Author: Tracy Cozzens

Estimating heights with subsidence changes using NGS data and tools

This column details the potential effects of crustal movement on published heights in various regions of the United States.

In my last column (in the April 2021 Survey Scene), I mentioned that the National Geodetic Survey (NGS) announced that it is suppressing height information in Southeast Texas.

The April column also highlighted one of NGS’ four use cases – “Use Case 1: Flood Mapping.” The case study discusses the Elevation Certificate (CE) Example, Flood Insurance Rate Map (FIRM) and Flood Insurance Study (FIS).

The column highlighted the potential effects of subsidence on published heights in the Houston region, which implied that most of the published heights that are based on older surveys in the region are not current or accurate.

This column will provide more details of the suppression of heights in the Southeast Texas region, and potential effects of crustal movement on published heights in other regions of the United States.

NGS announcement that it suppressed height information for Southeast Texas. (Image: NGS)

According to NGS’ announcement, only 28 marks will have publicly available orthometric heights on NGS datasheets in Southeast Texas.

The “Link to Map: SE TX Valid Ortho. Heights” button provides the benchmarks available to users (see the box titled “Link to Map SE TX Valid Ortho Heights”). The website provides links to the published stations.

Link to Map SE TX Valid Ortho Heights. (Image: NGS website)

Clicking on an icon provides the PID and name of the station with a link to a datasheet. Click “Get Datasheet” for a datasheet of the station. Below is an excerpt from the datasheet of Station P 1200.

Excerpt from Datasheet of Station P 1200.(Image: NGS Website)

Let’s address why NGS is suppressing the stations in Southeast Texas. My last column provided plots depicting the amount of movement in the Harris-Galveston, Texas, region. See the box titled “Estimate of Amount of Subsidence in 5 Years in Harris-Galveston, Texas, Region – Units Feet.”

As indicated in the plot, some of the marks are estimated to have moved almost ½ foot (approximately 0.15 meters) in 5 years. In addition, some of the relative height differences approach 1/3 of a foot (approximately 0.1 meter) between neighboring stations. See the highlighted stations in the box titled “Estimate of Amount of Subsidence in 5 Years in Harris-Galveston, Texas, Region – Units Feet.”

Estimate of Amount of Subsidence in 5 Years in the Harris-Galveston, Texas, Region – Units Feet. (Image: David Zilkoski)

The last major releveling incorporated into NGS’ Database in the Harris-Galveston, Texas, region was performed more than 30 years ago in the 1986/1987 timeframe. Therefore, some of the published stations in the region could have subsided more than three feet (or about a meter).

As stated in NGS’ Blueprint 3, “Most leveling data in NGS archives comes from the mid-20th century, in support of the NAVD 88 project.” Of course, most regions of the United States are not subsiding at the same rates as in the Houston-Galveston, Texas, region.

In a previous newsletter, I discussed NGS’ second Multi-Year CORS Solution of the National CORS (MYCS2). I downloaded the coordinates and velocities from NGS’ website and created a plot of the vertical velocities. For those who prefer to use feet as opposed to meters, I provided velocities with units in feet/year and mm/year.

See the boxes titled “Estimate of Velocity Rates Based on MYCS2 – CONUS (feet/year),” “Estimate of Velocity Rates Based on MYCS2 – Alaska (feet/year),” “Estimate of Velocity Rates Based on MYCS2 – CONUS (mm/year)” and “Estimate of Velocity Rates Based on MYCS2 – Alaska (mm/year).”

It should be noted that the intent of these four plots is to provide a wide-ranging view of the values and some of the variation in rates across the United States.

Estimate of Velocity Rates Based on MYCS2 – CONUS (feet/year). (Image: David Zilkoski)

Estimate of Velocity Rates Based on MYCS2 – CONUS (feet/year). (Image: David Zilkoski)

Estimate of Velocity Rates Based on MYCS2 – CONUS (mm/year). (Image: David Zilkoski)

Estimate of Velocity Rates Based on MYCS2 – Alaska (mm/year). (Image: David Zilkoski)

The rates appear to be small in most regions of the United States. As an example, the rates are all less than -0.0062 feet/year (-0.0019 meters/year) in the Lake Norman region in North Carolina (see the box titled “Potential Subsidence Rates in the Lake Norman Region in North Carolina). It would take many years for the crustal movement to make a difference to some projects in this region.

Potential Subsidence Rates in the Lake Norman Region in North Carolina. (Image: David Zilkoski)

That said, let’s look at another region of the country. For example, in the vicinity of Maryville, Missouri, the rate of subsidence is around -0.0187 feet/year (-0.0057 meters/year). See the box titled “Potential Subsidence Rates in the Maryville, Missouri, Region.” These subsidence rates don’t appear to be large values but if you take into account the last time the height of a mark was established by leveling data it could result in a large difference from the true orthometric height.

Potential Subsidence Rates in the Maryville, Missouri, Region. (Image: David Zilkoski)

According to NGS’ database, it appears that many of the marks in the Maryville, Missouri, region were last leveled in 1935. I used NGS’ Passive Mark Lookup tool and Leveling Project Page tool to identify the marks and associated leveling lines in the area of the CORS stations in the Maryville, Missouri, region.

I described the Passive Mark Lookup webtool in a previous column. As previously mentioned, these subsidence rates all seem very small, but if you take into account the last time the height of mark was established by leveling data, the subsidence value can be very large.

See the box titled “Potential Subsidence in 86 Years in the Maryville, Missouri, Region.” The box indicates that, if you account for the last 86 years (2021 – 1935), the potential subsidence exceeds 1½ feet (-1.6082 feet, -0.4902 meters).

Potential Subsidence in 86 Years in the Maryville, Missouri, Region. (Image: David Zilkoski)

Continuing across the country to Colorado, the box titled “Potential Subsidence Rates in the Grand Junction Region, Colorado,” provides the estimate of subsidence rates in Mesa County, Colorado. As the plot indicates, the rates vary between -0.0046 feet/year (-1.4 mm/year) and -0.0128 feet/year (-3.9 mm/year). Once again, these rates all seem relatively small but many of the marks near CORS MC06 were last leveled in 1985. This means the potential change in height could be as large as 0.2592 feet (0.0792 meters).

