Swiss-based u‑blox, a provider of GPS/GNSS and wireless semiconductors, has achieved successful satellite positioning using China’s BeiDou Navigation Satellite System. According to u-blox, the technical achievement establishes u-blox as the first GNSS component vendor to demonstrate compatibility with all globally deployed positioning systems: GPS, GLONASS, Galileo, QZSS and now BeiDou.
However, NovAtel has also announced support for the BeiDou Navigation Satellite System on its OEM6 family and select OEMStar GNSS receivers.
Customer demonstration of the u-blox technology will begin during Q1 2013.
“We are thrilled to have achieved this milestone only three weeks after the BeiDou specification was published,” said Thomas Seiler, u-blox CEO. “China will become the world’s most important single market for devices relying on embedded satellite navigation, and u-blox plans to be a major player in this market.”
BeiDou-2 currently has 15 satellites in orbit, offering navigation and positioning services to users in China and Southeast Asia. It will ultimately consist of 35 satellites providing worldwide positioning capability over its open service to within 10 meters accuracy.
u-blox will be demonstrating BeiDou compatibility with their latest GNSS platform at embeddedworld 2013 February 26-28 in Nuremberg, Germany, stand 4A-325.
Two of the Galileo In-Orbit Validation satellites, E11 and E12, began transmitting navigation messages on their Open Service signals on January 17. Several stations in the Cooperative Network for GNSS Observation and the International GNSS Service’s Multi-GNSS Experiment network received the messages. The epheremis data in the messages appears to be updated every 10 minutes.
On December 21, 2012, GLONASS 712 was deactivated and replaced in almanac slot 8 by GLONASS 743, transmitting on frequency channel -6 (minus 6). At the time, the satellite was physically in orbital slot 2.
On January 4, the GLONASS System Control Centre announced that GLONASS 743 was to be moved from orbital slot 2 to orbital slot 8 beginning on January 5. The move is expected to take until February 15. IGS M-GEX stations stopped tracking GLONASS 743 at about 05:23:30 GPS Time on January 5.
Subsequently, the GLONASS System Control Centre announced that GLONASS 701K, the GLONASS-K test satellite (also known as GLONASS 801 by the
IGS), was re-introduced into the broadcast almanac beginning January 6. It will use almanac slot 8 and transmit on frequency channel -5 (minus 5). Note that the satellite is physically near orbital slot 21. Experimental work with GLONASS 701K will continue until GLONASS 743 completes its orbital slot move.
NovAtel announces support for the BeiDou Navigation Satellite System on its OEM6 family and select OEMStar GNSS receivers.
The long-anticipated BeiDou Navigation Satellite System (BDS) Interface Control Document (ICD) release is a significant milestone that facilitates global acceptance of BeiDou into the growing range of satellite-based positioning applications, NovAtel said.
NovAtel has a long-standing partnership with several Chinese GNSS system manufacturers. This partnership has allowed NovAtel to verify B1 and B2 signal tracking on its latest generation receivers. The company has been supplying GNSS receivers that include the BeiDou constellation since Q4 2010.
“We are excited to see what performance improvements BeiDou will provide to our AdVance RTK, GL1DE and SPAN GNSS/INS positioning algorithms,” said Pat Fenton, NovAtel CTO.
BeiDou positioning has been available through NovAtel’s Chinese partners utilizing the receiver Application Programming Interface (API) feature. With the BeiDou ICD made available to the public, NovAtel is now able to offer BeiDou positioning on its receiver products directly.
Firmware updates for the OEM6 and OEMStar receivers will enable tracking of the BeiDou signal in conjunction with GPS, GLONASS, Galileo and QZSS signals that are currently supported. Over the coming months NovAtel will be working with early-adopter customers to optimize their receiver positioning engines to support the BeiDou signals.
Customers interested in trialing BeiDou functionality on their receivers should contact NovAtel Customer Support at [email protected].
