Publicerad Lämna en kommentar

Indy Autonomous Challenge livestreams Saturday

Photo: IAC

Photo: IAC

Autonomous racecar competition takes place at the Indianapolis Motor Speedway

The Indy Autonomous Challenge will be livestreamed on Oct. 23 through Amazon Web Services for viewers worldwide. Teams from 21 universities from nine countries will compete for the $1 million grand prize, which will be used to advance the education and research missions of the winning universities.

Livestreaming begins at 1 p.m. EDT and can be viewed on the IAC website homepage and on Twitch @IndyAChallenge.

“Due to the generous support of Amazon Web Services (AWS), we will have a global audience for the first autonomous high-speed competition at the Racing Capital of the World — the Indianapolis Motor Speedway,” said Paul Mitchell, president and CEO, Energy Systems Network, co-organizer of the IAC. “This is critically important as the IAC is a global competition having involved at its inception 41 universities from around the world.”

Organized by Energy Systems Network and the Indianapolis Motor Speedway, the primary goal of the IAC is to advance technologies that can speed the commercialization of fully autonomous vehicles and deployments of advanced driver-assistance systems (ADAS). These enhancements will lead to increased safety and performance in motorsports as well as all modes of transportation.

In addition, the competition is a platform for students to excel in science, technology, engineering and math (STEM) and inspire the next generation of innovators.

Publicerad Lämna en kommentar

Video celebrates 10 years of Galileo

A new video celebrates the first decade of Europe’s satellite navigation system Galileo, which celebrates its 10-year anniversary on Oct. 21.

Galileo delivers meter-level accuracy anywhere on Earth. It is also saving lives, by relaying distress calls for search and rescue. Today, 26 Galileo satellites orbit 23,222 km above the Earth. The first was launched on Oct. 21, 2011; nine more launches followed to create the constellation.

The satellites in space are supported by a globe-spanning ground segment. The system as a whole is set to grow, with the first dozen Batch 3 about to join the current satellites in orbit and Galileo Second Generation satellites in development.

Galileo is financed by the European Union and developed by the European Space Agency. Services are delivered by the EU Agency for the Space Programme.

Illustration: Thales Alenia Space

Illustration: Thales Alenia Space

Publicerad Lämna en kommentar

Speakers, program announced for Geo Week conference

125+ speakers and 50+ sessions are confirmed for the 2022 edition of Geo Week in Denver

Image: Geo Week 2022

Organizers of Geo Week, which brings together geospatial technologies and the built world, have announced its conference sessions and speakers for the 2022 event, which will take place Feb. 6-8, 2022, in Denver, Colorado.

The conference program features more than 125 speakers across 50 sessions with content that explores best practices in 3D capture, working in the built environment, gaining return on investment (ROI) from building information management (BIM), defining what’s possible now with lidar, and more.

The coming together of AEC Next Technology Expo & Conference, International Lidar Mapping Forum, and SPAR 3D Expo & Conference to form Geo Week reflects the increased integration between the built environment, advanced airborne/terrestrial technologies, and commercial 3D technologies.

Partner events taking place in conjunction with Geo Week include ASPRS Annual Conference, MAPPS Winter Meeting and USIBD Annual Symposium, ensuring the presence of geospatial and built-world industry experts in one place.

Presenters represent Autodesk, Esri, USGS, The Beck Group, Hexagon Geosystems, GM, Caltrans, Velodyne Lidar, Draper, MLB and NASA. These experts will share their expertise on a range of topics. Sessions include:

Geo Week will have multiple tracks with content clearly identified as relevant to one or more of the audience groups feeding into Geo Week.

  • The International Lidar Mapping Forum (ILMF) audience has historically been comprised of precision measurement professionals in surveying and mapping who use airborne and terrestrial lidar and related remote sensing technologies.
  • The AEC Next audience has historically been comprised of professionals in architecture, engineering and construction that use technologies such as reality capture, automation, artificial intelligence and XR to bid and manage projects and improve workflows.
  • The SPAR 3D audience has historically been comprised of professionals who use 3D capture, scanning, visualization and modeling technologies across a variety of verticals.

