Abstract: An environmental control system includes sensors in a room for sensing the environment and a sensor which may be a sound sensor, for detecting the presence or absence of a person in the room. With the aid of a digital computer, the presence or absence of a person in the room as determined by the sound sensor enables the computer to control the environment and also to actuate an alarm when a presence is sensed during an unauthorized time period. The system is applicable to one or more rooms.

Abstract: A transmitting section periodically radiates a signal wave. A receiving section receives the signal wave radiated from the transmitting section and reflected from the monitored region to produce the received signal. A sampling circuit samples the output signal from the receiving section at given time intervals. A memory stores the output signal from the sampling circuit at the time of one period of transmission, and a judging circuit compares the output signal from the sampling circuit at each transmission with the signal previously stored in the memory to detect a change in a state of an object to be detected.

Abstract: A continuous strip of coiled material is provided with protrusions, such as barbs, which are oriented to eliminate mutual interference when the coiled material is stacked in a compact, collapsed nested condition and wherein each turn of the coil is permanently fixed at equiangularly spaced multiple points alternately to its adjacent trailing and leading turns of the coil. An intrusion detection system signals intrusion into the space encompassed by the above mentioned coil and features a microwave energy source, receiver and detector for indicating a reduction in received microwave energy at the receiver indicative of intrusion into or other disruption of the energy guided path determined by the coil.

Abstract: An ultrasonic surveillance system which emits pulse-like ultrasonic waves to an area under surveillance, which statistically compares a reflected-wave pattern established by receiving ultrasonic waves reflected from the under surveillance with a predetermined reference pattern, and which produces an alarm signal when these two patterns are not in agreement. According to this system, the alarm signal is prevented from being erroneously produced by ultrasonic noises.

Abstract: A directional loop antenna array is provided by two flat parallel spaced apart open loops with a shorted turn disposed between the open loops equidistant therefrom. The signals from the open loops are vectorially added and subtracted in a sum and difference circuit and the phase angle between the sum and difference signals is ascertained in a phase detector circuit that feeds an indicator. The so determined phase angle is either greater or less than 90.degree. depending upon the relative magnitudes of the loop signals.

Abstract: In the receiver of an outdoor intruder detection apparatus, which receiver is spaced from and receives signals from a microwave transmitter and provides an alarm output upon the occurrence of change in the received signal, eliminator means is provided for eliminating pulses which may be superimposed on the signals from nearby radar. Such eliminator means comprises a wide band amplifier which serves, by way of a monostable to actuate a switch which gates out, in synchronism with the superimposed pulses, the detected signals from an aerial and diode as supplied by way of amplifiers and a delay line to further signal-processing circuitry.

Abstract: A runway collision avoidance system having warning devices is provided for the safety of aircraft taxiing, taking off, and landing. The system is capable of detecting ground traffic and obstacles including aircraft, maintenance vehicles and wildlife that may encroach upon an active runway during low visibility conditions or when visual observation is impaired. The system includes an electromagnetic transmitter positioned beyond one end of a runway which directs a continuous beam of high frequency radio signals, for example microwaves, longitudinally along the full length of the runway. A plurality of electromagnetic receivers positioned beyond the other end of the runway pick up the transmitted signals and apply them to a balance circuit and then to a comparator circuit. With a clear runway, the transmitted signals are received without interruption and the receiver outputs remain balanced or equal.

Abstract: An electronic detection system for detecting intrusion thru a perimeter eoys a transmission line as a sensing element. In one embodiment, RF energy is transmitted: in another, pulses of DC. In either case, pseudo-random coding of the signals is employed. A preferred emboidiment of the invention utilizes a transmission line consisting of a twisted pair of wires enclosed in a non-deformable insulation and configured for shallow burial to effect concealment. Another shape is disclosed for laying-out over hard ground. A low ohmic ground is included under the line to improve performance. An intruder in the field of the line causes an RF reflection back towards the source, which reflection may be detected by Doppler range-gating techniques.

Abstract: A high frequency signal is beamed into a bunker and a reflected signal from the top of the contents in the bunker is detected and fed into electronic circuitry. This circuitry obtains a beat signal dependent in frequency on the height of material in the bunker and the signal is subjected to division in a processing circuit and subsequent treatment as a Fast Fourier transform. A store gathers all divided and transformed segments of the signal to provide a spectrum from which the level of the bunker can be obtained as a read out.