Potential Subsidence Rates in the Grand Junction Region, Colorado. (Image: David Zilkoski)

Obviously, this is only an estimate of the subsidence in the region and the actual amount of subsidence is unknown since the last time the mark was leveled. These estimates are based on the MYCS2, which uses current data to estimate the velocity. The processing included data spanning 1996 to 2016 (week 0834 to 1933), 1099 weeks or about 21 years in total.

The point of this column is not to provide the exact change in height of a mark, but to highlight that the publicly available orthometric height on a NGS datasheet may not be up to date based on crustal movement. The new modernized National Spatial Reference System will enable users to determine an accurate, current height on a mark and be able to efficiently and effectively monitor changes in a mark’s height.

As stated in NGS’ announcement to suppress the heights in Southeast Texas, the agency has developed tools to assist users in submitted data to NGS. See the box titled “Excerpt from NGS Announcement to Suppresses Height Information for Southeast Texas.”

This assistance is for every user, not just for individuals performing surveys in Southeast Texas. NGS has Regional Geodetic Advisors throughout the United States.

NGS Regional Geodetic Advisors. (Image: NGS Website)

The Regional Geodetic Advisors provide guidance and assistance to constituents within their region. They are subject-matter experts in geodesy and regional geodetic issues. These individuals can assist users that are planning GNSS campaigns to re-densify the network.

NGS also provides a website detailing how users can help densify the network to prepare for the new, modernized North American-Pacific Geopotential Datum of 2022 (NAPGD2022). See the box titled “NGS GPS on Bench Marks Webpage.”

As mentioned in previous newsletters, a benefit of the new modernized National Spatial Reference System (NSRS) will facilitate the establishment of consistent, accurate NAPGD2022 GNSS-derived orthometric heights.

NGS GPS on Bench Marks webpage. (Image: NGS Website)

This column provided details on the suppression of heights in the Southeast Texas region, and potential effects of crustal movement on published heights in other regions of the United States. NGS suppressed the heights in the Southeast Texas region because of the large amount of crustal movement since the last time the heights of the marks were established.

As indicated by NGS’ MYCS2 velocities, every mark could be affected by crustal movement. In my opinion, the question a user should be asking is “How much has the height of the mark changed since it was last determined? Not, “Has the height of the mark changed?”

June 2, 2021
Editorial Advisory Board PNT Q&A: GNSS diminishing returns?

As the number of GNSS constellations and satellites in orbit continues to grow,
will we reach the point of diminishing returns?

Ellen Hall

“More satellites equal more data, and redundant constellation systems — through GNSS interoperability — can give us more robust PNT, as restated in the January Memorandum on Space Policy Directive 7. That said, there are always diminishing returns. Treaties place liability on the launching country if something goes wrong, but with tens of thousands of small satellites expected to be launched over the next decade, it will be getting increasingly crowded. Concerns are growing about the necessity of increased maneuvers to keep these satellites from a chain reaction of collisions, which ultimately could cause debris to fall to inhabited areas of Earth.”
— Ellen Hall / Spirent Federal Systems

Jean-Marie Sleewaegen

“With already more than 130 GNSS satellites in orbit, the benefit of new satellites decreases while the risk of satellites interfering with each other increases. However, this is only considering GNSS as we know it, in the MEO orbit (altitude about 22,000 km). The future of GNSS may well be closer to Earth, in the LEO orbit (<1,000 km), with well-known benefits in terms of convergence time and resilience to jamming. Sooner than later, we can expect constellations of hundreds or thousands of LEO satellites carrying a GNSS-like payload supporting PNT services. No worries, there is still growth potential!”
— Jean-Marie Sleewaegen / Septentrio

Stuart Riley

“With the current four GNSS constellations and a typical survey elevation mask of 10˚in North America, we average around 30 visible satellites. Far more are visible in Asia with the addition of the regional systems. In an area with a clear view of the sky, this provides more than enough satellites for precision centimeter positioning. However, most professional GNSS users do not have the luxury of operating exclusively in open areas with ideal conditions. Accessing many satellites across multiple constellations increases the probability of receiving sufficient satellites that produce high-quality measurements in obstructed areas. As the constellations expand, we observe improvement in precision position availability in these locations. The large number of satellites, coupled with independence across the four systems, improves system integrity and continuity while also helping to reduce the converge time in PPP solutions.”
— Stuart Riley / Trimble

Bernard Gruber

“In a utopian vision of navigation, data gluttons and like-users of GNSS would say that there will never be enough! If capabilities remained static, then yes, I believe we would reach the point of diminishing returns. I would offer that innovation and competition will continue to drive capability improvements via power, signal quality, coverage, integrity and clock/timing accuracy. These innovations, coupled with user equipment flexibility utilizing signals from space, will drive an ever-maturing market balance and increasing return.”
— Bernard Gruber / Northrop Grumman

June 1, 2021
Thales Alenia Space to assess feasibility of EGNSS integrity service

Image: loveguli/E+/Getty Images

Thales Alenia Space, a joint venture between Thales (67%) and Leonardo (33%), has been selected by the European Commission for a new strategic contract to assess the feasibility of an integrity service to complement the European Global Navigation Satellite System (EGNSS) High Accuracy service, which will pave the way for use in autonomous vehicles.

Thales Alenia Space will focus on the development of a sensor-fusion approach, including and complementing evolutions of EGNSS High Accuracy. These service evolutions are aimed at providing the integrity level to serve the high-reliability and high-accuracy positioning needs of new, demanding applications such as autonomous vehicles on the road and autonomous transport in the maritime and rail sectors.

With this contract, Thales Alenia Space will assess the extension of the integrity and safety-of-life services for aviation into the road, rail and maritime sectors. In 2020, the company won the EPICURE project, based on an integrity concept for road travel (tolls and insurance), as well as the IMPRESS project, targeting an integrity service for rail signaling and train separation.

Thales Alenia Space has been a prime contractor for EGNOS (European Geostationary Navigation Overlay Service) for 25 years. It is a lead industrial contributor to the Galileo system and its ground mission segment and responsible for providing six Galileo Second Generation satellites. In April, the company was awarded a contract to support the implementation and experimentation of the navigation algorithms that will be used in the Galileo Second Generation program.

