The high resolution optical instruments for the Pleiades HR Earth observation satellites

Abstract

Coming after the SPOT satellites series, PLEIADES-HR is a CNES optical high resolution satellite dedicated to Earth observation, part of a larger optical and radar multi-sensors system, ORFEO, which is developed in cooperation between France and Italy for dual Civilian and Defense use. The development of the two PLEIADES-HR cameras was entrusted by CNES to Thales Alenia Space. This new generation of instrument represents a breakthrough in comparison with the previous SPOT instruments owing to a significant step in on-ground resolution, which approaches the capabilities of aerial photography. The PLEIADES-HR instrument program benefits from Thales Alenia Space long and successful heritage in Earth observation from space. The proposed solution benefits from an extensive use of existing products, Cannes Space Optics Centre facilities, unique in Europe, dedicated to High Resolution instruments. The optical camera provides wide field panchromatic images supplemented by 4 multispectral channels with narrow spectral bands. The optical concept is based on a four mirrors Korsch telescope. Crucial improvements in detector technology, optical fabrication and electronics make it possible for the PLEIADES-HR instrument to achieve the image quality requirements while respecting the drastic limitations of mass and volume imposed by the satellite agility needs and small launchers compatibility. The two flight telescopes were integrated, aligned and tested. After the integration phase, the alignment, mainly based on interferometric measurements in vacuum chamber, was successfully achieved within high accuracy requirements. The wave front measurements show outstanding performances, confirmed, after the integration of the PFM Detection Unit, by MTF measurements on the Proto-Flight Model Instrument. Delivery of the proto flight model occurred mi-2008. The FM2 Instrument delivery is planned Q2-2009. The first optical satellite launch of the PLEIADES-HR constellation is foreseen beginning-2010, the second will follow beginning-2011.

Trade-off Optimization Method for Infrared Imaging System Based on Modification of λF/d

“…Infrared (IR) imaging systems have become an essential tool in optical remote sensing [1], IR precise guidance [2], IR surveillance [3] and, deep-space exploration [4]. In order to reduce the size, weight, power consumption and cost (SWaP$) of IR imaging systems, it is necessary to reduce the optical system aperture and the detector size without reducing the comprehensive imaging performance [5].…”

First in-flight results of Pleiades 1A innovative methods for optical calibration

“…In order to optimize image sharpness during the satellite lifetime, the instrument includes an innovative thermal refocusing device which avoids the need for a complex mechanism [2]. Image quality also requires a minimum signal to noise ratio that is achievable thanks to a Time Delay Integration (TDI) detection device for the PA band which allows to select between 7, 10, 13, 16 and 20 TDI lines.…”

Self-Calibration Method Based on Surface Micromaching of Light Transceiver Focal Plane for Optical Camera

“…The Pleiades-1B can acquire panchromatic (0.5 m) and multispectral (2 m) images with high geo-location accuracy (3 m @ CE90) and high resolution [10]. The system also employs a push-broom imaging concept [11]. NAOMI [12] is a product line of high-resolution optical cameras applied to SPOT-6 satellite and is based on the same telescope concept implementing one or several focal plane units in the same camera.…”