Abstract: A sensitive intrusion detection system has an RF excited antenna located within the area to be protected and a leaky coaxial cable extending around the perimeter. The presence of an intruder alters the coupling between the antenna and the coaxial cable thereby changing the signal received by the cable. The detection system is responsive to incremental changes in the in-phase and quadrature components of the received signal. When these components are plotted against each other a cardioid-like curve is obtained in the .DELTA.I,.DELTA.Q plane. By tracking both magnitude and angle of this curve as it is generated a sensitive detection mechanism is provided. When the variations in magnitude and angle exceed a threshold an alarm is sounded. To avoid the possibility of intruders using a particular path would gives a null angle response, a second cable adjacent to the first may also be employed.

Abstract: An intrusion detector is provided having transmission and receiving cables wherein the cables are leaky from an RF standpoint so that a portion of the RF energy from the transmission cable escapes and is picked up on the receiving cable. Both sine and cosine signals are detected. The cables can be buried.

Abstract: A system for providing perimeter security, intra-building communication and control functions, utilizes a pair of single wire loops placed about the periphery of the building, and spaced from one another. At least one facilities unit, for fire detection, appliance control and the like functions, has the powering battery thereof series-connected in one of the perimeter loops, and with that loop being connected to battery trickle-charging circuitry. Each of the unit batteries is bypassed by a capacitive element, selected for the frequency, partly determined by the capacitance between the pair of loops, of an oscillator for detecting proximity of intruders adjacent to the building periphery. The proximity-detection oscillator includes a transformer for coupling a data transceiver to and from the remaining loop, whereby voice and/or digital communications may be modulated upon a magnetic field extending throughout the interior of the building for communications to and from independent units therein.

Abstract: A continuous loop transmitting winding assembly is disposed in one panel and a vertically oriented figure eight receiving coil winding assembly is disposed in a second panel, the two panels being mounted on pivots for swinging gate type movement straddling the pathway to be controlled by a magnetic surveillance system. This arrangement confines the surveillance field to the pathway and tends to follow the passage of an object bearing a marker therealong. No marker detecting backfield is generated. Alternatively, one winding assembly is moveable while the other is stationary thereby similarly confining the field.Special winding configurations are used to reduce interference from third harmonic signals produced in adjacent metallic counters. The arrangement also imposes immunity to signals emanating from cash registers, motors and the like.Door and single gate mounted magnetic and microwave surveillance systems are also disclosed.

Abstract: Radiation energy is emitted intermittently to an area under surveillance and a pattern of reflections is formed. Thereafter, the pattern of reflections is statistically compared with a reference pattern which is prepared in advance. When the two patterns are different, an alarm is activated.

Abstract: Apparatus for registering a chance event, particularly the passage of a ball over a closed boundary line in a game, is described wherein the ball contains an oscillatory circuit. Two parallel conductors, fed by an a.c. generator in phase opposition extend along the boundary line so that a receiving conductor extending between the transmitting conductors is subject to a resultant zero voltage until the ball approaches and passes the boundary line so disturbing the electromagnetic fields radiated by the transmitting conductors. The receiving conductor current then passes through an amplifier, phase comparison means, a pulse generator and display device. The phase comparison means is connected to distinguish the direction in which the ball crosses the line and also enables a zero setting device to accommodate prolonged extraneous signals. A compensating antenna and circuit eliminate stray field effects. The transmitting and receiving conductors can encircle a goal structure.

Abstract: A dual mode sensor having a seismic channel and an RF channel with a logic circuit recognizing both channels. The seismic channel detects disturbances with a geophone and determines the spacing and the density of the impulses while the RF channel radiates electromagnetic energy and detects impedance changes in the oscillator circuit driving the antenna when the target is in the field. The rates of changing impedances and their thresholds are determined.

Abstract: A balance system detects ferrous or non-ferrous metallic objects carried by people or present in certain articles. This balance consists in the generation of a fixed oblique magnetic field of detection, substantially constant, whatever the orientation or positioning of the objects to be detected in the search area. The balance in combination with a search gate, includes a transmitting coil and a receiving coil, each having an L-shape, inverted relative to each other.

