Trimble Navigation Limited

Radio Frequency Systems, Inc.

Active Noise and Vibration Technologies, Inc.

Noise Cancellation Technologies, Inc.

David A Dye

John R Coffee

Kevin Marvin

Robert W Lewis

Sheldon Kent Meredith

Richard W Rudow

Robert F Allen

Robert D Sleeper

Mark L Kirchner

Dennis S Barnes

William A Tekniepe

Mark Billings

John J Cain

Dennis Hugh Barnes

Jamie Chait

John A Cain

A vehicle fleet management information system identifies location and direction of movement of each vehicle in a fleet in real-time, and automatically reports such information, as well as status of predetermined events in which the vehicle is engaged, directly to the fleet manager. One aspect relates to automated reporting of status of a ready mix slurry material truck having a mixer drum. A sensor detects the begin pour event by detecting the mixer drum being run in a discharge direction.

Vehicle tracking, communication and fleet management system

A vehicle fleet management information system for identification of location and direction of movement of each vehicle in the fleet in real-time and automatic communication directly with management offices to report its location and heading, and status of predetermined events in which the vehicle may be engaged. One example is a cement delivery truck which monitors location, speed and status information such as start pour, pouring, end pour, wash and leave job, and automatically transmits this information with a management office without requiring affirmative action by the vehicle operator.

A vehicle fleet management information system identifies location and direction of movement of each vehicle in a fleet in real-time, and automatically reports such information, as well as status of predetermined events in which the vehicle is engaged, directly to the fleet manager. Each fleet vehicle has an assigned time slot to transmit its reporting information over a communications network without interfering with transmissions from other vehicles in their own respective time slots. A timing control phase lock loop (PLL) provides precise time synchronization for timing corrections from a global positioning system (GPS) based time reference. A dual band full-duplex interface of the network has TDMA on one-half and broadcast on the other half. Microprocessor time processing units in components of the network perform precise clock synchronization. Space diversity performed on received vehicle transmitted messages avoids data corruption. Different vehicles have different periodic transmission intervals, by dynamically allocating the slots for various update rates. Auxiliary reporting slots enable prompt reporting of important data by the respective vehicle transmitters independent of the slower periodic transmission intervals.

In a land mobile radio system including at least one base site having a system for interconnecting a plurality of radio channel units with a plurality of directional antennas and/or antenna beams, the base site further includes an interference avoidance system for controlling communications between each radio channel unit of the base site and mobile radio units communicating with the base site so as to avoid causing potential interference at the operating frequency of each radio channel unit at other base sites. The interference avoidance system monitors potential interference at the operating frequency of each radio channel unit on each antenna beam. If potential interference exists on an antenna beam determined to be the antenna beam best suited for transmitting and receiving signals at the operating frequency of the radio channel unit, a determination is made if adjacent antenna beams have reduced chance of potential interference and sufficient signal strength for communication and therefore are better suited for transmitting signals at the operating frequency of the radio channel unit. To further enhance interference avoidance, a comparison is made of the signal strength of received signals at the operating frequency of the radio channel unit with one or more threshold values to assess the proximity of the mobile radio unit to the base site, and the transmission signal strength for signals transmitted from the radio channel unit to the mobile radio unit are controlled based on the proximity assessment.

Continuous interference assessment and avoidance in a land mobile radio

In a system for interconnecting a plurality of radio channel units in a single trunk group with a plurality of directional antennas and/or antenna beams, each radio channel unit has a receive section and a transmit section and the system dynamically connects the receive and transmit sections of each one of the radio channel units with any one of the plurality of antennas which, on average during a sampling period, is best suited for receiving and transmitting RF signals at the operating frequency of the radio channel unit. The system further includes traffic distribution monitor for monitoring, storing and displaying information on a periodic basis indicative of the usage of each antenna and/or antenna beam. The specific antenna or antenna beam being utilized by a radio channel unit is monitored on a periodic basis during communications between the radio channel unit and a mobile radio unit, and this information is stored in a memory associated with the radio channel unit.

Traffic distribution analysis in a land mobile radio system

An electronic muffling device is disclosed for suppressing the noise emitted by an outlet of an exhaust pipe of an engine. The device comprises a housing having an outlet and a plurality of audio transducers. The transducers supply anti-noise to cancel detected unwanted noise. A microphone appropriately positioned to detect residual noise is coupled to a cancellation signal generator, which controls the anti-noise generated by the transducers. Anti-noise and unwanted engine noise propagate through a front volume within the housing so that exhaust gases are transmitted through the housing, but engine noise is canceled before leaving the housing. Exhaust gas may be transmitted into the housing, or may be passed through the housing without leaving the exhaust pipe. In either embodiment, engine noise enters the front volume and is canceled.

Electronic muffler

A noise suppression system for use on internal combustion engines and small enough for use in automotive applications is disclosed. A cancellation noise generator and actuator speakers produce a noise to combine with and cancel the engine noise carried in exhaust gases in a mixing chamber. The resultant noise leaving the mixing chamber is measured by a circular tubular microphone array to control the noise generator.

Single cavity automobile muffler

A noise cancellation system, comprising a symmetrical assembly of microphone inputs is disclosed. A controller receives the output of the microphone assembly and generates an electrical cancellation signal having a polarity opposite the polarity of a portion of a noise to be cancelled and a magnitude equal to the magnitude of the portion of the noise to be cancelled. An actuator receives the electrical cancellation signal and outputs an audio cancellation signal.

Growing community of inventors

Phoenix, AZ, United States of America

David A Dye