U.S. Secretary of Transportation Elaine Chao has launched an initiative to safely test and validate advanced drone operations in partnership with state and local governments in select jurisdictions.
Prospective local government participants are asked to partner with the private sector to develop pilot proposals. After evaluating all of the applications, USDOT will invite a minimum of five partnerships.
The department also will publish a Federal Register Notice with more details about how applications will be evaluated and how the program will work.
More about the program is available on the DOT website.
The program will help tackle the most significant challenges in integrating drones into the national airspace while reducing risks to public safety and security, USDOT said. The program is designed to provide regulatory certainty and stability to local governments and communities, UAS owners and operators who are accepted into the program.
In less than a decade, the potential economic benefit of integrated unmanned aerial systems into the nation’s airspace is estimated to equal up to $82 billion and create up to 100,000 jobs, according to an economic report by the Association for Unmanned Vehicle Systems International (AUVSI).
The program will help the USDOT and Federal Aviation Administration (FAA) develop a regulatory framework to:
allow more complex low-altitude operations;
identify ways to balance local and national interests;
improve communications with local, state and tribal jurisdictions;
address security and privacy risks; and
accelerate the approval of operations that currently require special authorizations.
“This program supports the president’s commitment to foster technological innovation that will be a catalyst for ideas that have the potential to change our day-to-day lives,” Chao said. “Drones are proving to be especially valuable in emergency situations, including assessing damage from natural disasters such as the recent hurricanes and the wildfires in California.”
The pilot program will evaluate a variety of operational concepts, including night operations, flights over people, flights beyond the pilot’s line of sight, package delivery, detect-and-avoid technologies, counter-UAS security operations, and the reliability and security of data links between pilot and aircraft.
Industries that could see immediate opportunities from the program include commerce, photography, emergency management, precision agriculture and infrastructure inspections and monitoring.
“Stakeholders will have the opportunity through this program to demonstrate how their innovative technological and operational solutions can address complex unmanned aircraft integration challenges,” said FAA Administrator Michael Huerta. “At the same time, the program recognizes the importance of community participation in meaningful discussions about balancing local and national interests related to integrating unmanned aircraft.”
A Belgian container terminal is about to become Europe’s largest, and GNSS technoloy will be integrated.
The MSC PSA European Terminal (MPET) in Antwerp, Belgium, is moving its operations from the Delwaidedock on the right bank of the river Schelde to the Deurganckdock on the left bank.
The move is part of an expansion of its capacity of 9 million TEUs annually. TEUs are a 20-foot equivalent unit, a term used to describe the capacity of container ships and container terminals.
When fully moved and operational, the left bank terminal will feature a total of 41 quay cranes across 10 berths, 200 straddle carriers and a quay length of 3,550 meters.
“For this project, we were looking for a positioning solution that was compatible with the solution that has been in use on the terminal since 2008,” said Douwe Witteveen, senior project manager at PSA MPET. “We need to accurately know where every container is picked up and dropped off without interfering with the actions of the driver. “Based on sensors in the vehicle, the GNSS unit must detect a pick-up or drop-off and provide a position to our system. Unfortunately, the receivers used previously were no longer available, so we needed to find someone who could make a new custom integration fast.”
Multipath mitigation copes with GNSS reflections caused by metal cargo containers. (Photo: Airobot)
Airobot was selected by MPET to create a solution, and did so in less than four months, said Jan Leyssens, managing director at Airobot.
The SC-PSA-GNSS unit integrates the AsteRx-m GNSS receiver from Septentrio NV and uses EGNOS to provide submeter accurate positions. The receiver has multipath mitigation technology on board to cope with the many GNSS reflections caused by all the metal containers, and combines GPS and GLONASS to provide a solution close to the quay cranes.
“We started discussions about the requirements in January and have delivered 100 units in less than four months’ time,” Leyssens said. “Fortunately, we have a lot of experience integrating GNSS technology into our drone solutions, so we could act fast. We also listened to the people in the field to make sure the unit is easy to install and existing cable installations could be used.”
“We believed that the know-how and expertise of the Airobot team could help us to get a solution fast, and they delivered what they promised,” said Douwe.
Organized by Professor Zak Kassas from the University of California, Riverside, the workshop will feature presentations and panels by experts and leaders from government (National Science Foundation, Office of Naval Research, Air Force Research Laboratory, Department of Transportation), industry (Google, Daimler, and Ford) and academia (The Ohio State University, UC San Diego, University of Southern California).
The workshop will discuss opportunities and challenges (technical, commercial, ethical, and legal) associated with developing fully autonomous systems that are cognizant and trustworthy for safety-critical applications. Examples include unmanned aerial vehicles (UAVs), self-driving cars and unmanned underwater and surface vehicles.
Kassas, director of the Autonomous Systems Perception, Intelligence, & Navigation Laboratory (ASPIN), leads a team of researchers developing reliable and accurate navigation that exploits existing signals of opportunity, rather than GPS, to meet the stringent requirements of fully-autonomous systems, such as UAVs and self-driving cars.
A new tool that gives users a detailed view of the world’s mountains is now available from the U.S. Geological Survey (USGS).
The Global Mountain Explorer can help users ranging from hikers to scientists, resource managers and policy makers seeking information on these prominent yet often understudied landscapes.
