Optical metrology offers techniques that can be used to control
the deployment and servo-actuation of space-based reflectors,
as well as to measure small deformations for earth-based applications.
Because space-based devices operate in a hostile and remote
environment, they must be robust and satisfy stringent hardware
specifications (size, mass, and power consumption are particularly
important). The need for optical hardware also imposes physical
constraints. Conventional laser interferometry requires a
computationally expensive fringe analysis to derive displacement
data from the visual image of an object; the additional overhead
that this imposes, in terms of both computing power and time,
is a distinct disadvantage.
A recently developed double-exposure
heterodyne interferometry technique for measuring line-of-sight
displacement has the potential to significantly simplify this
The Tanner Labs innovation is to
implement the core computation of double-exposure heterodyne
interferometry using analog integrated circuitry, thereby
bringing power consumption, size, and weight to an absolute
minimum. The resulting technology promises to provide unprecedented
terrestrial and space-based capabilities.