide customized environmental information to a range of clients.

Under the agreement, AER will adapt UCAR’s SatDAACâ software system to process observations from satellites using GNSS radio occultation to observe the atmosphere. Those observations can lead to significantly improved weather forecasts.

From basic research to industry

GNSS radio occultation measures the extent to which the radio signals from GNSS transmitter satellites (including GPS satellites) bend as they propagate through denser regions of the atmosphere.

The measurements can be further processed into information about temperature, pressure, and humidity in the lower atmosphere as well as the electron density in the ionosphere. The technique provides considerable accurate knowledge about a large volume of the atmosphere from near-Earth orbit down to the surface.

Image: NOAA

NASA’s Jet Propulsion Laboratory was first to use radio occultation to profile the atmospheres of Mars, Venus, and the outer planets starting in the 1960s. UCAR, in collaboration with JPL, pioneered the GNSS radio occultation observing technique for Earth’s atmosphere, building on basic research with funding from the National Science Foundation.

In 2006, UCAR began producing the first operational GNSS radio occultation data from a specialized constellation of small satellites known as the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC). The observations from COSMIC led to improved predictions of tropical cyclones and other storms as well as information about space weather and global climate.

A second constellation of small satellites, known as COSMIC-2, was launched in June 2019. It will provide twice as many soundings of the atmosphere with higher quality than COSMIC.

More GNSS-RO satellites coming

Now that the technology has been successfully demonstrated, additional satellites with GNSS radio occultation technology are being launched.

“This technology has moved quickly from being a research concept to providing vital information to forecasters,” said Ying-Hwa “Bill” Kuo. “The original investment in basic research is generating substantial benefits for society.”

Lead GNSS radio occultation researcher at AER Stephen Leroy said, “Earth radio occultation has a nearly 30-year history and has been a revolutionary force in numerical weather prediction and climate science in that time; and now with the commercialization of RO [radio occultation] data, we are looking forward to an explosion in RO data volume. I am really excited that we are performing the operational processing of this new data stream and expanding its scope and utility.”

The UCAR-AER agreement will likely lead to further advances in GNSS radio occultation technology, according to Bill Schreiner, director of the UCAR COSMIC Program.

“By transferring technology to the private sector, AER can take it to the next level in terms of distributing the data and finding new applications that help society,” he said. “This agreement will leverage SatDAAC’s advanced capabilities to develop new products for use by the environmental observing and prediction communities and will help us continue to innovate.”

At least three commercial enterprises are currently developing and deploying nanosatellites and microsatellites that perform GNSS radio occultation — Spire, GeoOptics and PlanetiQ — as well as several international space agencies.

AER works with governments and businesses worldwide to advance understanding of climate- and weather-related risks. The company develops analytical tools to help measure and observe the properties of the environment and translate those measurements into actionable information.

UCAR is a nonprofit consortium of 120 colleges and universities focused on research and training in the atmospheric and related sciences.

March 9, 2020
GPS Innovation Alliance celebrates NASA’s 60th anniversary

Association recognizes key role the agency has played in furthering GPS.

The GPS Innovation Alliance (GPSIA), an organization dedicated to furthering GPS innovation, creativity and entrepreneurship, commends NASA — the U.S. National Aeronautics and Space Administration — on its momentous 60th anniversary. GPSIA celebrates the occasion by recognizing the vital role NASA has played in furthering and facilitating the growth of GPS around the world.

NASA has long been an integral supporter of GPS technologies, from its origins in the first space shuttle program, to the launch of the International Space Station (ISS), to the recent announcement of plans to develop an artificial intelligence-based GPS for space.

Throughout its history, NASA has played a critical role in the success of expanding GPS systems. NASA manages the Navigator GPS receiver, developed by its Goddard Space Flight Center, which has pushed GPS satellites out of lower earth orbit and beyond to enable high altitude applications and track weaker and more rural GPS signals with increased accuracy.

The Global Differential GPS System (GDGPS), a network of more than 350 GPS monitoring stations from 200 contributing organizations in 80 countries developed and operated by NASA’s Jet Propulsion Laboratory, provides an unparalleled combination of real time positioning accuracy and availability and acts as the largest network providing global, multiply-redundant, real time coverage of all GPS satellites at all times.

“GPS contributes immeasurable value to our economy and is used in almost every industry sector,” said NASA Administrator Jim Bridenstine. “It is crucial for our way of life on Earth — the way we communicate, navigate, conduct banking transactions, and so much more rely on our GPS systems. As NASA looks to its future endeavors in exploration and discovery, GPS will remain a cornerstone of technology to accomplish its missions. NASA looks forward to its continued work with the GPS Alliance.”