Abstract: A warning apparatus comprises a Gunn oscillator, a transmitting antenna, a receiving antenna, a detector, and a comparator which produces a detecting signal when the output signal from the detector is belowed a reference level. The warning apparatus further comprises a drive circuit for applying a rectangular pulse voltage to the Gunn oscillator, a band-pass filter allowing only a microwave with the transmitting frequency band of microwaves received by the receiving antenna to pass therethrough, and a signal generator for applying the reference signal, which changes in accordance with the output signal of the detector, to the comparator.

Abstract: A proximity detector processes voltages induced across the sections of at least one antenna.The antenna sections are each connected to means (30, 31 and 36 to 39) for rectifying the positive and negative alternations of the alternating signal providing two first and second signals relating, one, to the "peak" value of the voltage induced across the section whose voltage is the highest and, the other, to the mean value of the voltage across the various sections, the first signal supplying an adder controlled by a gate and the second signals are supplied to another input of the adder led by a limiter said means being, in turn, connected to means (21, 22) for analyzing these two signals.The detector may be used with elevator doors.

Abstract: An intrusion detection apparatus including a sensor for sensing an objectionable interference phenomenon within a detection area and developing a pulse train coincident therewith, signal processing circuitry responsive to the pulse train and operation to actuate a Gunn diode microwave generator or the like in a pulsed manner causing it to transmit microwave energy into the detection area in synchronism with the interference phenomenon, a microwave receiver for detecting microwave energy reflected from the detection area and for developing detection signals indicating motion within the monitored area, and further signal processing circuitry responsive to the detection signal and operative to actuate an alarm or the like.

Abstract: Range and elevation measurement ambiguities in upward looking intruder detection systems are eliminated by look-up sensor instrumentation that utilizes monostatic and bistatic radar principles. Intruder detection systems that have the capability of monitoring the air space over the perimeter of an area to be protected and that employ radar ranging techniques and guided wave sensor generate only limited or ambiguous intrusion event information. That is, the r.f. signals that are transmitted and received travel from the transmitter-receiver-processor location through the sensor, up to the intrusion and back through the same path. The data developed is thus the same for high altitude close range intrusions as it is for low altitude distant intrusions. This ambiguity is eliminated by utilizing a transmitter and receiver at one end of the upward looking sensor and a second receiver at the other end.

Abstract: A floor mat consisting of a conductive grid laminated to a conductive sheet with a layer of dielectric material therebetween to form a capacitor is disposed between the pedestals that house means for radiating a microwave signal through a surveillance area. A low frequency signal is applied to the capacitor mat for direct capacitive coupling through the body of a pedestrian to any surveillance tag carried thereon.

Abstract: A fail-safe relay system for use in infrared security barriers or other apparatus producing a sensing signal so as to control the de-activation and permit the re-activation of an interconnected device; such as a machine press. The relay system uses two relays with contacts in series in conjunction with electronic circuitry. Safe-start operation for preventing reactivation of the interconnected device if any unsafe condition exists, including failure of either pair of relay contacts to open when an unsafe condition is sensed, is also accomplished.

Abstract: Electromagnetic radiation object position detection system and method are disclosed for detecting when an object is located in the path of a powered sliding gate. In a preferred embodiment, polarized microwave radiation is emitted from a source fixed relative to the sliding gate. This radiation is projected along and spaced ahead of the leading edge of the sliding gate by a redirecting means which moves with the gate. A second redirecting means also moves with the gate and redirects the radiation back to a detector fixed relative to the sliding gate which provides a signal when this radiation is detected. The presence of an object in the path of the sliding gate is indicated by the blockage of radiation in the beam moving with the leading edge of the sliding gate.

Abstract: A shopping cart theft prevention system which includes signal sending means and a receiver carried by the cart for receiving a cart-immobilizing or cart-mobilizing signal from the transmitter. The cart includes a frame and a sub-frame pivoted to the frame and bearing spaced cart-supporting wheels, the sub-frame being connected to the frame by a latch. The latch is opened whenever a signal is received from the transmitter by a receiver attached to the cart. Alternatively, a signal can be sent to keep the latch closed, and upon removal of the signal, the latch can be opened. The cart may carry a battery operated solenoid triggered by the radio signal. The plunger of the solenoid may comprise or activate a crossbar on the latch. Thus, when the solenoid is operated, the crossbar is moved so that the latch is open or closed, allowing the sub-frame and associated wheels to automatically swing out of operative position when open, thereby immobilizing the cart.

