GPS World

Category: GNSS

  • EGNOS Operations Introduced in Mediterranean Region: MEDUSA

    EGNOS Operations Introduced in Mediterranean Region: MEDUSA

    By Ugo Celestino, European Commission, Antonella Di Fazio, Telespazio SpA, Vicente José Giner Herrera, Ineco, Patrizio Vanni, ENAV SpA, and Francisco Javier Deblas, ESSP.

    This article describes a live demonstration of an aviation application in Tunisia, to help the local aviation community in validating the use of the European Geostationary Navigation Overlay Service (EGNOS) to guide airplanes during landing operations. This activity constitutes the first complete experience of EGNOS Safety of Life (SoL) service for aviation approaches outside Europe. We present here the obtained results that are useful not only for Tunisia, but as a valuable case study for other countries outside Europe interested in using EGNOS in aviation.

    EGNOS, operational since 2009, has a European regional coverage that could be quite easily extended to areas adjacent to European Union through the deployment of limited additional ground infrastructure elements, but sharing the same existing space segment and leveraging the other core ground infrastructure.

    The European Commission has put in place a series of actions since 2006 to support the EGNOS service extension in neighbouring areas. The MEDiterranean follow-Up for EGNOS Adoption (MEDUSA) is an on-going European initiative related to EGNOS extension in the Euromed region, including North African and Middle East countries around the Mediterranean basin: Algeria, Egypt, Israel, Jordan, Lebanon, Libya, Morocco, Palestine, Syria, and Tunisia. MEDUSA runs a program of technical assistance action in these Euromed countries, in order to prepare them for an optimal adoption and exploitation of European GNSS services in their priority market segments.

    The Mediterranean Extension of EGNOS

    EGNOS is Europe’s first venture into satellite navigation and paves the way for Galileo, Europe’s independent global satellite navigation system currently under deployment.

    EGNOS is a satellite-based augmentation system (SBAS), whose signal is compliant to the international SBAS interoperability standards: standards – MOPS (Minimum Operational Performance Standards) and ICAO SARPs (International Civil Aviation Organization Standard and Recommended Practices).  In its current version (V2) it augments the open public service offered by the American Global Positioning System (GPS), by providing correction data that enables to improve GPS position accuracy, and provides integrity information about the GPS system (integrity information is fundamental for aeronautical applications like approaches). EGNOS is interoperable with the other equivalent regional systems. Today other SBASs are the U.S Wide Area Augmentation System (WAAS), the Japanese Multi-functional Satellite Augmentation System (MSAS), the Indian GPS Aided Geo Augmented Navigation (GAGAN) and the Russian System for Differential Correction and Monitoring (SDCM). The future version (V3) of EGNOS will augment Galileo signal as well.

    Today EGNOS is operational, and available for use in aviation since 2011, giving opportunities for users to have more accurate and reliable positioning for enhancing existing applications, developing new applications and particularly the safety critical ones. Already more than 150 landing procedures are operational across Europe (some of them also in countries out of the European Union, such as Switzerland, Norway, Guernsey), with many others under development to reach 100 percent Approaches with Vertical Guidance (APV) coverage in the European instrumental runways as per ICAO recommendation.

    EGNOS provides three services:

    • EGNOS Open Service (OS), launched in 2009, is delivered free of charge. It is open for use to anyone with an EGNOS-enabled receiver. This can be any receiver compatible with satellite-based augmentation systems. Being based on GPS, the EGNOS signal does not require major changes for receivers. Today, many mass market receivers available on the market are also EGNOS enabled. EGNOS OS is particularly suitable for mass market and some applications like surveying.
    • EGNOS Safety-of-life Service (SoL) is authorized for European civil aviation and operational since March 2011. EGNOS SoL delivers the integrity message providing the verification of the GPS system and timely warnings (within six seconds), when the system or its data should not be used for navigation. Since integrity relates to the trust that can be placed in the correctness of the location information supplied by GPS, thanks to this feature EGNOS is able to meet the demands of safety-critical applications in sectors such as aviation.
    • EGNOS Data Access Service (EDAS) launched in 2012, delivers a terrestrial commercial data service. It consists of a server that gets the data directly from EGNOS system and disseminates it via terrestrial networks in real time, within guaranteed maximum delay, security and performance. EDAS is particularly suitable for professional applications. It provides EGNOS raw data and corrections enabling software solutions that implement products and value added services built on them.

    EGNOS infrastructure consists of three geostationary satellites over Europe and a network of ground stations (Ranging and Integrity Monitoring Station – RIMS) located to provide services whose coverage includes southern Europe, North Africa and some Middle East countries.

    The EGNOS RIMS network supports a flexible network geometry that gradually adapts to service coverage requirements evolution. From the originally envisaged coverage over European Union’s countries, the EGNOS RIMS network is being expanded over Europe’s neighbouring areas, thus increasing the number of beneficiary countries. EGNOS SoL service is highly sought by several non-EU countries for the benefits it can bring to their civil aviation, in providing a solution to comply with ICAO requirements for Performance Based Navigation (PBN).

    The present layout of the EGNOS RIMS network is presented in Figure 1.

    Medusa_image001
    Figure 1. EGNOS ground segment.

    Figures 2 and 3 show respectively  today’s coverage of EGNOS OS availability (source: European Satellite Services Provider, the service provider of EGNOS) and the APV-I availability performance commitment provided by EGNOS SoL (source: EGNOS Safety of Life Service Definition Document, EGN-SDD SoL, V2.0, European Commission, 2013), obtained relying on the above presented ground segment.

    Medusa_image002
    Figure 2. EGNOS OS Availability.

    EGNOS OS Availability. The Figure 2 map is obtained by projecting the error at pseudorange level into the position domain. The computed error assumes that the GPS satellites used are those with an elevation angle above the local horizon (with a mask angle of 5º) and does not consider any possible factor depending on local characteristics that could produce different results (optimistic or pessimistic) with respect to the results computed using real receivers located in the considered areas. Moreover, it represents an estimation of EGNOS OS availability during a very limited period of time being an estimation, thus it does not imply any commitment or reference for the performances which can be obtained during different periods.

    Medusa_figure3
    Figure 3. EGNOS APV-I Availability.

    Other initiatives for a further extension in North Africa and Middle East are already being developed, under the umbrella of the Euromed GNSS programme. In parallel with the infrastructure deployment, the Euromed GNSS programme also includes actions to support the introduction and exploitation of EGNOS services. The first stage was completed in the frame of the Euromed GNSS I/MEdiTerranean Introduction of GNSS Services (METIS) project in the period 2006-2009, the second stage is presently running in the frame of the Euromed GNSS II/MEDUSA project. Further initiatives are being planned for 2015 and beyond.

    EGNOS Use in Aviation

    EGNOS was initially designed and developed to be used in aviation, similarly to the U.S. Federal Aviation Administration  WAAS, to support different types of aviation applications and, in particular, to meet the performance requirements set by the International Civil Aviation Organization (Annex 10) for the implementation of APV-I, which enable the implementation of LPV final approaches, as reported in Table 1.

    Medusa_image004
    Table 1. ICAO Operational Requirements.

    EGNOS is one of the GNSS elements recognised by ICAO (Annex 10) as a radionavigation aid. It is an important element of a global SBAS systems mosaic, that started with the American system WAAS in 2003, and that is gradually completed by other more recent SBAS: EGNOS itself, MSAS (Japan), GAGAN (India), SDCM (Russia), and some countries like Australia and South Korea that have launched feasibility studies to develop their own SBAS.