With the establishment of the National Executive Committee for Space-Based Positioning, Navigation, and Timing in 2004 and other governing bodies since, NASA has also acted as a thought leader on policy trends in the field, advising on and advocating for protections of GPS , one of the world’s most important and ubiquitous public resources.

“The alliance, on behalf of its members and the GNSS industry, congratulates NASA on six decades of cutting-edge innovation and wishes the agency continued success for many decades to come,” said J. David Grossman, executive director of the GPS Innovation Alliance. “As one of the most recognizable technologies in the world, GPS supports navigation, public safety, financial transactions and utilities and varied industries worldwide. We applaud NASA for its unwavering commitment to scientific innovation and to GPS around the globe, now and in the future.”

The GPS Innovation Alliance recognizes the ever increasing importance of GPS and other GNSS technologies to the global economy and infrastructure and is firmly committed to furthering GPS innovation, creativity and entrepreneurship. The GPS Innovation Alliance seeks to protect, promote and enhance the use of GPS.

November 7, 2018
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
Septentrio to supply GNSS reference stations, timing receivers to JPL

Septentrio has received a contract to supply 35 high-precision GNSS receivers to the Jet Propulsion Laboratory (JPL) for use in the NASA Global GNSS network (GGN).

The NASA GGN is one of the world’s largest global GNSS tracking networks with nearly a hundred reference receivers deployed worldwide and is a participant in the International GNSS Service (IGS). The GGN is also the core tracking network of JPL’s Global Differential GPS (GDGPS) System, a highly available and reliable service providing mission-critical position, navigation and timing data, as well as environmental monitoring for industry and government operations.

The Septentrio PolaRx5 GNSS receiver.

Under the contract, Septentrio will supply 35 of its new-generation PolaRx5 GNSS receivers, including 25 reference stations and 10 timing instruments. Deliveries began in August and will be completed in September.

The PolaRx5 incorporates Septentrio’s most advanced multi-frequency GNSS engine, which tracks all major satellite signals including GPS, GLONASS, Galileo and BeiDou, as well as the regional QZSS and IRNSS satellite systems. It provides measurement quality and interference mitigation, and operates on less than two Watts when receiving GPS and GLONASS satellite signals.

“This major contract with JPL — a widely recognized industry leader in GPS and GNSS technology — is an important validation of Septentrio’s position as the number one preferred supplier of highly accurate GNSS receivers for scientific applications, and recognition of the superior performance of our next-generation GNSS receivers,” said Neil Vancans, vice president of Septentrio Americas.

September 14, 2016
GPS scientist Michael Watkins named next JPL director

Michael M. Watkins has been appointed director of the Jet Propulsion Laboratory and vice president at Caltech, the Institute announced. Watkins is the Clare Cockrell Williams Centennial Chair in Aerospace Engineering and director of the Center for Space Research at the University of Texas at Austin.

Watkins has written for GPS World about the GRACE project, which uses GPS and a microwave ranging system to map Earth’s gravitational fields.

Watkins will formally assume his position on July 1. He succeeds Charles Elachi, who will retire on June 30 and move to the Caltech faculty.

Watkins is an internationally recognized scientist and engineer. Before assuming his current position at the University of Texas in 2015, he worked at JPL for 22 years, where he held leadership roles on some of NASA’s highest-profile missions.

Watkins served as mission manager and mission system manager for the Mars Science Laboratory Curiosity Rover; led review or development teams for several missions including the Cassini, Mars Odyssey, and Deep Impact probes; and was the project scientist leading science development for the GRAIL moon-mapping satellites, the GRACE Earth science mission, and the GRACE Follow-on mission, scheduled for launch in 2017. He last served at JPL as manager of the Science Division, and chief scientist for the Engineering and Science Directorate.

“He has been one of the early pioneers of using GPS for very high-precision geodetic applications including precise orbit determination, precise point positioning, mapping of mass variability using high precision gravity field measurements, to name only a few of his major accomplishments in geodesy,” said JPL senior researcher Attila Komjathy, who was one of the first to investigate the use of GPS signals to study the ionosphere.