“We’ve witnessed the growing convergence between geospatial and the built world,” said Lee Corkhill, group event director at Diversified Communications, organizer of Geo Week. “We believe the market is ready and eager for this next step of leveraging the confluence of technologies for improved collaboration, increased efficiency, and better outcomes. Much of the conference content and technology being showcased will reflect and support this increasing integration. At the same time, we recognize that individuals and organizations are at differing levels of adoption, and so there will be ample content more focused on what were traditional AEC Next, ILMF and SPAR 3D topics.”

Geo Week will provide education, technology and resources for professionals in industries including AEC, asset and facility management, disaster and emergency response, Earth observation and satellite applications, energy and utilities, infrastructure and transportation, land and natural resource management, mining and aggregates, surveying and mapping, and urban planning and smart cities.

More than 80 companies have confirmed booths on the Exhibition Floor with additional companies being confirmed every week and more than 100 associations and media companies are signed on as supporters.

Geo Week takes place Feb. 6-8, 2022, with conference programming and exhibits all three days. Additional features of the programming are vendor-delivered product reviews, exhibition theaters, workshops and programming hosted by ASPRS, MAPPS and USIBD. Visit www.geo-week.com for more information on attending or exhibiting. Register before Dec, 10 for early bird rates.

Publicerad Lämna en kommentar

QZSS successor satellite set to launch Monday

A successor to the first Quasi-Zenith Satellite System (QZSS) satellite is planned for launch from the Tanegashima Space Center on Monday, Oct. 25, from 11 a.m. to 12 p.m. Japan Standard Time (2-3 a.m. UTC).

Michibiki Unit 1 was launched on Sept. 11, 2010, and entered its quasi-zenith orbit 10 days later. QZSS began service in November 2018 with four satellites. The Japan Aerospace Exploration Agency (JAXA) plans to have seven aircraft aloft by 2023.

The satellite, designated QZS-1R, will be carried aboard H-IIA rocket No. 44. The QZSS launch will be streamed live. The broadcast program will begin at 10:35 a.m. JST.

Local launch times

Houston: Sunday, October 24, 21:00
New York: Sunday, October 24, 22:00
London: Monday, October 25, 03:00
UAE: Monday, October 25, 06:00
Singapore: Monday, October 25, 10:00

More information on the launch is available at the QZSS site and rocket maker Mitubishi Heavy Industries site.

To follow upcoming GNSS satellite launches, see our launch table, provided by Innovation editor Richard Langley.

H-IIA Launch Vehicle No. 44 at the Yoshinobu Vehicle Assembly Building, JAXA Tanegashima Space Center. in preparation for launch of the successor to the Michibiki Unit 1 on Oct. 25. (Photo: MHI)

H-IIA Launch Vehicle No. 44 at the Yoshinobu Vehicle Assembly Building, JAXA Tanegashima Space Center. in preparation for launch of the successor to the Michibiki Unit 1 on Oct. 25. (Photo: MHI)

Shinichi Nakasuka, professor at the University of Tokyo Graduate School of Engineering and member of the Cabinet Office Space Policy Committee, released the following statement about the upcoming launch.

“Three years after the full operation of the four-machine Michibiki started in 2018, as the chairman of the Quasi-Zenith Satellite System Business Promotion Committee of the Cabinet Office, we strive to ensure the reliable operation and expansion of the use of this world-class system.

“I feel that high-precision positioning and two-way communication services in the event of a disaster, which cannot be achieved by GPS alone, are gradually taking root as social infrastructure. In modern society, the provision of highly accurate position and time is exactly the infrastructure that is indispensable as the ‘nerve network’ of society.

“To make that more reliable, the successor to the first machine, which pioneered this system, is about to be launched. We pray for the success of the launch and satellite operation, and hope that the Quasi-Zenith Satellite System will become more and more established in society, and that many people will be able to use this system for various purposes, including business.”

Publicerad Lämna en kommentar

Senate proposes $15M to develop GPS alternatives

This week Sen. Patrick Leahy (D-Vt.), chair of the Senate Appropriations Committee, released that body’s version of nine different appropriations bills. The accompanying report for the bill to fund the Transportation Department (DOT) outlines the Senate’s intentions and way forward for establishing alternatives to GPS.

The report provides $15 million for the fiscal year that began on the first of October “to establish a program that leads to wide adoption of multiple technologies that provide the necessary GPS backup and complementary PNT as identified by the Department’s report.”

