In an embodiment, a coordinate determiner is operable to identify at least first and second surfaces that each approximately intersect an object, and to determine at least two approximate coordinates of the object from the first and second surfaces, where at least one of the surfaces is nonplanar. For example, if the coordinate determiner is disposed on a fighter jet having at least two short-baseline-interferometers (SBIs), then two surfaces may be the surfaces of two cones having two of the SBIs as respective vertices, the object may be a close-in target, and the coordinate determiner may determine the azimuth and elevation of the target from the cone surfaces. Furthermore, the coordinate determiner or another computation unit onboard the jet may determine the slant range of the target from the elevation and the altitude of the jet. The coordinate determiner may at least facilitate ranging of the target quickly enough to allow a pilot sufficient time to evade detection by the target, to destroy the target, or to evade or destroy a projectile fired by the target.