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Hexagon’s Autonomy & Positioning division and Munhwa Broadcasting Corporation (MBC) have partnered to bring precise positioning to South Korea through the TerraStar-X Enterprise Correction Service. The hardware-agnostic correction service provides instant convergence and lane-level accuracy in automotive, mobile and autonomous applications.

As a leader in real-time kinematic (RTK) positioning across South Korea, MBC’s atmospheric data enhances the redundancy of Hexagon’s fast converging and reliable precise point positioning (PPP) network across the country. Through this collaboration, the TerraStar-X Enterprise service is now supported in testbeds across South Korea, China, Japan, Europe, and North America to accelerate development for advanced driver assistance systems, safety-critical applications, micromobility, industrial and smartphone applications.

“With TerraStar-X Enterprise Correction Services now available across autonomous and consumer market applications, developers can design once and then deploy that design at scale worldwide,” said Paul Verlaine Gakne, positioning services product manager at Hexagon’s Autonomy & Positioning division. “TerraStar-X Enterprise is designed to be as flexible as possible for large-scale testing and deployment.”

Topcon Positioning Systems is joining Septentrio’s Agnostic Corrections Partner Program. This program was launched earlier this year to facilitate the use of Septentrio receivers with various high-accuracy services, offering integrators the flexibility to choose the most suitable correction service for their specific application.

Topcon’s Topnet Live is a real-time GNSS corrections service that delivers high-quality centimeter-level real-time kinematic (RTK) corrections data with a broad worldwide network coverage and a variety of subscription options.

“This collaboration with Topcon enables us to bring more high-quality corrections options to our customers,” Gustavo Lopez, senior market access manager at Septentrio said. “Septentrio’s robust GNSS receivers combined with Topcon’s reputable infrastructure creates a powerful synergy that offers high precision and reliability to industrial sectors, including construction and mining, while also catering to emerging applications such as robotics and automation.”

ComNav Technology has collaborated with FUNDCORSRD, a non-profit institution, to establish a comprehensive network of continuous reference stations (CORS) across the Dominican Republic for conducting topographic surveys.

As a result of this collaborative effort, there are now 32 CORS stations spread throughout the Dominican Republic that are fully implemented with the SinoGNSS CORS solution from ComNav.

ComNav Technology’s choice of equipment for this project included the M300 Pro GNSS receivers and AT600 choke ring antennas for the CORS reference stations.

The M300 Pro features robust satellite tracking capabilities, supporting multiple satellite constellations such as GPS, GLONASS, BeiDou, Galileo, SBAS, L-band, and QZSS. It also comes equipped with a built-in web server, interfaces for external devices, a user-friendly front panel display, optical fiber interface, and a secure TF-card with password protection.

The AT600 high-performance choke ring antenna features high gain, accuracy, and reliability, along with full-constellation compatibility.

SBG Systems will release the newest version of its Qintertia technology, Qinertia 4, on November 7, 2023. This version introduces several innovative features that provide users with a complete solution for precise trajectory and motion analysis.

Qinertia is a post-processing software delivering better precision and reliability compared to RTK systems. Qinertia 4 has an enhanced Geodesy engine to boasts an extensive selection of preconfigured coordinate reference systems (CRS) and transformations, making it a versatile solution in applications that use diverse geodetic data, including land surveying, hydrography, airborne surveys, construction and more.

To tackle the challenges of variable ionospheric activity, the new technology uses Ionoshield PPK mode. This feature compensates for ionospheric conditions and baseline distances, allowing users to perform post-processing kinematics (PPK) even for long baselines or harsh ionospheric conditions.

Another addition to Qinertia 4 is extended continuously operating reference stations (CORS) network support. This feature offers users a vast network of 5000 SmartNet for reliable GNSS data processing.

Qinertia has more than 10,000 bases in 164 countries. This global coverage ensures that Qinertia remains a reliable and efficient solution, regardless of geographic location. In addition, users can import their own base station data and verify its position integrity with precise point positioning (PPP).