The department report referenced was on a demonstration project that examined GPS backup and complementary technologies from 11 different vendors. That DOT report found, based on the technologies demonstrated, a combination of signals delivered from space, terrestrial low frequency (LF) and ultra-high frequency (UHF) broadcasts, and fiber would best meet the nation’s needs.

The Senate report accompanying the funding bill outlines components of the GPS alternatives program, including:

  • development of safety-critical PNT requirements and standards,
  • user adoption models to facilitate responsible use of resilient PNT, and
  • procurement of services deemed appropriate by the department.

The Senate Committee report can be found here. Relevant provisions are on page 12.

Services Contracts

While not setting a deadline for issuance of a Request for Proposal, the mention of procuring services is seen by many as a strong indication that Congress expects more than just additional studies.

Services contracts, as opposed to the government building its own system, have long been advocated by numerous members of industry and by the Resilient Navigation and Timing Foundation. Contracting for services with commercial providers is a better model, they have argued, as the needed technologies are mature and commercially available. Also, issuing one or more services contracts would avoid the need for the huge funding lines and lengthy delays inherent in a government major systems acquisition.

Many have suggested that services contracts would also be a much more economical approach for the government. They say commercial interests can operate their systems more efficiently, and that they could offer additional services to other customers, potentially reducing costs to the government.

ADS-B Sets Example

Such an approach was used by the Federal Aviation Administration (FAA) for the ADS-B air traffic safety and management system. The FAA needed to monitor and use signals from ADS-B equipment aboard a wide variety of aircraft flying in U.S. airspace. Rather than building a nation-wide ground infrastructure, the FAA issued a long-term service contract for a company to collect and provide the signals. The awardee, Exelis (now L3Harris), won the contract, built the infrastructure, and now provides ADS-B information to the FAA and others on a subscription basis.

Most observers expect the portions of the Senate bill and report about the GPS alternatives program to be adopted in conference with the House and then enacted into law.

How far the Department of Transportation will be able to develop the program this fiscal year remains to be seen. The Senate provisions do require DOT to report on its progress in a year’s time. Earlier informal reports and updates to the committee are likely to inform funding and other legislation on this effort for fiscal year 2023.


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

Publicerad Lämna en kommentar

RUAG Space partners with UAE’s MBRSC on satnav services

The Mohammed Bin Rashid Space Center builds and operates earth observation satellites. (Photo: MBRSC)

The Mohammed Bin Rashid Space Center builds and operates Earth observation satellites. (Photo: MBRSC)

The Mohammed Bin Rashid Space Center (MBRSC) in the United Arab Emirates (UAE) will use a RUAG Space GNSS navigation receiver to determine the position of its new satellite. Founded in 2006, MBRSC is home to the UAE National Space Program.

RUAG Space’s LEORIX receiver will precisely determine the satellite’s position in orbit, with an accuracy of about 1 meter. The high accuracy is achieved through simultaneously processing of multi-frequency signals from GPS and Galileo satellites.

The LEORIX receiver from RUAG Space. (Photo: RUAG Space)

The LEORIX receiver from RUAG Space. (Photo: RUAG Space)

Based in Switzerland, RUAG Space offers three types of space-hardened navigation receivers. The LEORIX for low Earth orbit, the GEORIX for geostationary Earth orbit and the PODRIX for precise orbit determination are all based on the European Space Agency’s latest GNSS processing technology.

The PODRIX receiver had its maiden flight to space in November 2020 and precisely determines the position of the European environmental satellite Sentinel-6. The LEORIX receiver flew for the first time in space in March 2021. In total, more than 80 receivers of the latest receiver generation (LEORIX, GEORIX and PODRIX) have been ordered by customers in Asia, Europe, the Middle East and the United States. They will be launched for different low-Earth and geostationary orbit missions within the next months and years.

The MBRSC builds and operates Earth observation satellites, offering imaging and data analysis services to clients around the world. The center launched the first Emirati-made satellite, KhalifaSat, in 2018, and the DubaiSat-1 and DubaiSat-2 satellites in 2009 and 2013 respectively. MBRSC is also responsible for the Emirates Mars Mission Hope probe, the first Arab interplanetary mission, which is collecting data from the Red Planet.