June 1, 2021
Why radar is the future of autonomous transportation
By Steven Hong, Founder and CEO, Oculii

Steven Hong, Founder and CEO, Oculii

Radar has been around since the late 19th century, but today it is poised to revolutionize how autonomous vehicles (AVs) navigate the road. From its nautical origins as a tool to detect the location of ships in heavy fog to being a cost-effective way to prevent collisions in self-driving cars, radar has a wide range of applications.

For more than 30 years, carmakers and drivers have embedded radar in vehicles to assist with automated cruise control, automatic emergency braking, parking, and more. This effective, hardy technology plays a critical role in the driver experience today, and the same hardware will be used to help AVs navigate the road soon.

I believe that the next chapter of radar use in vehicles will be in the AV market, where software powered by artificial intelligence (AI) will use radar sensors to read a vehicle’s surroundings and get riders safely to their destination.

Radar Is a Market-Proven Hardware Solution

Radar has been around for so long, and the sensors we rely on in our vehicles every day are so reliable, that most drivers are not even aware that they have radar to thank for the assist on their perfect parallel parking job.

In this era of auto innovation and smart tech, the benefits of turning to this proven hardware solution abound:
- Radar can perform well in poor weather conditions.
- It is cost-effective, especially when compared to lidar and camera-based options.
- Thanks to its low power requirements, adding radar sensors does not significantly impact a vehicle’s energy budget.
- It is market-proven hardware that is robust and reliable in the field.
While competing technologies such as lidar are still years away from demonstrating that they can stand up to weather conditions and the toll that mileage takes on equipment, there is no question that radar sensors are up for the challenges of the road.

The flip side of this coin is that we also have the benefit of knowing the limits of traditional radar technology: It has poor spatial resolution, limited sensitivity, and a narrow field of view. However, this hardware can be greatly enhanced with the right software boost.

An Oculii sensor placed at the front corner of a vehicle. (Photo: Oculii)

Unlocking the Potential of Radar with AI

Until recently, the best way to improve radar technology was to add more antennas until you got the resolution quality you were seeking. While this approach solves the problem of resolution, it introduces two other problems:
1. Adding antennas exponentially increases a radar’s complexity, power consumption and size, while only improving performance linearly.
2. In turn, this added complexity significantly increases the radar’s cost.
Consider the F-35 fighter jet, which relies on a radar system that costs more than the jet itself. While adding antennas may be a reasonable solution for military-operated airplanes, the consumer AV market would never tolerate the consequent cost increases. However, there is a way that existing automotive radars can be augmented with AI software to improve resolution, without increasing cost, size or power.

In the same way that AI software transformed what the automotive manufacturers were able to achieve with camera hardware, AI software can revolutionize how radar hardware is used for navigation in AVs.

Traditional radar sensors emit a constant, repetitive signal that delivers a reliable but low-resolution result. By using innovative AI software to emit an adaptive phase, modulated waveform that changes in real time, the resolution of traditional radar can be increased by up to 100 times. The key to transforming how we use radar hardware is all in the software.

street view of a driving car (center). At right, the same view is shown with high-resolution radar, with 400+ m of range with precise Doppler/point in all weather conditions. At left, is the view using a standard lidar camera, which has >100 m of range, no Doppler and weather limitations. (Image: Oculii)

Radar with AI

Reliable sensors with AI software can enable autonomous functions by augmenting the hardware that is already in today’s vehicles. What makes this solution so exciting is that it does not require a design overhaul: the smart sensors in question fit within existing radar packaging.

Augmenting radar hardware with AI can significantly improve performance while reducing the cost to the consumer. This formula — better performance at a lower price tag — has the potential to greatly accelerate the speed with which AVs make it safely to the consumer market and to revolutionize the automotive industry.

Rather than pushing forward with the development of costly alternatives that are prohibitively expensive for the consumer market, intelligent radar sensors can bring AVs to the road sooner and for more drivers.

Steven Hong is the founder and CEO of Oculii, a high-resolution radar company enabling the next generation of autonomous systems. Powered by AI, Oculii software increases the resolution of commodity radar hardware by up to 100 times and works in any environment.
June 1, 2021
How medium-definition maps help navigate dynamic roads

By Ethan Sorrelgreen
Chief Product Officer, Carmera

Ethan Sorrelgreen, Carmera

Since the early days of autonomous vehicles (AVs), maps — specifically, so-called “high-definition” maps — have played a critical role in their technology stack. Central to perception, localization and path planning, these highly detailed, highly precise maps provide vehicles a baseline understanding of the world around them, delivering key priors that form the basis of the AV’s navigational decision making.

These maps come with exacting standards: a 3D network graph, spatial accuracy within 10 centimeters, attribute support in the thousands, and so on. Additionally, with AV deployments becoming more frequent — covering broader, more complex driving domains — these requirements are growing ever more demanding.

Of particular import is the increased need for temporal accuracy — that is, a map’s ability to represent current conditions (as opposed to conditions at some point in time). Roads — especially urban roads — are highly dynamic environments. Things like construction, repaving, signal upgrades and, now, on-street dining constantly affect the flow of traffic.

For example, in a summer 2020 survey of New York, Carmera found 88 drive-lane-impacting events (out of a total of 251 road events) over 72 hours in midtown Manhattan alone.

A map’s failure to reflect such events and changes can have a major impact on an AV’s reliability (Will the autonomous-driving feature remain engaged?), motion-planning (Will the AV safely and smoothly navigate through/around the obstacle?) and/or path planning (Will the AV choose the most efficient route despite the obstacle?). Maintaining a map, however, is exponentially more complicated than creating it. Not only does the data need to be good, it also needs to be fast and cheap to produce.

The key to solving the fast and cheap legs of this classic “good-fast-cheap” trilemma is simplifying the initial problem, using what Carmera calls a medium-definition map. If an HD map is a map with high feature detail and high spatial accuracy, then an MD map is a map with high feature detail but a slightly lower spatial accuracy. It essentially atomizes the dense, complex HD world into discrete, manageable blocks, or “zones.”

An MD map of a California intersection showing road features — including control attributes — placed with zonal accuracy. (Image: Carmera)

These zones — each a logical section of the road network — become the new unit of fidelity. The MD map catalogs all the features in a zone — a traffic light with a left arrow that controls the left two lanes, a bike path, a solid median, etc. — but not their precise location in the real world.