Mountains occupy from 12 to 31 percent of the land surface of the Earth, but despite their importance, few attempts have been made to scientifically define and map these regions worldwide with detail, the USGS said.
The Global Mountain Explorer “allows anyone with access to the Internet to explore where mountains are, whether they are low or high, scattered or continuous, snowy or snow-free,” said USGS ecosystems geographer Roger Sayre, who led the project.
Mountain Explorer provides information from global scales down to specific mountains, such as Borah Peak, Idaho, pictured here. (Public domain)
“Mountain Explorer users can visualize and compare in one place and for the first time the three major global mountain maps that have been produced,” he said.
Mountains provide significant water, timber and mineral resources, and food, fiber and fuel products. They are home to diverse ecosystems and wildlife and are valued for their esthetic beauty and recreational offerings.
Mountain areas are also prone to natural hazards. But despite their importance, surprisingly few attempts have been made to scientifically define and map these regions worldwide with detail.
The USGS developed the Global Mountain Explorer, in partnership with Esri, and three organizations at the University of Bern in Switzerland — the Center for Development and Environment, the Global Mountain Biodiversity Assessment and the Mountain Research Initiative.
Twilight image of snow-covered Mount Shasta with city lights visible at its base. The Global Mountain Explorer allows users to view mountains and surrounding terrain. (Public domain)
The tool was developed as part of a Group on Earth Observations initiative to accurately delineate mountain regions using best available data. It is intended to provide information on the global distribution and a variety of mountain data with a resolution 16 times more detailed than previous mapping efforts.
Users can select an area by zooming in or by typing a place name like Mt. Kilimanjaro to view its elevation and type. They can also select from a number of backdrops — satellite images, topographic maps or political boundary maps— on which to display the different types of mountain classes. A tutorial showing the full features for the Global Map Explorer is shown below.
Thales has launched commercially its next-generation Doppler VHF Omnidirectional Radio ranging system, the DVOR 532. At the same time, Austro Control was announced as the launch customer for DVOR 532 with the signature of a frame contract for deployment in Austria.
While aviation increases its reliance on GNSS, the VHF omnidirectional radio remains a critical aviation infrastructure system due to vulnerability of GNSS signals and nearly universal equipage of aircraft to use VOR signals for navigation, Thales said.
The agreement will see Austrian air space equipped with a modern short- and medium-range enroute navigation technology, help to ensure safe and accurate flight navigation across the Austrian airspace.
DVOR 532 delivers superior navigation signal performance and reduced lifecycle costs in an easy to maintain package.
Thales will deliver, install and provide training for up to eight new DVOR systems to Austro Control. Austro Control will begin to take over operation of the systems as flight checks for the new systems are completed, with the first to take place before the end of 2017.
Thales provides air traffic management systems worldwide, with more than 7,000 navigation aids installed in 170 countries.
The DVOR 532 is a ground-based radio navigation aid for short and medium range for en-route and technical guidance. It transmits an omni-directional signal that enables an aircraft to determine its bearing relative to the location of the beacon.
The Doppler version of the VOR system provides a highly precise azimuth signal, suitable for difficult geographical conditions.
The DVOR 532 meets increasingly demanding international design and safety standards such as DO 278/ED 109 for software assurance.
The NMAS will be the next-generation version of the IAFC’s Mutual Aid Net tool built in 2008. The NMAS will use Esri ArcGIS and Intermedix’s WebEOC, a crisis information management software, to manage and track emergency services resources during mutual-aid responses.
During large-scale emergencies and disasters, it is critical for response personnel to have easy access to a mutual-aid system for managing their resources. WebEOC will allow IAFC to manage information sharing, event reporting and task management in a central, web-based environment that allows IAFC to connect to partner agencies and organizations during response efforts.
The use of spatial data to identify and respond quickly and effectively is also paramount. Esri’s ArcGIS platform brings mutual aid management data into a location context, integrating that information into spatial analysis technology that emergency responders around the world use every day.
The IAFC has long been the leader in supporting state and local fire and emergency management communities in disaster management. The current Mutual Aid Net is used to identify, request and deploy resources for mutual aid support.
The NMAS will use the latest technology to help decision makers accomplish these tasks faster, easier and more accurately.
The use of Intermedix’s WebEOC and Esri’s ArcGIS platforms provides information sharing, decision support and situational awareness capabilities to jurisdictions, regions and countries around the globe.
The foundation of NMAS will be on the WebEOC platform which through the ArcGIS Extension for WebEOC will provide access and integration to Esri online tools and dashboards.
The result of this integration is the near real-time data availability of WebEOC information within ArcGIS Online applications, without the need for any development, middleware or technical expertise.
“The IAFC is extremely pleased to partner with Intermedix and Esri to build the next generation of the National Mutual Aid System,” said Tommy Hicks, IAFC’s Chief Programs & Technology Officer and Assistant Executive Director. “Ensuring that emergency managers and responders have real-time information and resources at their fingertips is an essential to protecting their communities from harm.”