Spirent started shipping BeiDou-ready test systems to customers in 2012. The solution will now be upgraded to full-BeiDou capability using the information from the recently released first full issue of the BeiDou-2 Signal-In-Space Interface Control Document (ICD).
“Spirent has successfully demonstrated BeiDou-2 in simulation systems at its offices in Beijing, China,” said Stuart Smith, product manager for Spirent’s positioning and navigation group. “Prior to the ICD release we used recorded navigation data to enable our systems to drive a full BeiDou receiver and qualify the implementation. With the release of ICD information, navigation data is generated automatically, as with the other constellations that the system simulates.”
Spirent’s BeiDou-2 system includes testing for GPS, GLONASS and Galileo, as well as IRNSS, QZSS and SBAS along with options such as interference generation, MEMS sensor simulation and systems targeted at transport segments.
Background on BeiDou. The BeiDou navigation system, sometimes known as Compass, is a project by China that is being deployed in three phases. BeiDou-2 (the second phase) supports regional operation from a network of geostationary, medium earth orbit and inclined orbit satellites. BeiDou-2 adds to the benefits from “Multi-GNSS” where increased accuracy, availability and integrity are possible from using separate, but interoperable GNSS systems.
As with any other GNSS, systems using BeiDou require testing. As well as testing the BeiDou stand-alone operation, Spirent’s systems enable testing of interoperability and co-existence testing with other navigation systems and sensors.
Septentrio announced on January 7 that it has successfully implemented BeiDou support in the company’s high-precision receiver software, taking advantage of the recent official release of BeiDou’s Interface Control Document (ICD) to including the Chinese satellite navigation signals into its position-velocity-time (PVT) solution.
According to the Belgian GNSS receiver manufacturer, its engineers “are currently processing further data sets to finalize the implementation of full BeiDou support. Although the BeiDou constellation is still being deployed, the data analysis already shows promising results.”
The top panel of Figure 1 compares the height from a stand-alone solution of GPS-only with a GPS+GLONASS solution and a third (in light blue) including BeiDou. “The value added by BeiDou is more than what was expected from a constellation that is still being deployed,” according to Septentrio business development manager Laurent Le Thuaut. “Although the solution is not aided by differential corrections, the position shows an increase in accuracy when sufficient BeiDou satellites are included.”
The bottom panel of Figure 1 shows that, even with the current BeiDou constellation (15 satellites total, of which five are geostationary over China, five in full mid-Earth orbit similar to GPS and GLONASS, and five in inclined geosynchronous orbit over Asia), the total number of satellites used over the European region reached 26 for a short moment.
Figure 2 shows the L1 pseudorange residuals for all constellations individually. This comparison highlights the advantage of the GPS constellation, which builds on two decades of real-time orbit prediction. The BeiDou orbits are “quite accurate for a relatively young constellation, but show typical meter-level jumps when ephemerides are updated,” according to Septentrio.
Septentrio says that the new feature will soon become available on selected company platforms. Users of its multi-constellation receivers will then benefit from improvements in urban availability and signal integrity, thanks to the augmented signal coverage.
On December 29, two days after the Compass Interface Control Document (ICD) was made publicly available, JAVAD GNSS announced that it had tracked “B3 signal from all launched Compass satellites, using TRE-G3T-E E6-band capable receiver. Graphs shows SNR and ‘code-minus-phase’ combination of GEO svn #5 (sat #215 on graph), IGSO svn #8 (sat #218) and MEO svn #14 (sat #224). ‘C/A’ stands for B1, ‘L5’ for B2, ‘CL2’ for B3.”
An announcement on the JAVAD GNSS website states “On December 21, 2012, we have tracked E6 B/C signal from all launched Galileo satellites, using TRE-G3T-E E6-band capable receiver.
“The following graphs shows SNR and ‘code-minus-phase’ combination of svn #11 (sat #81 on graph), svn #12 (sat #82) , svn #19 (sat #89) and svn #20 (sat #90). C/A stands for E1, P2 for E5B, CL2 for E6, L5 for E5A.”
