Stanley R. Czyzak

GLINT: program overview and potential science objectives

The GEO Light Imaging National Testbed (GLINT) system will image objects in geo-synchronous and semi-synchronous orbits using a synthetic aperture technique known as Fourier Telescopy. The testbed will be located in the vicinity of Socorro, New Mexico, and will form one of the most powerful imaging systems on Earth in terms of resolution, with an angular resolution of about 10 nano-radians, or 2 milli-arc seconds. Various parts of the system have strong similarities to astronomical instruments, and these similarities can be exploited to perform long-baseline interferometry, long- baseline intensity interferometry, gamma-ray observation, stellar spectrometry, and remote sensing with unprecedented sensitivities and state-of-the-art resolution.

Geo Light Imaging National Testbed (GLINT): past, present, and future

Object identification in deep space is a surveillance mission crucial to our national defense. Satellite health/status monitoring is another important space surveillance task with both military and civilian applications. Deep space satellites provide challenging targets for ground-based optical sensors due to the extreme range imposed by geo-stationary and geo-synchronous orbits. The Air Force Research Laboratory, in partnership with Trex Enterprises and our other contractor partners, will build a new ground-based sensor to address these deficiencies. The Geo Light Imaging National Testbed (GLINT) is based on an active imaging concept known as Fourier telescopy. In this technique, the target satellite is illuminated by two or more laser sources. The corresponding fields interfere at the satellite to form interference fringes. These fringes may be made to move across the target by the introduction of a frequency shift between the laser beams. The resulting time-varying laser backscatter contains information about a Fourier component of the target reflectivity and may be collected with a large solar heliostat array. This large unphased receiver provides sufficient signal-to-noise ratio for each Fourier component using relatively low power laser sources. A third laser source allows the application of phase closure in the image reconstruction software. Phase closure removes virtually all low frequency phase distortion and guarantees that the phases of all fringes are relatively fixed. Therefore, the Fourier phase associated with each component can be recovered accurately. This paper briefly reviews the history of Fourier telescopy, the proposed design of the GLINT system, and the future of this research area.

Use of laser radar for small space object experiments

This report briefly reviews the development, capabilities, and current status of pulsed high-power coherent CO2 laser radar systems at the Maui Space Surveillance System (MSSS), HI, for acquisition, tracking, and sizing of orbiting objects. There are two HICLASS systems, one integrated to the 0.6 m Laser Beam Director and one just integrated Summer 2000 to the 3.7 m Advanced E-O System (AEOS). This new system takes full advantage of the large AEOS aperture to substantially improve the ladar range and sensitivity. These improvements make the AEOS HICLASS system potentially suitable for tracking and characterization experiments of small < 30 cm objects in low-earth-orbits.

Active imaging of space objects using the HI-CLASS (high-performance CO2 ladar surveillance sensor) laser system

The HI-CLASS is a high power, wideband, coherent laser radar for long range detection, tracking, and imaging located at the Maui Space Surveillance Site (MSSS). HI-CLASS will be used to provide high precision metrics as well as information for images of space objects and remote sensing with the same system. The HI-CLASS system is currently in the final of four phases. During Phase 1, breadboard hardware was built which led to a fully integrated laser radar system at MSSS. During Phase 2, an improved system oscillator and receiver-processor were built and integrated which brought the system capability to 12 Joules at 30 Hz. The Phase 3 system has the addition of a power amplifier to the transmitter which brought the system capability to 30 Joules Hz. The HI-CLASS system will validate technology and designs required for fielding operational systems since it has the potential to address operational areas of need for increased capability for information about space objects. HI-CLASS will provide high accuracy tracking in position and velocity simultaneously, and by ultimately providing size, shape and orientation information which will help assess adversary capabilities.

Acquisition, tracking, and sizing of small space objects

High-powered, pulsed CO2 coherent ladar systems and their potential application to space debris tracking and characterization.

Satellite feature reconstruction using reflective tomography: field results

The Air Force Phillips Laboratory is in the process of demonstrating an advanced space surveillance capability with a heterodyne laser radar system to be used, among other applications, for range-resolved imaging of orbiting satellites. In this paper, we present our first satellite feature reconstruction from field results using reflective tomographic techniques.

Applications of the HI-CLASS (high-performance CO2 laser radar surveillance sensor) laser system for active imaging of space objects

The HI-CLASS is a high power, wideband, coherent laser radar (ladar) for long range detection, tracking, and imaging located at the Maui Space Surveillance Site. HI-CLASS will be used to provide high precision metrics as well as information for images of space objects and remote sensing with the same system. The four phases of the HI-CLASS hardware development program were completed in Fall 1997. During this development contract, hardware and software were developed for two different modes of operation; a ladar mode for active imaging of satellites, and a lidar model for remote sensing atmospheric measurements. Throughout the contract, data were collected which provided a demonstration of the system capabilities which validated technology and designs required for fielding operational systems. The HI- CLASS follow-on demonstration program is currently being performed under an Air Force contract. The follow-on demonstrations will provide the groundwork to an upgrade program currently under consideration by the Air Force. HI- CLASS provides high accuracy tracking in position and velocity simultaneously, and by ultimately providing size, shape and orientation information, it will help assess adversary capabilities. HI-CLASS has the potential to address operational areas of need for increased capability for information about space objects. The follow-on contract effort and the HI-CLASS upgrade effort will provide a demonstration of these potential applications of the HI- CLASS system.