Publicerad Lämna en kommentar

UAV company AgEagle to acquire senseFly from Parrot

AgEagle will acquire senseFly, a Parrot Group subsidiary, for US$23 million.

AgEagle Aerial Systems Inc. is a a provider of drones, sensors and software, and Parrot is a European drone company. Founded in 2009, senseFly develops and produces a proprietary line of eBee-branded, high performance, fixed wing drones for professional use.

Photo: SenseFly

The eBee Geo drone was introduced in March. (Photo: SenseFly)

The development positions AgEagle to provide a full-stack fixed-wing drone solution for agriculture, government, engineering and construction, among other industry verticals. SenseFly also brings to AgEagle solid engineering talent focused on advanced research and development, a well-established global reseller network, and a strong portfolio of intellectual property, AgEagle stated in a press release.

The eBee drones are designed to be safe, ultra-light and easy to use. They are in use by thousands of customers around the world in agriculture, government, engineering and construction to collect aerial data. Headquartered in Lausanne, Switzerland, senseFly employs 90 people, generating total annual revenues of US$12.5 million in 2020.

“Recognized as the producer of the world’s most widely used fixed wing drones, senseFly is an ideal strategic fit for AgEagle,” said Brandon Torres Declet, chief executive officer of AgEagle.

Moving forward, Parrot will focus its expertise and resources on the growth of its professional quadcopter drone equipment and drone data analysis software activities, according to Parrot founder and CEO Henri Seydoux. “The transaction will provide additional cash and lower operational expends to drive Parrot’s growth and industry standing,” Seydoux said. “With the capabilities of the ANAFI line of professional drones and of the Pix4D software suites, Parrot will continue to address its core market segments: 3D mapping, surveying and inspection, agriculture, and defense and security.”

In tandem with the closing of the acquisition, which is expected shortly, Labossiere will resign as CEO of senseFly. Michael O’Sullivan, who previously served as the company’s head of global marketing, will be appointed managing director of the new AgEagle subsidiary. All other senseFly employees will retain their current responsibilities.

For details relating to the terms and conditions of the acquisition, refer to the Form 8-K to be filed by AgEagle with the U.S. Securities and Exchange Commission upon closing of the transaction and accessible at www.sec.gov.

Publicerad Lämna en kommentar

Global GNSS constellations: Why 2 + 2 equals more than 4

The tremendous benefits of having four complete GNSS constellations

In 2020, with the completion of China’s BeiDou-3 (aka BDS) and Europe’s Galileo, the number of available global navigation satellite system (GNSS) constellations doubled. 

Analogously to the addition of GLONASS to GPS a quarter century earlier, but much more so, this sharp increase in the number of available satellites and frequencies greatly improved the precision of satellite-based positioning, the speed of first fix, and the confidence in the results — especially in GNSS-challenged places, such as under thick canopy and in deep urban canyons. 

Additionally, this new ability to track three or four GNSS constellations makes the overall positioning solution more resilient to malicious RF interference (jamming and spoofing), to accidental GNSS service disruptions such as Galileo’s one-week service outage in July 2019, and to deliberate withholding of service such as might occur in times of war.

While all this may make little practical difference to a driver needing to know which highway exit to take or to a pedestrian looking for the nearest pharmacy, it is very valuable in high-end applications, such as surveying and construction. In fact, surveyors who have transitioned to using all the available constellations are ecstatic.

This month’s cover story, on the benefits of having four complete GNSS constellations, is in two parts. First, Oliver Montenbruck and Peter Steigenberger discuss “the practical relevance and implications of having four GNSS in parallel for both mass-market and high-end users.” Next, I present the comments of three surveyors and a receiver manufacturer:

  • Gavin Schrock, PLS, is a practicing land surveyor, the operator of a cooperative real-time GNSS network in Washington state, and a technology writer
  • James Richards is the senior land and utility surveyor at Benchmark Surveys in Venny Bridge, UK
  • Choice Sterling is the survey manager at Kiewit Corporation in Federal Way, Washington
  • Xiaohua Wen is the CEO and founder of Tersus GNSS, a manufacturer of GNSS surveying receivers based in Australia.
(Satellites from left) GPS: In July 1995, GPS achieved full operational capability (FOC). GLONASS: In December 1995, the (then) Soviet system achieved FOC. BeiDou: On June 23, 2020, China launched the final satellite of the BeiDou-3 constellation. Galileo: The constellation has 21 usable satellites.(Credit: Satellites from public sources; background image: NASA/Chaykovsky Igor/Shutterstock.com)

