Mobile version

The ground segment

The Jason-1 ground segment is made up of three components providing the human (teams) and equipment resources required to ensure the mission's success:

  • The Proteus Generic Ground Segment (PGGS, based in Toulouse, France)
  • The Project Operation Control Center (POCC, based in Pasadena, California, USA)
  • The Ssalto multimission ground segment (based in Toulouse, France).

Mission operations

This comprises the Proteus Generic Ground Segment (PGGS) located in Toulouse, France, the Project Operations Control Center (POCC) located in Pasadena, Ca, USA and the CCI (Instrument Control Center) also located in Toulouse, France.


The Proteus Generic Ground Segment provides the necessary capability for operating a Proteus spacecraft. It includes an Earth terminal, a command and control centre and a data communications network. Proteus adapted its facilities to meet Jason-1's requirements. It was used to perform satellite operations during the early phase of the mission (launch, station acquisition, in-orbit acceptance) and then performed spacecraft analysis and navigation functions when the POCC took over routine satellite operations. The PGGS is broken down into three main components: the TTCET Earth terminal, the command control centre (CCC) and the data communications network (DCN). Development of the generic product and the specific adaptation to the Jason-1 mission were managed by the same team.


The POCC provided the capability for operating Jason-1 during its routine phase, including 1) real-time telemetry and command (JTCC), 2) sequence generation (JSEQ), 3) Earth terminal (ET), 4) science processing and distribution (JSDS), and 5) data archiving (Po.Daac) functions. It was derived from the Topex/Poseidon POCC and simultaneously supported Topex/Poseidon and Jason-1.


The Ssalto multimission ground segment (Segment Sol multimissions d'ALTimétrie, d'Orbitographie et de localisation précise) encompasses ground support facilities for controlling the Doris and Poseidon instruments, processing data from DORIS and the altimeters onboard Topex/Poseidon, Jason-1 and Envisat-1, and providing user services and expert altimetry support.

Ssalto was designed by Cnes, the French space agency, in partnership with its subsidiary CLS and local French industry. Ssalto serves as a common ground segment for the Doris/Spot, Doris/Envisat, Topex/Poseidon, Jason-1 and Envisat missions. It thus responds to a growing commonality of user needs and supports the continued operation of Doris instruments and altimetry payloads flying simultaneously on different satellites.

Ssalto encompasses the resources for:

  • controlling onboard Doris and Poseidon instruments, and the Doris orbitography beacon network (CCI)
  • obtaining precision orbits (POD)
  • processing altimeter and radiometer data (CMA)
  • providing user services, and archiving and managing data (Aviso)

The CMA (Multi-mission Altimetry Centre) processes altimetry data from Jason-1 and Envisat, and from Ssalto components that control the instruments (CCI) and determine precise orbits. Other components process Topex/Poseidon and Doris data from other satellites (Spot, Envisat) and distribute data (Aviso).

S. Coutin-Faye et al., 2000: SSALTO: a new ground segment for a new generation of altimetry satellites, Aviso Newsletter, n°7 January 2000.

Rss feedsContactPartnersFAQLexiconMobile
You must enable cookies in your browser preferences to save the modifications
You are using an older version of Internet Explorer, please update to take full advantage of Aviso+ features

Customize the home page

View all widgets
Reduce display
Public profile
User profile

Select/Deselect widgets

Discover AVISO+

Customizable home, reading tools, products search guide, etc.. Discover step by step the features of the new site AVISO+.

Customizable homepage

This home page is composed of blocks called "widgets".

Rearrange the blocks with a "Click & Drop".

Hide a widget with the cross at the top right. Reset or add a widget with the "wrench" icon. The "User" and "Public" profiles offer a predefined organization.

All the modifications are automatically saved as cookies on your machine so as to enable you to have your own specific AVISO+.

Reading tools

Ease your reading by choosing the page background colour (black/white) and/or by modifying the font size.

Browsing menu and breadcrum trail

To ease your browsing through AVISO+, you can use at any time the main banner items with the interactive submenus or use the browsing menu on the left side of the screen (it is open by default). For more readiness of the page contents, you can fold and unfold the browsing menu by clicking on the tab. At any time you can know where you are thanks to the browsing menu or the breadcrum at the top of the page.

Products search guide

The first submenu of the "Data" banner item leads you to a new search form enabling you to find quickier the product that suits your needs. The list of results is updated according to your selection criteria.

AVISO+ Multimedia

The first submenu of the "Multimedia" banner item leads you to AVISO+ collections of images and videos linked to altimetry and its applications. Have a nice visit!