High-Resolution Solid-State Range-Doppler Ladar

Period of Performance: 07/24/2003 - 01/23/2004


Phase 1 SBIR

Recipient Firm

Coherent Technologies, Inc.
135 S. Taylor Avenue,
Louisville, CO 80027
Principal Investigator


CTI proposes to develop a novel range-Doppler imaging ladar based upon an efficient, compact, solid-state, 1 um, 25 Watt, ladar technology for Exo-atmospheric Kill Vehicles (EKV). This technology will be capable of unresolved target detection and discrimination at ranges in excess of 300 km. The laser transmitter contains an efficient MOPA architecture, using just one active resonator to increase sensor structural integrity and a frequency offset-locked local oscillator to minimize receiver bandwidth requirements for high velocity engagements. The sensor employs an adaptive coherent array receiver, providing single-pixel diffraction-limited long-range performance. At shorter ranges, where single pixel SNR is large, the transmit beam divergence is increased, enabling additional receiver pixels for a wider field-of-view and precision angular error estimates. This approach, results in the most efficient use of the available laser power for a fixed waveform repetition frequency. A novel high-PRF transmitter waveform, optimized for range-Doppler imagery, has been designed. This waveform extends the waveform range ambiguity interval, beyond cueing target state estimator errors. Multiple-target interference attenuation (i.e., clutter rejection) is accomplished through combinations of pulse-interval modulation and discrete frequency switching. In Phase I CTI will conduct performance analysis trade studies to develop an optimal Phase II brassboard design and demonstrate the first stage of the laser transmitter. The sensor technologies developed here will have dual commercial applications. One key application is detection, characterization and tracking of unresolved space debris.