“Identifying the status and availability of resources for mutual aid support has always been challenging,” said Russ Johnson, Esri global director, emergency response. “In today’s environment with increasingly complex multi-jurisdictional incidents, this need is greater than ever. Through the leadership of IAFC and the partnership between Esri and Intermedix, the ability to know the availability of required mutual aid resources and immediately request them will be realized. This will be a major step forward in supporting public safety agencies throughout the country.”
“Intermedix looks forward to our partnership with IAFC and an expansion of our partnership with Esri,” said Bob Watson, Intermedix president of preparedness solutions. “Our mission is to serve those who save lives, and the National Mutual Aid Net project is perfectly aligned with that mission. The only effective way to respond to emergencies is through collaborations and partnerships between public and private organizations. The National Mutual Aid Net takes that principle and puts it into practice. We are honored to be a part of this undertaking.”
Orbital Witness will receive a voucher worth €50,000 for the acquisition of satellite data and will benefit from both technical and business coaching.
The competition encourages startups to innovate and develop new applications primarily based on Airbus’ satellite data. The winning British startup Orbital Witness proposes to use satellite imagery to provide a new perspective for legal due diligence in real estate.
Launched on May 30, the goal of the four-month challenge was to create added value for new businesses focusing on themes identified as important topics for the global population, ranging from forestry and agriculture to smart cities and maritime.
More than 130 projects from five continents were entered for the competition, among which 23 startups were pre-selected based on their originality and relevance as well as their technical and commercial feasibility.
These “semi-finalists” entered a subsequent round to further develop the proposals — this ended with a second selection phase in which the six finalists were chosen.
During the final, held Oct. 20 at the Airbus PlayLab in Toulouse, the six finalists presented their projects in front of representatives of different Airbus departments, including strategy, innovation, and marketing and sales.
The other finalists were:
23insights (the Netherlands), which tracks and predicts the human footprint in forests.
Ozius (Australia), which creates new landscape intelligence by fusing a variety of remote-sensing data to identify where the environmental risks and opportunities occurred in the past, where they are today, and project where they will occur in the future.
Ursa Space Systems Inc. (U.S.), which utilizes radar satellite data to deliver global and unbiased economic intelligence to energy and financial enterprises, providing reliable information about areas of the world that are traditionally opaque.
Qirate (Italy), which enhances position appeal for boosting business locations and helps people find their ideal place to live by rating the quality of life.
Kermap (France), which uses satellite imagery to support the ecological transition of cities.
The runner-up projects also received satellite data vouchers: €20,000 for 23insights, €15,000 for Ozius, €10, 000 for Ursa and €5,000 for Qirate and Kermap.
Two more Galileo satellites have reached Europe’s Spaceport in French Guiana, joining the first pair of navigation satellites and the Ariane 5 rocket due to haul the quartet to orbit this December.
Inside the 747. (Photo: ESA)
Galileos 21 and 22 left Luxembourg Airport on a Boeing 747 cargo jet on the morning of Oct. 17, arriving at Cayenne-Félix Eboué Airport in French Guiana on the same day.
Resting within distinctive white air-conditioned containers, the satellites were driven to the cleanroom environment of the preparation building within the space centre.
Waiting for them there were Galileos 19 and 20, which arrived in September.
The four satellites will be launched together in mid-December by a customised Ariane 5, the elements of which reached French Guiana last month by sea.
Galileos 21 and 22 being unloaded from their 747 cargo aircraft at Cayenne – Félix Eboué Airport in French Guiana on Oct. 17. (Photo: ESA)
Galileo is Europe’s own satellite navigation system, providing an array of positioning, navigation and timing services to Europe and the world.
A further eight Galileo Batch 3 satellites were ordered last June, to supplement the 26 built so far.
With 18 satellites now in orbit, Galileo began initial services on Dec. 15, 2016, the first step towards full operations.
Further launches will continue to build the constellation, which will gradually improve performance and availability worldwide.
Septentrio debuted the AsteRx-m2a and AsteRx-m2a UAS GNSS OEM engines at Commercial UAV 2017, held Oct. 24-26 in Las Vegas.
The two new OEM boards provide precise and reliable multi-frequency, all-in-view real-time kinematic (RTK) positioning and heading — along with interference technology — with low power consumption, the company said.
Both boards are smaller than a credit card and feature Septentrio’s AIM+ interference mitigation and monitoring system. AIM+ can suppress a wide variety of interferers, from simple continuous narrowband signals to the most complex wideband and pulsed jammers.
The AsteRx-m2a board by Septentrio. Photo: Septentrio
Increasing levels of radio-frequency pollution, coupled with the intrinsic danger of self-interference in compact systems such as UAS, makes interference mitigation a vital element in any UAS system that uses GNSS positioning.
Both boards are designed to bring high-precision positioning and attitude to any space-constrained application. According to the company, both receivers are designed to serve as core components in any multi-sensor application.
The AsteRx-m2a UAS is aimed specifically at unmanned applications, bringing plug-and-play compatibility for autopilot systems such as ArduPilot and Pixhawk. Event markers accurately synchronize camera shutter events with GNSS time. The board can be powered directly from the vehicle power bus via its wide-range input.
The AsteRx-m2 UAS board by Septentrio. Photo: Septentrio
The AsteRx-m2a UAS works seamlessly with GeoTagZ software, providing offline re-processed RTK accuracy without the need for either ground control points or a real-time datalink.