(Satellites from left) GPS: In July 1995, GPS achieved full operational capability (FOC). GLONASS: In December 1995, the (then) Soviet system achieved FOC. BeiDou: On June 23, 2020, China launched the final satellite of the BeiDou-3 constellation. Galileo: The constellation has 21 usable satellites.(Credit: Satellites from public sources; background image: NASA/Chaykovsky Igor/Shutterstock.com)


See also

GNSS today: A four-leaf clover, b and 

How land surveyors grapple with rapid evolution, discussion with surveyor Gavin Schrock


Thoughts from surveying experts

James Richards
Senior Land and Utility surveyor
Benchmark Surveys, Venny Bridge, UK

James Richards, Benchmark Surveys

James Richards, Benchmark Surveys

What kinds of surveying projects do you run?
We run many different types of surveying projects. From small single-story bungalow extensions and redevelopment to development of new home sites of several hundred acres. We cover land, underground utility, and measured-building surveys of any size project, using the latest equipment in total stations, laser scanners, drones, GPS receivers, ground-penetrating radar (GPR) and electromagnetic location (EML).

How have you transitioned to using multiple constellations?
Ordnance Survey benchmarks in the UK are no longer maintained. Therefore, it has been a must to move forward with the surveying world and use multi-constellation GNSS equipment. We have stayed at the forefront of GNSS receivers, starting with a Topcon GRS1 then moving onto a Trimble R10 and a Topcon HiPer SR. Now, I feel we’ve taken another leap with the Trimble R12i, working in areas where we previously did not even consider using a GNSS receiver.

How does the availability of four complete GNSS constellations, plus two regional ones, benefit your work?
The availability of four complete GNSS constellations and two regional ones gives us more reliability as well as improved position and time accuracy in the data that we receive. It also gives us better coverage over the entire UK, including near buildings and under foliage. The Trimble R12i has 672 available channels, which makes it future-proof to new frequencies and additional space vehicles.


Choice Sterling
Survey manager, Kiewit Corporation
Federal Way, Washington

What kinds of surveying projects do you run?
I am the survey manager on $1–3 billion mega projects, ranging from bridges and highways to tunnels and rail, including a couple of projects for the U.S. Department of Defense.

How have you transitioned to using multiple constellations?
The use of multiple constellations became available as we adopted technologies that could capitalize on their availability. Through the latest hardware and software, we have begun leveraging GNSS to a greater magnitude than we would have just a few years back.

How does the availability of four complete GNSS constellations, plus two regional ones, benefit your work?
Not long ago, the use of GPS for construction staking was an extremely risky proposition given its unreliability, primarily in the vertical component, and lack of confidence in its horizontal accuracy. With residuals exceeding most construction tolerances, GPS was primarily utilized for earthwork or to establish geodetic pairs that could then be traversed to establish control for more precise work. With the utilization of multiple GNSS constellations, we have gained confidence in the accuracy of our results and have started leveraging GPS for construction staking where we were once not willing to take the risk.

Having the ability to leverage GPS under a canopy of trees or against structures or walls has proved invaluable when running traverses or levels, typically enabling us to use a single person rather than a two-person crew. Increased confidence in repeatability and accuracy while using GPS has been a game changer when working on projects where efficiency and cost management are of the greatest importance.


Xiaohua Wen
CEO and Founder, Tersus GNSS

Xiaohua Wen, Tersus GNSS

Xiaohua Wen, Tersus GNSS

How have you transitioned to manufacturing multiple-constellation GNSS receivers?
Early in 2016, we produced a GNSS receiver evolution road map to take advantage of GPS/GLONASS modernization, the continuing development of Galileo and QZSS, and the completion of BeiDou-3. In 2019, we released our current GNSS receiver, which has 576 tracking channels and supports all five major GNSS constellations (GPS, GLONASS, Galileo, BeiDou-3 and QZSS) and triple-band broadcasts (GPS L1+L2C+L2P+L5, GLO G1+G2+G3, GAL E1+E5a+E5b, BDS B1+B2a+B2b and QZSS L1+L2C+L5). We expect to release our next generation receiver, with 832 channels, in February 2022. It will support all available constellations (GPS, GLO, GAL, BDS, QZSS, IRNSS/NavIC, SBAS) and all civil signals, including the AltBoc and AceBoc.

