Tag: Washington

Review benefits of GNSS rover accuracy
Douglas County Public Works needed a GNSS rover to support its UAS operations. The pay-as-you-go option was appealing as they only needed high-precision a few times per month. (Image: Jason Schilling)

This is part II of our III part feature story. Check out part I, Minnesota company develops new system for mapping underground utilities and part III, Robotic total stations add scanning capabilities.

High precision GNSS rovers play a vital role in a broad variety of field surveying and mapping applications. Different users have different value propositions in mind when choosing field hardware and software: expected precision, sources of corrections, configurations for specific workflows, and, of course, cost. Weighing these many considerations, GNSS manufacturers have come up with portfolios of multiple models to fill these varied needs.

That said, GNSS manufacturer Bad Elf took a different approach when it designed its flagship rover, the Bad Elf Flex. The Flex is designed to meet the cost-precision-workflow needs of everyone, from asset mappers to surveyors. (Hence the name “Flex.”) To inform the design of the Flex, Bad Elf listened to field users who wished for a scalable solution in a single rover, rather than having to buy multiple different models, and without breaking the bank.

Options for the Infrequent User

“I had one of the little Bad Elf GNSS surveyor handhelds for many years,” said Jason Schilling, wildlife biologist with Douglas County Public Utility District in central Washington State. “That worked great for rough mapping, between a foot and a meter of precision, and I could connect it via Bluetooth to mapping software on my mobile.”

But this all changed when Schilling began an unmanned aerial system (UAS) program for the utility several years ago.

“I really needed survey-level precision for ground control points to geolocate the images from the UAS,” said Schilling.

He was aware of the high cost of centimeter-precision-capable surveying rovers and it was too big of an investment, considering that he only did UAS mapping a few times a month. As an existing Bad Elf customer on the company mailing list, Schilling learned about the new Flex rover, which offered multiple options, and he found one that seemed quite enticing for the needs of his utility.

Schilling purchased a Flex Standard bundle at a low base price, about $3,000, with the pay-as-you-go plan for high precision. In the standard configuration, the Flex is capable of autonomous positioning (1–5 m), and mapping grade (sub-meter precisions) via free satellite-based augmentation services (SBAS), such as WAAS. But when the user activates a pre-purchased “token,” the full centimeter-precision capability, using external corrections, is enabled.

“On the day of a UAS survey, we turn it on, activate a token from our account, and then we have 24 hours of high precision,” Schilling said. “It costs us $25 per day.”

For two to three UAS surveys a month, this works out to far less over many years than the cost of buying a typical surveying rover.

Correction Sources

For real-time kinematic (RTK) corrections, Schilling connects via NTRIP to the statewide cooperative real-time network (RTN); sometimes in a network RTK mode (such as VRS) or single-base RTK to a nearby reference station on the same network. The Flex accommodates NTRIP connections to RTN or IP-enabled reference stations, but Bad Elf has added even more flexibility for corrections.

In some scenarios there is no access to an RTN or no cell service (needed for NTRIP access). One option in these cases is to add a second Flex, set it up as an RTK base, and connect the base and rover via radios that Bad Elf offers.

Bad Elf has added other options for corrections: the Bad Elf RTK service taps into a nationwide real-time network operated by Point One Navigation. This is accessible via NTRIP in the same manner as regional, state or local RTN, and is offered for a monthly fee. In addition, for situations where there is no RTN or cell service, a global precise point positioning (PPP) service (Atlas) can be enabled on the Flex.

PPP differs from RTK/RTN in that it does not need the dense arrays of reference stations, or cell service to access. Instead, PPP derives very precise clock and orbit data from a global array of tracking stations and delivers this to the Flex via geostationary satellites. After a short convergence time, PPP from the Atlas service will yield 5 –10 cm precision over most of the globe.

The Full Boat

Full Configuration. Brian Cortese works for the City of Ellensburg, where he uses the FLEX Extreme Bundle for multiple field applications. (Image: Brian Cortese)

The City of Ellensburg, a college town and farming community in central Washington State, chose the Flex Extreme bundle for about $6,000 — the “full boat” configuration. The Extreme bundle enables all the add-on services all the time, eliminating the need for tokens. In their case, the frequency of use made the higher initial investment worthwhile.