    It is expected that, in a not too far future, most parts of the world will profit from SBAS services, following the current coverage extension plans and SBAS system evolutions. The final objective, as also shared at ICAO level, is that as many airdromes worldwide, as possible, can offer instrument approaches with vertical guidance, with an outstanding increase in global safety rates.

    Additionally, the use of EGNOS allows taking full advantage of GNSS for all phases of flight, including final approach. Therefore, EGNOS means for aviation a fundamental and strategic tool to help meet ICAO’s recommendations, aimed at the adoption of a PBN oriented airspace use policy, for all countries. The 37th Assembly of ICAO (28 September – 8 October 2010) resolved that APV procedures should be implemented as either a primary or backup strategy for precision approaches at all instrument runway ends by 2016.

    APV is a major safety initiative. ICAO recognises SBAS and Barometric Vertical Navigation (Baro-VNAV) as the two acceptable (and often complementary) means of implementing APV procedures, which are safer than NPA (Non Precision Approach).

    GNSS based navigation enables RNAV (aRea NAVigation) with a higher cost effectiveness in comparison with the old conventional, sensor ground-based, navigation procedures. This is especially true for wide, even desert unequipped areas (or difficult to maintain) like those in North Africa and Middle East.

    EGNOS benefits are maximized in final approach manoeuvres, providing GNSS lateral and vertical guidance, and enabling APV-I approaches.

    Final approach procedures based on GNSS are classified as RNP approaches (RNP APCH, as shown in the next figure), namely: Lateral Navigation (LNAV) with GPS lateral guidance and no vertical guidance; LP with GPS + SBAS (EGNOS) for lateral guidance (CAT-I localizer performance) and no vertical guidance; Lateral Navigation/Vertical Navigation (LNAV/VNAV) with GPS lateral guidance and Baro-Vertical Navigation (VNAV) vertical guidance (Baro-VNAV approach procedures can be flown with SBAS vertical guidance upon the approval of the Air Navigation Service Provider (ANSP)) and the LPV (Localizer Performance with Vertical Guidance) with GPS + EGNOS for both lateral and vertical guidance.

    Medusa_image005
    Figure 4. RNP approaches.

    Those procedures not including vertical guidance are intended to be flown with the Constant Descent Final Approach (CDFA) technique (to avoid dangerous dive and drive practices), supported by most Flight Management Systems (FMS).

    Regarding the operational LPV main figures, the European regulation (EU OPS -REGULATION (EC) No 859/2008 usually known as EU OPS) allows LPV operational minima (Decision Height – DH) down to 250 ft, expected to be possibly lowered down to 200 ft by 2015 (LPV-200), similarly to what is already permitted by the FAA, in the United Sates for WAAS based LPV approaches (a DH of 200 ft would make LPV approaches very competitive, when benchmarked against ILS CAT-I, precision approach, or even Ground Based Augmentation System (GBAS) CAT-I precision approach).

    In the last few years, about 150 LPV procedures (status as of July 2014) have been published in European airports, and the number of procedures and countries introducing EGNOS is continuously increasing.

    Euromed GNSS I/METIS and Euromed GNSS II/MEDUSA

    In parallel with the development of the infrastructures necessary for extending EGNOS availability across the Euromed region, the European Commission has put in place initiatives to prepare and assist the Euromed countries for the optimal use and adoption of the relevant services.

    These consist in two sequential projects, the first being Euromed GNSS I/METIS project and the second being Euromed GNSS II /MEDUSA.

    Running from mid 2006 up to the end of 2009, METIS acted as a pioneer in the Euromed countries and built national/regional liaisons with decision-makers and key stakeholders, interested in sharing experience and absorbing know-how. The project assisted the 10 Euromed countries to identify their priorities in relation to the use of EGNOS services, to validate the relevant opportunities from the strategic/social and economic perspectives, and to elaborate a suitable strategy and a plan of actions for facilitating EGNOS adoption and exploitation.

    MEDUSA Case Study in Tunisia: LPV Approaches in the Airport of Monastir Using EGNOS

    As part of the technical assistance actions programme in the priority domains, MEDUSA implements demonstrations and validations of EGNOS services in concrete applications.

    For EGNOS SoL, the technical assistance action consisted in the validation of GNSS approaches, including LPV approaches, designed and constructed in MEDUSA along with the relevant safety assessment and business case for the airport of Monastir in Tunisia (35°45’29’’ N 10°45’17’’ E). The selection of the airport was driven by a trade off between the EGNOS service availability with required APV-I performances and the specific needs of the Tunisian Air Navigation Service Provider – ANSP (OACA, Office de l’Aviation Civile et des Aéroports). According to OACA, Monastir is among the airports in Tunisia presenting favourable conditions, in terms of operational constraints and traffic, for concretely proving the added value of EGNOS for final approaches.

    The airport has two runways, RWY 07 and RWY 25, the former is equipped with an ILS CAT-I, the latter only supports NPA approaches. The installation of an ILS in RWY 25 was discarded due to technical constraints. This infrastructure has proven to be insufficient to fully cover the airport needs, that suffers some Delays-Diversions-Cancellations (DDCs) as a result of local specific meteorological conditions, frequent fog banks entering from the sea in the early morning, combined with desert haze. These conditions make LPV ideal procedures, as backups to RWY 07, and enabling APV approaches to RWY 25. Finally, Monastir’s TWR ATC (Tower Air Traffic Control ) staff has been involved in OACA’s PBN development, for which they were ideal candidates to evaluate the benefits possibly achievable from the use of EGNOS.

    This MEDUSA’s technical assistance action is the first complete experience for the use of EGNOS SoL service outside Europe. It was conceived as a realistic exercise of RNP APCH procedures implementation, following the guidelines provided by ICAO in the “EUR RNP APCH Guidance Material (EUR Doc 025)” and including all the activities required, from the scenario adequacy study to flight validation and the requirements analysis for the final publication in the AIP (Aeronautical Information Publication).  OACA was directly involved in all activities, providing inputs/feedbacks and for training purposes.

    A set of three GNSS based approach procedures was produced for each RWY, following ICAO 8168 PANS OPS design principles. The next figures show the combined charts type elaborated, that include minima boxes for three RNP approaches (LNAV, LNAV/VNAV and LPV). The procedures construction preserves the current Monastir arrivals structure, following airspace management principles and facilitating the operational approval. As illustrated in the charts, in both cases for the three minima the calculated OCH (Obstacle Clearance Height) values improve with respect to the already existing conventional approaches, providing significant operational and safety benefits.

    Figure 5. GNSS approaches for RWY 07.
    Figure 5. GNSS approaches for RWY 07.
    Figure 6. GNSS approaches for RWY 25.
    Figure 6. GNSS approaches for RWY 25.

    An on-site GNSS performance monitoring campaign was performed by OACA, with the support of GEMCO’s staff, 3 months before the flight trials schedule, covering both EGNOS and GPS signal performances. Besides, an APV-I availability study for the area and specifically for Monastir airport during 1 month before the flight validation was purposely elaborated by the European EGNOS service provider (ESSP). Both analyses, confirmed suitable APV-I performance in terms of availability and continuity, making feasible the implementation of LPV approach procedures in line with ICAO prescriptions.

