First, by allowing the virtual viewing direction to be changed, the observer may explore the entire virtual environment with only a narrow
instantaneous field of view. Second, by presenting a detailed HSD in the viewing direction and a simple image in the periphery, less visual information is presented.
An antenna best suited to eavesdrop upon signals arriving at arbitrary frequencies from arbitrary directions should be broadband and omnidirectional, or at least have a very wide
instantaneous field of view. To accurately determine the angle of arrival of this same signal, once detected, requires a highly directional antenna or some relatively sophisticated signal processing techniques.
The main advantages of interferometric techniques include wide instantaneous bandwidth, wide
instantaneous field of view (120 [degrees] typically), and sub-degree accuracy.
