Surveying is both an ancient profession and one of today’s most technologically advanced. Surveyors are among the first on the site of a new construction project, staking out its corners and boundaries, and mapping elevation contours, as well as among the last, surveying the project “as built.” This is particularly important for features that will no longer be visible once the project is complete, such as underground utilities.
While many surveyors work in quiet, uncrowded environments — such as surveying the boundaries of farm fields — those who work on large construction projects operate among the hustle and bustle of bricklayers, carpenters, electricians, plumbers and other tradespeople, as well as cranes, backhoes and other heavy machines. This chaotic environment means that in addition to accuracy and efficiency, surveyors also are concerned with safety.
In the following cover story, a Minnesota-based construction company describes a new system it developed for surveying and mapping underground utilities. Also, professional surveyor Gavin Schrock discusses the benefits of a flexible approach to GNSS rover accuracy and of adding scanning capabilities to robotic total stations.
GMV is using high-resolution optical imagery as a part of emergency management efforts, to map the population and infrastructure of several cities in Turkiye after the 7.8 magnitude earthquake. The imagery of the aftermath is thanks to Europe’s Copernicus program, which keeps satellites and Earth observation services operational to support management and decision-making in different areas, particularly in the field of emergency management.
The satellite images show the challenge faced by rescue teams and reveal the massive amounts of destruction caused in cities across Turkiye and northern Syria. (Image: GMV)
GMV is one of the suppliers of Copernicus program infrastructure. GMV monitors the database architecture and ensures its integrity, analyzes the data required by the service chains, and identifies the most suitable technologies to keep the entire program operational.
GMV is working with the EU Civil Protection Mechanism’s Emergency Response Coordination Center to keep them updated on the ongoing emergency situation.
For more on the emergency satellite mapping, visit the Copernicus website.
Maxar Technologies shared via Twitter satellite imagery from the aftermath of the train derailment and explosion in East Palestine, Ohio. The train derailed on Feb. 3 and was carrying toxic materials.
The satellite images show the ongoing cleanup efforts following the derailment. The wrecked train can be clearly seen as well as blue storage containers being used to collect hazardous materials.
Hundreds of East Palestine residents had to evacuate their homes after a Norfolk Southern Railroad train carrying vinyl chloride derailed and exploded, emitting deadly fumes into the air and toxic material into the Ohio River.
A Feb. 8 press release from Ohio Governor Mike Dewine stated that it was safe for residents to safely return to their homes. “There will be ongoing air monitoring in the area, but for those who would like air quality readings to be conducted within their homes, Norfolk Southern Railroad has hired an independent contractor to work with local law enforcement, the U.S. EPA, and state officials to take air quality samples and provide results at no charge to residents,” it said.
New #satellite imagery from today, February 15, 2023, showing the aftermath of the recent freight train #derailment that occurred on February 3 in #EastPalestine, #Ohio. Imagery reveals an extensive cleanup operations in progress, and blue material storage containers nearby. pic.twitter.com/B1xvhM0ETJ
A unique workflow enabled by scanning robotic total stations is the simultaneous operation, with the same data controller and software, of a GNSS rover while scanning and imaging are being performed. Pictured: a Trimble SX12 and R12i GNSS. (Image: Gavin Schrock)
Scanning capabilities, in one form or another, have been added to models of robotic total station (RTS) since 2007 — for instance, on the Trimble VX. Such capabilities were limited to a pattern of individual shots, as the RTS would “nod.” While not designed to compete with traditional scanners, even such painfully slow “pseudo-scanning” capabilities demonstrate the value of new options for capturing detailed features.
It was not long before nearly all RTS offered limited (nodding scanning) capabilities, though at rates as slow as 15 shots per second. By 2013, the release of the Leica MS50 took the nodding scan to the next level, with a rate of up to 1,000 points per second, and then up to 30,000 in the subsequent MS60 model (which now also supports a tilting prism pole).
The end of 2016 saw the release of Trimble’s SX10 (and SX12 more recently). This routed the laser through a pair of rotating prisms to capture a swath of points as it nodded. In 2019, Topcon took the approach of adding a piggy-backed compact conventional scanner to the top of an RTS: the GTL-1000 and GTL-1200 models.
