The ERS satellites carry instrumentation consisting of a core set of active microwave sensors supported by additional, complementary instruments:

• AMI - active microwave instrument consisting of a synthetic aperture radar (SAR) and a wind scatterometer 
• RA - radar altimeter 
• ATSR - along-track scanning radiometer 
• GOME - global ozone monitoring experiment 
• MWS - microwave sounder 
• PRARE - precise range and range rate equipment 
• LRR - laser reflector

The satellite concept is based on reusing the Multi-mission Platform, developed within the French SPOT programme. This platform provides the major services for the satellite and payload operation, in particular attitude and orbit control, power supply, monitoring and control of payload status, telecommunications with the ground segment.