For data that cannot be processed using PPK, Qinertia 4 offers an alternative solution with its new tightly coupled PPP algorithm. This new processing mode, available for all users with active Qinertia maintenance, provides post-processing anywhere in the world without a base station, with a horizontal accuracy of 4cm and a vertical accuracy of 8cm.

Qinertia’s new functionalities will be demonstrated live at Intergeo 2023 in Berlin.

Clocks are at the heart of GPS. Advances in space-qualified atomic clocks that kept time to within 10 nanoseconds over a day were a key development that made GPS possible. It turns out that GPS must account for both special relativity and general relativity to deliver position at 1-meter level and time at 100-nanosecond level to its users. We’ll use these round numbers as user expectations from GPS.

In the simple engineering analysis below, we consider the problems that would have arisen if the engineers had ignored relativity in their design of GPS. The issues related to positioning and time transfer are distinct, so we treat them separately.

GPS is basically a bunch of synchronized, near-perfect clocks in orbit

It’s a mantra worth repeating: To measure ranges to GPS satellites with meter-level accuracy, the clocks on the satellites must keep time with nanosecond-level accuracy.

The clocks aboard GPS satellites are extraordinarily stable, typically to one part in 1013 over a day, which is another way saying that they could gain or lose on average 10-8 seconds, or 10 nanoseconds, over 105 seconds, which is roughly the length of a day. It’s a simple calculation. Suppose you measure a time interval of length with an oscillator advertised to have frequency f  by counting its periods of oscillation. If the actual frequency is (f + Δf ), you’d measure the time interval as (T + Δt). It is easily shown that:

The fractional frequency stability (f / Δf ) is a key parameter. For an oscillator with stability (f / Δf ) of 10^-13  over a day, as noted above, we can limit to 10 nanoseconds on average with data uploads to satellites once a day to re-sync the clocks. An error of 10 nano-seconds in time amounts to an error of about 3 meters in range computation and, speaking roughly, an error of about 3 meters in the position computed by the receiver. We can live with that.

Gravitational and motional effects on GPS clocks

Our previous calculation of the timekeeping error of a satellite clock would have been fine had we not overlooked an important fact: We pretended as though the clocks were at rest on Earth at mean sea level. So, let’s see what relativity has to say about clocks in 20,000-kilometer-high circular orbits around Earth. The satellite orbits are not perfectly circular, or identical, but for now let’s pretend that they are. We call that modeling. The clocks would move at a rate of about 4 kilometers per second and exist in an environment where Earth’s gravity is only about one-fourth that at sea level.

According to the theory of special relativity, a moving clock ticks more slowly when compared with one that’s stationary at sea level. A clock aboard a GPS satellite will lose about 7 microseconds per day. That is three orders of magnitude larger than our budget for satellite clock error discussed earlier, therefore we can’t simply ignore it.

According to the theory of general relativity, on the other hand, a clock in a weaker gravitational field will tick faster than one that’s stationary at sea level. Apparently, gravity weighs down time, too. A clock aboard a GPS satellite in a medium Earth orbit will gain about 45 microseconds per day over a clock that’s at sea level on the earth.

The net effect: A GPS satellite clock will gain about 38 microseconds per day over a clock at rest at mean sea level. This effect is secular, meaning the time offset will grow from day to day.

So, you ask: Can you show me how you came up with these numbers, 7 micro-seconds and 45 microseconds? No, but I can point you to the references listed below and I can come close using simple mathematical models: (i) Earth’s gravitational potential is complicated and to simplify things we model Earth as homogeneous in composition and spherical in shape with a radius (rE) of 6,400 kilometers; (ii) aGPS satellite orbit is a circle with radius 4 rE; and (iii) the satellites move at the rate of 4 kilometers/second. We saved ourselves a lot of trouble by agreeing on this simple model.