GPS and microwave ranging. GRACE (the Gravity Recovery and Climate Experiment) maps the Earth’s gravity fields by making accurate measurements of the distance between the two satellites, using GPS and a microwave ranging system. It provides scientists from all over the world with an efficient and cost-effective way to map the Earth’s gravity fields with unprecedented accuracy. The results from this mission have revealed detailed information about the distribution and flow of mass within the Earth and it’s surroundings.

The gravity variations that GRACE studies include: changes due to surface and deep currents in the ocean; runoff and ground water storage on land masses; exchanges between ice sheets or glaciers and the oceans; and variations of mass within the Earth. Another goal of the mission is to create a better profile of the Earth’s atmosphere.

Michael Watkins (Photo: NASA/JPL-Caltech)

“Michael’s record of successful mission leadership and impressive management skills quickly distinguished him as a leading candidate for this position,” said Caltech president Thomas F. Rosenbaum, the Sonja and William Davidow Presidential Chair and professor of physics. “As JPL director, Michael will build upon the laboratory’s outstanding achievements in planetary exploration and Earth science, strengthening the connections between Caltech’s campuses and partnering with NASA to deliver highly complex and nuanced missions.”

“I’ve known Mike Watkins for more than 20 years now,” Elachi said. “Mike has played important and varying roles in a number of important JPL areas. His intimate knowledge of the lab and staff, combined with his highly diversified set of skills and knowledge base in science and engineering, will serve JPL very well in the years to come.”

A committee composed of Caltech trustees, faculty, senior administrative leaders, and a member of the JPL executive council conducted an extensive search and recommended Watkins to Caltech’s president.

Watkins holds a bachelor’s degree, master’s degree, and Ph.D. in aerospace engineering from The University of Texas at Austin. He has published broadly in both engineering and science, contributed more than 100 conference presentations, and has served on the boards of numerous international scientific and engineering societies.

“JPL has such a talented and deeply committed staff,” said Watkins. “It is a privilege to have this opportunity to lead the laboratory to even greater discoveries. I look forward to working with my colleagues on campus and across NASA to forge new directions in space exploration and Earth science.”

GPS World article:

“Instrument of GRACE: GPS augments gravity measurements,” GPS World, 14(2), 16-28, 2003 (C. Dunn et al.).

May 3, 2016
GPS Data Show How Nepal Quake Disturbed Earth’s Upper Atmosphere

The April 25 magnitude 7.8 earthquake in Nepal created waves of energy that penetrated into Earth’s upper atmosphere in the vicinity of Nepal, disturbing the distribution of electrons in the ionosphere. These disturbances were monitored using GPS signals received by a science-quality GPS receiver in Tibet, a neighboring region to Nepal.

The data show that after the initial earthquake rupture (indicated by the vertical black line on the graphic), it took about 21 minutes for the earthquake-generated ionospheric disturbance to reach a GPS station (LHAZ) about 400 miles (640 kilometers) away from the epicenter in Lhasa, Tibet, China.

Image Credit: NASA/JPL/Ionosphere Natural Hazards Team

The disturbance measurements, known as vertical total electron content (VTEC) (depicted in blue in the upper panel), have been filtered using processing software developed by NASA’s Jet Propulsion Laboratory in Pasadena, Calif., to show wave-like disturbances (circled in red) in the distribution of electrons in the ionosphere. The waves have periods of between two and eight minutes in length. The disturbance measurements following the earthquake rupture are circled in black in the lower panel. The colors represent the relative strengths of the earthquake-induced ionospheric disturbances as captured by the GPS signals, with red being high and blue being low.

Attila Komjathy, a principal investigator of the Ionospheric and Atmospheric Remote Sensing group at JPL and adjunct professor at the University of New Brunswick, is leading this effort. Komjathy is also a GPS World annual award winner and named a Fellow of the Institute of Navigation in January.

The LHAZ GPS station is hosted at the Tibet Autonomous Regional Bureau of Surveying and Mapping Institute. The site collects both GPS and GLONASS (the Russian global navigation satellite system) data at a rate of 1 Hertz and is part of the International GPS Service (IGS).

Scientists study ionosphere-based measurements caused by natural hazards such as earthquakes, volcanic eruptions and tsunamis to better understand wave propagation in the upper atmosphere.The ionosphere is a region of Earth’s upper atmosphere located from about 37 miles (60 kilometers) to 621 miles (1,000 kilometers) above Earth’s surface.

The disturbances caused by earthquakes help scientists develop new first-principle-based wave propagation models. These models may become part of future early warning systems for tsunamis and other difficult-to-detect natural hazards.

The data is available on this FTP site.

May 2, 2015