This simplified map provides the ideal basis for a system of triaging change, which dramatically lowers the cost — in both time and money — of HD map updates. Indeed, it provides the foundation for Carmera’s change-as-a-service offering — a modular, on-demand feed of road events and map updates that plug into existing consumer or HD maps.

Because of its lower spatial accuracy, an MD map can be updated with consumer-grade tools — a camera and a consumer-grade GNSS, let’s say — coupled with basic consumer vision algorithms. Contrast that to an HD map, which requires either expensive equipment, like a lidar rig, or — in Carmera’s case — sophisticated algorithms that can convert visual and telemetric data into HD road graphs.

MD map maintenance, therefore, is relatively cheap, which is good news for those who want to use MD data for next-generation consumer applications, such as natural-language navigation, or to support sub-L4 levels of automated driving (both excellent MD use cases).

An MD map of the same interaction, showing road features—including control attributes—placed with zonal accuracy. (Image: Carmera)

For HD updates, an additional pass is needed. Think of this as a tip-and-cue system: When a functional change in the map is detected (the tip), data from the identified zone is reprocessed using more complex algorithms to create the new HD vectors (the cue). In some cases — either because of customer requirements or because the change is superficial — a simple MD update may be sufficient. Thus, expensive computing resources are only deployed when needed.

This approach is equally effective for those using traditional lidar-based methods. There, the MD tip allows for targeted dispatching of lidar rigs, which results in significant cost-savings vis-à-vis the typical practice of sequential resurveying.
As technology evolves, so too will the role of the MD map.

Carmera sees a world where an AV’s onboard sensors will become so sophisticated that the HD maps’ utility may diminish. MD maps, however, will still provide vehicles key rules-of-the road relationships, helping optimize route planning and similar beyond-line-of-sight decision making. Employing this new standard now, therefore, not only makes driving safer today, it paves the way for the road ahead.

Screenshot: Carmera

June 1, 2021
Geoflex cloud-based geolocation company honored with award

Geoflex, a geolocation company, won the Jury Award of SPRING 50, a competition of deep tech startups that took place on May 20 in Paris-Saclay, the largest French research cluster, located south of Paris.

Geoflex is a cloud service operator that enhances GPS/GNSS-based applications to provide 4-centimeter positioning on land, at sea and in the air.

Geoflex was initially selected among the 10 most promising companies within the 50 startups promoted at the event. All 10 startups founders were subsequently showcasing their companies in a 4 minutes pitch, and Geoflex’s CEO Romain Legros won this last leg of the competition.

Geoflex’s hyper-geolocation service has been available globally since 2018. The service, which corrects inherent GNSS inaccuracies, is provided in real time or in post processing. It works across all types of GNSS hardware receivers and includes correction data for all constellations: GPS, GLONASS, Galileo and BeiDou and for all their frequencies.

The technology was initially developed by the French space agency CNES in a 12-year research project. It is protected by seven patents licensed to Geoflex, which continues co-development of the technology with the CNES.

Geoflex also has developed a positioning engine that includes sensor fusion with other technologies such as inertial, optical and communications. A hardware development kit is available.

May 26, 2021
Launchpad: GNSS antennas and PC boards

A roundup of recent products in the GNSS and inertial positioning industry from the June 2021 issue of GPS World magazine.

OEM

Grandmaster Clock

Multi-constellation receiver

Photo: Microchip

The upgraded TimeProvider 4100 2.2 is now more redundant and resilient. It provides secure, precise timing and synchronization for critical infrastructure such as 5G wireless networks, smart grids, data centers, cable and transportation services. The 4100 2.2 introduces a software-redundancy architecture for flexible deployment, and supports a new GNSS multi-band, multi-constellation receiver to protect against time delay from space weather, solar events and other disruptions. The 4100 2.2 offers options for software and hardware support.

Microchip Technology, microchip.com

External Antennas

GNSS-ready multi-port models

Photo: Maxtena

The NETZ 5-in-1 multiple-input and multiple-output (MIMO) solution combines two LTE antennas and two Wi-Fi antennas with a GNSS antenna for high data throughput and streaming, video, industrial and internet of things (IoT) applications. It offers a low-profile design with integrated SubMiniature version A (SMA) connectors and is designed with rugged PC+ABS plastic black housing for demanding environmental challenges.

Maxtena, maxtena.com

Mini-PCLe Adapter

For industrial applications

Photo: Gateworks

The GW16143 is a high-precision GNSS/GPS Mini-PCLe adapter card that provides precise positioning to applications using Gateworks single-board computers. Based on the U-blox ZED-F9P, the GW16143’s multi-band real-time kinematic (RTK) technology enhances convergence times and performance. The module receives GPS, GLONASS, Galileo and BeiDou; supports L1 and L2/L5 bands; and provides GNSS positioning accuracy
of <2 cm.

Gateworks, gateworks.com

Inertial unit

Tactical grade for higher order integrated applications

The IMU-NAV-100. (Photo: Inertial Labs)

The IMU-NAV-100 is a fully integrated inertial solution that measures linear accelerations, angular rates, and pitch and roll with high accuracy utilizing three-axis high-grade micro-electro-mechanical systems (MEMS) accelerometers and three-axis tactical-grade MEMS gyroscopes. It features continuous built-in test, configurable communications protocols, electromagnetic interference protection, and flexible input power requirements that allow it to be easily integrated in a variety of higher order systems. The IMU-NAV-100-S offers high performance stabilization for line-of-sight systems, motion-control sensors, and platform orientation and stabilization systems. The IMU-NAV-100-A is for GPS-aided INS, AHRS and motion reference units.

Inertial Labs, inertiallabs.com

Mass Market Board

Single-board computer with up to three receivers

SimpleRTK2B-SBC. (Photo: ArduSimple)

The SimpleRTK2B single-board computer is built around up to three u-blox ZED-F9P high-precision GNSS receivers to simplify development of centimeter-level positioning solutions supporting real-time kinematics (RTK). It was developed to make RTK technology as close to plug-and-play as possible, and make the technology accessible to broader audiences. In addition to working as a stand-alone solution, customers can program their own applications with the company’s microPython API. The SimpleRTK2B-SBC delivers mechanical integration with centimeter position on three axes (heading, pitch, roll), outputting on NMEA, RTCM, RS232 and CANBus interfaces via Ethernet, Bluetooth, Wi-Fi and 2G/3G/4G communication.

