Abstract: A positioning system, method and computer program product determine a position of a mobile device, such as in instances in which the mobile device is indoors. In regards to a positioning system, the positioning system is caused to determine a signal strength of signals received from at least first and second directive antennas of a beacon and at least a non-directive antenna of the beacon. The positioning system is also caused to normalize the signal strength of the signals received from the first and second directive antennas based on the signal strength of the signals received from the non-directive antenna in order to determine normalized signal strengths of the signals received from the first and second directive antennas. The positioning system is further caused to determine an angle at which the signals from the beacon propagate based upon the normalized signals strengths.

Abstract: A transceiver includes a vector modulator and a phased array antenna including a plurality of quad polarization antenna cells. The vector modulator is configured to modify an information signal to generate two excitation signals based on a selected polarization. The polarization is selected as one of at least vertical, horizontal, right hand circular, and left hand circular. The vector modulator is configured to drive at least one of the quad polarization antenna cells with the two excitation signals to achieve the selected polarity.

Abstract: Embodiments of the present invention provide a transmitter including a plurality of amplifier circuits, a plurality of antennas adapted to have different main transmit directions and a transformation unit. The transformation unit includes a plurality of inputs connected to the plurality of amplifier circuits and a plurality of outputs connected to the plurality of antennas. The transformation unit is configured to transform a plurality of amplified transmit signals present at the plurality of inputs into a combined power transmit signal and to provide the combined power transmit signal at one of the plurality of outputs.

Abstract: Embodiments include methods and apparatus for detecting proximity of an electronic article surveillance (EAS) tag. A proximity detection system (e.g., a radio frequency identification (RFID) tag reader) detects a presence of an object within a first area. In response to detecting the proximity of the object, an EAS tag reader alters characteristics of an EAS tag detection signal that is produced by the EAS tag reader in order to detect an EAS tag within range of the EAS tag reader.

Abstract: The angle of arrival is estimated for a received signal received by an array of commutated antenna elements, wherein there is a temporal boundary at the instant of commutation between antenna elements. Samples of the signal received by the elements of the array are preprocessed to construct maximum-likelihood-estimates of the received signal for points in time that are immediately adjacent the temporal boundaries and thereby provide a preprocessed signal. A maximum-likelihood-estimation of the angle of arrival of the received signal is made for the array of commutated antenna elements by processing the preprocessed signal.

Abstract: It is an object of the present invention to provide an indoor mobile communication device having a simple structure, providing a sufficient communication range, and also providing for stable communication with a small fading effect.

Abstract: A system designed to detect and identify fixed utility objects, such as telephone pedestals, power transformers, man-holes, anchor cables, and the like, that are hidden by heavy overgrowth of vegetation. The system provides for automatic look-ahead detection of such objects during mowing and clearing operations with heavy machinery using passive radio frequency transponder technology to both detect the immediate presence of a tagged object as well as basic identification of the type of object replying to the interrogation. The operator can be signaled audibly and/or visually when a tagged object is detected. The transmitter and antennae are mounted in the cab of a mobile machine for protection from physical damage. An integrated microprocessor performs the requisite algorithms needed to process the reply form one or more RFID (Radio Frequency Identification) tags and generate the alert signals for the operator alerts.

Abstract: A system designed to detect and identify fixed utility objects, such as telephone pedestals, power transformers, man-holes, anchor cables, and the like, that are hidden by heavy overgrowth of vegetation. The system provides for automatic look-ahead detection of such objects during mowing and clearing operations with heavy machinery using passive radio frequency transponder technology to both detect the immediate presence of a tagged object as well as basic identification of the type of object replying to the interrogation. The operator can be signaled audibly and/or visually when a tagged object is detected. The transmitter and antennae are mounted in the cab of a mobile machine for protection from physical damage. An integrated microprocessor performs the requisite algorithms needed to process the reply form one or more RFID (Radio Frequency Identification) tags and generate the alert signals for the operator alerts.

