Patent
Intruder detection radar system and automatic nulling antenna array
Reads0
Chats0
TLDR
In this paper, a bistatic VHF Doppler radar is utilized to detect and track one or more intruders crossing a large annular ring surveilance zone surrounding a central high security installation.Abstract:
A bistatic VHF Doppler radar is utilized to detect and track one or more intruders crossing a large annular ring surveilance zone surrounding a central high security installation. A central omni-directional transmitter radiates the surveillance zone with a continuous wave (CW) signal. Predetermined ones of a plurality of receiver antennas circumferentially spaced around the surveillance zone receive a portion of the signal which is reflected by an intruder crossing the surveillance zone and a portion of the signal which is directly radiated from the transmitter antenna. The reflected signal portion may be received by antenna arrays each of which is controlled to form a null in its pattern toward the transmitter antenna to overcome direct signal overload. The direct signal portion may be received by stub antennas. Each antenna array and each stub antenna is connected to a separate channel of a dual channel receiver. An intruder moving across the surveillance zone causes signals representative of Doppler cycles of phase change to be generated. The outputs of the two separate channels are compared and their relative phase changes measured. A detected intruder causes an alarm signal at a central processing station and the Doppler information is processed to generate tracking data which is shown on a display device. An automatic null control circuit may also be utilized to accommodate multipath conditions and static clutter due to environmental factors.read more
Citations
More filters
Patent
System and method for standoff detection of human carried exposives
TL;DR: In this paper, a system and method for standoff detection of human carried explosives (HCE) automatically detects HCE up to a range of (200) meters and within seconds alerts an operator to HCE (112) threats.
Patent
Methods and apparatus for obtaining positional information
Gordon Kenneth Andrew Oswald,Alan Trevor Richardson,Michael Hugh Burchett,Eric Nicol Clouston,Danielle Emma Toutoungi +4 more
TL;DR: In this article, an array including a transmitting element and a plurality of receiving elements is provided, where a truncated cross-correlation function is applied to determine the interval between signals received by the receiving elements, thereby to determine an angular position of an object.
Patent
Method and apparatus for monitoring the position of a machine
TL;DR: In this paper, a mobile communicator adapted to communicate with a remote monitoring station is presented, which includes the steps of receiving a configuration message from the remote monitoring base via a wireless communication link, comparing at least one of a current machine position to the configuration information a current time of operation to the message, and sending an alarm message to the monitoring base in response the comparison.
Patent
Method of automated signature verification
Mohamed Ali Moussa,Chih Chan +1 more
TL;DR: In this paper, a test signature entered by an operator may be preprocessed and examined for test features, and compared against features of a set of template signatures, and verified in response to the presence or absence of the test features in the template signatures.
Patent
Motion detector based on the doppler principle
TL;DR: In this article, a motion detector based on the Doppler principle contains a microwave module for emitting a microwave signal containing at least two frequencies into a room under surveillance and for receiving the radiation reflected from the latter.
References
More filters
Patent
Radio frequency intrusion detection system
TL;DR: In this article, one or more long wire antennas are buried in the ground and located orthogonal to a vertically polarized souce of VHF radiation, such as a continuous wave transmitter which feeds an elevated vertical dipole.
Patent
Large area motion sensor using pseudo-random coding technique
TL;DR: In this paper, a Doppler detecting, bi-static system utilizing range (time-delay) areas of varying shapes was proposed for industrial security, where range discrimination was effected by bi-phase modulating the transmitted radio frequency waves according to a maximal length pseudo-random code.
Patent
Adaptive clutter cancellation and interference rejection system for AMTI radar
TL;DR: In this article, the antenna phase and amplitude weights were adjusted to trim for uncalibrated errors and to put nulls in the antenna receive patterns in the direction of the source of interference or jamming signals.
Patent
RF loop intruder detection system
TL;DR: In this article, 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, and the area within the loops are protected against intrusion.