We present a passive millimeter wave imager for aerial vehicle navigation in degraded visual and GPS-denied environments. The sensor employs aperture synthesis imaging techniques with optical upconversion of millimeter wave signals and coherent reconstruction in the optical domain to enable a suitably small form factor.
We demonstrate an optical filter to cancel 20 dB of various multipath self-interference components over a multioctave 600 MHz band centered around 400 MHz. This enables significant gains in transceiver effectiveness by enabling Simultaneous Transmit and Receive (STAR).
Low-power GPS signals are easily jammed, making it crucial to evaluate complementary technologies which can provide geolocation information in GPS-denied environments. We introduce the concept of skylight polarization-based navigation and evaluate the feasibility of this new technique.