    The next figures show the EGNOS APV-I availability and continuity measured on one day during the period of the flight validation (conducted from 30 January to 1 February 2014), in particular at Monastir airport for the considered time-lag:

    • APV-I availability was over 99%;
    • APV-I continuity presented a total value lower than 5×10-4/15s;
    • 95th percentile of Horizontal APV-I accuracy was between 1.1 and 1.2 meters and the 95th percentile of Vertical APV-I Accuracy is around 1.4 meters, thus showing a very good accuracy level;
    • Horizontal and Vertical safety indexes were lower than 0.25, representing a very good integrity margin.

    Additionally, the results of the on-site GNSS performance monitoring campaign showed quite stable performances with small fluctuations during the whole period of observation, and no problems or outages were observed.

    (EGNOS APV-I Availability is defined as the percentage of epochs in a month in which the Protection Level are below Alert Limits for this APV-I service (HPL<40m and VPL<50m) over the total period (source: ESSP).

    EGNOS APV-I Continuity Risk is defined as the result of dividing the total number of single continuity breaks using a time-sliding window of 15 seconds by the number of samples with valid and available PA navigation solution. A single continuity break occurs if the system is available at one epoch and becomes not available for the following 15 seconds (source: ESSP).)

    Figure 7
    Figure 7. APV-I availability on 31.01.2014.
    Figure 8
    Figure 8. APV-I continuity on 31.01.2014.

    The flight validation campaign was carried out according to ICAO doc 9906 with a Piaggio P180 Avanti II (from ENAV flight inspection department) suitably equipped with UNIFIS 3000 system and a Rockwell Collins FMS 3000 with SBAS LPV approach capabilities.

    Figure 9
    Figure 9. Piaggio P180 Avanti II aircraft and the FMS messages during the flight validation.

    The outcomes of this concrete experience have allowed the Tunisian authorities to identify the main elements for the publication of the validated procedures in their national AIP. They have also contributed to the analysis of the necessary process for the operational adoption of GNSS, including EGNOS, in aviation in countries beyond the EU boundaries.

    The activities performed on performance assessment have been preparatory for discussions on GNSS monitoring and data recording on going at ICAO Navigation System Panel level, that would produce ICAO guidelines for States.

    Therefore, this Tunisia’s “case study” represents a practical and realistic example that could be beneficial for the other non-EU countries in terms of best practice and lesson learnt. Moreover, methodology and guidelines have been derived to be possibly injected to other non-European countries interested to introduce EGNOS operations in aviation.

    Lessons Learned and Outlook

    Through its achievements, MEDUSA is opening the way for the introduction of EGNOS SoL service in North Africa and Middle-East region, and it is also defining a suitable path to be followed by other interested non-European countries. Overall, MEDUSA is continuing to confirm the ability to foster cooperation and involvement in EGNOS programme of the great majority of the Euromed countries. Further to Tunisia, other Euromed countries have already expressed their interest in relation to the EGNOS use in aviation, considering each country’s strategy and also in the light of a common shared regional perspective. Besides, the results obtained by MEDUSA are useful also for other regions interested to use EGNOS in aviation.

    Additionally, MEDUSA is clearly showing that Euromed region, presently lacking the full support of SBAS technologies, represents an opportunity for EGNOS service extension, with many benefits for the countries of the region and for Europe.

    On one hand, being SBAS an effective and efficient technology to enable the aviation community of the Euromed countries to comply with ICAO recommendations on PBN implementation by year 2016 across the region, the services coverage extension of existing SBAS systems (EGNOS in the case of the Euromed countries) can be one of the most efficient ways to move forward. In fact, the Euromed national ANSPs consider the readiness of EGNOS SoL service as one of the main drivers and factors when designing their PBN strategy. EGNOS, which is already operational since 2009 and available for use in aviation since 2011, can deliver added-value services to the Euromed region, just by leveraging the existing European infrastructure with only incremental, marginal and natural extension. The EGNOS coverage extension across the Euromed region can provide significant benefits and particularly to those Euromed countries with few ILS or reduced navaids coverage, and enhance safety and efficiency to the whole aviation community.

    On the other hand, the European Union has to gain from an EGNOS-based long term links with its neighbouring regions, by increasing bilateral/multilateral cooperation and interaction (e.g. assistance, mutual cooperation) among public and semi-public bodies (e.g. ANSPs, Civil Aviation Authorities), by strengthening EGNOS SoL coverage in the southern/peripheries of EU (e.g. Malta, Cyprus, Greece, Southernest Italian islands, Canary islands), by pursuing and supporting other EU policies in several sectors (like transports, e.g. harmonizing aviation safety standards across the Mediterranean, Transport Policy of the Mediterranean Partners), and last but not least by achieving a first step towards EGNOS extension to the whole African continent which will bring in similar, additional benefits just described above.

    A win-win opportunity to be seized.

  • An Early Gift from — and for — Galileo

    They said it wasn’t possible — well to be frank, I said it wasn’t possible – but one of the two “misplaced” Galileo satellites, plucky Doresa, has delivered an early Christmas present to the European GNSS community by providing a first fix on Tuesday, December 9. The signal was received at the European Space Agency’s (ESA’s) technical centre in Noordwijk, the Netherlands and at the Galileo In-Orbit-Validation (IOV) test station at Redu in Belgium. Doresa teamed with the remaining three functioning Galileo IOV satellites to provide a Galileo positioning data first fix with horizontal accuracy better than two metres.

    Since then fixes have also been performed using Galileo’s Public Regulated Service (PRS), the civilian encrypted highest-precision signal and one of the constellation’s unique selling points.

    The satellite had transmitted its first navigation signal in space on November 29, following its attainment of a safer, more stable, and more circular orbit with the perigee some 3,500 kilometres higher than its original placement.

    Doresa’s salvage has been a slow and steady journey since it was placed, with sister satellite Melina, into a fairly useless orbit in August following a launch anomaly. The original orbit, with a 26,000-kilometer apogee and a 13,800-kilometer perigee, prevented their use for navigation services because they were too low during part of their orbit to sense the horizon and correctly determine their own position. They were also getting a daily dose of radiation from the Van Allen belts.

    Elevation

    The elevation of the satellite started in late October and involved 11 firings of Doresa’s on-board thrusters. The craft now has only 15 kilos left from its original 65 kilo fuel payload but, given the fact that normally Galileo satellites are not required to make regular orbital manoeuvres, ESA engineers estimate this should be enough for a good 12 years of operation in the new orbit.

    The next stage will be to repeat this manoeuvre with the second Full Operational Capability (FOC) satellite, Melina, according to a plan to get that into a similar orbit by the New Year. Pending tests of their positioning, navigation, and timing payloads, the two spacecraft are then likely to be able to contribute to the future Galileo navigation constellation. This was confirmed by Didier Faivre, ESA’s director for navigation, during the agency’s ministerial council meeting on December 2 in Luxembourg.

    This end result is the best possible scenario given where the satellites were left after launch and is a considerable triumph for ESA’s mission control teams and flight engineers. Doresa is now able to use its Earth sensor continuously and keep its antennae orientated towards the Earth. Despite more than a month’s exposure to the Van Allen radiation, testing so far has shown no ill effects.