Ardusimple, ardusimple.com

SURVEYING & MAPPING

Utility locator

Software with GNSS receiver enables mapping

Photo: ProStar

PointMan software is now integrated into the Vivax Metrotech vLoc3 with a GNSS real-time kinematic (RTK) receiver to create a utility-locate device. Using the RTK-Pro internal cellular module with 4G LTE capabilities, the operator can connect to the NTRIP RTK caster that provides RTCM 3 corrections. With the integration of PointMan with the vLoc3 RTK-Pro, critical buried infrastructure can be captured, recorded and displayed at survey-grade without additional external equipment or post-processing. The integration provides centimeter accuracy of the precise location of buried utilities in real time. Data collected includes the type of utility, the depth of cover and the utility’s precise location.

ProStar Holdings, prostarcorp.com

GIS platform

Geospatial and location intelligence for smart cities

Screenshot: Hexagon Geospatial

M.App Enterprise 2021 is a significant update to the platform for creating geospatial and location intelligence applications. The latest release features new browser-based 3D capabilities and enhanced visual effects, plus the ability to create and configure custom applications more easily. It allows users to access LuciadRIA’s 3D features with support for panoramic imagery, shading, ambient occlusion and other visualization effects to build browser-based solutions. It also features a new browser app configurator that makes it easier to create spatio-temporal dashboards, or Smart M.Apps. Feature Analyzer now allows users to add and manage multiple datasets on the fly and set up workflows.

Hexagon Geospatial, hexagongeospatial.com

TRANSPORTATION

Nearshore receiver

Measures positioning, heading, attitude, velocity and heave

Photo: Hexagon | NovAtel

The MarinePak7 marine-certified GNSS receiver is designed for nearshore applications. The multi-constellation, multi-frequency receiver was engineered to receive the Oceanix Correction Service from NovAtel, providing horizontal accuracy up to 3 cm (95%) in a marine environment. With SPAN GNSS+INS technology capabilities, the MarinePak7 couples GNSS and inertial measurement units (IMUs) for 3D positioning.

Hexagon | NovAtel, NovAtel.com

Expansion Card

For lane-level positioning

Photo: Antzertech

The ANNA-F9 high-precision GNSS Mini-PCIe card can achieve centimeter-level accuracy. It integrates the U-blox ZED-F9 receiver platform, providing multi-band GNSS (GPS, GLONASS, BeiDou, Galileo, QZSS and SBAS) and RTK positioning, and can be integrated with embedded systems. It provides high-accuracy positioning for applications including lane-level navigation and railway transportation. The ANNA-F9 series supports RTCM formatted corrections and centimeter-level positioning from local base stations or virtual reference stations in a network RTK setup.

Antzertech, antzer-tech.com

Marine Antennas

Two added to VeroStar line

Photo: Tallysman

Marine vessels often host both Iridium (1616–1626.5 MHz) and Inmarsat (uplink: 1626.5–1660.5 MHz) satellite communication antennas that transmit and receive signals. The VSP6037L-MAR and VSP6337L-MAR VeroStar marine antennas strongly attenuate interference from both signal sources, providing 75 dB to 85 dB of attenuation over Iridium and 85 dB to 95 dB over Inmarsat uplink, enabling clean GNSS signal reception and precise positioning. The VSP6037L-MAR supports the full GNSS spectrum; the VSP6337L-MAR supports GPS/QZSS-L1/L2/L5, GLONASS-G1/G2/G3, Galileo-E1/E5a/E5b, BeiDou-B1/B2/B2a, and NavIC-L5 signals. Both antennas support L-band correction signals. Every VeroStar antenna features a robust pre-filter and a high-IP3 LNA architecture, minimizing desensing from high-level out-of-band signals, including 700 MHz LTE, while still providing a noise figure of 1.8 dB. They meet IEC 60945 and IEC 61108 marine certifications for challenging marine environments.

Tallysman Wireless, tallysman.com

Cargo Service

For tracking high-value assets

The managed internet of things (IoT) Acculink Cargo can track the location and condition of high-value and sensitive assets, providing real-time visibility, product-level tracking and exception-based monitoring as goods move through their supply chains. Tracking can be used to avoid delays, minimize dwell time, prevent theft and remediate environmental conditions that can cause asset damage.

Sierra Wireless, sierrawireless.com

Tracking Antenna

Rugged external mount

Photo: Laird Connectivity

The GNS1559MPF or Mini GNSS is a rugged, high-performance and cost-effective solution for most GNSS or asset-tracking applications. The small form factor makes it easy to install on or in vehicles or buildings. It is IP67 rated to withstand impact as well as water and dust intrusion in demanding environments and operating conditions. The antenna can be configured with different cable types in varying lengths and with various connector types. Uses include public safety, in-building, fleet management, asset tracking, vehicle and personnel tracking.

Laird Connectivity, lairdconnect.com

UAV

Long-Flight UAS

Unmanned system for long-distance flights

Photo: Zala Aero Group

The Zala 421-16E5G long-flight UAS is a domestic unmanned aerial system with a hybrid power plant. The non-aerodrome-based system is capable of providing aerial monitoring covering distances of more than 150 kilometers and staying in the air for more than 12 hours. Its power plant charges a buffer battery for an hour, allowing the UAV to fly long distances. It is equipped with two thermal imagers and a 60x video camera. Alternatively, it can carry a payload of up to 10 kg.

Zala Aero Group, zala-aero.com/en/

Inertial navigation system

Ready for drone surveys

Photo: OxTS

The xNAV650 inertial navigation system (INS) provides surveyors with absolute position, timing and inertial measurements (heading and pitch/roll) that they can integrate into their projects. When combined with data from other devices (such as lidar sensors and cameras), the INS measurements can greatly enhance the surveying process. The xNAV650 has the latest micro-electro-mechanical (MEMS) inertial measurement unit (IMU) technology and survey-grade GNSS receivers. At 77 x 63 x 24 mm and 130 grams, it is suitable for a wide range of UAV data-collection applications: surveys of bridges, buildings, forests and rail; coastal monitoring; map creation; and pipeline exploration. Data collected can be fused with data from almost any lidar sensor. OxTS NAVsuite software is included with all OxTS INS. Other optional software is available, including precision time protocol and GX/IX tight-coupling technology.

