GPS antenna systems
First Claim
1. An antenna system, having a first circular polarization characteristic horizontally and upward from a plane, comprising:
- a plurality of element arrays spaced along an axis normal to said plane and configured to operate with circular polarization, each said element array including a plurality of radiating elements positioned around said axis, with said radiating elements of each array in vertical alignment with corresponding radiating elements in other arrays;
distribution means, coupled to said element arrays, including;
transmission line means for distributing signals;
first coupling means, coupled to said transmission line means, for coupling to the respective radiating elements of a first element array of said plurality of element arrays, first signals of relative phase effective to produce a first radiation pattern having a 360 degree progressive phase characteristic around said axis, said first signals having a first average amplitude;
a plurality of additional coupling means, coupled to said transmission line means, for coupling to the respective radiating elements of the remaining element arrays of said plurality of element arrays additional signals of relative phase effective to produce respective additional radiation patterns each having a 360 degree progressive phase characteristic around said axis with at least one of said additional radiation patterns rotated in azimuth phase by a predetermined angle relative to said first radiation pattern, said additional signals coupled to at least one of said remaining element arrays having an average amplitude differing from said first average amplitude; and
means for supporting said antenna system above said plane.
1 Assignment
0 Petitions
Accused Products
Abstract
Antenna systems particularly suited for reception of GPS satellite signals include a vertical stack of element arrays. Each array, which may comprise four dipoles positioned around a central axis, receives signals phased to produce a circularly polarized 360 degree progressive phase radiation pattern around the axis. By rotating in azimuth the radiation patterns of certain of the element arrays and controlling the amplitude of signals applied to different arrays in the stack of arrays, a circularly polarized radiation pattern can be provided encompassing the entire upper hemisphere above the horizon, with a sharp pattern cutoff at or slightly below the horizon. A seven array stack of individual arrays each including four angled dipoles, with a distribution network for providing signals of desired relative phase and relative amplitude to each of the 28 included dipoles, is described. GPS antenna systems can be provided in lightweight three inch diameter by 40 inch length cylindrical form, for example, for use in land surveying applications, as well as for use in aircraft approach and landing systems and other applications. For use on moving motor vehicles, antenna systems can be provided in a configuration about ten inches high including only three element arrays and having a reduced cutoff characteristic so as to accommodate antenna tilting during use.
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Citations
25 Claims
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1. An antenna system, having a first circular polarization characteristic horizontally and upward from a plane, comprising:
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a plurality of element arrays spaced along an axis normal to said plane and configured to operate with circular polarization, each said element array including a plurality of radiating elements positioned around said axis, with said radiating elements of each array in vertical alignment with corresponding radiating elements in other arrays; distribution means, coupled to said element arrays, including; transmission line means for distributing signals; first coupling means, coupled to said transmission line means, for coupling to the respective radiating elements of a first element array of said plurality of element arrays, first signals of relative phase effective to produce a first radiation pattern having a 360 degree progressive phase characteristic around said axis, said first signals having a first average amplitude; a plurality of additional coupling means, coupled to said transmission line means, for coupling to the respective radiating elements of the remaining element arrays of said plurality of element arrays additional signals of relative phase effective to produce respective additional radiation patterns each having a 360 degree progressive phase characteristic around said axis with at least one of said additional radiation patterns rotated in azimuth phase by a predetermined angle relative to said first radiation pattern, said additional signals coupled to at least one of said remaining element arrays having an average amplitude differing from said first average amplitude; and means for supporting said antenna system above said plane. - View Dependent Claims (2, 3, 4, 5)
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6. An antenna system, having a first circular polarization characteristic horizontally and upward from a plane, comprising:
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first, second and third element arrays for radiating circularly polarized signals, each said element array including a plurality of radiating elements positioned around an axis normal to said plane, with said radiating elements of each array in vertical alignment with corresponding radiating elements in other arrays said first element array positioned a first distance above said plane, said second element array positioned a second distance above said first element array and said third element array positioned a third distance below said first element array; distribution means, coupled to said element arrays, including; transmission line means for distributing signals; first coupling means coupled to said transmission line means for coupling, to the respective radiating elements of said first element array, first signals of relative phase effective to produce a first radiation pattern having a 360 degree progressive phase characteristic, said first signals having a first average amplitude; second coupling means coupled to said transmission line means for coupling, to the respective radiating elements of said second element array, second signals of relative phase effective to produce a second radiation pattern having a 360 degree progressive phase characteristic which is shifted in azimuth phase by a predetermined angle relative to said first radiation pattern, said second signals having a second average amplitude; third coupling means coupled to said transmission line means for coupling, to the respective radiating elements of said third element array, third signals of relative phase effective to produce a third radiation pattern having a 360 degree progressive phase characteristic which is shifted in azimuth phase by a predetermined angle relative to said first radiation pattern, said third signals having a third average amplitude; and means for supporting said first, second and third element arrays above said plane; said antenna system being configured for receiving satellite signals. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. An antenna system for receiving GPS satellite signals, said antenna system having a first circular polarization characteristic horizontally and upward from a plane, comprising:
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at least five element arrays each including four dipoles positioned around an axis normal to said plane with the arm portions of each dipole tilted relative to said plane, said four dipoles of each array in vertical alignment with corresponding dipoles in other arrays, with said element arrays numbered and spaced along said axis successively further from said plane as follows 5, 3, 1, 2 and 4; distribution means, coupled to said element arrays, including; four transmission lines for distributing signals effective to cause the four dipoles of each said element array to have relative phasing of zero, 90, 180 and 270 degrees; coupling means for coupling each of said four transmission lines to a different single dipole of each of said five element arrays; and feed means, coupled to said four transmission lines, for dividing input signals into four signal portions having relative phases which are integral multiples of 90 degrees and for coupling each of said four signal portions to a different one of said four transmission lines; said distribution means configured to provide said signals having said relative phase relationship as coupled to the dipoles of said element array No. 1 to produce a first radiation pattern having a 360 degree progressive phase characteristic and said signals as coupled to the dipoles of the remaining element arrays to produce similar radiation patterns which are rotated in azimuth phase relative to said first radiation pattern as follows;
element arrays Nos. 2 and 4, negative 90 degrees phase rotation;
element arrays Nos. 3 and 5, positive 90 degrees phase rotation. - View Dependent Claims (22, 23, 24, 25)
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Specification