Imaging LADAR is a hybrid technology that offers the ability to measure basic physical and morphological characteristics (topography, rotational state, and density) of a small body from a single fast flyby, without requiring months in orbit. In addition, the imaging LADAR provides key flight navigation information including range, altitude, hazard/target avoidance, and closed-loop landing/fly-by navigation information. The Near Laser Ranger demonstrated many of these capabilities as part of the NEAR mission. The imaging LADAR scales the concept of a laser ranger into a full 3D imager. Imaging LADAR systems combine laser illumination of the target (which means that imaging is independent of solar illumination and the image SNR is controlled by the observer), with laser ranging and imaging (producing high resolution 3D images in a fraction of the time necessary for a passive imager). The technical concept described below alters the traditional design space (dominated by pulsed LADAR systems) with the introduction of a pseudo-noise (PN) coded continuous wave (CW) laser system which allows for variable range resolution mapping and leverages enormous commercial investments in high power, long-life lasers for telecommunications.
For a number of years high speed space to ground data links have been a topic of interest. Improvements in mass storage devices, laser transmitters, EO modulators, and laser receivers have made implementation of a high speed optical down link physically and financially practical. This paper highlights a concept for a many gigabit per second optical data down link using a laser transmitter as the core of a down link device. The laser communication system is scalable using wavelength division multiplexing (WDM). Impact of probability of cloud free field of view (PCFFOV) is addressed on data storage needs. The trade space of the baseline concept between number of channels, data transmit size, number of ground stations, laser power, and climatology is presented. The resulting concept uses COTS equipment and consists of 16 channels multiplexed together producing an effective data transmit rate of 32 Gbps. This optical down link will transmit in 1 minute what an X-band transmitter needs more than 11/2 hours to down link.
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