Oxford Technical Solutions, oxts.com

Lidar System

With GNSS receiver and IMU

Photo: CHCNAV

The AlphaAir 450 (AA450) lidar system is a lightweight, compact all-in-one sensor. Featuring an inertial measurement unit (IMU), GNSS receiver and 3D scanner and camera, the AlphaAir 450 is suitable for power-line inspections, topographic mapping, emergency response, agricultural work and forestry surveys. The unit can be rapidly deployed in the field to collect geospatial data. It achieves absolute accuracy of 5 cm (vertical) and 10 cm (horizontal) for small survey areas. Adjustment algorithms applied in CHCNAV CoPre software further improve precision and accuracy. The AA450 weighs 1 kilogram for easy mounting on a UAV. It is IP64 rated against dust and water spray and operates at –20° C to +50° C.

CHC Navigation, chcnav.com

Imaging systems

Survey-grade with lidar

Photo: Geocue

The True View 635/640 3DIS is GeoCue’s second-generation lidar/camera-fusion platform designed to generate high-accuracy 3D colorized lidar point clouds using the Riegl miniVUX-3UAV. All 3DIS platforms include GeoCue’s data-processing software suite True View EVO, which integrates with the Applanix POSPac. With its 120° fused field of view, the True View 635/640 provides 3D mapping with excellent vegetation penetration and wire detection in a payload package of 3.2–3.6 kg. True View EVO supports the direct creation of ground classified point clouds, surface models, contours, digital elevation models, volumetric analysis, wire extraction and similar products, without the need for additional third-party software.

GeoCue Group, geocue.com

May 25, 2021
Seen & Heard: S’mores, penguins and sinkholes

“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.

Screenshot: Missing Children Society of Canada

Network Tool Helps Find Children

Microsoft and Esri Canada have developed the Child Search Network to enhance Canada’s national strategy for missing children. The network provides police services with a quick way to share information and collaborate with others, as well as with the general public, to find missing children faster and reunite them with their families. Police can put out information on a missing child via a website and smart-phone app. Members of the public can then offer tips by downloading the MCSC rescue app to register to receive alerts and share any information they may have regarding a missing child or youth. The tool helps meet the “gap of response” for high-risk cases of missing children that do not meet the strict criteria for the AMBER Alert.

Photo: Kroger

S’more Delivery Options

Grocery chain Kroger and Drone Express have launched a pilot delivery program in Centerville, Ohio, filling orders in as quickly as 15 minutes. Orders are sent to the customer’s smartphone location, which could include sending picnic supplies to a park or sunscreen to a beach. As part of the project, Kroger is selling bundled products within the payload weight — about five pounds, such as a S’mores bundle with graham crackers, marshmallows and chocolate.

Photo: Photodynamic/iStock/Getty Images Plus/Getty Images

Multiple UAVs Shorten Penguin Survey

One of the largest Adélie penguin colonies in the world was surveyed with multiple UAVs in March. Survey time was reduced from three days (with a single drone manually piloted) to under three hours. The work was led by a team of experts from Stanford University, Point Blue Conservation Science and Conservation Metrics. UgCS software by SPH Engineering was used to develop a system to autonomously survey the penguins. Thousands of high-resolution images were taken on each survey. An artificial intelligence model by Conservation Metrics is under development that will automatically identify and count adult penguins and their chicks. Using UgCS with a Stanford-provided planning algorithm, the survey team efficiently photographed more than 300,000 breeding pairs at Cape Crozier, Antarctica. The surveys will contribute to large-scale assessments of penguin populations and breeding success, key metrics for monitoring the health of the Antarctic marine ecosystem.

Photo: Bryngelzon/E+/Getty Images

Seeing Sinkholes with Satellites

Synspective Inc. is offering a sinkhole-detection prediction tool using satellite imagery analysis. Part of the company’s Land Displacement Monitoring service, an algorithm uses data science and machine learning to detect spatial and temporal variations. It can identify areas where sinkholes are likely to occur, areas where cave-ins have occurred, and areas where cave-ins are in progress. The input data is automatically updated, and the platform handles the processing and analysis of the complex satellite imagery.

May 25, 2021
Research Roundup: Guiding vehicles on busy city streets

Image: NatalyaBurova/iStock/Getty Images Plus/Getty Images

Of the hundreds of papers researchers presented at the Institute of Navigation’s annual ION GNSS+ conference, which took place virtually Sept. 21–25, the following four focused on autonomous vehicle positioning for automobiles on city streets. The papers are available at www.ion.org/publications/browse.cfm.

Digital Maps with Tethered Positioning

The authors propose a new method for tight integration of digital map and dead-reckoning (DR) system (inertial measurement unit plus wheel odometer) to provide reliable navigation solutions in challenging GNSS environments for extended periods. Integrated DR and GNSS have been widely used as the backbone of any navigation system for the internet of things (IoT) and vehicle navigation applications. Dollar-level micro-electro-mechanical system (MEMS) inertial measurement units (IMUs) aided by vehicle-wheel odometers have been recently used as low-cost DR systems to bridge GNSS gaps in harsh environments, such as urban canyons, tunnels and under bridges.

However, DR drift errors rapidly increase over time and cannot satisfy most IoT and land-vehicle navigation requirements. Plus, the GNSS receiver may fail to provide accurate position or even experience a complete outage for more than 15 minutes, causing the tethered positioning error to reach several hundred meters. Because land vehicles are supposed to travel on roads, feedback from a digital map can be used to constrain their position.

The authors used a fuzzy-logic map-matching algorithm to identify the correct road segment on which the vehicle moves. A feedback filter senses a correct map-matched position as well as the road segment as measurement updates to the Kalman filter (KF) of the tethered positioning system. The proposed tight integration of digital maps and a DR system is evaluated using datasets collected by Profound Positioning Inc. in Calgary, Alberta, Canada. Results show the proposed method has an average of 0.15% of relative horizontal position error for Calgary datasets — a considerable improvement over the tethered-solution-only with 3.3% of relative horizontal position error. The average azimuth error of the proposed system is 1.3 degrees, while the tethered positioning system shows an average azimuth error of 9.7 degrees.

