The Canadian Space Agency and the Defence Research and Development Canada are jointly developing an advanced
miniaturized imaging spectrometer for future Mars rover and onboard a small aircraft. This work is the further
development of the two previous concept studies for Mars: Canadian Hyperspectral Imager for Mars Exploration and
Resource Assessment (CHIMERA) and Hyperspectral and Luminescence Observer (HALO). Based on outcomes of the
concept studies, a Dyson spectrometer design was selected as the imaging spectrometer due to its compactness, high
optical output and low distortion. This paper briefly describes the options of imaging spectrometers proposed in the
HALO study. Then the requirements of the advanced miniaturized imaging spectrometer system are provided. Finally
the preliminary results of the development of the Dyson imaging spectrometer system will be reported.
The Near Earth Object Surveillance Satellite (NEOSSat) is a small satellite dedicated to finding near Earth asteroids. Its
surveying strategy consists of imaging areas of the sky to low solar elongation, while in a sun synchronous polar orbit
(dawn-dusk). A high performance baffle will control stray light mainly due to Earth shine. Observation scenarios
require solar shielding down to 45 degree solar elongation over a wide range of ecliptic latitudes. In order to detect the
faintest objects (approx 20th v mag) given a 15 cm telescope and CCD detection system, background from stray light is a
critical operational concern. The required attenuation is in the order of 10-12. The requirement was verified by analyses;
testing was not attempted because the level of attenuation is difficult to measure reliably. We report consistent results of
stray light optical modelling from two independent analyses. Launch is expected for late 2012.
One of the challenges in the development of a hyperspectral satellite is the extremely high data rate due to the huge data
volume generated on board, which exceeds the downlink capacity, and may quickly exhaust the onboard storage
capacity. To deal with this challenge the Canadian Space Agency (CSA) has been developing data compression
technologies for satellite imagery data for many years. Compression techniques for operational use have been developed.
Recently, two near lossless data compression techniques for hyperspectral imagery have been developed and
implemented in hardware. The CSA is considering a near lossless data compressor for use on-board a hyperspectral
satellite in order to reduce the requirement for on-board storage and to better match the available downlink capacity.
This invited paper is to review the research and development of satellite data compression for hyperspectral imager at
CSA, briefly summarize the two near lossless compression techniques, to address the application based assessment of
the impact of lossy or near lossless data compression on Earth observation applications, and to provide up-to-date status
of the hardware implementation of the on-board data compression technologies.
Rapid advances in photonic and electro-optic technologies have given rise to sophisticated spaceborne optical instruments with important applications ranging from remote sensing to high-resolution hyperspectral imaging systems. This paper reviews past, present and future space missions employing Canadian optical instruments, discusses required detector technologies and their key performance parameters.
The Canadian Space Agency (CSA) is developing a pre-operational spaceborne Hyperspectral Environment and Resource Observer (HERO). HERO will be a Canadian optical Earth observation mission that will address the stewardship of natural resources for sustainable development within Canada and globally. To deal with the challenge of extremely high data rate and the huge data volume generated onboard, CSA has developed two near lossless data compression techniques for use onboard a satellite. CSA is planning to place a data compressor onboard HERO using these techniques to reduce the requirement for onboard storage and to better match the available downlink capacity. Anomalies in the raw hyperspectral data can be caused by detector and instrument defects. This work focuses on anomalies that are caused by dead detector elements, frozen detector elements, overresponsive detector elements and saturation. This paper addresses the effect of these anomalies in raw hyperspectral imagery on data compression. The outcome of this work will help to decide whether or not an onboard data preprocessing to remove these anomalies is required before compression. Hyperspectral datacubes acquired using two hyperspectral sensors were tested. Statistical measures were used to evaluate the data compression performance with or without removing the anomalies. The effect of anomalies on compressed data was also evaluated using a remote sensing application.
This paper's objective is to present a new, computationally efficient method for automatic exploration, detection and recognition. The automatic mineral homogeneous region separation algorithm developed by A.U.G. Signals in cooperation with the Canadian Space Agency (CSA) using AVIRIS data and mineral signatures from the Nevada's (U.S.) Cuprite site is described. The hyperspectral data and spectral signatures were provided by the Canada Center for Remote Sensing (CCRS). The algorithm is able to successfully divide the image in regions where the mineral composition remains constant. Hence, it can be used for reducing the noise is estimating the abundance parameters of the minerals on a pixel-by-pixel basis, for image region selection and hyperspectral image labeling for data storage and/or selective transmission. This may be another form of lossless hyperspectral image compression. Through the presented approach we are able to: a) divide a hyperspectral image into regions of adaptivity where pixel unmixing algorithms are able to extract the abundance parameters with higher degree of confidence, b) increase the signal to noise ration (SNR) of the present spectral signatures in a region and c) apply the proposed hyperspectral homogeneous region separation for data reduction (hyperspectral image compression). Experimental and theoretical results and comparisons/tradeoff studies are presented.
Imaging spectrometers must be calibrated and characterized in order to accurately interpret collected data, especially for sharp spectral features in the target spectra. Two key aspects of this characterization are the spectral bandwidth and spectral registration. Calibration and characterization methodologies are being developed, with the casi (Compact Airborne Spectrographic Imager) as a test instrument.
The Satellite Attitude Sensor (SAS) utilizes IR bolometer arrays to perform the role of a staring horizon sensor with good accuracy and a wide field of view that avoids mechanical scanning. An innovative concept has resulted in simple and inexpensive design suitable for the requirements of both low and high altitude orbits. Although SAS was designed especially for Earth-observing micro-satellites, it is applicable to satellites with geosynchronous or highly elliptical orbits and the update rate is sufficient for use with a spinning satellite or a rocket. The ability of the sensor to operate in both spinning and 3-axis stabilized modes will allow it to fulfill the needs of large variety of scientific and remote sensing applications. Laboratory test are in process to verify the design.
KEYWORDS: Sensors, Infrared sensors, Infrared radiation, Signal processing, Diffraction, Detector arrays, Infrared detectors, Signal detection, Signal to noise ratio, Switching
Airborne infrared fire location can be used to augment other techniques for the detection of small, incipient forest fires. Described here is a new real-time spatial/spectral scanner concept, the Adaptive Infrared Forest Fire Sensor, which employs an acousto-optical tunable filter (AOTF), an indium antimonide or similar array detector, and a steerable scan mirror to enhance the probability of detecting small wildfires and to reduce the rate of false alarms caused by variations in the forest scene, atmosphere, and sun position. Rapid switching of the wavelength of operation in response to the received signal permits the scanner system to optimize the spectral information about a particular spatial location. Measurements on a laboratory prototype system are in progress to verify the salient features of the design concept.
The Electro-Optics Laboratory of the Institute for Space and Terrestrial Science characterizes array detectors under a wide range of operating conditions in a test facility based on a uniform optical source, a flexible array controller, a cryostat, and comprehensive and data acquisition hardware and software. Source characteristics, ambient temperature, clock/bias parameters, and output signal conditioning can be varied to maximize the useful information about the devices under test. Emphasis has been placed on achieving a high level of accuracy and reproducibility in the measurements. Results from representative CCD arrays are used to illustrate design highlights and facility capabilities.
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