摘要:
A system computing the distance of a reflecting object from the position of an echo pulse within a range gate or telemetering window includes, as the second one of two cascaded integrators, an incrementor for converting the output voltage of the first integrator into a train of counting pulses with a cadence proportional to speed, these counting pulses being fed to a distance register which is periodically discharged into a countdown register to provide a pulse count proportional to distance. The countdown register is progressively read out by clock pulses over a period beginning with the emission of a highfrequency burst by the radar transmitter and ending upon the attainment of a zero count, or possibly a negative count establishing the lower limit of a range gate, as determined by an associated decoder controlling the telemetering-window generator. The output voltage of the decoder may be used to ascertain, with the aid of a comparator receiving a fixed reference voltage, the instant when a craft equipped with the radar system approaches a target to within a critical distance whereupon the first integrator is disconnected from the radar receiver to operate as a speed memory on the basis of data previously stored therein; the decoder output then continues its decrease, by extrapolation, in accordance with the diminishing target distance until another comparator gives rise to a firing pulse detonating a charge aboard the craft.
摘要:
1. In a radar system for searching and tracking objects in space, a voltage comparator circuit comprising: a source of serially generated time base pulses having a predetermined pulse repetition frequency, bias means coupled to said pulse source and controlled by said pulses for deriving a control voltage extended over a predetermined duration, a first sawtooth generator biased by said control voltage to produce for said predetermined duration a sawtooth voltage encompassing a period greater in length than a plurality of periods of said pulse repetition frequency, a second sawtooth generator, multivibrator means normally having a first quiescent state and one output level and being switchable to a second state and another output level by each of said pulses, said second sawtooth generator being controlled by said multivibrator means, an input connection between said source and said multivibrator means whereby in response to the switching of said multivibrator means from said first to said second state said second sawtooth generator produces a second sawtooth voltage, a comparator having first and second input electrodes and an output electrode and characteristics of producing an output pulse on said output electrode each time the signals simultaneously applied to said input electrodes agree in amplitude, cathode follower means for applying said first sawtooth voltage to the first input electrode of said comparator, circuit means for applying said second sawtooth voltage to the second input electrode of said comparator, means connected between said output electrode and said multivibrator means for restoring the initial quiescent state of said multivibrator means upon the occurrence of said output pulses, whereby said second sawtooth voltage undergoes termination upon each reversal of said multivibrator means from said second state to said first quiescent state, the improvement lying in gradually increasing the delay between each of said output pulses and the related one of said time base pulses which spatially precedes it.
摘要:
The subject invention comprises a short range monopulse marine search radar for detecting small targets such as channel markers in the water. The radar has its antenna directed so that its monopulse null intersects the surface of the water at an initial minimum range proximate the radar over which sea clutter is below the boresight line. This initial range is investigated by very narrow transmitted rf pulses to determine the presence of targets therein. The antenna is subsequently controlled in elevation by a signal coupled through a balanced modulator to the antenna so that the intersection of the monopulse null and the water surface is positioned at successive increased ranges which are investigated by the very narrow transmitted pulses. At each successive range, the geometry provided by the position of the radar antenna and the position of the monopulse null-water surface interface is such that sea clutter is below the boresight line and each successive range segment is increased exponentially by a range gate. When the range gate and the elevation monopulse both interpret the same time as corresponding to the time interval between the firing of the transmitter and the time corresponding to the range to the surface of the water, aboveboresight targets in the range segment preceding this interface are interpreted as being other than sea clutter and are displayed on a display device.
摘要:
This invention relates to a monopulse coherent doppler radar system for use at the end of a runway for detecting moving targets on the runway and vicinity of said runway. A multiplicity of range gates and threshold circuits define contiguous range increments on the runway. When a target is detected, a light signal indicates the proper range increment.
摘要:
An glideslope position detection system wherein a pair of passive reflectors are located in a spaced apart configuration at a known position adjacent an airport runway. Each of the reflectors are shaped to direct different reflection patterns in response to radar signals transmitted from an aircraft during a glideslope approach to the runway. One of the reflectors directs a reflection pattern beneath the glideslope and the other of the reflectors directs a radar reflection pattern above the glideslope, the reflection patterns providing equal amplitude radar returns to an aircraft traveling along the glideslope. The aircraft carries a radar system for detecting the relative radar return signal amplitudes from the two reflectors. Circuitry is responsive to comparison of the radar return signal amplitudes from the reflectors to generate indications of the position of the aircraft relative to the runway glideslope.
摘要:
A radar system for use on an aircraft or spacecraft for determining and controlling the attitude of the system antenna or of the craft, the system including an antenna unit producing four equiangularly spaced beams each of which is angularly offset by a substantial amount from a center reference axis, and means for applying radar pulse signals to each beam in succession and for deriving, from the received pulses returning from the ground, range and velocity information which is employed for orienting the antenna unit or the craft on which the system is mounted so as to impart a vertical orientation to the antenna system reference axis.
摘要:
COMPLEMENT VALUE. ANOTHER COUNTER CIRCUIT COUNTS UNSECCESSFUL TRANSMISSION AND RECEPTION (RANGING) PERIODS AND AFTER A REDETERMINED NUMBER OF CONSECUTIVE SUCH PERIODS THE SYSTEM SWITCHED FROM THE TRACK OF THE ACQUISITION MODE.
A DIGITAL SYSTEM FOR MEASURING THE RANGE OF A REMOTE OBJECT IN RESPONSE TO LASER ENERGY REFLECTED FROM THE OBJECT AND FOR CONTROLLING THE MODE OF OPERATION. WHEN LOGIC CIRCUITS DETERMINE THAT A SIGNAL IS A VALID RETURN SIGNAL (I.E. NOT NOISE ENERGY) THE SYSTEM SWITCHES TO A TRACK MODE OF OPERATION WHEREIN IT RESPONDS ONLY TO SIGNALS CONCIDENT WITH A RELATIVELY NARROW TRACKING GATE. IF THE RETURN SIGNAL SHOULD FADE (DETECHABLE SIGNAL NOT RECEIVED) A COUNTER, WHICH STORES THE DIGITAL COMPLEMENT OF THE RANGE INFORMATION AND WHICH POSITIONS THE TRACKING GATE, IS AUTOMATICALLY RECYCLED TO THE LAST STORED RANGE
摘要:
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.