The announcement includes a link to a short article describing how these codes were found. The Galileo E6 codes have not been published by the European Space Agency.
News compiled with assistance of CANSPACE Listserv.
Beidou
The interface control document (ICD) describing the details of the BeiDou B1I open service signal on 1561.098 MHz was released December 27 at a news conference held in Beijing by the Chinese State Council Information Office. Download the English version here. The ICD specifies the relations of the signal in space interface between BeiDou Navigation Satellite System and users’ terminal receivers. It is the essential technical document to develop and make receivers and chips.
Anyone who has questions about the ICD is invited to submit them to this email: [email protected]
The document, BeiDou Navigation Satellite System Signal In Space Interface Control Document — Open Service Signal B1I (Version 1.0), includes a system introduction, signal standards and navigation message, which defines the related contents of the open-service signal B1I between the BeiDou Navigation Satellite System and users’ terminals.
In a previous presentation given at the Seventh Meeting of the International Committee on Global Navigation Satellite Systems (ICG) held in Beijing November 5-9, 2012, BeiDou officials stated that by 2020 there will be five GEO and 30 non-GEO satellites. The number of IGSO and MEO satellites isn’t stated, but previous presentations have said three IGSOs and 27 MEOs. This is also stated in the official ICD.
Goodbye, Compass. At the news conference, Ran Chengqi, the director of the China Satellite Navigation Office, announced that the English name of the system is henceforth the BeiDou Navigation Satellite System. A new, slightly modified logo for the system was also introduced by Ran. The new version drops the parenthetical “Compass” translation of BeiDou.
Galileo IOV-3 Broadcasts E1, E5, E6 Signals; Russian SBAS Luch-5B in Orbital Slot; EGNOS and Galileo in Emergency Call, Road Tolling; Compass ICD Rumored
Galileo IOV-3 Broadcasts E1, E5, E6 Signals
By Oliver Montenbruck, German Space Operations Center and Richard B. Langley, University of New Brunswick
After reaching its final position, the Galileo IOV-3 satellite started transmitting its first ranging signals on December 1. Within three days, the various carriers (E1, E5, E6) and associated modulations were activated, and full in-orbit testing is now in progress. Anyone with commonly available GNSS receivers can presently access the open signals in the E1, E5a, and E5b frequency bands as well as the wide-band E5 AltBOC signal.
According to statements made at the recent 6th ESA Workshop on Satellite Navigation Technologies (Navitec 2012) in Noordwijk, The Netherlands, the IOV-3 satellite, which is also identified as Flight Model 3 (FM3) and E19 after its pseudorandom noise code, will continue to use binary offset carrier modulation — specifically BOC(1,1) — on the E1 Open Service signals for the time being. In contrast to this, the first pair of IOV satellites has already started to use composite binary offset carrier modulation, which offers better multipath suppression in the received signal.
Right after its activation, IOV-3 could be tracked immediately by the global network of stations participating in the Multi-GNSS Experiment (MGEX; http://www.igs.org/mgex) initiated by the International GNSS Service (IGS).
Figure 1. Pseudorange errors of IOV-3 tracking at Tanegashima, Japan, using the E1 BOC(1,1) signal (top) and the E5 AltBOC signal (center). The elevation angle over time is shown in the bottom panel.
The high quality of the IOV-3 signals is illustrated by measurements collected by the Tanegashima station during a 10-hour pass of the satellite over Japan (see Figure 1). The E5 AltBOC pseudorange measurements in particular exhibit an exceptionally low noise and multipath level of better than 10 centimeters at mid- and high-elevation angles.
An attractive feature of the Galileo system is the availability of multiple signal frequencies, which opens up numerous prospects for precise positioning and scientific investigations.
