The CHRIS Hyperspectral Imaging Mission - Five Years In-Orbit Experience
- Paper number
IAC-07-B1.3.02
- Author
Dr. Mike Cutter, Surrey Satellite Technoloy Ltd, United Kingdom
- Coauthor
- Coauthor
Prof. Martin Sweeting, Surrey Satellite Technology Ltd., United Kingdom
- Coauthor
Mr. Frédéric Teston, European Space Agency (ESA)/ESTEC, The Netherlands
- Year
2007
- Abstract
This paper will summarise the results of a hyperspectral imaging mission that has now completed five years in orbit and is providing a wealth of data to Users across the world. The mission has demonstrated, fairly conclusively, that such sophisticated payloads can be implemented successfully on a small satellite platform. The instrument being flown is the Compact High Resolution Imaging Spectrometer (CHRIS) developed within the Optical Payload Group (OPG) of Surrey Satellite Technology Ltd (formerly the Sira Space Group). The instrument is flying on PROBA, a small agile satellite, which was launched in October 2001. The PROBA platform is flying in a sun-synchronous polar orbit with an inclination of 97.89°. The altitude of the platform varies over a range approximately from 545 to 675 km. The platform period is 96.8min. The apogee of the orbit rotates around the Earth with an approximate 110 day periodicity. The main purpose of the instrument is to provide images of land areas. The platform provides pointing in both across-track and along-track directions, for target acquisition and multi-angle observations, particularly for measurement of the Bi-directional Reflectance Distribution Function (BRDF) properties of selected targets. One of the main novel features of this instrument is the provision of pitch motion compensation during imaging in order to increase the integration time of the instrument, increasing the number of spectral bands that can be read and enhancing radiometric resolution. This also results in a smaller instrument, which is more compatible with small satellite dimensions. The instrument covers a spectral range from 400nm to 1050nm, at <11nm resolution. The spatial sampling interval at perigee is approximately 17m. In this mode it is possible to read out 19 spectral bands. The locations and widths of the spectral bands are programmable. Selectable on-chip integration can increase the number of bands to 63 for a spatial sampling interval of 34m. The swath width imaged is 13km at perigee. Observations requests for the science mission are selected by the CHRIS Steering Group, prioritised and scheduled into feasible observations on a daily basis. These observations are then compared with a UK Met Office 48 hour cloud predictions before selecting the preferred image acquisition for each day. Instrument configurations files and target coordinates are then transmitted to the platform from SSTL via the ESOC ground station in Redu, Belgium. The platform implements the request and downloads the data to either Redu or Kiruna in Sweden. Data is then transmitted to SSTL for Level 1a processing before being placed on an FTP server for access by the investigators. Quick-look images are also placed on User accessible website. Other sites are available to provide details such as the observational programme and investigator details. The Mission continues to operate successfully even in its sixth year and demonstrates the success of the mission and the utility of the platform and instrument.
- Abstract document
- Manuscript document
IAC-07-B1.3.02.pdf (🔒 authorized access only).
To get the manuscript, please contact IAF Secretariat.