The calculation of the fractional frequency stability (f / Δf ) due to the relativistic effects is now easy and given in the sidebar. The answers are only approximate, but surprisingly close to the numbers cited above. That’s the beauty of good models. To calculate time gained or lost over a day, multiply by the length of a day in seconds.

As an interesting aside, note that the effects predicted by special relativity and general relativity cancel each other for clocks located at sea level anywhere on Earth. Consider two clocks, one located at the North or South Pole, and the other at the equator. The clock at the equator would tick slower because of its relative speed due to Earth’s spin, but faster because of its greater distance from Earth’s center of mass (about 22 kilometers) due to Earth’s flattening. Because Earth’s spin rate determines its shape, the two effects are not independent, and it’s no coincidence that they cancel exactly.

What if GPS forgot about relativity?

What would have happened if the engineers responsible for designing GPS had disregarded relativity? If the GPS satellites were in fact in identical, circular or-bits, their clocks would have shown a puzzling, but identical, behavior of gaining time over clocks of the Control Segment on Earth at a steady rate, about 38 microseconds over a day, the combined effect of special and general relativity.

What would that do to range measurements? A GPS receiver would have meas-ured the ranges to all satellites in view as too short by a common amount (up to about 11 kilometers between daily uploads of clock corrections). However, GPS receivers don’t measure ranges. To measure ranges, the receiver clock would have to be synchronized with the satellite clocks, an onerous requirement. The receivers use inexpensive clocks that drift and have frequency stability no bet-ter than . The receivers measure pseudoranges, i.e., ranges with a common bias on account of the receiver clock offset relative to GPS Time. This bias is es-timated by the receiver, along with its three-dimensional position. The price of an inexpensive receiver clock is that we now have four parameters to estimate and need pseudorange measurements from four satellites.

So, what would that do to positioning? The answer is that the common bias introduced by the relativistic effects would get lumped with the typically much larger bias introduced by the offset in the receiver clock. The position estimate would be unaffected.

Now, what about time from GPS? A GPS receiver used for timing is typically stationary with its antenna location carefully surveyed. In principle, a single pseu-dorange measurement can sync it to GPS Time (and UTC). So, if the relativistic effects had been ignored, the timing accuracy would have suffered to the ex-tent of 38 microseconds per day between updates of the clock parameters. That’s a deal-breaker, considering that we expect 100-nanosecond accuracy.

The relativistic effects discussed so far can be compensated for easily by setting the frequency of the satellite clocks lower (by 0.0045674 hertz) in what’s called “factory offset”: The frequency of a satellite clock is set to 10.22999999543 megahertz so that it will tick in orbit at the same rate as a 10.23-megahertz atomic standard at sea level on Earth. What an ingenious solution!

This factory offset would have accounted for the relativistic effects completely if the GPS satellite orbits were perfectly circular and identical. They are not. You can’t control an orbit perfectly.

So, what about eccentric orbits?

Yes, that’s a complication.

Each orbit is distinct and slightly elliptical. A consequence of this is that the sat-ellite speed is not constant (due to Kepler’s second law): the farther away a sat-ellite gets from Earth in its elliptical orbit, the slower it moves; and the farther away the satellite, the lower is the gravity field. That means the clocks in differ-ent satellites are speeding up and slowing down at different times and at differ-ent rates. The effect for each clock is periodic and quasi-sinusoidal. Averaging the effect over an orbit, we get zero.

For a satellite in an orbit with an eccentricity of 0.02, the net effect is that a clock can be ahead or behind by as much as 45 nanoseconds. The corresponding range error would amount to ± 15 meters. This effect must be accounted for specifically for each orbit. It would require serious bookkeeping on where the satellite has been in its elliptical orbit since the last data upload to sync its clock. It’s a messy business but can be simplified. We’d leave it at that. See ICD-GPS-200C, Section 20.3.3.3.3.1, if you want to see how it is implemented in your GPS receiver.