Abstract: A direction finding system utilizing a single monopole/crossed slot antenna in combination with associated electronic circuitry. Each of the four ports of the antenna are connected to amplitude varying elements whose outputs are combined by a power combiner. A microcontroller stores the signal. The microcontroller also generates the signals which control the amplitude variation supplied by each of the amplitude varying elements. Two configurations of the amplitude varying elements are provided by predetermined settings within the microcontroller. The two settings are selected to configure the antenna on two distinct reception patterns, each with a predetermined angular offset from a reference direction. In operation the antenna will be configured for a first reception pattern. The signals received will be detected, quantified, and stored by the microcontroller which subsequently reconfigures the antenna for a second reception pattern.

Abstract: An antenna configuration system for determining the bearing angle of a radio frequency signal includes a plurality of loop antennas and at least one sense antenna. Through the utilization of combining networks with the loop antennas, in-phase and out-of-phase output signals are summed with the signal from the one sense antenna. The summed signal is sent to an adaptive processing system to allow for the determination the bearing angle of the radio frequency signal.

Abstract: The range from which transponder replies can be received at a virtual secondary surveillance radar of the type described in U.S. Pat. No. 4,115,771 is extended by replacing the omnidirectional antenna previously utilized to receive replies from transponders within the range of the SSR with a stationary array of a plurality of directive antennas arranged in a circle and having radiation patterns pointing in different directions from the center of and covering a respective sector of the circle, and sequentially switching on the antenna of the array covering the sector in which the rotating beam of the associated SSR is then pointing.

Abstract: A single null miniature direction finder which may be worn on the arm of the user and is fully automatic in operation. Signals from a single loop antenna and a sense antenna are summed; however, the amplitude of the sense signal is adjusted at first and second phase angles and the phase of the sense antenna is automatically switched from the first phase angle to the second phase angle prior to summing to produce either a single null or a no null pattern. These patterns are compared to each other as the user extends his arm horizontally and rotates his body. When the null occurs an indicator gives the relative direction to the transmitter.

Abstract: A method and a system are disclosed for measuring the baseline vector b between a pair of survey marks on the ground by radio interferometry using radio signals broadcast from the earth orbiting satellites of the NAVSTAR Global Positioning System (GPS), the radio signals broadcast by the satellites being double-sideband modulated with their carriers suppressed. An antenna is positioned at each survey mark. The signals received by one antenna during a predetermined time span are separated into upper and lower sideband components. These separate components are filtered, converted to digital form, and then multiplied together. Their product is analyzed digitally by means of correlation with quadrature outputs of a local oscillator to determine the power, and the phase relative to that local oscillator, of the carrier wave that is implicit in the double-sideband signal being received from each satellite. Differences in Doppler shift are utilized to distinguish the carriers of different satellites.

Abstract: Described herein is a system providing an electronic null-seeking goniometer for use in automatic direction finding equipment. A microprocessor is used to generate sine and cosine information in response to the detected phase of the bearing signal. The microprocessor iteratively locates the transmitter in the null of the cardioid response pattern of the loop and sense antennas, without rotating either the loop and sense antenna set or the goniometer. This eliminates the requirement for moving antenna and goniometer components and is constructed entirely devoid of any rotating machinery. A loop feedback signal functionally related to the detected null angle provides a stable null location method, without audio distortion, at relatively high feedback/signal ratios.

Abstract: An antenna device for a direction finder includes a substantially grounded conductive base plate, a plurality of web-shaped antenna elements mounted in spaced relation on the base plate and having central portions extending in crisscross relation and insulated from each other, an electronic switching circuit for alternately grounding ends of the antenna elements and picking up reception outputs from opposite ends of the antenna elements at a constant period with the antenna elements being switched out of phase at an angle corresponding to the angle at which the antenna elements extend across each other, and a circuit for combining outputs from the antenna elements. According to another embodiment, the antenna elements comprise the web-shaped antenna elements and a vertical antenna element disposed substantially centrally in the web-shaped antenna elements.

Abstract: A swept interference canceller including a multiplexed interference cancelling receiver coupled to a scanned notch antenna and an omni-directional antenna as well as an estimator type of angular beam splitting system for accurately measuring angular bearing of a plurality of sequentially received radiating sources in a dense communication environment. A difference signal between the signals received by the two antennas is developed which is then split into a plurality of equal time samples which are then simultaneously fed into two synchronous multi-stage shift registers. The output stages of one of the shift registers operate so that they all have the same output states. The output stages of the other shift register, however, operate so that the first half have the same output state as the first shift register while the second half are of the opposite output state.