Citation. Yashar Balazadegan Sarvrood, Haiyu Lan, Aboelmagd Noureldin, Naser El-Sheimy and Profound Positioning Inc., Calgary, Alberta, Canada. “Tight Integration of Digital Map and Tethered Positioning and Navigation Solution for IoT applications and Land Vehicles.”

5G Signals for Opportunistic Navigation

This paper presents a navigation framework in which 5G signals are used for navigation purposes in an opportunistic fashion. A carrier-aided code-based software-defined receiver (SDR) produces navigation observables from received downlink 5G signals. The SDR produces navigation observables from 5G signals and a navigation filter in which the observables are processed to estimate the user equipment’s position and velocity.

An experiment was conducted on a ground vehicle to assess the navigation performance of 5G signals. In the experiment, the vehicle-mounted receiver navigated using 5G signals from two 5G base stations (also known as gNodeBs, or gNBs) for 1.02 km in 100 seconds. The proposed 5G navigation framework demonstrated a position root-mean-squared error of 14.93 m, while listening to signals from only two gNBs.

Citation. Ali A. Abdallah, Kimia Shamaei and Zaher M. Kassas, “Assessing Real 5G Signals for Opportunistic Navigation.”

Using Low-Cost Onboard Sensors

For autonomous vehicles, accurate positioning must be ubiquitous — reliably available at all times and in all places in which the vehicle is expected to operate. While GNSS commonly provides the basis for absolute positioning, it suffers from the problem of availability whenever a direct view of enough satellites is not possible. To address this failure mode, additional complementary sensors can be added to the overall navigation solution through a technique known as sensor fusion. Sensors such as inertial measurement units (IMUs), cameras, lidars, radar and more can be selected in such a way that the individual shortcomings of each sensor are mitigated, and the overall robustness and reliability are improved.

Although current autonomous-vehicle applications employ sensor-fusion techniques, they tend to rely on high-performance sensors to meet the accuracy requirements. These high-performance sensors tend to induce a much higher cost burden than would be acceptable for commercial production, and therefore make mass autonomy too expensive.
This paper focuses on using the lower cost sensors already available on most modern vehicles. These include low-resolution odometry and consumer-grade IMUs currently used for dynamic stability control and wheel-slip detection. A novel approach for combining vehicle speed, steering angles, transmission settings and multiple odometry inputs is presented along with achievable results while operating under a GNSS-denied environment. The test trajectory mimics a typical parking structure with many corners and short, straight segments. The only a priori information required for the filter is the wheel track and wheelbase (separation distance of the wheels).

A 90% performance improvement compared to the stand-alone GNSS/INS solution was observed during GNSS outages of up to 30 minutes. Furthermore, up to a 50% improvement was observed when comparing the multi-odometry to the single-odometry outages during the same 30-minute outage condition. Beyond GNSS outage performance, this paper shows how the use of the extra input to the filter can improve the positioning system’s protection levels to allow for more frequent engagement of the autonomous navigation system.

Citation. Ryan Dixon, Michael Bobye, Brett Kruger and Jonathan Jacox, “GNSS/INS Sensor Fusion with On-Board Vehicle Sensors.”

Radar and INS/GNSS

An autonomous vehicle requires a ubiquitous, accurate, precise and reliable localization system. Many sensors can be used for positioning and navigation, each with its strengths and weaknesses. Inertial measurement units (IMU) are usually used to build inertial navigation systems (INS). INS can be accurate for short durations; however, an INS accumulates errors and loses its accuracy quickly, especially when using low-cost MEMS-based sensors. GNSS can provide an absolute position and velocity to update the INS over time. A barometer provides absolute elevation information, and an odometer provides a speed update.

An integrated navigation solution consisting of an IMU, a GNSS-RTK receiver and odometer can perform well in open-sky areas and on highways. This system can achieve lane-level accuracy most of the time based on the condition of the sensors and the quality of the measurements. However, in downtown and urban environments, the degradation, multipath and blockage of the GNSS signal leads to poor performance for such an integrated navigation system, which is challenged to maintain lane-level positioning.

This paper presents a version of AUTO (formerly known as Coursa Drive), a real-time integrated navigation system that provides an accurate, reliable, high-rate and continuous navigation solution for autonomous vehicles by integrating INS, RTK GNSS, odometer and radar sensors with TomTom’s HD Maps. AUTO performs a tight nonlinear integration of the radar data and maps with the INS/GNSS/odometer system.

Results demonstrate that radar measurements and HD Maps can be tightly integrated with INS/GNSS in an effective manner, such that the integrated system can provide a high-rate, accurate, reliable and robust navigation solution. This is a crucial requirement for realizing a fully autonomous vehicle that can operate in urban environments under a wide range of conditions, including adverse weather and lighting conditions, even in downtown areas with degraded or denied GNSS signals.

Citation. Abdelrahman Ali, Billy Chan, Amr Shebl Ahmed, Medhat Omr, Dylan Krupity, Qingli Wang, Amr Al-Hamad, Jacques Georgy and Christopher Goodall, “Tight Coupling Between Radar and INS/GNSS with AUTO Software for Accurate and Reliable Positioning for Autonomous Vehicles.”

May 25, 2021
GNSS software-defined radio metadata standard published

The GNSS Software Defined Radio Metadata Standard document has been published in NAVIGATION: Journal of the Institute of Navigation’s Spring 2021 issue, Volume 68, No. 1, pp. 11-20.

The metadata standard is the product of a three year-long effort of the ION GNSS SDR Standard Working Group and defines the parameters and schema to express the contents of SDR sample data files. The standard promotes the interoperability of GNSS SDR data-collection systems and processors.

In the past several years there has been a proliferation of software-defined radio (SDR) data-collection systems and processing platforms designed for or applicable to satellite navigation applications. These systems necessarily produce datasets in a wide range of different formats.

To correctly interpret this SDR data, essential information such as the packed sample format and sampling rate is needed. Communicating this metadata between creators and users has historically been an ad-hoc, cumbersome, and error-prone process.

