Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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. Each fleet vehicle is assigned a unique time slot to transmit its reporting information over a communications network without substantially interfering with transmissions from other vehicles in their own respective time slots. Precise time synchronization is provided by a timing control PLL which provides timing corrections as necessary from GPS based time reference. The network includes a dual band full-duplex interface with TDMA on one-half of the interface and broadcast on the other half. Additionally, time processing units of microprocessors in components throughout the network perform precise clock synchronization.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.