“We have big plans for our rovers,” said Brian Cortese, Engineering Tech/Inspector for the City of Ellensburg Public Works & Utilities.

Ellensburg is a vibrant town that is attracting a lot of new development and it is being proactive in surveying and mapping assets as they are added or replaced.

“We’re recording manholes and valves, sewer systems, storm water systems, irrigation, hydrants — everything that gets built in the city gets as-built surveyed,” Cortese said. “Precise, real-time positioning, it’s been a benefit to us already. We can go out before they work on the subgrade for new developments and take measurements, and then when they finish the subgrade and pave it, we can go back and locate those exact positions.”

Ellensburg uses corrections from the statewide cooperative RTN. In fact, one of the RTN reference stations —also part of the NOAA National CORS Network — is right in the center of town atop the science building of Central Washington University. While the city does a wide variety of surveying and mapping, with the Flex and RTN corrections surveyors get the same centimeter-precision for everything they measure in the field.

“We’ve done design projects with it,” Cortese said. “For instance, we recently took measurements in an area of downtown for a proposal by recording positions and elevations to develop a new park and entertainment area for the community. We are also marking Americans with Disabilities Act (ADA) ramps to meet federal specs out in the field — it’s been really handy for so many things.”

Survey-Grade Rover

To serve the full range of precision needs, the Flex had to be designed as a survey-grade rover. It has a full-constellation GNSS and RTK engine: GPS, GLONASS, Galileo, BeiDou, and support for other regional constellations. With more satellites in view, it can perform in sky-view-challenged locations, such as around buildings and under tree canopy.

“Ellensburg is on the Tree City, USA list; our streets are very well lined with a variety of trees, which is also where a lot of our utilities are and development is going on,” Cortese said. “We have been able to get good precisions in and around those trees. Actually, someone on our staff is taking an inventory of the trees with the Flex and loading the data directly into ArcGIS.”

Even in the more rural areas of Grant County that enjoy a lot of open sky, Schilling said, some areas planned for mapping are along upper tributaries and in the hills with a lot of tree coverage. He said the Flex has performed well in those areas.

Choices

The Flex offers these options and combinations:
- Flex Extreme. Full survey-grade rover that can use a variety of correction types.
- Base-Rover RTK. Two Flex Extreme units connected via radio.
- External RTN/RTK corrections via NTRIP.
- Bad Elf RTK Service. Single-tap access to a nationwide RTK corrections service.
- PPP service. Atlas PPP corrections via L-band geostationary satellites.
- Flex Standard. Pay-as-you-go high-precision-enabled service using tokens.
- Static Logging. Observation file logging for post-processing (supported by Flex Extreme).
- Compatibility with multiple field-mapping software applications.
While many modern GNSS rover systems support one or more options similar to those listed above, Bad Elf’s Flex supports all of them, making it capable of a wide variety of applications.
February 22, 2023
US West Coast now has access to GNSS-powered ShakeAlert app

After 15 years of planning and development, the ShakeAlert earthquake early warning system is now available to more than 50 million people in California, Oregon and Washington, the most earthquake-prone region in the conterminous U.S.

ShakeAlert provides alerts to the general public through public alert systems such as TV, radio and mobile phones. It also slows down trains, opens firehouse doors, closing water and gas valves and

May’s addition of Washington State to the system completes the U.S. Geological Survey and partners’ West Coast rollout of ShakeAlert.

ShakeAlert first launched in California in 2019 and expanded to Oregon in March of this year. People in all three states can now receive alerts from FEMA’s Wireless Emergency Alert system, third-party phone apps, and other technologies.

The ShakeAlert system relies on sensor data from the USGS Advanced National Seismic System. ANSS is a USGS-facilitated collection of regional earthquake monitoring networks operated by partner universities and state geological surveys on the West Coast and throughout the nation.

Part of that data comes from GPS, which the USGS uses to measure crustal deformations over time. The USGS measures the precise position (within 5 mm or less) of GNSS stations near active faults relative to each other.