How does the availability of four complete GNSS constellations, plus two regional ones, benefit your end users?
The most significant advantage of modern GNSS receivers is their robust high-accuracy performance with the aiding of the new constellations and signals, especially in harsh GNSS environments, such as deep canyons and heavy foliage. It greatly extended the RTK fix capability, and now reliable GNSS RTK fix solutions can be easily achieved in areas where it was impossible to do in the past.

In the past, multipath always has been a problem for RTK GNSS receivers, as it might cause blunder errors. The improved RTK fix reliability based on robust RTK integrity monitoring takes advantage of the redundancy of observations to identify and isolate deteriorated observations and confirm the fixed result. Additionally, RTK achieves RTK fix solutions faster and maintains the RTK fix solutions easier with better accuracy than before.

Compared to the dual-band (L1+L2) of GPS plus GLONASS, the triple-band (and multi-band) can allow long-range RTK capability, which can provide reliable RTK solutions with a remote GNSS base station far from the 20–30 km base and rover separation of the past. It also will provide more confidence in RTK positioning during the coming ionospheric disturbance peak in 2023.

Publicerad Lämna en kommentar

GNSS today: A four-leaf clover

Knowing your position is only part of navigation. (Photo: Oliver Montenbruck)

Knowing your position is only part of navigation. (Photo: Oliver Montenbruck)

By Oliver Montenbruck and Peter Steigenberger

A year ago, the U.S. Global Positioning System celebrated its silver jubilee upon completing 25 years in operation. Also, it was more than 20 years ago that President Clinton agreed to switch off Selective Availability, thus offering seamless positioning to the civil community. The 10-bit GPS week count experienced its second rollover, and people worldwide got addicted to a ubiquitous positioning capability in those decades. Be it for finding the nearest restaurant or to track a Sunday afternoon bike ride, positioning-related services building on GPS have become an integral part of our daily life. In fact, GPS has almost become a synonym for navigation itself.

One cannot underestimate the contribution that GPS has made to society. It is for sure most deserved that the fathers of GPS were ultimately awarded the highly prestigious Queen Elizabeth Prize for Engineering in the year of the above jubilee. As always, success creates followers, and GPS is no longer the sole player. Next to the Russian GLONASS, two new actors — namely the European Galileo and the Chinese BeiDou-3 GNSS — have mounted the stage. So, users are now offered a choice of four independent GNSS.

However, do we really need so many systems? Isn’t one enough and all others just a waste of taxpayers’ money? The answer to the last question is certainly a clear “no.” Our society already depends on, to a large extent, the availability of positioning, navigation and timing (PNT) services in much the same way we depend on electricity and telecommunication. While mass-market applications such as the ones mentioned above may appear dispensable, there are “hidden” but much more critical applications of GPS, such as synchronizing power lines, stock trading or the base stations of cellular networks.

Clearly, there is a well-justified rationale for nations or groups of nations to build their independent, space-based navigation systems. Well beyond possible military considerations, this is a basic strategic interest for protection of the local economy and of critical infrastructure. Along with these interests, various regulatory conditions may apply that only endorse the use of selected systems for specific applications, such as emergency call systems. Overall, however, all GNSS in place today can be received and utilized by all interested users around the globe.

So, let’s have a closer look at the practical relevance and implications of having four GNSS in parallel for both mass-market and high-end users. The most obvious consequence is certainly an almost four-fold increase in the number of satellites. As of today, the four GNSS comprise more than 100 satellites, out of which 30 to 40 are simultaneously visible and available for positioning at common sites with open-sky conditions. As a rule of thumb, this provides a factor-of-two reduction of statistical errors compared to using only GPS.

Most importantly, however, the prospects for tracking enough satellites for positioning in obstructed sites is greatly improved. The larger number of visible satellites is particularly appealing for GNSS radio scientists who aim to derive temperature and humidity profiles from subtle variations in GNSS signals passing through diverse atmospheric regions. Multiple GNSS allow for better resolution and ultimately benefit weather forecasts.