Carrier-Phase Measurements
While the E6 signals foreseen for a future Commercial Service are not presently supported by geodetic receivers due to the lack of information on the transmitted codes and possible licensing issues, users can already benefit from the E5a and E5b signals in addition to E1. By way of example, the ionosphere-free and geometry-free linear combination can be formed from carrier-phase measurements on these frequencies. Results of some first tests using this combination for IOV-3 are shown in Figure 2, based on measurements made at four MGEX stations: CUT0 (Perth, Australia), GMSD (Tanegashima, Japan), KZN2 (Kazan, Russia), and SIN1 (Singapore).
The results provide an indication of carrier-phase noise and multipath effects but are free of long-term variations that have earlier been found in GPS L1/L2/L5 signal combinations.
It is anticipated that similar measurement quality will be obtained with the E1 and E5 signals of IOV-4, which were activated on December 12 and 13.
This level of performance highlights the potential benefit of Galileo signals in advanced triple-frequency techniques such as undifferenced ambiguity resolution and ionospheric monitoring.
Figure 2 The difference between the ionosphere-free carrier-phase combinations formed from E1/E5a and E1/E5b signals received at four MGEX stations: CUT0 (Perth, Australia), GMSD (Tanegashima, Japan), KZN2 (Kazan, Russia), and SIN1 (Singapore).
Russian SBAS Luch-5B in Orbital Slot
The second Russian satellite-based augmentation system (SBAS) satellite, Luch-5B, has now been positioned at its designated orbital slot of 16 degrees west longitude. The satellite had been in a drift orbit since its launch on November 2 at 21:04:00 UTC along with the domestic communications satellite Yamal-300K.
NORAD/JSpOC tracking data showed Luch-5B arriving at its geostationary position by about December 13. Figure 3 shows the footprint of the satellite with the elevation-angle contours at 30-degree intervals.
Luch-5B, the second of a set of three geostationary satellites being launched to reactivate Roscosmos’s Luch Multifunctional Space Relay System, is expected to use PRN code 125.
The Luch system will relay communications and telemetry between low-Earth-orbiting spacecraft, such as the the Russian segment of International Space Station, and Russian ground facilities. The system’s satellites also carry transponders for the System for Differential Correction and Monitoring (SDCM), Russia’s SBAS. The transponders will broadcast GNSS corrections on the standard GPS L1 frequency.
Luch-5A, launched in December 2011, resides in an orbital slot at 95 degrees east longitude. It began transmitting corrections on July 12, 2012 using PRN code 140.
Figure 3. Geostationary position of Luch-5B, carrying a transponder for the Russian System for Differential Correction and Monitoring.
EGNOS and Galileo in Emergency Call, Road Tolling
The Intelligent Transport Systems (ITS) World Congress in Vienna this fall drew attention to the multi-constellation advantages provided by Galileo during a session on eCall, the European initiative for safer mobility. “Galileo will provide accuracy and reliability in all the transport markets, but in the case of emergency rapid assistance, the positioning need is even more critical,” said Fiammetta Diani, market development officer at the European GNSS Agency (GSA).
A multiconstellation approach for eCall and similar initiatives will deliver better performance without additional costs. Yaroslav Domaratsky from NIS-GLONASS, the Russian national navigation services provider, confirmed that ERA-GLONASS, the Russian version of eCall, will benefit from multiconstellation. “Solutions including also Galileo are welcome in the Russian initiative.”
Satellite ITS applications in road transport cover much more than in-car navigation. They include road-user charging with satellite-based toll collection systems; in-vehicle dynamic route guidance for drivers; intelligent speed adaptation to control the speed of vehicles externally; traveller information systems; and fleet-tracking systems for better management of freight movements and goods delivery.
Road Tolling
European road-toll operators outlined how they plan to emply the European Geostationary Navigation Overlay Service (EGNOS) and Galileo to provide new tolling solutions.
Luigi Giacalone, managing director of Autostrade Tech, which provides the technology for the French Ecomouv project, said EGNOS will contribute to reliably collect taxes on the heavy trucks using the road charging scheme. “This is a tax, not a toll. It aims to collect a new tax reliably and fairly according to distance travelled, while dissuading fraud,” he said. “Thanks to GNSS multi-constellation, only 10 locations out of the 15,000-kilometer network need support beacons.”