Abstract: Uniform detection sensitivity along the periphery of an r.f. loop intruder detector system is realized by periodically electronically interchanging the input and termination ends of the system's leaky transmission line transmitting element. The intruder detector system comprises a length of leaky transmission line that encompasses the region to be protected, a receiving antenna within the protected region, an r.f. transmitter and a remotely located receiver and detector. R.F. energy is transmitted through the leaky transmission line and received by the receiving antenna and detector means to establish a normally quiescent field. Violation of the protected region by crossing the leaky transmission line disturbs the quiescent field condition and the intrusion event and the location is signaled by the detector. The effects of attenuation along the leaky transmission line are obviated by periodically switching the transmitter to alternate leaky transmission line ends.

Abstract: A scanning barrier which can detect and discriminate objects which are within the scanned area. A transmitter on one side of the scanned area transmits a laminar barrage of electromagnetic microwaves across the scanned area. The laminar barrage of electromagnetic microwaves have a thin width and a predetermined height. A receiver across the scanned area receives the microwaves. The receiver is formed of a plurality of vertically adjacent elemental receivers which divide the laminar barrage into a series of horizontal slices. A logic circuit is connected to each of the elemental receivers and can detect the interruption of the laminar barrage to that elemental receiver.

Abstract: An intrusion or movement detector including an oscillator for generating a radio signal, an antenna for transmitting said radio signal into an area to be surveyed by said detector, said antenna exhibiting a variable radiation resistance relative to the position and movement of objects in the area to be surveyed resulting in a variable loading on said generator when in use, a monitor for monitoring said variable loading and activating a signal or alarm when said variations in loading reach a predetermined threshold level to indicate an intrusion or movement in the area surveyed.

Abstract: The intrusion detection capability of a guided wave radar intrusion detection system is selectively disabled in certain areas, such as gates or portals to permit ingress and egress of personnel and vehicles without affecting overall system performance and without requiring an independent detection system. This is realized by means of an integral system portal enable-disable device. Guided wave radar intrusion detection systems employ two parallel leaky transmission lines, one transmitting and the other receiving radar signals. Violation of the area between the leaky transmission lines by an intruder results in a signal that indicates the occurrence and its location. Gate areas are remotely enabled or disabled by a switching circuit that switches a segment of non-radiating transmission line into or out of the transmitting leaky transmission line in each selected gate region.

Abstract: An intrusion detection system utilizes a radio frequency radiative system whose near electromagnetic field is monitored by receiving devices which respond, in a measurable way, to any disturbance of the near electromagnetic field by physical intrusion.

Abstract: The detection, location and tracking of an intruder in an area to be protected is accomplished by dividing the area into a multiplicity of discrete regions, transmitting r.f. signals from transmitting transducers that comprise lengths of transmission lines deployed along the boundaries of the discrete regions, and receiving intrusion occurrence signals from receiving transducers located within each region. Violation of a boundary by an intruder results in an intrusion signal from the receiving transducers of as many as four possible adjacent regions thereby indicating an intrusion event. A coincidence logic circuit indicates which boundary has been violated. Intrusion occurrence signals are stored for suitable periods of time while past and current intrusion events are indicated on a display in order to locate and track intruders.

Abstract: An intrusion alarm system has a number of satellites each connected to a master by an unshielded cable having only four conductors, namely two power conductors, a drive signal conductor which supplies drive to the satellite transmitter and the satellite control circuit, and an alarm conductor. When an intrusion is detected by a satellite, its control circuit transmits a high level alarm signal on the alarm conductor to the master and also sets a latch in the satellite. The master has a rocker switch which an investigator turns off when he arrives at the supervised premises. This turns off the drive signal to the satellite and causes a counter in the master to send a set of interrupting counting pulses to the satellites on the drive conductor. Each satellite has a counter which counts the pulses if that satellite's latch has been set and sends a pulse back to the master on the alarm conductor immediately after the count associated with that counter.

Abstract: A microwave radar type of intruder detection system incorporating signal sensing, storing and comparison logic which enables the system to self-adapt to any preselected environment and produce a signal in the event of a predetermined change from the ambient conditions of the preselected environment.