“We’ve taken the hugely successful AsteRx-m2 and added a second antenna input for high-precision GNSS heading,” said Gustavo Lopez, OEM product manager at Septentrio. “No need to manoeuvre around in a figure of ‘8’ trying to initialise INS heading or find space or additional power for a separate INS module now. All you need is a second antenna and you’re good to go.”
Septentrio is located at booth 206 of Commercial UAV Expo 2017.
We examine the performance of EGNOS in Finland, which lies near the northeast periphery of the coverage area, and how this performance can be improved now and in the future.
By Mohammad Zahidul H. Bhuiyan, Heidi Kuusniemi, Auryn Soderini, Salomon Honkala and Simo Marila
INNOVATION INSIGHTS with Richard Langley
“[O]NE ORBIT, WITH A RADIUS OF 42,000 KM, has a period of exactly 24 hours. A body in such an orbit, if its plane coincided with that of the earth’s equator, would revolve with the earth and would thus be stationary above the same spot on the planet. … [A] transmission received from any point on the hemisphere could be broadcast to the whole of the visible face of the globe, and thus the requirements of all possible services would be met.” So wrote writer and futurist Arthur C. Clarke in his October 1945 Wireless World article “Extra-terrestrial Relays: Can Rocket Stations Give World-wide Radio Coverage?,” envisaging the geostationary orbit (GEO) communication satellite.
The first GEO satellite was Syncom III, orbited by the United States in August 1964. Since then, more than 1,000 satellites have been launched into what is known as the Clarke Belt and around 450 are presently active. Most of them are used for civil or military communication. Some are used for direct-to-user TV and radio. Some are used for weather monitoring and other kinds of surveillance. And some are used for augmenting GPS.
While GPS is a remarkable positioning system, its real-time accuracy using L1-frequency pseudorange measurements and its instantaneous integrity are not sufficient for some applications such as aircraft navigation. That is why the U.S. Federal Aviation Administration developed the Wide Area Augmentation System (WAAS), the first satellite-based augmentation system (SBAS). WAAS provides differential correction data and integrity information to GPS users in real time throughout most of North America using a “bent pipe” from a ground station through the GEO satellite to a user’s equipment. It uses a state-space-domain correction approach, which provides corrections for the satellite orbit and clock data transmitted by GPS satellites along with ionospheric propagation delays, all computed from measurements collected by a continent-wide tracking network.
The WAAS concept has been duplicated for other regions. Three other SBASs are in full operation: the European Geostationary Navigation Overlay Service (EGNOS), Japan’s Multifunctional Transport Satellite Satellite-based Augmentation System, and India’s GPS-aided GEO Augmented Navigation System. Russia’s System for Differential Correction and Monitoring is currently in development.
One hitch with GEO satellites whatever their function is their inability to service high latitudes well. At a latitude of 65°, a GEO satellite has an elevation angle of only around 17° at most and at 75°, it’s about 6° or less. Even if a GEO satellite is above the local horizon, communication might be difficult due to the longer signal path length between the satellite and the user.
And so it is with GEO satellites used for SBAS at high latitudes. And there is an additional problem that even if the signals from an SBAS satellite can be received, corrections for some GPS satellites will not be received if they are outside the coverage area of the SBAS tracking network. In this month’s column, we examine the performance of EGNOS in Finland, which lies near the northeast periphery of the EGNOS coverage area, and how this performance can be improved now and in the future.
FIGURE 1. Finnish national GNSS network, FinnRef. The three stations highlighted in red had the worst positioning accuracy in our analyses.
The European Geostationary Navigation Overlay Service (EGNOS) is the first European-operated satellite navigation system and is a precursor to Galileo, Europe’s independent global navigation satellite system (GNSS), now being deployed. EGNOS, as a satellite-based augmentation system (SBAS) similar to the U.S. Wide Area Augmentation System (WAAS), was developed with the vision to improve the performance of GNSSs, such as GPS and Galileo. At the moment, EGNOS only augments GPS, making it suitable for safety-critical applications such as flying aircraft or navigating ships through narrow channels.
Additionally, EGNOS also supports new applications in many different sectors, such as agriculture (for high-precision spraying of fertilizers), transport (enabling automatic road-tolling or pay-per-use insurance schemes) or even precise personal navigation services for general and specific use.
At present, there are two operational geostationary Earth orbiting (GEO) satellites and until March 2017, these satellites had pseudorandom noise code (PRN) numbers 120 and 136 that simultaneously broadcast EGNOS correction messages to European GPS users. The PRN satellites 120 and 136 are located at 15.5°W and 5.0°E. (Since March, PRN 123 has replaced PRN 136 as one of the operational EGNOS satellites.) The use of EGNOS in the northern Europe is much more challenging than elsewhere in Europe due to the relatively low-elevation angle of some EGNOS satellites as seen from there of about 14° or less.
To improve our understanding of the true performance of EGNOS in Finnish territory, we recently carried out a project entitled “Finland’s EGNOS Monitoring and Performance Evaluation (FEGNOS).” At the northeastern edge of the EGNOS coverage area, the availability of the EGNOS geostationary satellites is compromised due to their low-elevation angles. The Finnish Geospatial Research Institute (FGI) at the National Land Survey of Finland (NLS) maintains a network of 20 permanent GNSS reference stations (FinnRef) all over Finland. The core objective of the FEGNOS project is to evaluate the performance of EGNOS at all of those reference stations to determine if the EGNOS system performance reaches its target in Finland.