All these implementations were built upon high-quality RTS. Foremost, they can be operated as an RTS, with all the same integrated surveying capabilities as instruments with which surveyors were familiar, and in the same field software.
This includes all the integrated GNSS workflows: resections, combining optical and GNSS captured points in the same survey, and adding a rover to the prism pole for track-on-GNSS methods. One huge advantage of scanning total stations is instant deliverables already fully registered, as adopters of these new systems quickly realized.
Some initial users seemed skeptical of the relatively slow scan rates of these various models: 12 to 30 minutes for full-dome scans, and then a photo capture pass. Others, though, discovered that the time did not necessarily need to go to waste.
First, it is not necessary to do a full-dome scan and image pass every time; it is sufficient to pre-select specific areas to scan and image.
The real kicker is that while the RTS is scanning, it is possible to fire up the GNSS rover and capture points that the RTS cannot see, such as behind curbs, cars and vegetation. This is true especially now, with the advent of no-compensation tilt capabilities on nearly every new GNSS rover system.
This can be done in the same project, using the same software and field controller. This struck this writer as one of the coolest lateral features of scanning total stations when he first tried out an SX10 in 2017.
Considering the benefits scanning total stations deliver (especially with the integrated GNSS bonus), what has the reception been like among surveyors and other segments of the architecture, engineering and construction (AEC) community?
“As an industry, we’re getting better at tying solutions and workflow elements together, and not seeing them, or treating them, as individual functions or pieces of hardware,” said Derek Shanks, director of Geospatial Optical Product Management for Trimble. “We bring the system aspect, a case of using the best tool, using the strengths of each tool to their fullest.”
Accoring to multiple manufacturers, sales numbers indicate that the adoption of scanning total stations for AEC applications — and not just surveying — has exceeded expectations.
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)
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.
The danger of hitting a buried water or gas pipe when digging for a construction project persists despite many efforts to reduce it, such as “call before you dig” phone numbers. For example, in Minnesota there were 4,000 such hits in 2019. That is one reason why it is very important to map “as built” underground utilities accurately. This must be done quickly and efficiently, before trenches are filled and without slowing progress of the project.
Traditionally, crews have mapped the underground pipes and cables on paper. In turn, when a construction project needs to know the location of underground utilities before digging, it typically relies on someone who consults those paper maps, uses an electromagnetic utility locating tool, and marks the ground with spray paint. The construction crew then must correctly interpret those marks on the ground. In 2019, Minnesota-based utility consultancy Ellingson Companies was asked to develop a new and more efficient process.
Capturing Data in Real Time
By leveraging solutions from Esri and from Canadian hardware and software manufacturer Eos Positioning Systems, Ellingson Companies GIS Manager Damon Nelton developed a solution that allows his team to capture new pipe construction in real time. By streamlining documentation workflows, the new process improved field productivity and allowed Ellingson Companies to produce digital as-builts that meet the needs of its gas utility clients and improve the safety of future construction projects.
While construction crews have been putting pipe in the ground for generations, today they are expected to produce a digital record of their work in real time — for the sake of safety and efficiency.
Using Esri’s Utility Pipeline Data Model, Nelton created a system that enables crews to map their as-built pipe projects while also tracking components. The system improves data integrity — in other words, reduces human error — by relying on scannable 16-digit alphanumeric bar codes developed by the American Society for Testing and Materials that provide seven attributes for each conduit, including thickness, diameter, lot number and manufacturer date. To collect and store these data, Nelton set up an ArcGIS Enterprise geodatabase.
Gas meters, which also need to be mapped, are often in locations that are hard to map directly with a GNSS receiver because line-of-sight to the satellites is obstructed by trees, roof eves, or adjacent buildings. Therefore, they must be shot with an offset. For these situations, Nelton used Eos Positioning Systems’ laser mapping solution, which enables surveyors to use lasers attached to their range poles to feed data directly into their GIS.
