Anti-jamming and reduced interference global positioning system receiver methods and devices
Global navigation satellite system (GNSS) radio frequency signals broadcast from geo-stationary satellites 20,000 km above the earth when received by GNSS receivers are fundamentally weak. Accordingly, these GNSS receivers are vulnerable to accidental and deliberate interference from a range of synthetic sources as well as natural sources. Existing anti-jamming technologies such as controlled reception pattern antennas, adaptive antennas, null-steering antennas, and beamforming antennas etc. are expensive and incompatible with many lower cost and footprint limited applications. However, in many applications the GNSS antenna is mounted upon a fixed or mobile element such that accidental and intentional jammers tend to be in the plane of the antenna or below it. Accordingly, there are presented designs and techniques to improve the anti-jamming or interference performance of GNSS receivers by further reducing the responsivity of the GNSS receiver to signals in-plane or below the plane of the antenna.
1. An assembly comprising:
a plurality of conductive planes where each conductive plane of the plurality of conductive planes is disposed at a predetermined spacing relative to one another along an axis of the assembly and a conductive plane of the plurality of conductive planes nearest a ground plane is disposed with the predetermined spacing above the ground plane; and
a plurality of sets of electrically non-conductive connectors; wherein
the plurality of conductive elements of the assembly when disposed above an antenna comprising an electrode disposed at another predetermined spacing above the ground plane act to reinforce the gain of the antenna in a zenith direction of the antenna and reduce the gain in a direction at an angle relative to a plane of the antenna at a predetermined frequency of operation of the antenna;
the direction at an angle relative to the plane of the antenna is established in dependence upon the predetermined spacing;
a first set of conductive elements of the plurality of sets of conductive elements are circular;
each other set of conductive elements of the plurality of sets of conductive elements is a series of annular rings of defined inner radius and defined outer radius;
the plurality of sets of conductive elements do not overlap radially;
each set of electrically non-conductive connectors of the plurality of sets of electrically non-conductive connectors couples an inner conductive element of the plurality of conductive elements in a set of conductive elements to an outer conductive element of the plurality of conductive elements in another set of conductive elements; and
at least one of:
the set of conductive elements of the plurality of sets of conductive elements having the outermost annular rings are mounted to a plurality of electrically non-conductive mounting elements disposed at predetermined positions around the periphery of the plurality of sets of conductive elements; and
the first set of conductive elements of the plurality of sets of conductive elements are mounted to a central electrically non-conductive mounting substantially perpendicular the electrode and passing through the centre of each conductive element within the first set of conductive elements of the plurality of sets of conductive elements.
2. An assembly comprising:
a plurality of sets of conductive elements where each set of conductive elements comprises a plurality of other conductive elements where each conductive element of the plurality of conductive elements in a set of conductive elements are disposed at a predetermined constant spacing relative to one another and a conductive element of the plurality of conductive elements nearest a ground plane is disposed with the predetermined constant spacing above the ground plane; wherein
the plurality of sets of conductive elements of the assembly when disposed above an antenna comprising an electrode act at a frequency of a plurality of frequencies to reinforce the gain of the antenna in a zenith direction of the antenna and reduce the gain in a direction at an angle relative to a plane of the antenna where the direction at an angle relative to the plane of the antenna is determined in dependence upon the predetermined constant spacing of a predetermined set of conductive elements of the plurality of sets of conductive elements; and
the electrode of the antenna is disposed at a predetermined distance above the ground plane;
a first set of conductive elements of the plurality of sets of conductive elements are circular;
each other set of conductive elements of the plurality of sets of conductive elements is a series of annular rings of defined inner radius and defined outer radius;
the plurality of sets of conductive elements do not overlap radially;
each set of electrically non-conductive connectors of the plurality of sets of electrically non-conductive connectors couples an inner conductive element of the plurality of conductive elements in a set of conductive elements to an outer conductive element of the plurality of conductive elements in another set of conductive elements; and
at least one of:
the set of conductive elements of the plurality of sets of conductive elements having the outermost annular rings are mounted to a plurality of electrically non-conductive mounting elements disposed at predetermined positions around the periphery of the plurality of sets of conductive elements; and
the first set of conductive elements of the plurality of sets of conductive elements are mounted to a central electrically non-conductive mounting substantially perpendicular the electrode and passing through the centre of each conductive element within the first set of conductive elements of the plurality of sets of conductive elements.
3. An assembly comprising:
a plurality of conductive elements disposed above the electrode where the plurality of conductive elements are disposed at a constant spacing relative to one another and the conductive element of the plurality of conductive elements nearest the ground plane is disposed with the constant spacing above the ground plane; wherein
the antenna operates at a plurality of frequencies and comprises an electrode disposed at a predetermined distance above the ground plane;
each conductive element of the plurality of conductive elements is substantially parallel to the electrode;
a gain of the antenna at a zenith is increased relative to the antenna gain at the zenith for the antenna alone;
the gain of the antenna has a null at a predetermined elevation established in dependence upon the the constant spacing of each conductive element relative to its neighbours within the plurality of conductive elements; and
either:
the plurality of conductive elements are mounted to a central mounting which is substantially perpendicular to the electrode and passing through the centre of each conductive element;
or:
the plurality of conductive elements are mounted to a plurality of mounting elements disposed at predetermined positions around the periphery of the plurality of conductive elements.
