Mobile version

Poseidon-2

The Poseidon-2 altimeter is the main instrument on the Jason-1 mission. Derived from the Poseidon-1 altimeter on Topex/Poseidon, it measures sea level, wave heights and wind speed. It operates at two frequencies and is also able to estimate atmospheric electron content.

Functions

Poseidon-2 measures range (the distance from the satellite to the Earth's surface), wave height and wind speed.

Principle

The altimeter emits a radar beam that is reflected back to the antenna from the Earth's surface (see how altimetry works for details). Poseidon-2 operates at two frequencies (13.6 GHz in the Ku band and 5.3 GHz in the C band) to determine atmospheric electron content, which affects the radar signal path delay. These two frequencies also serve to measure the amount of rain in the atmosphere.

Technical data

Poseidon-2, or SSALT (for Solid State ALTimeter), uses solid-state amplification techniques.

Emitted Frequency (GHz) Dual-frequency (Ku, C) - 13.575 and 5.3
Pulse Repetition Frequency (Hz) 2060 interlaced {3Ku-1C-3Ku}
Pulse duration (microseconds) 105
Bandwidth (MHz) 320 (Ku and C)
Antenna diameter (m) 1.2
Antenna beamwidth (degrees) 1.28 (Ku), 3.4 (C)
Power (W) 7
Redundancy Yes
Specific features Solid-State Power Amplifier.
Dual-frequency for ionospheric correction,
High resolution in C band (320 MHz)

On the tracks of Topex/Poseidon

The design of Poseidon-2 has been enhanced in several areas. In particular, a second frequency has been added in the C-band for ionosphere corrections, sampling has been improved, and digital components have replaced analog circuits wherever possible.

  Poseidon-1 Poseidon-2
Design life 3 years (operating 5% of time) 5 years (operating permanently)
Mass 25 kg 2x25 kg (backup)
Antenna mass 8 kg
Power consumption 50 W 70 W (C and Ku bands)
telemetry rate (all waveforms) 14 kbits/s 22 kbits/s
Reliability (target) >0.95
  Poseidon-1 Poseidon-2  
Ku-Band Ku-Band C-Band
Central frequency 13.65 GHz 13.575 GHz 5.3 GHz
Chirp bandwidth 320 MHz 320 MHz 320 MHz or 100 MHz
Chirp duration 0.1 ms 0.1056 ms 0.1056 ms
Pulse repetition frequency 1700 Hz 6Ku/1C: 1800 Hz±10%  
4Ku/1C: 1680 Hz±10% 6Ku/1C: 300 Hz±10%    
4Ku/1C: 420 Hz±10%      
Antenna gain 44 dB 42 dB 33 dB
Emitted peak power 5 W 7 W 16 W
Pulse number NIMP (50 ms cycle) 85 6Ku/1C: 90  
4Ku/1C: 84 6Ku/1C: 15    
4Ku/1C: 21      
Sample number (FFT) 64 128 128
Fine altitude correction (CFA) 1/16 1/64 1/64
EnglishFrançais
Rss feedsContactPartnersFAQLexiconLegal noticePersonal Data Protection PolicyMobile
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!