US 4,063,238 A · Range tracking apparatus in a doppler radar

Abstract

A first variable tracking gate is generated which activates a sample and hold circuit connected to receive incoming signals from a doppler radar receiver and apply output signals therefrom to a threshold circuit which in turn supplies a signal to a range counter each time the signal from the sample and hold circuit exceeds a predetermined threshold, whereupon an output from the range counter decreases the range at which the tracking gate is generated. A second tracking gate, generated a short time after the beginning of the first tracking gate, activates a second sample and hold circuit connected to receive signals from the radar receiver and supplies signals through a second threshold circuit to the range counter to increase the range of the first gate when the signal from the second sample and hold exceeds a predetermined threshold and signals from the first sample and hold circuit are below the predetermined threshold.

Claims15

Dependent claims

In a doppler radar having a transmitter for periodically transmitting pulses of electrical energy and a receiver for receiving reflected portions of energy of the transmitted pulses, range tracking apparatus comprising:

a. sample and hold means having a signal input, an output, and a gating input for causing said sample and hold means to sample a signal applied to the signal input when a gating signal is applied thereto;
b. threshold means having an input and an output and providing a signal at the output thereof only when a signal exceeding a predetermined threshold is applied to the input thereof, the output of said sample and hold means being coupled to the input of said threshold means;
c. range counter means, coupled to the radar for receiving a signal at the repetition rate of the transmitted pulses, for providing a gating pulse having a predetermined width a variable time after each pulse transmitted by the transmitter, said range counter means having an input coupled to the output of said threshold means for varying the time, that the gating pulse occurs after an associated transmitted pulse, by a predetermined fixed increment in response to each signal at the output of said threshold means;
and
d. means coupling the gating pulse from the range counter means to the gating input of said sample and hold means.

2 more elements

In conjunction with a doppler radar having a transmitter for periodically transmitting pulses of electrical energy and a receiver for receiving reflected portions of energy of the transmitted pulses, a method of range tracking comprising the steps of:

a. providing a doppler signal from received reflected portions of energy;
b. providing a variable range gate at a time subsequent to each transmitted pulse;
c. determining the amplitude of portions of the doppler signal occurring simultaneous with the range gate for each transmitted pulse;
and
d. changing the amount of time the range gate occurs subsequent to an associated transmitted pulse by a predetermined fixed increment each time the portion of the doppler signal occurring during the range gate exceeds a predetermined value.

2 more elements

Dependencies are inferred from the claim text.

Range tracking apparatus in a doppler radar

Life of this patent

Range tracking apparatus in a doppler radar

Life of this patent

Abstract

Claims15