There is more to relativity than the special theory and general theory. There is the Sagnac effect associated with our rotating reference frames attached to Earth, in which we’d like to determine a position. The principle of constancy of the speed of light cannot be applied in a rotating reference frame, where the paths of the radio rays are not straight lines, but spirals. (Receivers at rest on Earth are moving quite rapidly: 465 meters per second at the equator.) There is also the Shapiro delay associated with the slowing of electromagnetic waves as they near Earth, which amounts to a fraction of a nanosecond. See the refer-ences for more on these topics.

Final thought: Could Einstein have imagined one hundred years ago that a bil-lion people would unknowingly account for the effects of his esoteric theory in their everyday activities?

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Refrences 

1. Ashby (1993), “Relativity and GPS,” Innovation column in GPS World
2. Ashby (2003), Relativity in the Global Positioning System. Living Reviews in Relativity https://link.springer.com/article/10.12942/lrr-2003-1
3. https://www.gps.gov/technical/icwg/ICD-GPS-200C.pdf

INTERGEO 2023 will take place Oct. 10-12, in Berlin, Germany, and GPS World staff will be in attendance. The main topics of the annual conference include Earth observation, maritime solutions, unmanned systems and building information modeling (BIM).

The three-day event will also cover the topics of GIS and artificial intelligence, metaverse and cloud applications, Earth observation and environmental monitoring, smart city, infrastructure BIM, digital twins, satellite services COPERNICUS and Galileo, 4D geodata, 3D cadastre, smart mapping applications, Geobasis 2030 and 3D point clouds illuminated.

In addition to international keynote speakers, the conference will focus on expert exchange and live experiences with panel discussions and networking events.

While GPS World will not have a booth, attendees can catch Matteo Luccio, the magazine’s editor-in-chief, on the show floor.

The INTERGEO conference program can be found here.

Virtual Surveyor has added drone photogrammetry capabilities to its Virtual Surveyor smart UAV surveying software. The new Terrain Creator app photogrammetrically processes UAV images to generate survey-grade terrains which then transfer into the traditional Virtual Surveyor workspace.

The Virtual Surveyor software is now two desk apps in one subscription package, creating a seamless end-to-end UAV survey workflow, said Tom Op‘t Eyndt, Virtual Surveyor’s CEO.

Terrain Creator aims to simplify the aerial photogrammetry process by offering a visual and intuitive application to produce an orthomosaic and digital surface model (DSM) from drone photos, the company said.

Virtual Surveyor software was originally developed to bridge the gap between UAV photogrammetric processing applications and engineering design packages.

Prior to this new release, users had to rely on third-party software to generate elevation models and an orthomosaic on which they could work with the Virtual Surveyor toolset. Now, users can derive the 3D topographic information necessary for construction, surface mining and excavation projects in one package.

Once the survey-grade terrains flow from the Terrain Creator into the Virtual Surveyor desktop app, users can access an interactive virtual environment and robust toolsets to generate CAD models, create cut-and-fill maps and calculations, or calculate volume reports.

Users currently subscribed to Virtual Surveyor Ridge and Peak editions will see their software updated automatically with Terrain Creator. A flexible licensing setup will allow two users within a subscribing organization to use the Terrain Creator and Virtual Surveyor applications simultaneously from different computers.

About the Author: Matteo Luccio

Matteo Luccio, GPS World’s Editor-in-Chief, possesses more than 20 years of experience as a writer and editor for GNSS and geospatial technology magazines. He began his career in the industry in 2000, serving as managing editor of GPS World and Galileo’s World, then as editor of Earth Observation Magazine and GIS Monitor. His technical articles have been published in more than 20 professional magazines, including Professional Surveyor Magazine, Apogeo Spatial and xyHt. Luccio holds a master’s degree in political science from MIT. He can be reached at mluccio@northcoastmedia.net or 541-543-0525.