    “The very good geometry of the satellites in the sky relative to the receivers helped us to achieve this result, plus the signal strength of the fifth satellite,” explained Gustavo Lopez Risueno, coordinating the receiver team at the Navigation Laboratory in ESA’s ESTEC technical centre.

    The satellite signals should be usable immediately, in combination with additional navigation message information provided through ground networks, with mass market receivers. In fact the ESTEC Navigation Laboratory, working in conjunction with the European Commission and the European GNSS Agency (GSA), have already performed position fixes with both Galileo and GPS satellites using only navigation-assistance information.

    With some adjustments to the Galileo network’s ground infrastructure, it looks like Doresa and Melina will be able to carry out most of the roles they were originally designed to do. They are the first of 22 Galileo FOC satellites to be built by OHB and launched by ESA over the next few years.

    Toasted antennae

    More good news. The problem with Galileo’s fourth IOV satellite, named Sif, that took it out of action at the end of May seems to have been characterised and — again — indicates that the satellite is not a complete loss to the constellation. While Sif’s E5 and E6 frequency bands are definitively blown, the satellite’s E1 Open Service band should be capable of broadcast.

    The problem appears to have been a defective antennae. The four IOV satellites utilise one antennae design, while the FOC satellites have a different design. Fortunately there is no sign of a similar issue with the three other IOV craft, but they have been operating on reduced power as a precaution while the root cause of Sif’s failure is determined. ESA is currently fail-testing an example of the culprit antennae in the laboratory to see if the failure mode can be characterised.

    “One of the possible root causes links the problem with the power emitted by the antenna. When we know more we’ll decide what to do with the other three. Since this event occurred in May and June, no more issues have arisen,” Faivre said.

    Agreement

    This is all a remarkable turnaround and good news for the wider European GNSS community and those stakeholders who have invested in the Galileo programme and its burgeoning application industry. Let’s hope the good fortune continues through 2015.

    The administrative side of things is certainly moving on with the signing in October of an agreement which delegates a range of exploitation tasks for Galileo from the European Commission to the GSA, providing a framework and budget for the development of services and operations through to 2021.The signing of the agreement is an initial step towards the full Galileo Exploitation Phase. Current planning calls for this exploitation phase to be progressively rolled out from 2015, with full operability scheduled for 2020.

    “With Galileo, we aim to provide a tangible service to European citizens, and this Delegation Agreement ensures we have the tools and funding necessary to achieve this,” said GSA Executive Director Carlo des Dorides. The agreement was signed by Daniel Calleja Crespo of the European Commission and des Dorides. The document specifically sets the actions to be implemented, the amount of funding provided, and the conditions for the overall management.

    Innovation

    In the same month, the First Satellite Masters Conference took place in Berlin on October 23 and 24. The conference encompassed the 2014 edition of the European Satellite Navigation Competition (ESNC). The event was a great showcase for the innovation, skill, and passion of the entrepreneurs, usually young, who are building the satellite application market in Europe.

    For example, the winner of the GSA special prize at ESNC 2014 is developing Galileo modules for the Google Ara modular smartphone concept, a potential game-changer for positioning in the mobile-phone market. Ara uses interchangeable modules to deliver a smartphone that can be whatever a user wants it to be, complete with first- and third-party components including sensors, cameras, radio antennas, and more. Consumers will be able to order them as of January 2015.
    Google developers believe an Ara smartphone will last multiple years, much longer than current hardware, since it won’t be obsolete nearly as quickly. Further, Ara could open the smartphone market to billions of new users across the globe.

    I spoke with Giovanni Vecchione of Deimos Space, who received the € 40 000 GSA/ESNC prize during the awards ceremony at Deutsche Telekom’s magnificent headquarters in the German capital.

    “With a traditional chip structure, all of a smartphone’s functions are currently combined into a single component, which makes it difficult to add or change a function,” explained Giovanni. “With a modular structure, you have the option to simply switch out a component, meaning a smartphone’s capabilities can be easily enhanced.”

    Vecchione’s innovation is to use another of Galileo’s unique selling points: the E5 broadband signal. While mass market smartphones will use the E1 signal, the availability of high-end phones offering enhanced accuracy through the use of the E5 signal will appeal to many users. A second module will implement an external antenna interface. Together these developments could deliver an ARA phone offering high precision (centimetre-level accuracy) positioning and multipath-resistant solutions.

    Wishing you all a very peaceful and prosperous New Year and hoping Santa has your coordinates accurately entered in his sleigh satnav!

    A bientôt, as they say in these parts.

  • First Galileo FOC Satellite on the Air

    Will Be Employable for Surveying, Precise Positioning, and Geodesy

    By Peter Steigenberger and André Hauschild, German Aerospace Center (DLR) / German Space Operations Center

    The first Full Operational Capability (FOC) Galileo satellite started transmitting L-band navigation signals on November 29, 2014. Based on data collected by a global network of GNSS tracking stations of the Cooperative Network for GNSS Observation (CONGO) and the Multi-GNSS Experiment (MGEX) of the International GNSS Service (IGS), we determined that an E1 signal with pseudorandom noise code (PRN) E18 was first tracked at the station LLAG (La Laguna, Tenerife, Canary Islands) at 06:08 UTC.  A few moments later, the satellite’s transmissions were also tracked at other MGEX stations including the E5a, E5b, and E5 AltBOC signals. Based on the computed satellite visibility at various tracking stations, the satellite could be positively identified as GSAT0201, also known as Galileo FOC-FM1 or Galileo 5 with COSPAR ID 2014-050A and NORAD ID 40128.

    FIGURE 1 shows the carrier-to-noise-density ratio (C/N0) of the E18 signals tracked at the CONGO/MGEX station SIN1 (Singapore, using a Trimble NetR9 receiver with a Leica AR25.3 antenna). We selected the signals from this station for analysis due to an E18 pass occurring close to the zenith and covering almost the full range of elevation angles. The E5a and E5b signals (S5X and S7X RINEX identifiers) show very similar performance, whereas the C/N0 values of the E1 signal are 1–2 dB-Hz higher. The C/N0 values of the E5 AltBOC signal (S8X) reach 60 dB-Hz at high elevation angles, which is about 6 dB-Hz higher than the other signals.

    Figure 1. Galileo E18 carrier-to-noise-density ratio for the CONGO/MGEX station SIN1 (Singapore).
    Figure 1. Galileo E18 carrier-to-noise-density ratio for the CONGO/MGEX station SIN1 (Singapore).

    The first pair of Galileo FOC spacecraft was launched on August 22 with a Soyuz launcher from the Guiana Space Centre, Kourou, French Guyana. Due to a malfunction of the Fregat upper stage, the satellites were injected into elliptical orbits with an inclination of about 49° instead of near circular orbits with 55° inclination. In November, the perigee of the first FOC satellite was raised by about 3,500 kilometers by a series of 11 maneuvers with a corresponding reduction in orbit eccentricity from 0.23 to 0.16.

    E18 has been included in the precise orbit and clock solutions of the MGEX analysis center at Technische Universität München (TUM) in Munich, Germany, since December 5. FIGURE 2 shows the detrended estimates of the active Galileo E18 clock for December 7. The presence of a pronounced quadratic term as well the large drift of 33.9 microseconds per day indicate that the active clock is a rubidium atomic frequency standard rather than a more precise passive hydrogen maser. The FOC satellites carry two of each kind of clock.

