Northrop Grumman Systems Corporation

Kenneth Duane Gorham

Warren E Guthrie

David L Richardson

Scott Alan Stratmoen

Roger Brunner Williams

Daniel Joseph Blase

Andrzej Sobski

An RFID system using encoded digital information utilizing pulsed linear frequency modulation (LFM). The LFM waveform is sent from an aircraft or satellite and is received by a transponder. The LFM waveform is demodulated using both, an AM and an FM receiver. The demodulated data is compared to preprogrammed criteria tables, and after validation is decoded and utilized. Algorithms in the transponder are used to determine the frequency deviation and for calculating the direction of the slope of the LFM input signal. The valid RF signal is stored in a delay element, encoded with the transponder data using phase modulation (PM), and frequency modulation (FM). The tag transmission is synchronized to the input LFM waveform. The transmit/receive chopping signal prevents unwanted oscillations and is capable of randomization.

Radio tag for LFM radar

A method, and apparatus for accomplishing the method, for determining the frequency of an RF signal that operates by sequentially applying a received RF signal to sequentially selected individual filters having predetermined frequency pass bands and comparing the magnitudes of the filtered and unfiltered RF signals. The frequency of the RF signal is determined as being within the predetermined frequency pass band of a filter that outputs a largest magnitude output signal relative to the magnitude of the RF signal. Signals of insufficient magnitude are not processed by the system.

Detector system for identifying the frequency of a received signal useful in a channelized receiver

A three input comparator facilitates the comparison of a signal to the greater of two different reference voltages in a manner which mitigates propagation delay. A first differential pair of transistors facilitates comparison of the two reference voltages to one another, while second and third differential pairs of transistors facilitate comparison of the signal to the higher of the two reference voltages.

Three input comparator

A method for accounting for individual ones of a plurality of items based upon random times that occur as a function of a first specified time interval, and a random interval inventory system that operates in accordance with the method. The method includes a first step of transmitting information signals based upon random times from individual ones of a plurality of tags (5a1-5xx) to at least one of at least one master transceiver and at least one transceiver (4a-4n). The individual tags (5a1-5xx) are affixed to respective individual ones of a plurality of items. The information signals transmitted from each tag (5a1-5xx) correspond at least to the respective item to which the tag (5a1-5xx) is affixed. The random times occur as a function of a first specified time interval. For a case wherein the information signals are transmitted to the at least one remote transceiver, each at least one remote transceiver (4a-4n) receives information signals from at least one of the tags (4a-4n), and in response to receiving each information signal, relays the signal to the master transceiver (3). In response to the master transceiver (3) receiving an information signal, a next step includes supplying the signal to an associated confirmation device (2). Within the confirmation device (2), in response to receiving an information signal from the master transceiver (3), a next step includes confirming that the item corresponding to the information signal is accounted for.

Inventorying method and system for monitoring items using tags

A vehicle having a plurality of antennas each in association with a communications transmitter device disposed within the vehicle to thereby provide multiple signal transmission sites. At least one antenna is disposed substantially at a top site of the vehicle and at least one antenna is disposed substantially at a bottom site of the vehicle, thus providing antenna coverage irrespective of the spatial orientation of the vehicle. The invention includes a communications system employing a multiplicity of antenna sites as well as methodology for providing a communication link from a vehicle to a receiving site by incorporating the communications system. In this manner, vehicle occupants are provided with a communications link from the vehicle, irrespective of the position of the vehicle. Thus, if one antenna is shielded from transmission because it is situated at a top site of a vehicle and the vehicle is upside down because of a mishap, another antenna which is situated to be operable from a non-shielded site (e.g. a bottom site of the vehicle) will provide effective signal transmission. The invention thereby provides enhanced safety and security for vehicle occupants in most travel environments.

Growing community of inventors

Palatine, IL, United States of America

Kenneth Duane Gorham