The HRS instrument mounted on the satellite,
next to the VEGETATION instrument

Operating principle and optical path

The HRS instrument is designed to acquire images in the panchromatic band at viewing angles of 20° forward and aft of the satellite. It can thus obtain stereopair images quickly to generate digital elevation models.

HRS uses the same pushbroom scanning technique as HRG.

HRS instrument architecture

The HRS instrument consists of:

• A carbon-skin sandwich/aluminium honeycomb instrument panel supporting the mechanical interface with the SPOT 5 satellite and the instrument systems.
• A stereo video module (MVS), which handles and processes data from the detection units, actively controls the instrument's temperature and provides the ancillary systems required to operate it (chiefly power and TM/TC).
• A thermal cocoon encloses the temperature-sensitive components vital to achieve the instrument's required performance, i.e.:
  · The front and rear objectives, mounted on a quasi-isostatic structure to ensure stability. The objectives collect incoming light in the panchromatic band and focus it onto the lines of detectors. It filters out all rays outside the panchromatic band to minimize stray light.
  · The front and rear detection units, which house the CCD sensors and electronics. These units convert the light signal into an

  The HRS instrument during integration in October 2000

  electrical signal.
  The cocoon maintains the instrument's components within the required temperature range.

Technical data

HRS instrument during tests

More:
Optical subassembly
Image electronics