    Figure 2. Galileo E18 clock estimates for December 7, 2014, with respect to the hydrogen maser at the Ottawa IGS station (NRC1) after removing an offset and drift (blue) or a second order polynomial (red).
    Figure 2. Galileo E18 clock estimates for December 7, 2014, with respect to the hydrogen maser at the Ottawa IGS station (NRC1) after removing an offset and drift (blue) or a second order polynomial (red).

    The TUM orbit and clock product allows researchers to again compute dual-frequency positioning solutions using only Galileo observations, as the In-Orbit Validation satellite E20 has not transmitted an E5 signal since May, when a power anomaly left the satellite with the capability to only transmit an E1 signal. Furthermore, E20 currently does not transmit a navigation message.

    TABLE 1 shows the scatter of single-point positioning using pseudorange (code) observations from the MGEX station MAS1 (Maspalomas, Gran Canaria, Canary Islands) for a Galileo-only, a GPS-only, and a combined Galileo+GPS solution for December 6. At an elevation cut-off angle of 10°, four Galileo satellites were visible from 10:15 until 12:25 UTC (see FIGURE 3). The GPS-only solution covers the same time interval. The start time is not limited by the cut-off angle but an E18 transmission outage from 3:45–10:15 UTC.

    TABLE 1. Single point positioning results for the MGEX station MAS1 (Maspalomas) for December 6, 2014.
    TABLE 1. Single point positioning results for the MGEX station MAS1 (Maspalomas) for December 6, 2014.
    Figure 3. Galileo visibility at the MGEX station MAS1 (Maspalomas) on December 6, 2014. The time period considered in the single-point positioning is indicated by vertical lines.
    Figure 3. Galileo visibility at the MGEX station MAS1 (Maspalomas) on December 6, 2014. The time period considered in the single-point positioning is indicated by vertical lines.

    We used an ionosphere-free linear combination of Galileo E1 and E5 AltBOC code observations and GPS L1 and L2 code observations with a 30-second sampling interval. As the Galileo-only solution suffered from position dilution of precision (PDOP) values of up to 830, a total of 32 epochs with PDOP values greater than 25 were excluded. The geometry of the remaining epochs is still pretty unfavorable. At a mean PDOP value of 7.4, the standalone position solution exhibits a 3D standard deviation (STD) error of 3.4 meters. Use of the Galileo satellites in a combined GPS+ Galileo solution improves the positioning performance. In particular, the height component benefits from the inclusion of the four Galileo satellites with a standard deviation improvement of 25 percent.

    Despite the orbit injection error, the new Galileo FOC satellite has now been successfully activated and added to the Galileo constellation. Unfortunately, the current orbit is incompatible with the standard Galileo almanac format, which may cause restrictions for some commercial receiver types.

    Nevertheless, the satellite can already be tracked by a wide range of geodetic receivers with existing firmware versions and it will, in fact, be possible to use the new satellite for diverse applications in surveying, precise positioning, and geodesy, as well as in general multi-GNSS studies. We now look forward to the activation of the second FOC satellite, which can be expected in early 2015 and will, for the first time, offer multi-frequency signals from a total of five Galileo satellites.

  • GNSS Frontiers: BeiDou and Ubiquitous Location

    BeiDou Signals, Future Receiver Design Highlighted at Stanford PNT Symposium

    By James D. Litton and Tom Langenstein

    James L. Litton
    James L. Litton

    The Stanford Center for Position, Navigation and Time conducted its eighth symposium on PNT in October 2014. These symposia have always been a superb two (this year three) days of excellent presentations, ranging over the entire domain of PNT, including policy factors as well as technical ones.

    This year the first day featured student speakers, either from Stanford or the students of former Stanford students who are now faculty at other universities. The conference is by invitation only; sponsors include Lockheed Martin, Boeing, and other companies involved with GNSS. This essay highlights two presentations that struck us as harbingers of change in the industry: Greg Turetzky’s paper on ubiquitous location, and Minquan Lu’s and Zheng Yao’s paper on new signal structures for BeiDou.

    Brad Parkinson gave a keynote address mixing challenges and opportunities from the frontiers of policy formation. David Last did not fail to amuse with his lighthearted and satirical commentary on navigation and society at dinner. Many others gave noteworthy presentations, and all of the presentation slides can be found online.

    Tom Langenstein
    Tom Langenstein

    Both papers that we selected for this article have very broad scope with considerable strategic significance in GNSS design and applications. It seems a little impertinent, as well as superficial, to try to convey their essence in fewer than 2,000 words, but the material presented is available elsewhere, too.

    New Signal Structures for BeiDou

    Professors Mingquan Lu and Zheng Yao of Tsinghua University laid out in clear and detailed fashion the motivations for BeiDou’s choosing to introduce new signals for the Phase III global system, analyses of alternative modulations, and the results of bench testing in service to the desired properties (interoperability, acquisition and tracking thresholds, receiver complexity, in-band interference, and so on).

    They emphasized one non-technical or operational motivation: independent proprietary designs for patent protection. No declaration of policy intention was made; however, the direction was clear, even though the authors are university professors and not government officials.

    Some of this work has been published elsewhere in IEEE Transactions by the same authors and has a substantial history, reflecting the lessons learned from the predecessor system designs and very thorough analysis, simulation and bench testing. Space does not allow extensive citation, but the key drivers for the designs and the results are summarized below. The preferred modulations chosen or synthesized are quadrature multiplexed binary offset carrier (QMBOC) for B1C and asymmetric constant envelope-binary offset carrier (ACE-BOC).

    The principal deficiencies cited of the earlier-proposed BeiDou Phase III signals (circa 2010-ICG) were given as:

    • no independent intellectual property rights; thus, a big patent risk 
    • signal performance needs to be improved
    • more flexible receiving modes and more varied application scenarios should be considered.

    The principal requirements for BeiDou Open Service signals were cited as:

    • independent intellectual property rights
    • better compatibility and interoperability with GPS and Galileo
    • smooth transition from Phase II to Phase III
    • improved performance

    Separate requirements were stated for the B1C and B2 signals, as follows:

    B1C: (QMBOC)

    • compatibility with other signals of the same carrier frequency
    • better interoperability with GPS L1 and Galileo E1 signals
    • better ranging accuracy (than GPS C/A and BeiDou Phase II B1(I))
    • receiving mode diversity for different receivers (low-end and high-end)
    • independent Intellectual property rights

    B2C: (ACE-BOC)

    • multiplexed B2a and B2b into a constant envelope signal
    • better interoperability with the GPS L5 and GALILEO E5 signals
    • high ranging accuracy
    • in-band interference-resistant ability (MAI, DME, TACAN, Near-far effect, etc.)
    • joint optimization with B1C
    • independent intellectual property rights

    In the quoted case study tests, simulated ACE-BOC and AltBOC signals were generated at several fixed transmitting power levels and processed using software receivers. For each given transmit power level, the ACE-BOC was allotted three times power for the pilot channel over that of the data channel while the AltBOC allocated equal amount of power for both the pilot and the data channel, that is, 3:1 for ACE-BOC and 1:1 for AltBOC.

    The resulting tracking performance of the ACE-BOC is more robust than that of the AltBOC.

    Table 1, taken from the presentation, provides an overview of the signals.

    Table 1 New signal structures proposed for BeiDou.
    Table 1. New signal structures proposed for BeiDou.