The phrase “positioning, navigation, and timing” (PNT) — widely used in our industry, including on this magazine’s cover — encapsulates a wide range of applications for global navigation satellite systems (GNSS) and for other technologies that provide some or all the same services. Subsumed under “positioning” is one of the most widespread uses of GNSS, which is data collection to make maps, enable geographic information systems (GIS), and populate the databases that power the many location-based services (LBS) applications on smartphones.
Increasingly, GNSS positioning is also integrated with systems for indoor positioning to enable seamless tracking of people, equipment and products, and with a variety of sensors to monitor their status and environmental conditions.

GNSS positioning and mapping will benefit from the advent of G5 cellular networks, which will vastly increase download speeds, decrease latencies and expand connectivity. While it will transform every industry, 5G’s impact will be especially felt in urban settings and pave the way for tomorrow’s smart cities.

In this month’s cover story, we focus on these aspects of GNSS by presenting three brief case studies:

• Industrial automation, using u-blox receivers.
• Golf course irrigation planning and construction, using Trimble Catalyst.
•  Land surveys to update China’s national GIS, using a CHC Navigation LT700 receiver.

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Safety with industrial automation

Industrial automation is an extremely wide area,” said Ludger Boeggering, u-blox senior principal segment manager, EMEA Energy & Automation. “It includes process and production automation, where it is used to automate the production environment. In more remote conditions, where it is less time-critical, it is used to understand what happens in the automation environment. Lastly, it is used to remotely supervise and monitor what is happening in such an environment.”

Nowadays, businesses want to monitor their production environment “all the way down to the production of a single device,” Boeggering said. “That’s the area in which we operate.”

One application of industrial automation on which u-blox is increasingly focusing is the safe, connected worker, which can refer to someone inside a building on a factory floor or someone outside, such as on a construction site. Another one is mobile robotics and collaborative robotics.
“Our customers are in all segments and verticals — including electronics, machine manufacturing, oil and gas, transportation, chemical, food, water, paper and energy,” Boeggering said. “It’s really a broad spectrum of industrial companies that are using these tools and products. We are focused on the leading customers in that area and are working with well-known players in the market.”

5G is an umbrella for different flavors of the technology that includes enhanced mobile broadband and ultra-low latency. “There has been much hype about this,” Boeggering said. “In the beginning, everyone focused on low latency and, potentially, high bandwidth. In reality however, customers realized that it would be too expensive to implement it so as to have both.” This led to the emergence of 5G RedCap, which stands for reduced capability. “It covers a bit of the low latency stuff and a bit of the higher bandwidth stuff, but also makes it more cost effective.”

For many applications, such as video and augmented reality, latency is less important than speed. Then there’s the question of reliability. “Nowadays, reliability and availability are the most important issues,” Boeggering said. “If you have an automation process with very high motion, you definitely need high reliability and low latency.”

Factories can now set up their own environment and combine communication technologies, using low latency and many sensors. “For example, on the campus of a chemical factory you have some critical processes that require reliable connectivity,” Boeggering explained. “There, 5G can provide that. At the same time, there are hundreds of thousands of sensors to be connected. This requires a private network environment that can be controlled.”

“The reason for going wireless is less about being mobile and more about being flexible — such as setting up or re-arranging a production line in a very short time,” Boeggering said. “It normally takes a car manufacturer nine to 12 months to set up a production line for a car. It requires a lot of cables and installations. These guys aim to bring that time down to three months. That means that when they are starting to rebuild a construction area, in the best case, they can make the connectivity for all the communications entirely wireless and just plug the machines into the power.”

Construction sites require a solution that provides a seamless indoor-outdoor location. For example, a construction company may want to know the location of all its tools on a large campus. When they are outside, they can be easily located with GNSS. More often, however, they are inside concrete walls. “Nowadays, we don’t really have a solution that covers that indoor-outdoor area seamlessly,” Boeggering said. “On a construction site, you can’t set up an infrastructure to do that. So, you need one that is already available. There 5G might be able to help.”

u-blox can provide solutions that fit across the communication technologies. “5G is not the only technology that will be used in industrial automation environments,” Boeggering pointed out. “We have the portfolio, starting with GNSS when it comes to location, and, when it comes to short range, wireless, Bluetooth, Wi-Fi, and of course, cellular. We are providing to these OEMs the right components to create the final solution, including positioning and communication services.”