USGS works closely with ANSS partners and state emergency management agencies on the system’s development as well as public communication, education and outreach. “USGS science is the backbone of hazard assessment, notification, and response capabilities for communities nationwide so they can plan for, and bounce back from, natural disasters,” said David Applegate, associate director for Natural Hazards Exercising the Delegated Authority of the USGS Director.

See also:

Early earthquake warnings: GNSS could enable 10-second alerts

“Systems powered by ShakeAlert can turn mere seconds into opportunities for people to take life-saving protective actions or for applications to trigger automated actions that protect critical infrastructure,” Applegate said. “An effort like this takes the dedication, ingenuity and hard work of dozens of partners with the same vision, and the USGS is proud to have been part of a collaborative team that made this robust public safety system available for millions of citizens on the West Coast.”

The ShakeAlert earthquake early warning system can save lives and reduce injuries by giving people time to take protective actions like drop, cover and hold on before potentially dangerous earthquake shaking arrives at their location.

In addition to supporting public alerts to mobile phones, ShakeAlert system data has, since late 2018, been used to develop applications that trigger automated actions. Automatic actions can be used to slow down trains to prevent derailments, open firehouse doors so they don’t jam shut and close valves to protect water and gas systems.

The technology will continue to improve over time with the addition of more seismometers to the network, by expanding alert delivery area and by improving messaging speeds.

A GNSS station in the Pacific Northwest geodetic array. (Photo: Central Washington University)

May 12, 2021
The GPS Innovation Alliance adds BAE Systems as member

The global security, defense and aerospace company joins alliance dedicated to protecting, promoting and enhancing the use of GPS technology

The GPS Innovation Alliance (GPSIA) is welcoming BAE Systems Inc. as the newest member of the organization. BAE Systems, a global defense, security and aerospace company, joins member companies John Deere, Garmin, Trimble, Lockheed Martin and Collins Aerospace, a unit of Raytheon Technologies Corp., as well as 11 national organizations that make up GPSIA’s affiliates program.

As the newest member of the alliance and the third aerospace and defense corporation to join the organization in eight months, BAE Systems will work with GPSIA to support its goal of enhancing GPS innovation, creativity and entrepreneurship — while advocating as the voice of the GPS industry in Washington.

“We are excited to welcome BAE Systems as the newest member of the Alliance — a monumental addition that marks the doubling of our membership in the past eight months,” said GPSIA Executive Director J. David Grossman. “The continued growth of GPSIA demonstrates the criticality of protecting GPS and the substantial value our organization delivers through advocacy, information sharing, and technical standards. We remain committed to ensuring the economic and societal benefits of GPS are fully realized.”

BAE Systems is a global leader in designing and implementing high-end technology to extend the reach and significance of GPS in defense. BAE Systems’ radiation-hardened electronics have been on board satellites and spacecraft for almost 30 years and are currently providing the high-performance onboard processing capability for the GPS III satellite mission. Promoting space resiliency for over 30 years, BAE Systems is a cornerstone of the growing importance of GPS technologies on the space frontier.

BAE Systems has not only pioneered critical technologies suitable for GPS applications in space, but has also developed, manufactured, integrated and supported GPS receivers and guidance systems for advanced military applications on land, sea or air.

The company was instrumental in the development of NAVWAR sensor technology, intended to meet growing challenges associated with maintaining military positioning, navigation and timing (PNT) advantage using satellite navigation, and has engineered top-tier jammers and navigation systems for decades. Their work has been critical in securing the safety and technological supremacy of our nation’s defenses.

“GPS is an essential part of our world — from our infrastructure and economy to the security of our nation,” said Frank Ruggiero, senior vice president, government relations, BAE Systems. “As a leading provider of defense electronics and communications systems, we are excited to join the GPS Innovation Alliance to expand the development of cutting-edge GPS technologies.”

August 7, 2020
FAA Tells D.C. Visitors ‘Leave Drone at Home’

As hundreds of thousands of tourists flock to the Washington, D.C., area for their summer vacations and residents join them on city streets and at public gatherings, the Federal Aviation Administration has a clear message for everyone: Leave Your Drone at Home.

