ENGINEERING TECHNOLOGIES / Doppler DF Systems
GTMR designs and builds several versions of lightweight DF antennas which support "to-purpose" and to-vehicle" requirements. These antennas are specifically designed to be immune to variations in downstream components: the specific receivers and post detection processors selected to optimize the system performance for the operational environment.
As shown above, the same receiver and link components can be coupled to either GTMR's Doppler DF or Spinning DF type antennas.
The GTMR Doppler DF antenna is a 4-element monolithic array with a groundplane footprint of 8" and height of 7.5" using doppler principles to derive the target signal direction of arrival. This array operates in the range 20MHz-3GHz and is capable, and suitable, for targets down to 500KHz. GTMR is also involved in the developmental test of a comparable, larger "dual array" using a groundplane of 12.5" in diameter (expandable up to 24") and upper (large diameter) and lower (small diameter) arrays totaling a combined height of 28" improving the lower frequency performance.
We have also developed and are testing a filter component for the GTMR DopplerDF which mitigates the multipath and Doppler performance issues encountered when mounting the array on propeller aircraft. While designed specifically for the DopplerDF, the filter unit is compatible with any similar DF suite.