Abstract: Perimeter protection in a security installation is achieved by detecting disturbances in a microwave beam sent from a transmitter to a receiver. The transmitter and receiver have associated beam antennas of extended vertical aperture of not less than 0.75 meters to mitigate the effects of ground reflection. The antennas are preferably slotted waveguide arrays and the advantages of using circular polarization are shown. Circularly-polarized slotted waveguide arrays are disclosed having a center feed to minimize frequency dependent beam-spreading.

Abstract: An electronic detection system for detecting intruders employs a transmission line as a sensing element. The transmission line is positioned about the perimeter of the area to be protected. An antenna applies pulsed RF energy to the line. An intruder in the field of the line causes an RF reflection back toward the source, which reflection may be detected by Doppler range-gating techniques.

Abstract: A radar receiver for indicating the presence of a source of microwave energy includes an antenna, a modulation oscillator and modulator diode, a detector diode connected to bandpass amplifier stages, a peak detector providing a signal proportional in level to the received microwave energy signal strength, and a voltage controlled oscillator (VCO) connected to the peak detector and having a frequency in proportion to the peak detector signal level, the frequency of the VCO being an indication of range from a source of radar and a change in frequency being an indication of a rate of approach thereto. The VCO controls a transistor switch, and alarm output devices are connected through the transistor with alarm power sources, whereby an alarm signal activates the output device at a frequency related to the microwave signal strength.

Abstract: An intrusion detector system for detecting the presence of moving targets in one or more surveillance zones and activated either by the presence of the moving target or directly by some positive action for transmitting an alarm signal causing the provision of a predetermined number of pulses having predetermined time periods. A tone generator and control circuitry receiving the timed pulses, generates a combination of multiple tones of discreetly different frequencies during the timed pulses, the combination of multiple tones of each timed pulse being of different frequencies than the combination of multiple tones of each other timed pulse, to provide a tone-coded message that is transmitted to a receiver.

Abstract: A single wire antenna placed in proximity to an area to be protected senses the presence of electromagnetic fields including the normal ambient field and modulation thereof resulting from the presence of a moving intruder. The antenna signals are demodulated and filtered to provide the input to circuitry for inspecting these signals and producing a signal based upon differentiation between normal transient signals and random modulation signals associated with the movement of an intruder. Digital counter circuitry provides the differentiation and various time-out features can be incorporated to control the generation and/or transmission of alarm signals. The system includes various elements to permit easy testing of system operations by the user.

Abstract: A receiver in which the detection sensitivity of a detection diode is adjustable as a function of the polarization current, and is controlled by means of a feedback circuit provided with a delay element so that changes in the received signals having a frequency below a value determined by the delay element are eliminated.

Abstract: An intrusion alarm system has a number of satellites each connected to a master by an unshielded cable having only four conductors, namely two power conductors, a drive signal conductor which supplies drive to the satellite transmitter and the satellite control circuit, and an alarm conductor. When an intrusion is detected by a satellite, its control circuit transmits a high level alarm signal on the alarm conductor to the master and also enables, but does not operate, a speaker in the satellite. The master has a rocker switch which an investigator turns off when he arrives at the supervised premises. This turns off the drive signal to the satellite. The control circuit of the satellite that caused the alarm responds by sounding its speaker, enabling determination of where the alarm occurred.

Abstract: An RF intruder system utilizes two concentric loops of wire spaced apart for a predetermined magnitude, either of which can transmit and/or receive electromagnetic energy. This area within the loops are to be protected against intrusion. Without intrusion, the received signal is steady. Upon intrusion, there are signal changes which are instantly noted by signal detection and processing.

Abstract: An intruder detection transceiver in which close-in sensitivity is reduced or eliminated to alleviate false alarm problems. An ultrasonic or microwave transceiver contains a transmitter and receiver for transmitting and receiving signals for intruder detection. By mounting the transmitter and receiver at the proper angle with respect to each other, close in sensitivity is reduced without materially affecting sensitivity at greater distances.

Abstract: A radar intrusion detection system for isolated resources uses only one bistatic radar in combination with multiple passive reflectors to define the zone to be protected. Any intruder crossing a boundary of the zone within which is located the isolated resources interrupts the radar beam and thus may sound an alarm.

