Unidirectional telemetry system

A telemetry system for use in monitoring wear in moving parts of a locomotive, comprising:

• at least one car control unit including a monitoring receiver operative to receive transmitted packets communicating performed measurements over successive frames, each frame being constituted by a plurality of equal length time slots, without acknowledging receipt of any of said transmitted packets;
• a plurality of beacons associated with said at least one car control unit, each beacon including a transmitter operative to transmit packets autonomously relative to any transmitter of any other beacon, and each transmitter being operative to transmit packets asynchronously relative to said monitoring receiver;
• and
• a plurality of sensors associated with said at least one car control unit, each respective sensor being operative to periodically perform a predetermined measurement and each respective sensor being operative to supply a signal representative of a performed measurement to a corresponding one of said plurality of transmitters;
• wherein each said transmitter is operative to transmit a given packet a plurality of times within a corresponding frame, with each packet transmitted by a respective transmitter being transmitted within any one of said time slots and retransmitted at random times within said corresponding frame;
• wherein random collisions between packets transmitted and retransmitted by corresponding transmitters occur during a frame, a frequency of random packet retransmission being selected in accordance with packet length and total number of transmitters to obtain a sufficiently small probability of jamming as to ensure receipt by said monitoring receiver of information contained in each transmitted packet;
• and
• wherein no beacon receives an acknowledgement that any transmitted packet has been received by said monitoring receiver.

A method of monitoring wear in a locomotive, comprising the steps of:

• providing in at least one car, a monitoring receiver operative to receive transmitted packets communicating performed measurements associated with said at least one car over successive frames, each frame being constituted by a plurality of equal length time slots, without acknowledging receipt of any of said transmitted packets;
• providing a plurality of beacons associated with said at least one car, each beacon including a transmitter operative to transmit packets autonomously relative to any transmitter of any other beacon, and each transmitter being operative to transmit packets asynchronously relative to said monitoring receiver;
• providing a plurality of sensors associated with said at least one car, at least some of said sensors being operative to periodically perform a predetermined measurement of one of temperature, vibration, and wheel revolutions per unit of time;
• supplying signals representative of measurements performed by said plurality of sensors to said plurality of transmitters;
• and
• transmitting to the monitoring receiver, using the transmitters, packets containing measurement data collected by said plurality of sensors, each packet being transmitted a plurality of times within a corresponding frame, with each packet transmitted by a respective transmitter being transmitted within any one of said time slots and retransmitted at random times within said corresponding frame;
• wherein during said transmitting step, random collisions between packets transmitted and retransmitted by corresponding transmitters occur during a frame, a frequency of random packet retransmission being selected in accordance with packet length and total number of transmitters to obtain a sufficiently small probability of jamming as to ensure receipt by the monitoring receiver of information contained in each transmitted packet;
• and
• wherein no beacon receives an acknowledgement that any transmitted packet has been received by the monitoring receiver.