Building on our initial research, in this article we report on the analysis of EGNOS performance at all 20 FinnRef stations for a year-long time-frame from November 2015 until October 2016. As it is of importance to compare the performance of EGNOS in a geographic region where EGNOS satellite visibility can be poor due to low-elevation angle, we assessed the performance of EGNOS by comparing the receivers’ own decoded SBAS messages against the SBAS messages provided by the EGNOS Data Access Service (EDAS). The daily EDAS SBAS messages can be freely downloaded from the EDAS server with prior authentication from EDAS. The performance analysis has been carried out for the following three cases:
Applying EGNOS corrections obtained from the EDAS server
Applying EGNOS corrections obtained from the receiver-decoded (Rx-decoded) EGNOS messages
GPS stand-alone solution without any EGNOS corrections.
We carried out the data analysis using the EGNOS analyzing tool called PEGASUS (which originally stood for Prototype EGNOS Analysis Using SAPPHIRE, where SAPPHIRE stands for Satellite and Aircraft Database Programme for System Integrity Research) from Eurocontrol. The results show that the Rx-decoded EGNOS performance is not as good as the performance obtained from the EDAS-offered message corrections. The ongoing experience and knowledge learned from the project has helped to identify weaknesses of the EGNOS system at high northern latitudes.
FINNISH NATIONAL GNSS NETWORK, FINNREF
The Finnish National GNSS network, FinnRef, was established on the initiative of the Nordic Geodetic Commission and the director generals of the Nordic Mapping Authorities in the 1990s. FinnRef is part of the Nordic GNSS network, and some stations of the FinnRef network also contribute to the global International GNSS Service (IGS) network and to the European Permanent Network (EPN). The primary function of FinnRef is to offer geodetic-grade GNSS measurements, which have been continuously used for forming and maintaining the national coordinate system (EUREF-FIN). In addition, the FinnRef network is used for many GNSS-related research activities. For example, it is now possible to analyze the positioning performance of different augmentation services via the FinnRef network. Currently, FinnRef also offers an open positioning service based on the differential GNSS (DGNSS) corrections for GPS and GLONASS.
The FinnRef network was renewed during the 2012–2013 timeframe. The renewed FinnRef network now consists of 20 GNSS reference stations, as shown in FIGURE 1. The raw GNSS data from all 20 reference stations is used in the FEGNOS project for EGNOS performance monitoring and analysis.
DATA COLLECTION
EGNOS signal monitoring at all FinnRef stations was carried out for one year from Nov. 4, 2015, until Oct. 31, 2016. There are in total about 360 days of data from the 20 stations out of a possible 366 days (2016 was a leap year). The day-of-year (DOY) information for the collected data set is detailed in TABLE 1. No data was available during DOY 233 and 234 of 2016 due to a technical fault at the FinnRef stations. There are 57 days of data from the year 2015 and 303 days of data from 2016.
Table 1. DOY information for the year-long data set.
Each FinnRef station is equipped with a dual-frequency geodetic-grade receiver. Each receiver generates 1-hour binary proprietary data files with a 1-Hz data rate. Data is pushed to the network server and saved at the conclusion of each hour. This means that there are in total 24 data sets for each single day for one single station. All the stations’ binary data files are then organized under one directory, which is named after DOY for that particular year. The FEGNOS data Collection Tool (FEGCoT) was developed in Matlab to collect data every day automatically from all 20 FinnRef stations.
These three steps are followed for automatic data collection:
Collect: 1-Hz hourly data is collected from the FinnRef server, and then saved to the local hard disk for further processing.
Convert: The saved raw binary-formatted hourly data files from the receivers are converted to RINEX observation, navigation and SBAS data files via the receiver manufacturer’s converter.
Combine: In this step, all 24 one-hour data sets from each station are combined into one single 24-hour data set for every RINEX file type (that is, observation, navigation and SBAS files).
The combined 24-hour RINEX data file for each station is then processed using the PEGASUS software. The key configuration parameters used in the data analysis are listed in TABLE 2. (Note that airborne accuracy designator refers to specifications in the WAAS Minimum Operational Performance Standards, MOPS.)
TABLE 2. PEGASUS configuration parameters.
Two PEGASUS modules are used for data analysis:
Convertor module: The Convertor module translates the RINEX observation, navigation and SBAS data into a generic format, which can then be used by the GNSS_Solution module for detailed analysis. Convertor can also use input from different GNSS/SBAS receivers and then transform the recorded binary data into readable ASCII data.
GNSS_Solution module: The GNSS_Solution module is used to compute a position solution in conformance with the MOPS for GNSS receivers used in avionics (GPS, SBAS or ground-based augmentation systems). In other words, the GNSS_Solution module can be considered as a post-processing MOPS-compliant GNSS receiver. It interfaces with other PEGASUS components, notably the Convertor module.
The elevation cut-off angle and the minimum accepted signal-to-noise ratio are kept low so as to have more satellites available for user-position computation. (The European Global Navigation Satellite Systems Agency (GSA) advises that range measurements from EGNOS satellites not be used for position computation.)