“The customers, who want to know where their equipment is, do not care whether that information is derived using GNSS, Bluetooth, or Wi-Fi,” Boeggering said. “They just want to know in which room it is, on which level, or in which area of their factory. Of course, customers certainly would like centimeter precision. However, the question is whether they want to pay for it. GNSS plays a huge role for location outside and close to windows. However, once you can’t get this data, you need an alternative solution. This can be done in combination with any wireless technology. There are use cases in which Bluetooth might work independently from GNSS, but when it comes to Wi-Fi or cellular 5G, GNSS is definitely helping to get the location. So, we always play a role.”

Irrigating the green

“We’ve always used GPS equipment to map out our clients’ properties across the country,” said Michael Kuhn, owner of Michael Kuhn & Associates Inc., in Birmingham, Michigan, which specializes in irrigation systems for golf courses. “Very rarely do they have an accurate base map of the property. So, instead of going to third parties, we decided 20 years ago to buy our own GPS equipment and map these properties ourselves as a starting point to do our design work for new irrigation systems,” Kuhn said.

Since starting his business, Kuhn is now on his third or fourth generation of Trimble equipment. “Convenience and time are always key factors with me,” he said. “As this equipment has evolved, it’s become more user friendly, and more convenient.”

He spends a lot of time on the road and needed a way to collect data on golf courses and get it to his staff back at the office, so that they could clean it up and get it ready for him as quickly as possible. Before Trimble released Catalyst, he had to go back to his hotel, remote into his office computer and transfer the data from his laptop through some kind of cloud-based device. “Now, with this new Catalyst equipment, it is so much more streamlined, and the price point has been fantastic,” Kuhn said. “Everything’s now going subscription-based anyway. Not just software but hardware as well. That allows me to do a few more things that I couldn’t do before.”

The golf courses around the country with which Kuhn works are constantly doing projects and updating infrastructure. “We end up being the gatekeepers for the overall mapping for our clients’ golf courses for infrastructure,” he said.

Before Trimble released Catalyst, Kuhn recalled, some of his clients spent up to $30,000 for equipment that would collect data sufficiently accurate to incorporate into his mapping.

“When Trimble came out with Catalyst and a subscription-based pricing, depending on what kind of accuracy you need, it was a no brainer. The first group that I thought of was my clients — giving them the ability to get entry-level subscriptions, but still be able to maintain centimeter-grade accuracy because they’re using an hourly subscription instead of paying thousands of dollars a year.”

Kuhn also uses aerial photogrammetry.

“Not that long ago, it was tough to get your hands on ortho-corrected aerial photography that could match up with my base maps,” he recalled. “I would typically go to municipalities. More and more of them have GIS departments now. Often, I could get access to ortho-corrected aerial photography from them, either for free or at a cost. It was accurate, but you would be at the mercy of whenever the county was doing its aerial photography,” Kuhn continued.

Then Kuhn came across Nearmap and began to use their aerial photography. “It wasn’t ortho-rectified at all, but they were flying multiple times a year,” Kuhn said. “It was nice to incorporate it into what we were doing, to make sure that I could see the latest and greatest overhead of whatever property I was looking at.” When Nearmap switched to a subscription-based business model, however, Kuhn did not sign up because the images were not georeferenced. “It’s a lot of work when you must manipulate an aerial and get it to match up to a base map. Then, probably two or three years ago, they started to geo-reference their aerial imagery and we signed up and they’ve been great.”

Right now, Kuhn’s equipment is close to centimeter-grade. “We were the first independent irrigation consulting partners to get this three-dimensional hydraulic modeling software to run our irrigation systems,” he said. “In a three-dimensional model, before we even finalized drawing, we were able to model the systems that we were designing that could tell us what pressure drops were across a 500-acre piece of property three dimensionally.” That required a topo map of the property, which he would get from the relevant county.

