GNSS
HIGH ACCURACY GNSS POSITIONING AND SPACE WEATHER
CLS PROVIDES A RANGE OF SERVICES IN SUPPORT OF PRECISE POSITIONING
Our unique involvement in Argos, Doris, and GNSS techniques allows us to apply our expertise to a growing portfolio of clients.
Many industries require higher accuracy for operations than traditional global navigation satellite systems (GNSS) can provide. Sensitive operations in agriculture, mining, oil and gas, construction, and maritime as well as space navigation may require centimeter accuracy, and can be critically impacted by imprecise or unreliable GNSS positions.
The Department of Orbitography and Geodesy at CLS is involved in both operational and research activities devoted to better satellite and ground station positioning.
ABOUT US
Collecte Localisations Satellites (CLS) is a subsidiary of CNES, IFREMER and the investment company ARDIAN. It has been operating satellite systems and providing high value-added products and services since 1986. Within CLS, the Department of Orbitography
As the department of orbitography, our team was historically in charge of calculating ARGOS satellite positions.
FROM ARGOS TO DORIS…
Our knowledge of the ARGOS Doppler technique allowed us to be one of the first teams to process data from the French DORIS satellite mission.
FROM DORIS TO GLOBAL NAVIGATION SYSTEMS…
DORIS (Doppler Orbitography and Radio positioning Integrated by Satellite) was proposed by CNES, GRGS (Groupe de Recherches de Géodésie Spatiale and IGN (Institut national de l’Information Géographique et Forestière) in 1982 as a dedicated fully optimized system in support of POSEIDON, a joint satellite mission between NASA, the U.S. space agency, and CNES, the French space agency, to map ocean surface topography.
FROM OCEAN TOPOGRAPHY TO SATELLITE IMAGERY
To get an in-flight validation of DORIS before TOPEX/POSEIDON, DORIS was flown on board the SPOT2 satellite as a passenger experiment. Recognizing the ability of the system to provide both precise positioning of ground beacons and precise orbit determination, DORIS was approved for flying on board SPOT3, SPOT4, ENVISAT-1, JASON-1, SPOT5, JASON-2, CRYOSAT-2, HY-2A and on Saral. In 2001, on behalf of CNES, CLS joined IDS (International Doris Service) as a member of CNES GRG (former LCA) IDS Analysis Center.
A LASTING PARTNERSHIP
Then, based on the successful partnership in DORIS activities and experience in GPS data processing from the CHAMP gravity mission, CNES and CLS work together to provide the IGS (International GNSS Service) Analysis Center. GNSS stands for Global Navigation Satellite Systems. The US GPS (Global Positioning System) is the best known of these satellite navigation systems which also include the Russian GLONASS, the Chinese Beidou and the European Galileo (under development) satellite constellations.
Read more about IGS real Time service
FROM RESEARCH TO OPERATIONS
After three years of effort, in May 2010, the GRG weekly products (orbits, station positions and Earth Orientation Parameters)started to be part of the IGS GPS final products. One year later, ourGLONASS products were included in the IGS GLONASS final products. Afterwards, in the frame of the IGS Multi-GNSS Experiment (MGEX) – designed to track, collate and analyze signals from the Beidou, Galileo and QZSS systems – , the CNES/CLS IGS Analysis Center initialized routine delivery of weekly Galileo orbits and stations positions.
Thus, CLS’s Department of Orbitography and Geodesy is involved in both operational (daily for ARGOS, weekly for GNSS and quarterly for DORIS) and research activities devoted to better satellite positioning as well to precise ground beacons localization by improvements of in flight dynamic and geophysical modeling. Our unique implication in ARGOS, DORIS and GNSS techniques, is extremely motivating and allows us to facilitate the transfer of model improvements between the techniques.
IDS and IGS related activities of the Department are funded by CNES and made on behalf of CNES-GRGS.
PRECISE POSITIONING
| Technique | Analysis center Acronym | Products | Format | Latency | Sample Interval | |
| GNSS | grg |
|
| Weekly |
| |
| DORIS | Ica |
|
| Quaterly |
| |
| ARGOS |
| Daily | 900 sec |
On behalf of CNES-GRGS and within the framework of theInternational Doris Service (IDS) and International GNSS Service (IGS) Analysis Center, we routinely process DORIS, GPS, GLONASS and Galileo data.
Ephemerides of these satellites are delivered as output to IGS and IDS Data Centers on a weekly and quarterly basis, respectively.
On behalf of CNES and as the Analysis Center, DORIS and GNSS (GPS, GLONASS and Galileo) station positions are estimated on a quarterly and weekly basis, respectively.
Then, these products are delivered to International Doris Service (IDS) and International GNSS Service (IGS) Combination Centers for routine evaluation and combination.
CLS provides users with precise and accurate positioning using a single GNSS receiver both in static and kinematic mode. Through the use of precise orbit and clock products produced by the CNES-CLS International GNSS Service, it is possible to achieve centimeter positioning in static mode given a sufficient convergence period and under some assumptions such as good data quality (clear sky view, calibrated antenna…).
If you would like to discuss your current or future positioning project needs with a CLS expert, please fill in our online form, and we will respond.
Please note: Data must be in RINEX format.
SPACE WEATHER
Although the Sun makes life on Earth possible, it is also a threat. Certain populations and infrastructures can be threatened by solar activity. Therefore, being able to predict solar proton eruptions is vital. Among all the international players involved in solar observation, CLS is the only company that produces an operational service.
CONTRIBUTING TO OPERATIONS SECURITY
As such, since 2008, CLS has been forecasting the risks of proton-related events that might disrupt or damage the Automated Transfert Vehicles (ATVs) of the European Space Agency during approach phases to the International Space Station, or during orbital maneuvers. In addition, CLS delivers bulletins to space operators: – forecasts of solar activity for the next 24 hours during the week preceding launches. – alerts in the event of potentially dangerous events occurring. In addition, solar radiation in the thermosphere can disrupt the satellite orbits that CLS calculates for CNES.
LINKS
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If you would like more information about :
- Precise Positioning, Satellite positioning, and network positioning, please contact : gnss@cls.fr
- Precise Point Positioning, please contact : ppp@cls.fr
- Our Space weather products, please contact : spaceweather@cls.fr