The FAA has announced a public outreach campaign for the region around Washington, D.C., to reinforce the message that the city itself, and communities within a 15-mile radius of Ronald Reagan Washington National Airport, are a “No Drone Zone.” The effort includes furnishing outreach materials to federal, state and local partners around the National Capital Region. The agency wants to ensure residents and tourists all understand that flying an unmanned aircraft in this area for any purpose is against the law.

The push follows two incidents when drones entered the no-fly zone around the White House. The most recent was on May 14.

Rules put in place after the 9/11 attacks establish “national defense airspace” over the D.C. area and limit aircraft operations — including unmanned aircraft — to those with an FAA and Transportation Security Administration authorization. Violators may face stiff fines and criminal penalties.

The bottom line: Enjoy your visit to the nation’s capital. Bring your family, your cameras and plenty of sunscreen. Just don’t bring your drone.

For more information, visit the FAA’s No Drone Zone webpage.

May 20, 2015
Esri Offers Interactive Map of Landslide Risk

Aerial photograph of the Oso mudslide, taken by the Washington State Patrol.

The March 22 mudslide in Oso, Washington, has drawn national attention to the danger of landslides. So far, the Snohomish County Medical Examiner’s office confirmed that 39 people had died and seven people remain missing.

Esri provides an interactive map for users to see where the risk of landslides is low, moderate, or high in the United States.

The map shows landslide suspectibility and incidence data from the USGS, which says this 1982 map was not intended to show landslide areas. Areas with low landslide incidence have been omitted.

Users can click any feature on the map for detailed information about the people living in that area.

April 16, 2014
Esri Offers Interactive Map of Landslide Risk

Aerial photograph of the Oso mudslide, taken by the Washington State Patrol.

The March 22 mudslide in Oso, Washington, has drawn national attention to the danger of landslides. So far, the Snohomish County Medical Examiner’s office confirmed that 39 people had died and seven people remain missing.

Esri provides an interactive map for users to see where the risk of landslides is low, moderate, or high in the United States.

The map shows landslide suspectibility and incidence data from the USGS, which says this 1982 map was not intended to show landslide areas. Areas with low landslide incidence have been omitted.

Users can click any feature on the map for detailed information about the people living in that area.

April 16, 2014
On the Edge: Tracking Slips and Creeps: Earthquake Monitoring Gets Substantial Boost from GPS

By Tracy Cozzens

The Earth’s surface is constantly shifting, being deformed as earthquake faults accumulate strain, and slip or slowly creep over time. Not long ago, scientists relied solely on seismometers to monitor the earth’s movements. Today, GPS has taken prominence as an indispensible tool.

PANGA, the monitoring network covering the Pacific Northwest, uses GPS to monitor this movement by measuring the precise position (within 5 millimeters or less) of stations near active faults relative to each other. By determining how the stations have moved, ground deformation can be determined.

If the plates near the coast or the Cascade Mountains move even a few centimeters, the scientists at PANGA know within seconds. The network is still being built, but eventually it’s expected that PANGA will be able to sense earthquakes faster and more accurately than traditional seismometers, and issue alerts to warn citizens of impending activity.

“GPS is helpful in distinguishing magnitude 8 from M9 earthquakes quickly,” explained Rex Flake, PANGA. “By design, seismometers only record high-frequency energy that becomes saturated during strong ground motion. Moreover, seismic data ‘clip’ at high magnitudes whereas GPS become more accurate. Seismographs are mainly intended to detect very small to moderately large earthquakes. GPS gives actual ground motions that in theory could be incorporated very quickly into tsunami models and warning systems. That is one of the things we are working on now.”

Volcano Watch. “A more speculative application is that some (not all by any measure) large earthquakes are preceded by slow creep events,” said Andrew Miner, PANGA. “While not really good enough to predict an earthquake, I think if we saw a very large transient creep event it would at least ring alarm bells. Unfortunately though, earthquakes are by their nature just not very predictable, at least to the level of a day or week that people could reasonably act on. On the bright side, volcanoes are reasonably predictable, and GPS is also an important tool in monitoring them. We work with the Cascade Volcano Observatory on several monitoring projects.”

