The payload of SENTINEL-6 (JASON-CS) comprises the primary radar altimeter payload with options for supporting instrumentation:
Radar Altimeter (POSEIDON-4): The primary measurement system of SENTINEL-6 (JASON-CS), POSEIDON-4 is a fully redundant normal incidence Ku and C band pulse-width limited radar altimeter with the capability of acquiring phase coherent measurements of a surface allowing synthetic-aperture processing to improve along-track sampling and reducing range and Significant Wave Height (SWH) noise as a function of SWH.
Overall performances will be improved with respect to other ocean topography altimeter missions by means of improvements in the design and in an optiminsed pulse timing pattern.
The main characteristics of the POSEIDON-4 (SENTINEL-6 Ku/C radar altimeter) are:
The AMR-C multi frequency NASA-JPL instrument extends the capability of the AMR of Jason -2 and -3 to retrieve Total Column of Water Vapour (TCWV) with the capability of minimising long-term drift by means of an on-board calibration mechanism and by periodic pointing of the platform (and radiometer) to deep space to obtain stable reference brightness temperatures. The manoeuvres option will also be used by Jason-3.
The precise orbit determination (POD) suite is provided from two payloads.
Laser Retro-Reflector Array
This is provided by NASA-JPL and is used to support POD by use of global Satellite Laser Ranging (SLR) facilities.
Although used as part of the Attitude and Orbit Control System (AOCS), processed star tracker data are a key component in processing POSEIDON-4 SAR data. Three star trackers are available to ensure continuous attitude measurements during Sun and/or Moon blinding.
As an extension to the primary mission objectives, a Radio Occultation (RO) package is used to measure physical properties of the atmosphere such as temperature, pressure and water vapour, by detecting the occultation of GPS signals as they pass through the limb of the atmosphere.
Sentinel-6 Mission pages