In terms of positioning, the simple statistical benefits of tracking a large number of satellites are probably outweighed by technological advances in GNSS satellites and ground systems, as well as substantial progress in receiver technology. For GPS, the signal-in-space range error (SISRE) that describes the contribution of broadcast orbit and clock errors to the position accuracy has decreased by more than a factor of three (Figure 1).

FIGURE 1. Evolution of the GPS signal-in-space range error over time. (Image: O. Montenbruck and P. Steigenberger)

FIGURE 1. Evolution of the GPS signal-in-space range error over time. (Image: O. Montenbruck and P. Steigenberger)

For GPS, but also Galileo and BeiDou-3, the use of highly stable atomic frequency standards has contributed to a notable reduction of the error budget of broadcast ephemerides. The same applies for fast upload capabilities, as in Galileo, or the use of intersatellite links in BeiDou-3. With SISRE values of 0.1–0.2 m and 0.3–0.4 m, these constellations enable even more accurate positioning today than GPS and GLONASS (Figure 2).

Figure 2. Signal-in-space ranging errors of the four GNSS. (Image: O. Montenbruck and P. Steigenberger)

Figure 2. Signal-in-space ranging errors of the four GNSS. (Image: O. Montenbruck and P. Steigenberger)

However, improvements from new signals and multiple constellations are not only limited to single-point positioning, but likewise apply for precise point positioning (PPP) users. Stable clocks onboard the satellites reduce the update rate and bandwidth for real-time correction users. Digital signal generation units in modernized satellites ensure clean chip shapes in the transmitted ranging signals and reduce the scatter of satellite/receiver biases. Last but not least, the increased number of tracked satellites contributes notably to reducing the convergence time required for successful ambiguity fixing.

Concurrent progress in receiver technology was certainly a prerequisite for being able to track the multitude of new signals that became available with the new and modernized constellations. Compared to early GPS receivers with a few tens of channels, modern geodetic receivers may (or even must) support in the order of 1,000 channels. For mass-market users, the recent introduction of dual-frequency chipsets for mobile phones and car navigation systems marks the most important step forward. These chipsets support joint tracking of signals from GPS, Galileo and BeiDou-3 at the common L1/E1/B1 and L5/E5a/B2a center frequencies. The signals’ chipping rates, modulations and signal power are designed to offer reduced measurement noise, better multipath protection, and improved weak-signal tracking. At the same time, the use of two signal frequencies allows for rigorous elimination of ionospheric path delays, thus removing the biggest contributor to the error budget of low-cost positioning devices.

All in all, the availability of four GNSS means better performance, robustness, diversity and flexibility for navigation users. We should not forget, however, that all GNSS use basically the same core technology and share the same vulnerabilities. We must still give due attention to the challenge of toughening, augmenting and complementing GNSS to meet society’s needs for robust and assured PNT.


Oliver Montenbruck is the head of the GNSS Technology and Navigation Group and Peter Steigenberger is a senior scientist at the German Space Operations Center, German Aerospace Center (DLR).

Publicerad Lämna en kommentar

UAVs, walking robots and an autonomous tugboat

In a slight expansion from our previous monthly UAV newsletter columns, we’re now looking at autonomous systems with a wider outlook, capturing the automated world as it evolves.

The Eve air taxi. (Image: EmbraerX)

The Eve air taxi. (Image: EmbraerX)

News this month covers steps toward air taxi qualification, highly challenging underground UAV and robotic capers, and long-distance watercraft autonomy in Denmark.

EVE gets order boost by Bristow

We’ll soon be seeing them — electric powered manned and unmanned flying taxis buzzing in the city skies above us. Embraer, the Brazilian commuter aircraft manufacturer (you might have taken their EMB-1xx series turboprop aircraft on short hauls between city centers) has apparently progressed its Eve manned/unmanned aircraft development to the stage of a program for qualification/certification being scoped by EmbraerX in Florida and the Bristow Group.

Parent company Embraer established EmbraerX in Melbourne, Florida, as a new-concept UAV developer and manufacturer, launching the Eve urban mobility vehicle as its first product.