    The compatibility properties of the new signals, if adopted, which seems quite likely, are desirable. The implicit intellectual property aspects of the development, both in motivation and in differential design of a signal structure which seems to be claimed as novel have a defensive basis, apparently, in earlier assertions of proprietary designs. It will be interesting to see whether similar international negotiations follow, or perhaps already have. The paper was well received and stimulated considerable hallway comment.

    Ubiquitous Location

    Turetzky’s paper laid out the phenomenal growth of location-based services and the implications of such growth for design requirements in GNSS-wireless at the user device level and at the silicon level. On growth (from various quoted sources):

    • The compound annual growth rate of GNSS devices will continue, from its current 22 percent level to a robust 9 percent for the years 2016-2022; heading for seven billion installed units by 2022.
    • The cumulative core revenue in the decade 2012-2022 will be 46 percent in LBS portable and wearable devices and 47+ percent in vehicles.
    • There will be many billions of installations of indoor location technologies by 2018, in virtually every venue imaginable.

    Some of the design implications of the requirements driving the growth in indoor location are:

    • Always Located, or continuous location. For this case, the energy dissipated per day (16 hours) and signal availability (100 percent) are the featured specification and the secondary specification, respectively. These specifications, in turn, require hybrid constellations and minimal standby power consumption.
    • The scaling down to very small (14 nanometer) dimensions enables much faster switching speeds, search rates and lower power dissipation in active modes and more complex algorithms, but at the expense of leakage current, which adversely affects standby power, an increasingly important factor.

    Thus, for GNSS design, the challenges are to:

    • Take advantage of benefits of smaller geometries to achieve higher clock speeds, more memory, lower active power and smaller size, while greatly reducing standby power from leakage;
    • Incorporate new methodologies at chip and system design level; Integrate multiple radios on a single die to reduce cost and size without creating interference to a very sensitive GNSS radio;
    • Integrate multiple radio sources into a single location solution;
    • Bring together a disparate value chain;

    Turetzky outlined a vision for his employer, Intel, to be a leader in all aspects of these revolutionary developments. The technology roadmaps embrace most modalities of positioning: GNSS, Bluetooth, WI-Fi, cellular, and SBAS, and cross most platforms, including wearables. We think that another, unemphasized challenge is in the increasing density of these units with the current specifications on out-of-band-emissions and the spectrum sharing and spectrum management factors in the ubiquity of the devices.

    From Greg Turetzky’s Ubiquitous Location paper, presented at Stanford PNT Symposium.
    From Greg Turetzky’s Ubiquitous Location paper, presented at Stanford PNT Symposium.

    Tune in to our free webinar Receiver Design for the Future, with Greg Turetzky of Stanford speaking on Ubiquitous Location, scheduled for Jan. 15 (1 p.m. EST/ 10 a.m. PST/ 6 p.m. GMT). Register today!

    Both papers represented the dynamism of our industry and its diversity of technologies and practitioners and the service to that industry provided by the remarkably consistent excellence of this symposium.

    James D. Litton heads the Litton Consulting Group and previously played key executive roles at NavCom Technology and Magnavox. 

    Tom Langenstein is executive director of the Stanford Center for Position, Navigation, and Time, and deputy program manager of the Gravity Probe-B project.

  • Eos Positioning Launches Arrow High-Accuracy GNSS Receiver

    Eos Positioning Launches Arrow High-Accuracy GNSS Receiver

    ipad-iphone-samsung-arrow-O Photo: Eos Positioning Systems
    Photo: Eos Positioning Systems

    Eos Positioning Systems has introduced a new line of high-accuracy GNSS receivers for smartphones and tablet computers, including both sub-meter and RTK performance for all mobile platforms: iOS, Android, and Windows.

    Eos’s entry-level product, the Arrow Lite, is Bluetooth compatible with all mobile devices.

    The Arrow 100 is Eos’s advanced real-time, sub-meter GNSS receiver that utilizes both GPS and GLONASS, and is expandable to Galileo, Beidou and QZSS. It offers superior tracking under tree canopy, around buildings and in rugged terrain, the company said. In addition to supporting SBAS in North/Central America, Europe, Northern Africa, Japan, India and Russia, the Arrow 100 also supports OmniSTAR’s worldwide, real-time sub-meter service.

    The most advanced Arrow receiver is the Arrow 200, a dual-frequency, multi-constellation RTK GNSS receiver capable of 1-cm accuracy in real time. The Arrow 200 is an iOS-compatible RTK and OmniSTAR receiver that works with all models of iPads and iPhones via wireless Bluetooth connection. An iOS NTRIP app that allows the user to log into any available RTK network. The Arrow 200 will provide quality RTK performance for years to come because it supports current and future satellite constellations: GPS, GLONASS, Galileo, BeiDou and QZSS, the company said. It also supports OmniSTAR’s G2, XP and HP real-time worldwide decimeter services.

    “After spending more than 12 years designing high-accuracy Bluetooth GNSS receivers, I believe Eos has set the new standard for high- accuracy GNSS receivers that work across all mobile platforms, no matter if it’s iOS, Android or Windows,” said Chief Technology Officer Jean-Yves Lauture.

    All Arrow receivers employ long-range (1-km) universal Bluetooth connectivity so the user can interface to any brand of smartphone or tablet, whether it’s iOS, Android, or Windows-based. A variable-power Bluetooth implementation allows the Arrow receivers to communicate up to one kilometer from the mobile device.

    Arrow receivers have been optimized to run all day on battery power. The battery pack is field-replaceable and rechargeable separately. It contains smart charging logic so expensive battery chargers are not needed.

    All Arrow receivers have been designed to meet IP-67 specifications for immersion in water and are completely dust-proof so they will survive in the harshest environments.

    The Arrow receiver product line is targeted at high-accuracy applications like GIS, environmental, agriculture, electric/gas/water utilities, surveying, machine control, and federal/state/local government.

  • Sanctions Delay Russia’s GLONASS-K2 Program

    Sanctions Delay Russia’s GLONASS-K2 Program

    The second GLONASS-K1 on its way to the launch pad.
    The second GLONASS-K1 rocket prior to launch.

    News courtesy of CANSPACE listserv.

    According to the GLONASS satellite manufacturer, the company will now produce nine GLONASS-K1 satellites rather than move to GLONASS-K2, because of the sanctions restricting the delivery of radiation-resistant electronic components from the West.

    Nikolai Testoyedov, CEO of Information Satellite Systems Reshetnev, told the Russian magazine Vestnik GLONASS, “For a smooth transition to a multi-functional group and due to issues with the very complex GLONASS-K2 satellites, we decided to continue with the GLONASS-K1 intermediate range of satellites, and we are preparing for the launch of nine units of this series.”

    He said the original plan was to launch two K1 satellites and then move to GLONASS-K2 satellites.

    “In the beginning, really, we wanted after the two GLONASS-K1 satellites No. 11 and 12, to go for the launch of more advanced GLONASS-K2 devices. But, unfortunately, the plans had to be adjusted somewhat because of the sanctions restricting the delivery of radiation-resistant electronic components from the West. We have to put a hold on the in-depth development of technical and technological documentation and that delays us in terms of moving ahead by at least a year or two,” he said.

    Russia launched its second GLONASS-K1 satellite on Nov. 30.

