Wide-field tracking of moving objects with a compact multi-object dispersed fixed-delay interferometer

We present a new concept for a Doppler imaging remote sensing instrument to track moving objects within a wide field of view using a compact multi-object Dispersed Fixed-Delay Interferometer (DFDI). The instrument is a combination of a Michelson type interferometer with a fixed optical delay and a medium resolution spectrograph. This takes advantage of the strength of the DFDI approach over the traditional cross-dispersed echelle spectrograph approach for high radial velocity (RV) precision measurements: multi-object capability, high throughput and a compact design. The combination of a fiber integral field unit (IFU) with a DFDI instrument allows simultaneous sampling of all of the objects within the observing field of view (FOV) to provide differential RV measurements of moving objects over background objects. Due to the three dimensional nature of the IFU spectroscopy the object location and spectral features can be simultaneously acquired. With the addition of RV signals to the measurements, this approach allows precise extraction of trajectories and spectral properties of moving objects (such as space debris and near Earth Objects (NEOs)) through sequential monitoring of moving objects. Measurement results from moving objects in a lab as well as moving cars in a field using this innovative approach are reported.