No More Battleship
Using Eos Positioning System’s Arrow Gold receiver and the MNCoors RTK network, Nelton said, his team was able to average an accuracy of 0.25 throughout a project in the city of Owatonna, Minnesota, as confirmed by spot checks with other survey equipment and with the city’s survey team.
“Not every shot was easy, and some took multiple attempts and tricks of the trade to get them,” Nelton pointed out.
On projects in the middle of mountains, where real-time kinematic (RTK) networks do not exist, the company has used the Atlas Service, averaging accuracies of 12 in.
“Given the circumstances of these projects,” Nelton said, “we still consider that to be great.”
Using the new system, foremen use a survey in ArcGIS Survey123 to input their inspection notes and other information, feeding it all from the field to the office and into layers shared between divisions. This way, the data are available in real time, not at the end of the project.
For customers who still want a piece of paper to file in a physical folder in a filing cabinet, Nelton creates a Microsoft Word document template in their format, populates it using dynamic text with syntax in ArcGIS Pro, inserts a map, then saves the Word document as a PDF.
“At the end of the project, we got almost 17,000 digits with no human entry other than pressing the button on the barcode scanner, which means zero data errors,” said Nelton.
No pieces of paper with critical data on the underground utilities languish in a glove compartment or are eaten by a surveyor’s dog, and all the data is available in real time.
Additionally, the combination of the barcode scanning workflow and the high accuracy GNSS receiver enables Nelton’s team to locate gas asset pieces that need to be replaced — for example, due to a recall by the manufacturer — “without playing battleship,” he said.
Quectel Wireless Solutions’ LC76G GNSS module has been named a Product of the Year byElectronic Products.The annual awardsrecognizeproducts that represent a significant advancement in technology or its application, an exceptionally innovative design, a substantial achievement in price/performance, improvements in design performance, and a potential for new product designs/opportunities.
Image: Quectel
The LC76G module is a compact, single-band, ultra-low power GNSS module thatfeaturesfast and accurate location performance. The module can concurrently receive and process signals from all satellite constellations including GPS, GLONASS, BeiDou, Galileo and QZSS.
Image: Quectel
The LC76G has an internal surface acoustic wave (SAW) filter and integrated low-noise amplifier (LNA), which can be connected directly to a passive patch antenna and provides filtering against unwanted interference. With a compact size of 10.1 mm × 9.7 mm × 2.4 mm, the footprint of the LC76G is compatible with other industry solutions, as well as Quectel’s legacy L76 and L76-LB modules.
The LC67G is designed for battery-operated, ultra-low power GNSS devices, such as wearable personal trackers, wildlife and livestock tracking, toll tags, portable container trackers, as well as several traditional markets such as shared mobility and low-cost asset trackers.
DroneShield and Pierce Aerospace have partnered to integrate Pierce Aerospace’s Flight Portal ID remote ID technologies into DroneShield’s counter-unmanned aerial system (C-UAS) and command and control systems (C2), which includes DroneSentry-C2. The integration will provide enhanced situational awareness to end users.
The inclusion of Flight Portal ID’s remote ID data feeds into DroneShield’s DroneSentry-C2 system enables end users to correlate and positively identify UAS. This enhances security operations and provides a holistic air picture with target discrimination.
Flight Portal ID remote ID technology consists of remote ID receivers, broadcast modules, software, integration capabilities and remote administration services. It has an integration service record with several commercial unmanned traffic management (UTM), detect and avoid, Department of Defense C2 and C-UAS systems.
“The integration of Flight Portal ID and DroneSentry-C2 provides users with the comprehensive picture needed to deconflict their airspace, maintain safe flight operations for both crewed and uncrewed aircrafts, while also having the real-time intelligence and means necessary to protect that airspace,” said Matt McCrann, CEO of DroneShield.
The combined technology has a wide range of end user applications, as UTM C-UAS solutions continue to merge for several user segments, across civilian government, military and private use cases.
The joint capabilities will be available to customers in 2023.
The European Union Space Programme Agency (EUSPA) has signed a framework contract entrusting France’s space agency with providing Galileo search-and-rescue (SAR) services. The 137 million euro 10-year contract includes maintaining assets in operational condition, coordinating with the host sites and interfacing with the Cospas-Sarsat community.