  • Salvaged Galileo Performs Its First Navigation Fix

    Salvaged Galileo Performs Its First Navigation Fix

    Scatter plot of the Galileo fix performed in ESA's Navigation Laboratory at its ESTEC technical centre on 9 December 2014. The plot was calculated by the Lab's Septentrio Test User Receiver, with dispersion of less than 2 m.
    Scatter plot of the Galileo fix performed in ESA’s Navigation Laboratory at its ESTEC technical centre on 9 December 2014. The plot was calculated by the Lab’s Septentrio Test User Receiver, with dispersion of less than 2 m.

    News from the European Space Agency

    Galileo’s fifth satellite — recently salvaged from the wrong orbit to begin navigation testing — has been combined with three predecessors to provide its first position fix.

    Test receivers at ESA’s technical centre in Noordwijk, the Netherlands, and at the Galileo In-Orbit Test station at Redu in Belgium received the signals at 12:48 GMT on December 9 from the quartet of satellites and fixed their horizontal positions to better than 2 meters.

    This achievement is particularly significant because the fifth satellite is the first of a new design of 22 Galileo satellites set to be launched over the next few years.

    Further position fixes were then made by France’s CNES space agency in Toulouse, France, as noted by Bernard Bonhoure: “The results are as good as those for the first Galileo fixes in 2013 with the initial four satellites.”

    The following day, fixes were performed using Galileo’s Public Regulated Service, the encrypted highest-precision class of signal.

    “The very good geometry of the satellites in the sky relative to the receivers helped us to achieve this result, plus the signal strength of the fifth satellite,” explained Gustavo Lopez Risueno, coordinating the receiver team at the Navigation Laboratory in ESA’s ESTEC technical centre.

    “This is a significant milestone for the Galileo program because it marks the very first time that a Full Operational Capability satellite has performed a fix together with its In-Orbit Validation predecessors — which were the first four satellites launched into orbit, in 2011 and 2012. This establishes they work together well.

    “While it is not yet possible to make routine use of the fifth Galileo, this shows such an outcome is within our reach.

    Galileo satellite geometry and received signal strength for the December 9 fix using the first Galileo FOC satellite. The first Galileo FOC satellite corresponds to E19 on the left display; IOV PFM to E11, FM2 to E12 and FM3 to E19.
    Galileo satellite geometry and received signal strength for the December 9 fix using the first Galileo FOC satellite. The first Galileo FOC satellite corresponds to E19 on the left display; IOV PFM to E11, FM2 to E12 and FM3 to E19.

    “In particular, it opens the door to its immediate use in combination with additional navigation message information provided through ground networks, which is a standard mode of operation for mass market receivers, such as those found in our smartphones.”

    The fifth and sixth satellites were delivered into the wrong orbit by their Soyuz–Fregat rocket in August. Their elongated orbit took them out to 25,900 km above Earth and back down to 13,713 km, rather than the planned circular path at 23,222 km. The angle of the orbit to the equator was also wrong.

    The satellites’ shifting altitude left them unable to lock onto Earth for part of each orbit, preventing them from being used for navigation purposes.

    But, last month, a series of 11 maneuvers took the fifth satellite into a more circular orbit, some 3500 km higher, allowing its navigation payload to be switched on for testing. A similar salvage operation is planned soon for its companion.

    The main hurdle in using the fifth (and subsequently sixth) satellite operationally is that mass market receivers in particular might take longer to find it. Their orbits fall outside the almanacs satellite-locating standard broadcast within navigation messages.

    Utilizing navigation-assistance information would be a way of shortening acquisition times — and ESTEC’s Navigation Laboratory has already demonstrated it with mass market receivers.

    Working in conjunction with the European Commission and Europe’s Global Navigation Satellite Systems Agency, the Lab performed position fixes with both Galileo and GPS satellites using only navigation-assistance information.

    Test position fix in the grounds of ESTEC, performed with a mass-market receiver using navigation-assistance information, based on signals from the fifth Galileo satellite plus GPS satellites. This satellite's elliptical orbit means extra data are needed to speedily utilize its signals, which could be provided through ground networks. Navigation-assistance information is already employed by the mass market receivers found within smartphones.
    Test position fix in the grounds of ESTEC, performed with a mass-market receiver using navigation-assistance information, based on signals from the fifth Galileo satellite plus GPS satellites. This satellite’s elliptical orbit means extra data are needed to speedily utilize its signals, which could be provided through ground networks. Navigation-assistance information is already employed by the mass market receivers found within smartphones. Source: European Space Agency

    EDITOR’S NOTE: Researchers at the German Aerospace Center (DLR) report on their success in producing a pseudorange-based all-Galileo position fix using precisely determined satellite orbits and clocks from Technische Universität München (TUM) in the January issue of GPS World. Richard Langley reports that his team at the University of New Brunswick has managed to produce a Galileo-only carrier-phase-based precise-point-positioning solution with better than decimeter accuracy using TUM’s orbits and clocks.

    Also, GMV performed a first Galileo-only PPP with IOV + FOC-1 satellite with data from December 6, obtaining centimetric accuracy. Read about their results on their blog.

  • GLONASS-K1 to Replace an Existing GLONASS-M in Six Months

    News courtesy of CANSPACE Listserv.

    According to the December 10 issue of Sibirskii Sputnik (Siberian Satellite), the internal newspaper of ISS Reshetnev, the GLONASS-K1 No. 12 satellite (GLONASS 702K) will be brought into service after a six-month test period and replace an existing GLONASS-M satellite, which will subsequently become a reserve satellite.

    In news reported by the Russian magazine Vestnik GLONASS, Information Satellite Systems Reshetnev, the manufacturer of the GLONASS satellites, will now produce nine GLONASS-K1 satellites.

    “For a smooth transition to a multi-functional group and due to issues with the very complex GLONASS-K2 satellites, we decided to continue with the GLONASS-K1 intermediate range of satellites and we are preparing for the launch of nine units of this series,” said Nikolai Testoyedov, CEO of Information Satellite Systems Reshetnev.

    Testoyedov recalled that the original plan was to launch only two GLONASS-K1 satellites and then move on to the GLONASS-K2 satellites. “In the beginning, really, we wanted after the two GLONASS-K1 satellites No. 11 and 12, to go for the launch of more advanced GLONASS-K2 devices. But, unfortunately, the plans had to be adjusted somewhat because of the sanctions restricting the delivery of radiation-resistant electronic components from the West. We have to put a hold on the in-depth development of technical and technological documentation and that delays us in terms of moving ahead by at least a year or two.”

  • GSA Kicks Off EGNOS GEO Transponder Service Contracts

    On November 25, the European GNSS Agency (GSA) kicked off the contracts for two new EGNOS GEO transponder services provided by SES.

    The kick-off was done with the support of the European Space Agency (ESA) and the EGNOS service provider ESSP. Initially awarded and signed by the European Commission, in line with a new delegation agreement  between the commission and the GSA, responsibility for the oversight of the contracts has been assigned to ESA.

    The contracts regard the provision of signals from two EGNOS transponders embarked on-board the SES-5 and ASTRA-5B geostationary satellites, both operated by Luxembourg-based SES. The ground-based signals are generated via redundant uplink stations located in Betzdorf, Luxembourg and Redu, Belgium.