Abstract: A system for detecting intruder motion in selectable zones of a defined area is disclosed. The system is principally used as a line protector to detect intruders in the vicinity of a fence or wall and may be used as a virtual fence by employing a narrow-beam antenna and deep range coverage to detect an intruder crossing its line of sight. The system utilizes a transmitter for periodically sweeping the area to be protected and a receiver incorporating a narrow band filter which is variable to select a plurality of overlapping zones within the protected area, the presence of a reflective target in a selected zone resulting in a corresponding output signal. Means are provided to store such output signals from each zone and to compare received signals with previously-stored signals to detect differences in the target pattern of each zone.

Abstract: An improved sensing unit for installation in a room to be monitored by a microwave intrusion detection system. The sensing unit comprises an omnidirectional microwave antenna made of a rectangular waveguide having a shaped aperture defined by cutting the free end of the waveguide at an angle from each short side wall. A scattering blade is positioned centrally between the pointed ends of the wide side walls thus formed.The antenna is coupled to a transceiver whose output signal is applied to a sensitivity control serially connected to a filtering amplifier. The amplified output signal is fed to a level detector whose output is applied to a triggering signal generator through a delay circuit which inhibits signals of insufficient duration.

Abstract: A microwave or ultrasonic detection system is disclosed which has a voltage controlled transmitter oscillator. The output of the transmitter oscillator is transmitted into a designated area from a transmit antenna and is reflected by objects in the area and received by means of a second antenna. The reflected signal is phase compared to the output of the transmitter oscillator. A phase error signal is generated that varies with the phase difference, and this signal is input to the transmitter oscillator to cause the frequency of the oscillator to vary in such a way to produce a null phase difference. When the position of an object which reflects the transmitted signal is changed, the length of the propagation path for the signal changes which produces a phase error signal. This phase error signal in turn causes the transmitter oscillator to shift frequency.

Abstract: A mathematical analysis reveals the existence of circular motion in the head of a rotating phasor which represents the received signal in a Doppler intrusion alarm system in the presence of a moving target. The circular motion is virtually nonexistent when a moving target is absent regardless of the presence of environmental disturbances such as air turbulence and noise transients. The mathematical revelations are confirmed by a considerable amount of experimental data representing hundreds of thousands of measurements under various environmental conditions. The invention makes use of these new findings in combination with a new signal processing system which incorporates a circle detector for recognizing the presence of circular motion in the head of a rotating phasor when it occurs in the received signal, thus permitting absolute detection of a moving target even in the presence of environmental disturbances, such as air turbulence, while the system remains immune to false alarms due to these disturbances.

Abstract: A dual-frequency keyable control circuit is triggered into providing an electrical control output signal when two passive keying circuits, tuned to the correct radio frequencies are brought close enough to a sensing element of the keyable control circuit to cause mutual influence between the passive keying circuits and the sensing element.When the keyable control circuit detects that modulation is present at both ratio frequencies in sequence, it produces control signals which can unlock a door, actuate or defeat an alarm, or perform other functions for which it is desired to require key combinations to attain access.

Abstract: An intrusion detection apparatus employing two or more diverse types of sensors for sensing entries into a room, building or other enclosure. The sensors are connected to a signal processor which processes sensor output signals to indicate when an intrusion has occured. One type of sensor is a local sensor which includes a sensor conductor in combination with a phase locked loop. Whenever an intruding object is within close proximity to the sensor conductor and disturbs the conductor field, the equilibrium condition of the phase locked loop is disturbed to provide a sensor output signal. A second type of sensor includes in one embodiment an omni-directional antenna having a field which is located in close proximity to or which is overlapping the field of the sensor conductor. Whenever the omni-directional antenna and the sensor conductor are disturbed, the two disturbances are detected by the signal processor to signal an intrusion if the proper time relationship exists between them.

Abstract: An intrusion alarm system has a number of satellites each connected to a master by an unshielded cable having only four conductors, namely two power conductors, a drive signal conductor which supplies drive to the satellite transmitter and the satellite control circuit, and an alarm conductor. When an intrusion is detected by a satellite, its control circuit transmits a high level alarm signal on the alarm conductor to the master and also enables (but does not operate) a speaker in the satellite. The master has a rocker switch which an investigator turns off when he arrives at the supervised premises. This turns off the drive signal to the satellite. The control circuit of the satellite that caused the alarm responds by sounding its speaker, enabling determination of where the alarm occurred.