Abstract In radio direction finders of the type in which the direction of propogation of a pulse reflected from a target is indicated, errors occur due to glint. The glint is due to the fact that all reflective parts of the target are not at the same distance from the direction finder whereby the several radio echoes reflected from the same target arrive at the direction finder at different times and are vectorially added in the direction finder, causing incorrect indication of the direction to the target by the direction finder. The various errors of direction, due to glint, measured by direction finders is averaged out by applying a variable range gate to the waves received by the direction finder, whereby angle reflection measurements from various parts of the target are averaged out to give a true indication of direction of the target.
A glint-reducing radio direction finder comprising means to detect the direction of a target as indicated by a short portion thereof in the range direction means to vary said short portion in position in the range direction to scan at least a large portion of said target and means to average the indications of direction as detected for the short portion over the scanned portion of said target whereby a true reading of the direction of said target is provided.
Claim 2
Dependent Claim
80 words
A glint-reducing radio direction finder comprising means to detect the direction of a target as indicated by a short portion thereof in the range direction means to vary said short portion in position in the range direction to scan at least a large portion of said target and means to average the indications of direction as detected for the short portion over the scanned portion of said target whereby a true reading of the direction of said target is provided.
Claim 3
Dependent Claim
40 words
The invention of claim 1 in which said means to detect the direction of a target comprises a radio receiver having a pair of antennas and means to measure the difference in phase of waves received by said two antennas.
Claim 4
Dependent Claim
18 words
The invention of claim 2 in which gating means are included between said receiver and said phase-measuring means.
Claim 5
Dependent Claim
25 words
The invention of claim 3 in which a range tracker is provided and range information is fed from said range tracker to said gating means.
Claim 6
Dependent Claim
34 words
The invention of claim 4 in which means are provided to vary the range of information fed out of the gating means cyclically with respect to the range information provided by said range tracker.