Communications: directive radio wave systems and devices (e.g. – Directive – Including a steerable array
Reexamination Certificate
2001-06-28
2003-05-27
Blum, Theodore M. (Department: 3662)
Communications: directive radio wave systems and devices (e.g.,
Directive
Including a steerable array
Reexamination Certificate
active
06570537
ABSTRACT:
BACKGROUND OF THE INVENTION
TECHNICAL FIELD OF THE INVENTION
The present invention relates generally to the field radiated wave communications and, more particularly, to a beam forming antenna processing system.
DESCRIPTION OF THE RELATED ART
A dish antenna directs a radar beam in a single fixed direction, and the antenna is mechanically repositioned to change the beam direction. The dish antenna is rotated to produce a 360 degree scanning beam. An electronic radar antenna produces directional beam control through phase control of individual antenna radiating elements, without requiring mechanically driven movement of the antenna.
Digital beam forming is a powerful technique for augmenting antenna performance. Typically, a digital beam former operates in conjunction with a phased-array antenna to enhance the overall quality of radiated data signals. Generally, the individual radiating elements are combined mathematically so that the collective radiation from the elements forms a beam which maximizes gain in the desired field of observation in accordance with electronic steering control.
In a receiver, a radiated wave front impinging on an array antenna causes signals received at various antenna elements to differ in phase due to the angle of the wave front relative to the array. The digital beam former compensates for this phase shift and sums together the different element signals such that an improved signal-to-noise ratio is obtained at its output. Electronic beam-steering antenna arrays can be used in various kinds of radar and communication systems. Thus, these arrays can be used in target acquisition systems, communication systems, pulsed radar systems, continuous wave radar systems, etc.
Many systems depend on apertures with relatively wide fields of view. In some cases the apertures are essentially omni-directional. As the field of view expands, this increases the susceptibility of the system to interference, multi-path reflections, and overlapping replies from non-synchronous, spatially diverse sources, introducing additional design constraints.
A common solution to these design challenges is to employ beam forming techniques such as fixed or electronically scanned phased arrays. The narrower beam allows the sensitivity to be focused in the direction of the desired signal while reducing sensitivity towards signals and interference from angles outside of the main-beam. Sensitivity for signals within the main-beam of the array is increased as the true or synthetic aperture gain is increased. For static circumstances such as point to point data links, this is an effective solution under most situations. For synchronous participants alternating time slots, the beam can be scanned or pointed towards each participant on a slot by slot basis.
As the participants become asynchronous, the data streams can overlap in time. Often it is necessary to be sensitive across a wider spatial field of view instantaneously. This in turn reduces the overall resistance to interference and the overall sensitivity in the direction of the signal or signals of interest. It also introduces a new problem; detection and separating signals that are coincident in time but spatially separated.
One way to address these problems is with digital beam-forming. Digital beam-forming allows beams to be defined and formed mathematically after the waveform has already been sampled by each individual element of an array. However, the throughput required to form and process many beams in each sample can be very large, often exceeding the capability of legacy systems. It also requires large amounts of information to be stored (memory) and processed though the detection algorithm, a large majority of which is not of interest.
SUMMARY OF THE INVENTION
The present invention achieves technical advantages as a method, system and apparatus for hyper-scanning digital beam forming, which includes a plurality of digitizing units (N) having respective inputs for receiving a respective signal from a plurality of elements of an antenna. The digitizing units are operably configured to digitally convert the element antenna signals at a first clock rate; a summing circuit having an input for receiving the digital signals from respective outputs of the digitizing units and operably configured to generate a plurality of output signals (M) by summing ones of the digital signals; and a channel processor having an input for receiving the M output signals and operably configured to process the M output signals at a second clock rate in which the second clock rate is at least M times aster than the first clock rate. Further, the beam former “pipeline processor” architecture enables retrofit for legacy systems.
REFERENCES:
patent: 5077562 (1991-12-01), Chang et al.
patent: 5856804 (1999-01-01), Turcotte et al.
patent: 0 654 915 (1995-05-01), None
Kuipers, Martin et al., “A Digital Chip Design For Smart Antennas”, (VTC 1999-Fall, IEEE VTS 50th, Vehicular Technology Conference, Gateway to the 21stCentury Communications Village. Amsterdamn, Sep. 19-22, 1999,)IEEE Vehicular Technology Conference, IEEE, US, vol. 3, Conf 50, Sep. 19, 1999, pp. 1870-1874, New York, NY.
Blum Theodore M.
Jakcson Walker, LLP
Lockheed Martin Corporation
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