    The signals include the navigation messages computed by the EGNOS Mission Control Centers. Both satellites are capable of transmitting dual-frequency signals compliant with GPS L1/L5 and Galileo E1/E5 signal specifications. The signals will be introduced into the EGNOS service provision (L1-only signals) between 2015 and 2016.

     

  • Customizable iPad Data Form for Wetlands Released

    Wetlands-Test-Pits-W

    CMTINC.COM has released the Wetland – Stakeout application for use on the Apple iPad. Besides providing Feature digitization and GPS Stakeout functions, this app will let the users create a custom data entry and report form. The form could be a simple inventory log, price quote, or job contract, or a sophisticated form for collecting GIS data.

    In particular, a customizable report form is built into the app to facilitate the data collection for wetland delineation. This wetland determination data form contains built-in logic as well as formulas for performing automatic computations. It is based on the “Wetland Determination Data Form — Arid West Region” provided by the U.S. Army Corps of Engineers. The data collection form can be modified by the users for use in other regions.

    The Wetland – Stakeout app will let the users digitize the test sites in a map job or import the test sites from Shapefiles or DXF files. The users can then use the stakeout function to help them get to the test sites and record the observation data. Now that the iOS devices are able to work with some external sub-meter GPS receivers, a user could also record fairly accurate location data for the test holes that are actually dug on site. After completing the wetland data entry, the users can send the report to a PDF file and email it back to the office.

    The Wetland – Stakeout app is one of a series of GPS-based iOS apps developed by CMTINC.COM. It is now available for download from the iTunes App Store.

    Wetland-Input3

  • Roscosmos, Transport Ministry Sign GLONASS Agreement

    An interagency agreement for the maintenance, development and use of GLONASS was signed Dec. 5 between Russia’s Ministry of Transport and the Russian Space Agency, according to Roscosmos.

    The agreement seeks to increase the efficiency of the use of civilian infrastructure for the development of GLONASS coordinate-time and navigation for the Russian Federation, as well as international cooperation in the field of satellite navigation.

    Priority areas of cooperation will be:

    • integration of resources in departmental networks for tracking GNSS signals to improve the performance of coordinate-time and navigation in Russian Federation territory using GLONASS, and improving the safety and efficiency of different modes of transport;
    • implementation of a coordinated technical policy to support the functioning of terrestrial systems for the efficient use of GLONASS;
    • the creation of a center for collection, storage, use and provision of information to interested consumers on the state of GNSS;
    • implementation of Russian Federation policy to create conditions that promote domestic navigation technologies based on the GLONASS system abroad.

    The interagency agreement will further improve certain aspects of GLONASS, which will make the services of the Russian navigation system more attractive not only for the domestic market, but also the international market.

    The agreement was signed during Transport Week, an annual business event that is one of the largest Russian forums on issues of development and improvement of Russia’s transport system.

  • Galileo Satellite Recovered, Transmitting Navigation Signals

    Galileo Satellite Recovered, Transmitting Navigation Signals

    Galileo satellite's revised orbit. Photo: Galileo
    Galileo satellite’s revised orbit. Photo: Galileo

    Report by the European Space Agency

    Europe’s fifth Galileo satellite, one of two delivered into a wrong orbit by VS09 Soyuz-Fregat launcher in August, transmitted its first navigation signal in space on Saturday, November 29. It has reached its new target orbit and its navigation payload has been successfully switched on.

    A detailed test campaign is under way now the satellite has reached a more suitable orbit for navigation purposes.

    Recovery

    The fifth and sixth Galileo satellites, launched together on August 22, ended up in an elongated orbit traveling up to 25,900 km above Earth and back down to 13,713 km.

    A total of 11 maneuvers were performed across 17 days, gradually nudging the fifth satellite upwards at the lowest point of its orbit. As a result, it has risen more than 3,500 km and its elliptical orbit has become more circular.

    “The maneuvers were all normal, with excellent performance both in terms of thrust and direction,” explained Daniel Navarro-Reyes, ESA Galileo mission analyst. “The final orbit is as we targeted and is a tribute to the great professionalism of all the teams involved.”

    The Launch and Early Operations Phase (LEOP) for Galileo satellites is overseen by a joint operations team from ESA and the French space agency CNES, alternately working from ESOC in Darmstadt, Germany, and the CNES LEOP Control Centre in Toulouse, France.
    The Launch and Early Operations Phase (LEOP) for Galileo satellites is overseen by a joint operations team from ESA and the French space agency CNES, alternately working from ESOC in Darmstadt, Germany, and the CNES LEOP Control Centre in Toulouse, France. Photo: ESA

    The commands were issued from the Galileo Control Centre by spaceopal, the Galileo operator, at Oberpfaffenhofen in Germany, guided by calculations from a combined flight dynamics team of ESA’s Space Operations Centre, ESOC, in Darmstadt, Germany and France’s CNES space agency. The commands were uploaded to the satellite via an extended network of ground stations, made up of Galileo stations and additional sites coordinated by France’s CNES space agency. Satellite manufacturer OHB also provided expertise throughout the recovery, helping to adapt the flight procedures.

    Until the maneuvers started, the combined ESA–CNES team maintained the satellites pointing at the Sun using their gyroscopes and solar sensors. This kept the satellites steady in space but their navigation payloads could not be used reliably.

    In the new orbit, the satellite’s radiation exposure has also been greatly reduced, ensuring reliable performance for the long term.

    A Galileo Full Operational Capability (FOC) satellite, following on from the first four Galileo satellites already in orbit. A total of 22 FOC satellites are on the way, built by OHB in Germany with navigation payloads from Surrey Satellite Technology Ltd. in the UK.
    A Galileo Full Operational Capability (FOC) satellite, following on from the first four Galileo satellites already in orbit. A total of 22 FOC satellites are on the way, built by OHB in Germany with navigation payloads from Surrey Satellite Technology Ltd. in the UK. Photo: ESA

    A suitable orbit

    The revised, more circular orbit means the fifth satellite’s Earth sensor can be used continuously, keeping its main antenna oriented towards Earth and allowing its navigation payload to be switched on.

    Significantly, the orbit means that it will now overfly the same location on the ground every 20 days. This compares to a normal Galileo repeat pattern of every 10 days, effectively synchronizing its ground track with the rest of the Galileo constellation.

    The navigation test campaign

    The satellite’s navigation payload was activated on November 29, to begin the full In-Orbit Test campaign. This is being performed from ESA’s Redu centre in Belgium, where a 20-meter-diameter antenna can study the strength and shape of the navigation signals at high resolution.

    “First, the various payload elements, especially the Passive Hydrogen Maser atomic clock, were warmed up, then the payload’s first ‘signal in space’ was transmitted,” said David Sanchez-Cabezudo, managing the test campaign.

    “The satellite-broadcast L-band navigation signal is monitored using the large antenna at Redu, with experts from OHB and Surrey Satellite Technology Ltd — the payload manufacturer, based in Guildford, UK — also on hand to analyze how it performs over time.”

    The first Galileo FOC navigation signal-in-space transmitting in the three Galileo frequency bands (E5/E6/L1) was tracked  by Galileo Test User Receivers deployed at various locations in Europe, namely at Redu (B), ESTEC (NL), Weilheim (D) and Rome (I). The quality of the signal is good and in line with expectations.

    The Search And Rescue (SAR) payload will be switched on in few days in order to complement the in-orbit test campaign.