A Matlab-script was written to download EDAS-provided daily SBAS messages automatically from the EDAS server. All the PEGASUS-related processing was also executed by a Matlab-based script.
ANALYSIS OF RESULTS
We analyzed the EGNOS/GPS performance for the above-mentioned cases with the collected year-long data set from the 20 FinnRef stations. The operational time or uptime of each FinnRef station was monitored throughout the FinnRef network nodes on a daily basis. The average uptime of each station for the one-year data set is shown in FIGURE 2. The “b” in station names indicates one of the two data streams available from each station. The figure shows that most of the stations were up for more than 98% of the time, while only few have uptimes close to 95%.
FIGURE 2. Station uptime for all FinnRef stations for the year-long data set.
According to EGNOS Open Service (OS) horizontal and vertical accuracy requirements, the 95% Horizontal Navigation System Error (HNSE) should be less than 3 meters, and the 95% Vertical Navigation System Error (VNSE) should be less than 4 meters in the EGNOS service provision area. The horizontal and vertical position errors at a defined time epoch are computed as the difference between the estimated navigation position and the actual position in horizontal and vertical planes, respectively. The HNSE (95%) and VNSE (95%) were computed for all FinnRef stations with the year-long data set.
The yearly EGNOS performance in terms of HNSE (95%) and VNSE (95%) are shown in FIGURES 3 and 4, respectively. It can be observed that GPS+EGNOS offers significant accuracy improvement compared to GPS stand-alone solutions for all of the stations. Vertical accuracy improvement for EGNOS is greater than the horizontal improvement, mostly due to the better mitigation of ionospheric error compared to stand-alone GPS. We also observed that the Rx-decoded EGNOS performance is not as good as the performance when corrections are obtained from the EDAS server. This might be due to the poor visibility of the EGNOS satellites at northeastern latitudes, which resulted in data aging or partial data loss of EGNOS messages.
FIGURE 3. HNSE (95%) for all FinnRef stations.FIGURE 4. VNSE (95%) for all FinnRef stations.
In FIGURES 5 and 6, the daily EGNOS performance in terms of VNSE (95%) are shown for the two cases: 1) applying EGNOS corrections from EDAS-provided EGNOS messages, and 2) applying EGNOS corrections from Rx-decoded EGNOS messages, respectively.
FIGURE 5. VNSE (95%) performance over time with GPS+EGNOS (EDAS) corrections.FIGURE 6. VNSE (95%) performance over time with GPS+EGNOS (Rx-decoded) corrections.
For a better understanding, the percentage of EGNOS OS requirement failure when analyzed on a daily basis with EDAS offered corrections is presented in FIGURE 7.
FIGURE 7. Percent of EGNOS OS requirement failure with EDAS-provided EGNOS correction messages.
The percentage of EGNOS OS requirement failure was computed from the number of days where the HNSE (95%) ≥3 meters in the case of horizontal navigation solution error and VNSE (95%) ≥ 4 meters in the case of vertical navigation solution error. As observed from Figures 5 and 7, the EDAS offered EGNOS corrections fail to meet the OS requirement only in a few instances. Similarly, the percentage of EGNOS OS requirement failure when analyzed on a daily basis with Rx-decoded corrections is presented in FIGURE 8. It can be easily seen from Figures 6 and 8 that the Rx-decoded EGNOS performance fails to meet the OS requirement in many instances. However, the daily fluctuations are averaged out when the year-long data is taken into account, providing satisfactory performance on the whole.
FIGURE 8. Percent of EGNOS OS requirement failure with Rx-Decoded EGNOS correction messages.
The yearly EGNOS performance in terms of VNSE (99%) is shown in FIGURE 9.
FIGURE 9. Sorted VNSE (99%) performance with GPS+EGNOS (EDAS) corrections for all FinnRef stations.
The three stations with the worst accuracy are highlighted in red in Figure 1. These stations are located on the northeastern border of the EGNOS coverage area. The EGNOS User Differential Range Error Indicator (UDREI) figure for three stations (FINb, VIRb, and SAVb) is shown in FIGURE 10(a), 10(b) and 10(c), respectively.
FIGURE 10. EGNOS UDREI as seen at (a) FINb, (b) VIRb and (c) SAVb.
The stations were chosen so that they represent a wide geographical spread over Finland. According to Figure 10, the satellite UDREI values are in the range of 14 and 15 (marked as blue) at the northeastern edge of the sky plot. A UDREI of 14 indicates “not monitored” and 15 indicates “do not use” for a particular satellite. Even though the satellites had a moderate elevation angle with respect to the user, the EGNOS system was unable to offer corrections to those satellites in the northeastern sky. Relatively lower availability of GPS satellites coupled with the lower number of EGNOS Ranging and Integrity Monitoring Stations (RIMS) at northeastern latitudes contributed to the poorer than expected positioning performance in the northeastern coverage area of EGNOS.
CONCLUSIONS
In this article, we presented a summary of an analysis of EGNOS in Finland for a year-long period, and we explained our automated data collection and data analysis procedure. The following key observations can be made based on the analysis of the year-long data set:
The use of EGNOS significantly improves the positioning performance compared to GPS stand-alone operation.
