Project Title:

Compact LIDAR for Simultaneous Range and Velocity Measurements

09.05-1010
901190
Compact LIDAR for Simultaneous Range and Velocity Measurements

Abstract:

A coherent LIDAR system for measuring the range and velocity of solid objects will
be developed. The illumination and local oscillator beam are both derived from a
frequency modulated laser. For stationary targets, this causes a beat signal related
to the range-induced time delay of the target scatter. For moving targets the range-induced
beat note appears at a Doppler shifted position. An appropriate modulation format
can decouple the effects of range and velocity; the method allows one to distinguish
between receding and advancing targets. The compactness, alignment robustness, and
sensitivity are enhanced by an innovative transceiver and mixer scheme based on fiber-optic
waveguides. Fiber-optic components minimize space requirements and inherently guarantee
high mixing efficiencies. A single-mode transmit and receive aperture optimally match
the receiving and transmitting directivities. A balanced mixer scheme liberates the
system from laser excess noise, leading to shot noise limited detection at low frequencies.
Estimates indicate excellent potential for measuring the range and radial velocity
with a precision in excess of 1 percent and .003 m/sec, respectively.
The benefits of the innovation are in the realm of motion control, flow measurements,
and ranging. The compactness and advanced features of the approach may prove valuable
in situations with a need of high performance at minimum space consumption.
LIDAR, LDV, heterodyne detection, monostatic transceiver