Ecomouv, which Includes anti-jamming and anti-spoofing mechanisms, covers 600,000 French lorries and 200,000 foreign ones, and will run from July 2013 for 11.5 years. Giacalone said its performance target was 99.75 percent accuracy of the entire collection chain, and its trials had already 99.8 percent accuracy.
Miroslav Bobošík from SkyToll, which operates Slovakia’s electronic tolling operations, explained how the system was able to cover not only 570 kilometers of motorways, but also 1,800 kilometers of first class roads in the country. “We needed a flexible system to cover different roads in different circumstances. And also to be fair to drivers, so they pay only for what they use,” said Bobošík. “We cover all services, not just toll collection, but enforcement, and technological maintenance and repair.”
GNSS tolling means flexibility as well as feasibility for SkyToll: since its launch in mid-2010, many changes have been made to the operation of the network, but thanks to the technology, they were easy to make. And they were cheap, he said. “While it is difficult to compare costs with other country, SkyToll has the lowest cost per kilometer to operate,” he said. “GNSS is the best possible solution for electronic tolling system in Slovakia, and GNSS is the most suitable for ITS.”
Changing the Game
Volker Vierroth from T-Systems, the German IT services subsidiary of Deutsche Telekom, explained GNSS’s game-changing role: the availability of a huge variety of additional data linked to actual positions; more computing power, notably mobile and cloud-based; fast and reliable networks available now with broad coverage, most recently with the shift from 3G to 4G; and smartphones, powerful and versatile, surging to the fore.
“GNSS [in the form of EGNOS] has proved to be a reliable technology for large-scale road charging on complex networks,” he said. “Galileo will bring further improvements, and may become the cornerstone of future road applications.”
Compass ICD Rumored
As this magazine goes to press, unconfirmed reports from Shanghai state that the Compass Interface Control Document (ICD) will be released on December 27.
Such rumors surfaced in late 2010 and again in late 2011. An October 2011 GPS World newsletter reported “The long-awaited signal ICD for China’s growing GNSS will appear this month, according to representatives of the system who spoke in a “Compass: Progress, Status, and Future Outlook” workshop in September [2011].
“The ICD has been rumored to be available previously to receiver manufacturers within China, creating some disgruntlement among companies outside the country. A workshop panelist affirmed that GPS/Compass chips and receivers are being actively developed by many Chinese manufacturers and research institutes.”
Beating up the backstretch neck and neck, tied for third in the GNSS race, Galileo and Compass today offer some signals and some satellites to GNSS users — as long as those users are researchers. Galileo has more going for it in the way of signals, while Compass holds an edge in the number of satellites. Without an interface control document (ICD) to guide user/researchers and most importantly manufacturers in the employment of its signals, Compass satellites, however they may increase, are practically useless to anyone outside China. A Compass ICD has been rumored before and is now rumored again. Wait and see before placing your bets.
The fourth Galileo in-orbit validation (IOV) satellite, Flight Model 4 (FM4), began transmitting signals on December 12, joining its co-launched confrère FM3, which began airing navigation signals on December 1. The FM4 spacecraft uses PRN code E20. As of this writing, FM3 is broadcasting E1, E5, and E6 signals, and FM4 is broadcasting E1 and E5 signals; we don’t know if and when FM4 E6 signals start(ed) until ESA tells us.
GPS World authors Oliver Montenbruck (German Space Operations Center) and Richard Langley (University of New Brunswick) have written an early analysis of the signals from FM3; this account will appear in the January issue of the magazine. A few selected excerpts from that article, and one figure:
“Anyone with commonly available GNSS receivers can presently access the open signals in the E1, E5a, and E5b frequency bands as well as the wide-band E5 AltBOC signal.
Figure 1: Pseudorange errors of IOV-3 tracking at Tanegashima, Japan, using the E1 BOC(1,1) signal (top) and the E5 AltBOC signal (center). The elevation angle over time is shown in the bottom panel.