To address this issue, the satnav SDR community developed the metadata standard and normative software library to automate the process, thus simplifying the exchange of datasets and promoting the interoperability of satnav SDR systems.

The standard was ratified and formally accepted as an Institute of Navigation Standard in January.

The formal standards document export citation is here.

Illustration of ad-hoc metadata exchange between SDR data creators and users. (Image: NAVIGATION)

May 25, 2021
Telecom groups press president, Congress for GPS alternatives

America urgently needs alternatives to GPS and the government must fund efforts to make that happen. So say separate documents sent to President Biden and senior members of Congress earlier this month.

On May 6, the government’s National Security Telecommunications Advisory Committee (NSTAC) issued its “Report to the President on Communications Resiliency.” The next day the industry group Alliance for Telecommunications Industry Solutions (ATIS) sent letters to Congress. Both organizations identify the need for alternatives to GPS to support telecommunications and other critical infrastructure. Both also urge government funding for the effort.

NSTAC is a federal advisory committee composed of 18 members from the telecommunications industry. Most are CEOs and very senior leaders in companies such as AT&T, Microsoft, and Iridium.

This month’s NSTAC report highlights the critical role that PNT, especially timing, plays in telecommunications. It notes that widespread use of GPS makes the system vulnerable to a host of threats. To address this, the group recommends the administration consider an approach “similar to that reflected in the Resilient Navigation and Timing Foundation’s paper entitled “A Resilient National Timing Architecture.” Further, to enhance the ability of commercial entities to afford leveraging this architecture, the Administration should appropriate sufficient funds to lay the foundation for creating this timing architecture, with the Federal Government being the first customer for what will ultimately become a resilient, interconnected network for PNT delivery.”

Federal funding is necessary, according to the board, because free GPS services eliminate market demand for alternatives.

ATIS sent letters to leaders in the House and Senate citing an “urgent need” for funding deployment and adoption of GPS alternatives for use in critical infrastructures, including telecommunications.

ATIS develops standards and other technical deliverables for information and communications technology (ICT) and services companies on a broad range of issues, including 5G and the Internet of Things (IoT).

Network and system synchronization is key for telecommunications. At present this is done almost exclusively using signals from GPS. ATIS had previously documented in reports and letters to Congress the vulnerability of GPS signals and the need for complementary and alternative systems to use when GPS is not available.

The letters outline the criticality of precision timing to critical infrastructure, industries, first responders, and U.S. government entities. They cite applications such as E9-1-1 and Assisted GPS used to find wireless handsets, as well as critical infrastructure networks, as some of the applications at risk.

ATIS also endorsed the findings of a recent Department of Transportation (DOT) report to Congress. That report documented that there exist “suitable, mature and commercially available technologies” able to provide alternatives to GPS.

Also mentioned was the appropriateness of government funding. “The role of government in protecting its citizens suggests an imperative to safeguard the capabilities of critical infrastructure industries by facilitating resilient PNT.”

Some in previous administrations had questioned whether it was necessary and appropriate for the government to fund GPS alternatives. According to NSTAC and ATIS, the answer is “yes” to both.

While the Biden administration has not made any official statements on the matter, reports of conversations with recent appointees seem to indicate that they agree with the need for government funding. There also seems to be bipartisan support for this view.

As one example, Ms. Diana Furchtgott-Roth, a conservative economist who served in the Trump administration as the leader for civil PNT issues, supports government funding wholeheartedly. At a recent webinar she indicated that the national need is beyond the business model of any company. “Just as the government funds national defense, it should also provide a complement to GPS,” she said.

The NSTAC “Report to the President on Communications Resiliency” can be found here.

ATIS letters to members in the House can be found here, and to members in the Senate here.

Dana A. Goward is President of the Resilient Navigation and Timing Foundation

Featured image: AnuchaCheechang/iStock/Getty Images Plus/Getty Images

May 25, 2021
Iridium invests in DDK Positioning, a GNSS solution provider

DDK Positioning solutions use the Iridium satellite constellation to deliver 5-cm GNSS accuracy to industrial users of the internet of things (IoT).

Iridium Communications Inc. has made a strategic investment in DDK Positioning, an Aberdeen, Scotland-based provider of enhanced GNSS accuracy solutions.

DDK uses the Iridium network to provide global precision-positioning services that can augment GNSS constellations, including GPS and Galileo, to significantly enhance their accuracy for critical industrial applications.

DDK is developing similar services for other GNSS constellations, such as GLONASS and Beidou. Terms of the investment are not being disclosed.

Standard positioning accuracy through a system like GPS is typically within 10 meters; however, by using the Iridium network, DDK’s enhanced GPS accuracy service brings incredibly precise positioning of 5 cm or less. This advanced level of accuracy is suitable for autonomous vehicles such as UAVs, precision agriculture applications, offshore infrastructure projects such as wind-farm construction, automotive applications like driverless cars, as well as a host of construction, mining, surveying and IoT use cases.

Historically, there have been limited geostationary satellite provider options for this type of service, but they suffer from line-of-sight blockage issues and coverage limitations in and around Arctic and Antarctic regions.

“We are delighted to have embarked on this journey with such a strong and well-respected company as Iridium,” said Kevin Gaffney, CEO of DDK Positioning. “This partnership is a perfect fit for DDK Positioning. With Iridium’s satellite communications network and our GNSS solution, we are in a position to deliver a truly unique service which is robust, resilient and secure. The investment made by Iridium will also allow us to grow the company even further whilst expanding our service offering globally.”

According to a report published by the European GNSS Agency, augmentation services like those offered by DDK will account for $76.5 billion (€65 billion) in global GNSS market revenue by 2029, while the global GNSS downstream market, including services delivered and hardware devices, is estimated to reach $382 billion (€325 billion).

“We are impressed with the team that DDK has put together and see great potential for this technology and how it takes advantage of the Iridium network,” said Iridium CEO Matt Desch. “DDK’s enhanced positioning is a unique capability that adds a high-value solution on top of our existing portfolio of custom network services. Solutions from Iridium and DDK partners that are focused on precision agriculture, autonomous systems, maritime and infrastructure projects can now experience incredibly precise GNSS accuracy from anywhere on the planet.”

May 24, 2021