Pump stations for golf course irrigation systems pump 2,000 or 3,000 gallons a minute across hundreds of acres, sometimes in the mountains and typically full of steep inclines.

“It could be in Colorado or Salt Lake City or in a place flat as a pancake, but it is absolutely critical to still have the ability to run that hydraulic model and have accurate data flow horizontally and vertically,” Kuhn said. “With the data that we have now, I can run an irrigation cycle in multiple different ways and tell the end user what the pressure is in the back left corner of a green within 1/100 psi. It’s invaluable.”

Kuhn supports his clients in many ways. “Since the Trimble Catalyst equipment came out, I’ve recommended to my clients and to contractors that they switch to it. Golf course building contractors have always had good equipment, such as total stations, and this was just another tool that they could have to collect data quickly and easily.”

Additionally, Kuhn pointed out, Catalyst provides a sharing platform. “So, I could create a team for a golf course and then they could get the same equipment and create a project and we can make each other part of each other’s team. So, they have access to all the data that they collect and all the data that I collect, to the extent that I give them permission to use them. That’s critical. I mean, sharing data with contractors is another component that we really didn’t have before.”

Collecting data for GIS

CHC Navigation is assisting China’s Ministry of Natural Resources to conduct its third national land survey. The ministry regularly organizes nationwide land surveys to update the country’s national GIS database, including spatial and attribute information. In addition, surveyors are required to take multiple high-resolution images of each area in different directions to provide verification information. As the project progresses, all data will be uploaded to a server via a cellular (4G) connection. In terms of accuracy, this project requires an expected accuracy in the order of one meter.

For this project, China’s Ministry of Natural Resources used the CHCNAV LT700 rugged Android tablet. Featuring an 8-in screen viewable in direct sunshine and in high-bright areas, the LT700 is well suited to display GIS data tables, complex vector and raster maps or high-resolution pictures. Unlike consumer tablets, the L700’s IP67 industrial design withstands daily use in harsh environments and conditions. Protected from dust, rain, extreme temperatures and accidental drops from 1.2 m, the LT700 is an advanced solution for such applications as forestry, utilities, asset management or environmental studies. Bearing the Google Mobile Service (GMS) certification, the LT700 runs seamlessly the most common professional data collection applications available from the Google Play store.

The main challenges associated with using data collectors in the field are related to the natural environment and the need to ensure reliable georeferencing accuracy down to the meter. Surveyors and GIS technicians work in a variety of environments, including cities, mountains, plateaus and forests. They can work for up to eight hours in rain, snow and extreme temperatures. As a result, their equipment must be well protected from shocks and bad weather, with long battery life and a high-brightness display.

With the LT700 rugged tablet, surveyors can focus on collecting data in the field without interruptions or wasted time, and without worrying about weather conditions. The device delivers metric accuracy with SBAS support, which greatly improves the reliability of georeferencing and the consistency of collected data, regardless of the operator. Its lightweight construction and convenient size make it easy to transport on foot, especially when working in mountainous terrain or crossing rivers. The LT700’s 4G connectivity has made it possible to continuously update data and organize work sessions based on updated data.

The Radio Technical Commission for Aeronautics (RTCA) has released a six-file document titled “DO-401 Minimum Operational Performance Standards (MOPS) for Dual-Frequency Multi-Constellation Satellite-Based Augmentation System Airborne Equipment.”

The document is designed to support validation of airborne requirements when using dual-frequency GPS, Galileo and satellite-based augmentation system (SBAS) signals as defined by International Civil Aviation Organization Standards and Recommended Practices (Annex 10, Volume I, Amendment 93), as well as the development of dual-frequency multi-constellation SBAS services.

The SBAS MOPs document does not provide specifications for a production approval.

The RCTA stated that a future release of the document will provide requirements supporting production approval, typically through a new Technical Standard Order or European Technical Standard Order.

This document is available for purchase here.