The vertical accuracy improvement for EGNOS is higher than the horizontal improvement compared to GPS stand-alone performance.
The performance of EGNOS with the receivers’ own decoded message corrections is not as good as the performance obtained through EDAS-provided EGNOS corrections.
EGNOS does not offer corrections for those GPS satellites that are setting in the northeastern sky of the EGNOS coverage area.
The percentage of EGNOS OS requirement failure when analyzed on a daily basis with Rx-decoded corrections is significant. This is mostly due to the poor visibility of GEO satellites from northeastern latitudes.
These findings emphasize the fact that there is a great need at northeastern latitudes for an alternative solution to the GEO satellites broadcasting EGNOS corrections. The existing alternative solution is to download the corrections from the Internet through EDAS at the cost of an additional communication link. The other possible alternative could be to broadcast corrections via inclined geosynchronous orbit satellites, or by some other means.
ACKNOWLEDGMENTS
This article is based on the paper “Performance of EGNOS in North-East European Latitudes” presented at the 2017 International Technical Meeting of The Institute of Navigation held Jan. 30–Feb. 1, 2017, in Monterey, California. The research was conducted within the FEGNOS project, funded by the Finnish Transport Agency and the Finnish Geospatial Research Institute at the National Land Survey of Finland. More information about the FEGNOS project can be found at www.fegnos.net.
MANUFACTURER
The receivers in the FinnRef network are JAVAD GNSS Inc. Delta-G3Ts and the antennas are JAVAD RingAnt_DMs with SCIS radomes.
MOHAMMAD ZAHIDUL H. BHUIYAN received his Ph.D. degree in 2011 from the Department of Electronics and Communications Engineering, Tampere University of Technology, Finland. He is a research manager in the Department of Navigation and Positioning at the Finnish Geospatial Research Institute (FGI) of the National Land Survey of Finland in Kirkkonummi. He is also the acting deputy head of the institute’s Satellite and Radio Navigation Research Group.
HEIDI KUUSNIEMI is the director of FGI’s Department of Navigation and Positioning. She is also an adjunct professor in the Department of Built Environment at Aalto University in Espoo and in the Department of Electronics and Communications Engineering at Tampere University of Technology. She is also the current president of the Nordic Institute of Navigation. She received her M.Sc. and D.Sc.(Tech.) degrees from Tampere University of Technology in 2002 and 2005, respectively.
AURYN SODERINI is an M.Sc. student in the Department of Electronics and Communication Engineering at Tampere University of Technology. He received his B.Sc. in 2012 from the Department of Electronics Engineering at The Third University of Rome.
SALOMON HONKALA is a researcher at FGI. He holds an M.Sc. (Tech.) degree in electrical engineering from Aalto University.
SIMO MARILA is a research scientist in FGI’s Department of Geodesy and Geodynamics. He received an M.Sc. degree in 2011 from Aalto University.
FURTHER READING
• Authors’ Conference Paper
“Performance of EGNOS in North-East European Latitudes” by M.Z.H. Bhuiyan, H. Kuusniemi, A. Soderini, S. Honkala and S. Marila in Proceedings of the 2017 International Technical Meeting of The Institute of Navigation, Monterey, California, Jan. 30–Feb. 1, 2017, pp. 627–636.
• Authors’ Related Work
“Performance Comparison of Differential GNSS, EGNOS and SDCM in Different User Scenarios in Finland” by S. Marila, M.Z.H. Bhuiyan, J. Kuokkanen, H. Koivula and H. Kuusniemi in Proceedings of ENC 2016, European Navigation Conference 2016, Helsinki, Finland, May 30–June 2, 2016, doi: 10.1109/EURONAV.2016.7530550.
“Low-Cost Precise Positioning Using a National GNSS Network” by M. Kirkko-Jaakkola, S. Söderholm, S. Honkala, H. Koivula, S. Nyberg and H. Kuusniemi in Proceedings of ION GNSS+ 2015, the 28th International Technical Meeting of the Satellite Division of The Institute of Navigation, Tampa, Florida, Sept. 14–18, 2015, pp. 2570-2577.
“Finnish Permanent GNSS Network: From Dual-frequency GPS to Multi-satellite GNSS” by H. Koivula, J. Kuokkanen, S. Marila, T. Tenhunen, P. Häkli, U. Kallio, S. Nyberg and M. Poutanen, in Proceedings of UPINLBS 2012, the 2nd International Conference and Exhibition on Ubiquitous Positioning, Indoor Navigation and Location-Based Service, Helsinki, Finland, Oct. 3–4, 2012, doi: 10.1109/UPINLBS.2012.6409771.
• European Geostationary Navigation Overlay Service
EGNOS – the European Geostationary Navigation Overlay System – A Cornerstone of Galileo, edited by J. Ventura-Traveset and D. Flament, ESA SP-1303, European Space Agency, Noordwijk, The Netherlands, 2006.
• EGNOS Data Access Service
“EDAS (EGNOS Data Access Service): Differential GNSS Corrections for Land Applications” by J. Vázquez, E. Lacarra, M.A. Sánchez and Pedro Gómez in Proceedings of ION GNSS+ 2016, the 29th International Technical Meeting of the Satellite Division of The Institute of Navigation, Portland, Oregon, Sept. 12–16, 2016, pp. 3550–3561.