PANGA is one of a series of earthquake monitoring networks stretching along the West Coast. The Pacific Northwest Geodetic Array is run by the PANGA Geodesy Laboratory at Central Washington University (CWU) in Ellensburg, and includes 300 continuously operating, high-precision GPS receivers located throughout the Pacific Northwest. Sixty more stations are expected to be installed this year. Trimble, Leica, Topcon, and Javad are the main receivers used in the region.

Data from these receivers is continuously downloaded, analyzed, archived, and disseminated. About one third of PANGA’s GPS stations are telemetered in real-time back to CWU, where the data are processed using NASA’s Jet Propulsion Laboratory’s GIPSY/OASIS II software for high-precision data analysis, and Trimble’s RTKNet Integrity Manager software for real-time analysis. The data provide relative positioning of several millimeters across the Cascadia subduction zone and its metropolitan regions. These real-time data are used to monitor and mitigate natural hazards arising from earthquakes, volcanic eruptions, landslides, and coastal sea-level hazards.

Sagging Bridges. The data are also used to monitor man-made structures such as Seattle’s sagging Alaska Way Viaduct, the State Route 520 and Interstate 90 floating bridges, and dams throughout the Cascadia subduction zone, including those along the Columbia River. For instance, for the S.R. 520 bridge, PANGA teamed up with Washington State Department of Transportation (WSDOT) to monitor movement of the 520 bridges during wind storms and seismic events.

The receivers continuously monitor and record structural deformation with about a millimeter precision. Raw GNSS satellite phase and pseudorange estimates are acquired and processed continuously into receiver positions estimated every 5 seconds and delivered with 10 and 30-second latencies. Daily-averaged receiver positions computed with predicted and post-processed satellite orbit and clock corrections are provided with 1-6 day latencies.

Seattle’s aging Alaska Way viaduct is one of several major man-made structures being monitored by PANGA’s GPS Network. (photos courtesty of CWU Geodesy Lab.)

Tremor Slips. The Northwest is at the forefront of earthquake-related GPS research, in large part because the area provides a lot to learn from GPS monitoring, Flake said. “For example, when we started it was strongly suspected but not definitely known that the Cascadia subduction zone was locked over parts of its surface and a major earthquake threat. Thanks to GPS monitoring we now have a pretty good idea not only exactly where it is locked, but also when parts of it do slip or creep.

“One important discovery made with GPS data, along this line, was that of the Episodic Tremor Slip (ETS) events that occur here in the Northwest U.S.,” Flake said. “Since the time duration of ETS motion takes place on the scale of days to weeks, these earthquake events were unrealized by traditional seismic detection methods.”

GPS data shed light on this peculiarly predictable earthquake phenomenon. “With these GPS data we can measure strain accumulation within the continental crust (where people live) and calculate the residual that can be expected to rebound in a large subduction zone earthquake,” Flake said.

“Even more detailed than that, we can use GPS data from past ETS events to constrain the locked zone of the subducting crustal plate by inferring the amount of slip at depth that best reproduces the observed GPS recordings — important in determining possible magnitude and location of the megathrust earthquakes (Mw = 8 to 9) that will someday occur. This is of obvious concern to society and is a major reason that we lead the geodetic applications of GPS research.”

Data Online. PANGA maintains a website that integrates daily GPS measurements from about 1,500 stations along the Pacific/North American plate boundary, ranging from Alaska to the U.S-Mexico border. Cleaned, network solutions from several arrays are merged and grouped into regional clusters.

Arrow on a Velocity Field Map of Oregon and Washington represent ground motion as measured by GPS at each particular location. The grey circles are 2 sigma error ellipses (click to enlarge.) (photos courtesty of CWU Geodesy Lab.)

The PANGA team constructs a bedrock drill-brace geodetic monument at Howard Hanson Dam east of Auburn, Washington. (photos courtesty of CWU Geodesy Lab.)

July 1, 2011