4. The assembly according to claim 3 , wherein the electrode of the antenna has a geometry that exhibits symmetry for a 90° rotation.
5. An assembly comprising:
one or more sets of conductive elements where each set of conductive elements comprises a plurality of conductive planes where each conductive plane of the plurality of conductive planes in a set of conductive elements are disposed at a predetermined constant spacing relative to one another and a conductive plane of the plurality of conductive planes nearest the ground plane is disposed with the predetermined constant spacing above the ground plane; and
a plurality of sets of electrically non-conductive connectors; wherein
the antenna operates at a plurality of frequencies and comprises an electrode disposed at a predetermined distance above the ground plane;
an antenna gain of the antenna at a subset of the plurality of frequencies has a radiation gain null at a predetermined elevation determined in dependence upon the predetermined constant spacing of a predetermined set of conductive elements of the one or more sets of conductive elements;
a first set of conductive elements of the one or more sets of conductive elements are of a predetermined geometry;
any other set of conductive elements of the one or more sets of conductive elements is a series of annular implementations of the predetermined geometry;
each set of electrically non-conductive connectors of the plurality of sets of electrically non-conductive connectors couples an inner conductive plane of the plurality of conductive plane of the plurality of conductive planes in another set of conductive elements; and
the set of conductive elements of the one or more sets of conductive elements having the outermost annular rings are mounted to a plurality of electrically non-conductive mounting elements disposed at predetermined positions around the periphery of the one or more sets of conductive elements.
6. An assembly comprising:
one or more sets of conductive elements where each set of conductive elements comprises a plurality of conductive planes where each conductive plane of the plurality of conductive planes in a set of conductive elements are disposed at a predetermined constant spacing relative to one another and a conductive plane of the plurality of conductive planes nearest the ground plane is disposed with the predetermined constant spacing above the ground plane; and
a plurality of sets of electrically non-conductive connectors; wherein
the antenna operates at a plurality of frequencies and comprises an electrode disposed at a predetermined distance above the ground plane;
an antenna gain of the antenna at a subset of the plurality of frequencies has a radiation gain null at a predetermined elevation determined in dependence upon the predetermined constant spacing of a predetermined set of conductive elements of the one or more sets of conductive elements;
a first set of conductive elements of the one or more sets of conductive elements are of a predetermined geometry;
any other set of conductive elements of the one or more sets of conductive elements is a series of annular implementations of the predetermined geometry;
the one or more sets of conductive elements do not overlap radially from a longitudinal axis along which the one or more sets of conductive elements are disposed;
each set of electrically non-conductive connectors of the plurality of sets of electrically non-conductive connectors couples an inner conductive plane of the plurality of conductive planes in a set of conductive elements to an outer conductive plane of the plurality of conductive planes in another set of conductive elements; and
the first set of conductive elements of the one or more sets of conductive elements are mounted to a central electrically non-conductive mounting substantially perpendicular the electrode and passing through the centre of each conductive element within the first set of conductive elements of the one or more sets of conductive elements.
7. An assembly comprising:
one or more set of conductive elements where each set of conductive elements comprises a plurality of conductive planes where each conductive plane of the plurality of conductive planes in a set of conductive elements are disposed at a predetermined constant spacing relative to one another and a conductive plane of the plurality of conductive planes nearest the ground plane is disposed with the predetermined constant spacing above the ground plane; and
a plurality of sets of electrically non-conductive connectors; wherein
the antenna operates at a plurality of frequencies and comprises an electrode disposed at a predetermined distance above the ground plane;
an antenna gain of the antenna at a subset of the plurality of frequencies has a radiation gain null at a predetermined elevation determined in dependence upon the predetermined constant spacing of a predetermined set of conductive elements of the one or more sets of conductive elements;
a first set of conductive elements of the one or more sets of conductive elements are of a predetermined geometry;
any other set of conductive elements of the one or more sets of conductive elements is a series of annular implementations of the predetermined geometry;
the one or more set of conductive elements do not overlap radially from a longitudinal axis along which the one or more sets of conductive elements are disposed;
each set of electrically non-conductive connectors of the plurality of sets of electrically non-conductive connectors couples an inner conductive plane of the plurality of conductive planes in a set of conductive elements to an outer conductive plane of the plurality of conductive planes in another set of conductive elements;
the first set of conductive elements of the one or more sets of conductive elements are mounted to a central electrically non-conductive mounting substantially perpendicular the electrode and passing through the centre of each conductive element within the first set of conductive elements of the one or more sets of conductive elements; and
the set of conductive elements of the one or more sets of conductive elements having the outermost annular rings are mounted to a plurality of electrically non-conductive mounting elements disposed at predetermined positions around the periphery of the one or more sets of conductive elements.