Eve subscale demonstrator. (Photo: EmbraerX)

Eve subscale demonstrator. (Photo: EmbraerX)

Although we are still only seeing concept-artist renderings of the Eve eVTOL (electric vertical take-off and landing) aircraft, and photographs of a small-scale flying prototype, Embraer has already built an impressive order book. There are reports of more than 500 orders on hand, originally led by Uber and recently joined by the Bristow Group with an order for 100. All orders are likely contingent on aviation agency approval of the aircraft for public transportation.

Based worldwide, Bristow has been around in one form or another since 1955, and currently operates more than 250 helicopters in support of the oil and gas industry, search and rescue (SAR), and various military-related applications, including unmanned aircraft operations with the U.S. Coast Guard. This experience is expected to aid EmbraerX through a joint program to eventually gain an operating certificate for the Eve air taxi.

An Elios drone from team CERBERUS roams a moulin in an earlier challenge. (Photo: DARPA)

An Elios drone from team CERBERUS roams a moulin in an earlier challenge. (Photo: DARPA)

DARPA’s Subterranean Challenge

The U.S. Army’s Defense Advanced Research Projects Agency (DARPA) has been running a competition since 2018 to find unmanned products and technologies that can find their way around underground environments such as subway systems, sewers, mines and naturally occurring caves and tunnels. The object is to rapidly and remotely map, navigate and search these complex underground locations.

Known as DARPA’s Subterranean Challenge, several groups of competitors were slimmed down to three very capable teams over several months through some initial selection evaluations. Then, on final competition day, teams CSIRO Data61, CERBERUS and MARBLE went at it in an array of challenging environments at the Louisville Mega Cavern — a massive retired limestone mine so large it not only hosts a ropes course and a mountain bike park, but also has tram-guided tours for visitors.

Finalists in the competition had to navigate through elements from previous events, including simulated underground mines, a metropolitan infrastructure, and cave systems. Smoke was even used in places to increase the confusion.

Team CERBERUS — an international consortium that included the University of Nevada Reno (UNR), ETH Zurich, the Norwegian University of Science and Technology (NTNU), the University of California Berkeley, the University of Oxford, Flyability, and the Sierra Nevada Corporation — was ultimately successful.

The ANYmal climbs stairs. (photo: ANYbotics)

The ANYmal climbs stairs. (Photo: ANYbotics)

In previous phases of the competition, Flyability used its caged Elios 2 UAV with video and thermal cameras and a high-intensity LED lighting system to create accurate internal maps of underground spaces. However, in the final competition, ANYbotics four-legged ANYmal C autonomous robots were primarily employed — carrying visual and thermal cameras, lidar and a spotlight.

In the final competition, Team CERBERUS managed to locate and identify 23 of 40 hidden “artifacts” in the allocated time and earned the $2 million DARPA first-place prize.

Autonomous Tugboat round Denmark

Sea Machines in Boston has been around since 2015, focusing on automating shipping control and monitoring. It hopes to bring a system to market that will enable an autonomous voyage all the way around Denmark.

With investors who include Toyota Ventures, Huntington Ingalls, Brunswick Corporation, Accomplice and Dolby Fund, the company is not a mega-million venture, but has still successfully engaged the likes of A.P. Moller-Maersk, the U.S. Department of Transportation and the U.S. Navy in autonomous waterborne projects.

The tugboat Nellie Bly on its 1,000 nm circumnavigation of Denmark will use an SM300 autonomous system that uses radar, inertial navigation, a depth transducer, the automatic identification system (AIS) and video cameras for obstacle avoidance. It will provide high-definition remote situation awareness to monitoring controllers in Boston, 3,600 miles away.

Autonomous tugboat Nellie Bly. (Photo: Arie Boer)

Autonomous tugboat Nellie Bly. (Photo: Arie Boer)

Throughout the voyage, the Nellie Bly will have two professional pilots onboard, and will stop at ports along the way to demonstrate the technology. Sea Machines will stream the journey live on a website with updates from the ship, the crew and the command center, enabling real-time and recorded access to “The Machine Odyssey” as the project is now known.

To sum up, lots of autonomous projects are proceeding, with progress toward getting air taxis up and running for business, DARPA sponsoring technology for underground navigating, and mapping and long-distance autonomous navigation around Denmark — lots of diversity and opportunity.

Tony Murfin
GNSS Aerospace