“According to an ESA statement, FM3will continue to use binary offset carrier modulation — specifically BOC(1,1) — on the E1 Open Service signals for the time being. In contrast to this, the first pair of IOV satellites has already started to use composite binary offset carrier modulation, which offers better multipath suppression in the received signal.
“The E5 AltBOC pseudorange measurements in particular exhibit an exceptionally low noise and multipath level of better than 10 centimeters at mid- and high-elevation angles.”
After discussing and displaying some carrier-phase measurements of the Galileo FM3 E1, E5, and E6 signals, Montenbruck and Langley conclude; “This level of performance highlights the potential benefit of Galileo signals in advanced triple-frequency techniques such as undifferenced ambiguity resolution and ionospheric monitoring.”
Theoretically, the total of four Galileo IOV satellites now in medium-Earth orbit yield the minimum number needed to perform a 3D navigation fix, although no statement of initial — or even sketchy — operating capability has been issued by the European Space Agency (ESA), nor is one expected.
Antonio Tajani, vice-president of the European Commission (EC) and head of the EC directorate-general responsible for industry and entrepreneurship, continues to publicly maintain a “political objective [of] the delivery of the first services before the end of 2014,” based on 18 orbiting satellites. In a December speech, he revised the basis for that position slightly to say the civil Open Service (OS) could be declared operational with as few as 12 satellites.
The system operators had announced three dual-satellite launches in 2013, two dual-satellite launches and one four-satellite launch in 2014, hypothetically producing an operable constellation of 18 satellites by the end of the promised 2014. However, unconfirmed reports from Europe suggest that problems with manufacture of the next set of 14 Galileo satellites mean that no launches at all will take place until Q4 of 2013. Whether this will push out the service delivery date beyond 2014 or not remains open to conjecture.
Compass
Another matter open to conjecture and much speculation is whether the world will soon — or ever — see an interface control document (ICD) for China’s Compass system. More than a year ago, I wrote that “The ICD has been rumored to be available previously to receiver manufacturers within China, creating some disgruntlement among companies outside the country . . . GPS/Compass chips and receivers are being actively developed by many Chinese manufacturers and research institutes.” Indeed, conference presentations, leading to a published article in this magazine’s October issue, “What Is Achievable with the Current Compass Constellation,“ confirm that this is so.
And yet, the rest of the world neither has nor holds a Compass ICD.
The end-of-year rumor mill has kicked into gear again, though. A GNSS industry representative stationed in Shanghai, China sent this message recently to a U.S. colleague: “Latest unofficial news said that the Compass Interface Control Document (ICD) will be released on 27th this month, and will be available on the internet on 28th.”
A GNSS industry representative stationed in Shanghai, China sent this message recently to a U.S. colleague: “Latest unofficial news said that the Compass Interface Control Document (ICD) will be released on 27th this month, and will be available on the internet on 28th.”
Such rumors have floated before, in late 2010, and again in late 2011. As the U.S. colleague noted in passing on this light intelligence, “There was a lot of hand-wringing at ICG [Seventh Meeting of the International Committee on Global Navigation Satellite Systems (ICG), organized by the Government of China, Beijing, China, 5 – 9 November 2012] around the Chinese keeping their promise for 2012 release of the ICD. Maybe they are just going to slip it under the wire.”
In an October, 2011 newsletter column, the GPS World editor wrote: “The long-awaited signal interface control document (ICD) for China’s growing GNSS will appear this month, according to representatives of the system who spoke in a “Compass: Progress, Status, and Future Outlook” workshop as part of ION GNSS and the CGSIC meetings in Portland in September [2011].
“The ICD has been rumored to be available previously to receiver manufacturers within China, creating some disgruntlement among companies outside the country. One of the workshop panelists affirmed that GPS/Compass chips and receivers are being actively developed by many Chinese manufacturers and research institutes.”
