Gradient antenna coils and arrays for use in locating systems
Buried object locators including an omnidirectional antenna array and a gradient array are disclosed. A locator display may include information associated with a buried object based on both omnidirectional antenna array signals and gradient antenna array signals.
1. A buried object locator, comprising:
a mast;
a housing coupled to the mast;
a processing element disposed in the housing;
a display element disposed on or within the housing; and
an antenna node coupled to the mast, the antenna node comprising:
an antenna array support structure;
an interior omnidirectional antenna array disposed on the antenna array support structure;
a gradient antenna comprising a quad gradient antenna array, including four or more outer antenna coils, disposed about the omnidirectional antenna array; wherein the centerline of an antenna element of the gradient antenna substantially intersect a center point of the omnidirectional antenna array; and
a central antenna assembly including one or more vertical antenna coils.
2. The locator of claim 1 , wherein the gradient antenna comprises two or more antenna elements and the centerlines of one pair of antenna elements of the gradient antenna array substantially intersect a centerpoint of the omnidirectional antenna array.
3. The locator of claim 1 , wherein the gradient antenna comprises four or more antenna elements and the centerlines of two pairs of antenna elements of the gradient antenna array substantially intersect a center point of the omnidirectional antenna array.
4. The locator of claim 1 , wherein the vertical antenna coils circumscribe a printed circuit board (PCB).
5. The locator of claim 1 , wherein the outer antenna coils and the central antenna assembly are nested in a substantially cylindrical housing.
6. The locator of claim 1 , wherein the central antenna assembly includes a plurality of vertical antenna coils.
7. The locator of claim 1 , wherein a horizontal plane containing a central axis of the gradient antenna coils does not intersect a center point of a central antenna coil array of the central antenna assembly.
8. The locator of claim 1 , wherein one or more of the coils of the quad gradient antenna array are tilted above or below a plane of the center point of an omnidirectional antenna array of the locator.