Image: EUSPA
The National Centre for Space Studies (CNES) has been responsible for operations of SAR-Galileo services for the European Union since 2016, providing the SAR-Galileo Forward Link Service and the Return Link Service. The coordination of operations and maintenance of the ground segment, deployed across Europe, is headquartered at the space center in Toulouse, France.
A network of reference beacons enables evaluation of the performance of the systems in real-time. CNES also provides its expertise to EUSPA for the definition of international standards, performance monitoring and future developments.
Emergency position-indicating radio beacon-based services is an addition to the framework contract. CNES has already been identified as the future operator of the Emergency Warning Service, an alert service for European communities scheduled to begin operations in 2024.
GeoCue has released the TrueView 535 imaging system for UAVs, and the TrueView 720, its fourth-generation Riegl integration. It also launched its LP360 software add-on called 3D Accuracy and the Accuracy Star hardware.
TrueView 535 is built on TrueView 515’s technology and consists of updated lidar sensors, adding a third return, increasing mapping abilities below canopy. An additional third nadir camera offers another point-of-view and improves photogrammetry quality. It also includes a longer, usable lidar range to increase flexibility.
TrueView 535. (Image: GeoCue)
TrueView 720 is a fourth-generation Riegl VUX-120 with three laser beam orientations. It provides high point-density corridor mapping. Using the Riegl VUX-120 with three laser beam orientations (nadir, +10-degrees forward and –10-degrees backward) and three oblique/nadir cameras enables data collection from more surfaces in one flight path.
Trueview 720. (Image: GeoCue)
One application of TrueView 720 is scanning power lines. Users can capture the poles vertically, front and back. The extreme range of this system means it can be integrated with UAVs, airplanes or helicopters.
In addition to the two sensor payloads, GeoCue has launched its LP360 software add-on for processing and visualization — the 3D Accuracy and the Accuracy Star hardware.
Accuracy Star. (Image: GeoCue)
“When used together, Accuracy Star and the 3D Accuracy add-on provide automated horizontal and vertical checks,” said Darrick Wagg, vice president of customer success for GeoCue. “You can automatically find a 3D target on a drone dataset. The software will calculate the correction for any 3D target and provide a seamless workflow to apply the correction on the point cloud.”
These products are suitable for geospatial professionals.
Trimble has released Trimble 4D Control (T4D) version 6.4 software and an add-on monitoring module for automated and semi-automated rail monitoring. The T4D Rail module enables simple data collection and reduces office work required to automate movement detection for rail monitoring projects.
The T4D software offers four main elements for automated monitoring: sensor management and data integration for GNSS, total station, geotechnical, vibration and environmental sensors; geodetic processing and adjustments for accurate results; analysis and visualization through several tools that provide real-time updates to support in-depth analysis and data presentation; and alarming and reporting.
The T4D Rail module enables integration of rail as-builts collected with the Trimble GEDO system or with a track measuring bar paired with the Trimble Access Gauge Survey app. It can also automate calculations for track geometry parameters, generate analysis charts, and trigger alarms.
The T4D software is offered in five editions to fit various project requirements. The editions include T4D Access, T4D Field, T4D Intermediate, T4D Geotechnical and T4D Advanced. T4D Access and T4D Advanced are the two editions that support the add-on Rail Module.
GEODNET has released a real-time kinematic (RTK), centimeter-precision, GNSS corrections service designed for OEMs and system integrators of agricultural robotics. GEODNET is compatible with several GNSS receivers from major brands, on-vehicle automated steering, spraying kits, and most UAVs and robots.
The GEODNET corrections service has more than 1,700 total full-constellation reference stations worldwide and supports GPS, Galileo, GLONASS and BDS signals. It also has the RTCM 3.2 data format for maximum rover/receiver compatibility and NTRIP sign-on and access.
Additional local reference stations can be added.
Free GEODNET correction service trials are available now for qualified OEMs and system integrators in most agricultural regions globally. Interested parties can apply for a trial stream here.