“Satellite Based Augmentation Systems” by T. Walter, Chapter 12 in Springer Handbook of Global Navigation Satellite Systems, edited by P.J.G. Teunissen and O. Montenbruck, published by Springer International Publishing AG, Cham, Switzerland, 2017.
Minimum Operational Performance Standards for Global Positioning/Satellite-Based Augmentation System Airborne Equipment, RTCA/DO-229E, prepared by SC-159, RTCA Inc., Washington, D.C., Dec. 15, 2016.
The Transportation Safety Board of Canada (TSB) is conducting an investigation into the collision between a drone and a passenger aircraft that took place on approach to the Jean Lesage International Airport in Québec City on Oct. 12.
On that day, a Beech King Air A100 operated by Skyjet M. G. was on an instrument flight rules flight from the Rouyn-Noranda (Quebec) airport to the Jean Lesage International Airport in Québec City with two crew members and six passengers on board.
The aircraft was approaching runway 24 and had just passed the final approach fix when the crew noticed an unmanned aerial vehicle (UAV) off the left wing. The aircraft struck the UAV at an altitude of 1500 feet and the crew declared an emergency.
Aircraft rescue and firefighting services were deployed and the aircraft safely landed on runway 24. The aircraft inspection revealed a few scratches and some paint transfer on the top surface of the left wing and scrape marks on the de-icing boot.
The aircraft was then returned to service. No one was injured.
As a U.S. military system, GPS provides all the PNT capabilities they need for defense — until it doesn’t.
Though the accuracies are great and the encrypted signal is resistant to spoofing, its weak signal is very susceptible to jamming. GPS World will host a webinar Nov. 16 to examine ways to augment GPS/GNSS to add resiliency so critical military systems have assured PNT. Registration is free.
Speaker Mikel Miller — Air Force officer (ret.), chief scientist for PNT and instructor — said, “As military operations have evolved over time, three critical technologies have become foundational in synchronized, precision military operations: resilient PNT, resilient communications and resilient cyber. A system-of-systems architecture that integrates and optimizes these three technologies is required to provide trusted and resilient PNT information in GNSS denied/degraded environments.”
Sponsored by precision time company Spectracom, the webinar takes place Nov. 16 at 1 p.m. EST / 10 a.m. PST / 7 p.m. (1900h) Central European Time.
Read about the speakers and their topics below.
Lisa Perdue Product Manager and Applications Engineer, Spectracom
Perdue is an expert in testing critical GPS and GNSS systems. She has trained hundreds of engineers and technicians who are responsible for high-reliability positioning, navigation and timing (PNT) applications. She took a lead role in the development of the first GNSS Vulnerability Test System and speaks widely on the topic at many industry conferences. Perdue is Spectracom product manager at Orolia, where she directs the organization’s GNSS simulation activities and contributes to its entire portfolio of resilient PNT solutions. She has more than 15 years of navigation and RF systems experience, which includes 10 years of service with the U.S. Navy, where she was a certified master training specialist.
Mike Jones
GPS World contributing editor for Defense; Capability Lead for Array Processing, Roke Manor Research
Jones leads the Array Processing group at Roke Manor Research, where he is also a senior consultant engineer. He has an exceptionally broad skill base encompassing sensing, communications, navigation and electronic warfare, and has particular specialist interest in GNSS adaptive antenna systems and direction-finding technology. He has detailed technical knowledge of adaptive antenna GPS systems and was jointly responsible for the development of a number of navigation protection systems using interference cancellation, adaptive beamforming and direction finding. His work is in service on a variety of MoD and DoD airborne platforms around the world. He specializes in the simulation, modeling and hardware implementation of advanced signal processing algorithms, and has led a number of FPGA and ASIC designs for radar, GPS and communications systems. He is also a Fellow of the Royal Institute of Navigation.
Mikel Miller Vice President for PNT Technologies at Integrated Solutions for Systems (IS4S); Former U.S. Air Force Research Laboratory
Miller is building a broad, multi-disciplinary research and development group at IS4S, focused on aspects of PNT and autonomous system science and technology. He began his career as a satellite systems engineer assigned with the U.S. Air Force, holding numerous test, research and development, and program management positions. After earning his Ph.D., he served as an assistant professor of electrical engineering at the Air Force Institute of Technology until his retirement from the Air Force as a lieutenant colonel in 2003. Most recently, he served as the chief scientist for PNT Technologies for the Air Force Research Lab Sensors Directorate. He has authored/co-authored more than 65 journal articles, technical papers and documents, as well as a NATO handbook on navigation technologies. He is a Fellow and past president of the Institute of Navigation (ION) and a past chairman of the Joint Service Data Exchange.
Randy Villahermosa Executive Director, iLAB, The Aerospace Corporation
Villahermosa will speak on research concepts in complementary PNT, including open-source frameworks and the potential role of signals-of-opportunity navigation.
Alan Cameron, Moderator Editor-In-Chief and Publisher, GPS World
Alan Cameron is editor-in-chief and publisher of GPS World magazine, where he has worked since 2000. He also writes the monthly GNSS Design & Test newsletter.
Mike Jones
Mikel Miller
Randy Villahermosa
