Digital Direction Finding

The Digital Direction Finding (DDF) Project will specify, design, and demonstrate a high throughput digital DF processor. We will implement a digital receiver integrated with each antenna element. The task of maintaining synchronization of all A/Ds acrossthe antenna array is accomplished by a novel method proposed herein. Direct RF sampling is specified and will provide the requisite signals for broadband instantaneous DF processing, which can either implement a digital Butler matrix or implement a digitaladaptive beamformer. Since digital technology relies on a reconfigurable digital implementation, it is very flexible. The resulting digital DF system will be more reliable for the harsh military environment, more flexible for use in different RF channels,and easier to set up and to tune compared to the analog DF systems. A digital direction finding system will provide more reliable performance when compared to their analog RF counterparts. The DDF relies on a reconfigurable logic implementation realized ona combination of DSPs and FPGA and is thus very flexible. The design allows adaptation to different RF bands by adjusting one parameter in the digital receiver, thus the same DF accuracy can be maintained across all RF channels. This improvement makes thistechnology a prime candidate for a Phase III program given the numerous DF systems in the marketplace today. The developed DF system may also be applied by commercial ships for information gathering.