Unidirectional telemetry system

• US 6,184,798 B1
• Filed: 03/30/1998
• Issued: 02/06/2001
• Est. Priority Date: 03/31/1997
• Status: Expired due to Term

• Current Assignee: Pine Valley Investments, Inc. (L3Harris Technologies, Inc.)
• Original Assignee: The Whitaker Corporation (Meggitt PLC)
• Inventors: Egri, Robert
• Primary Examiner(s): Horabik, Michael
• Assistant Examiner(s): WONG, ALBERT KANG
• Application Number:
  US09/050,819
• Time in Patent Office: 1,044 Days
• Field of Search: 340/870.13, 340/870.1, 340/870.15, 340/531, 340/521, 340/870.03, 246/169.A, 246/169.R, 246/182.R
• US Class Current: 340/870.13
• CPC Class Codes: G08C 15/08 the signals being represented by amplitude of current or voltage in transmission link
• CPC Class Codes: G08C 17/02 using a radio link

Abstract

A telemetry system comprises a plurality of beacons. Each beacon repetitively transmits a packet having a first predetermined time duration. The beacon transmits the packet a first predetermined number of iterations. A monitoring receiver observes for the transmitted packets within each of a plurality of time slots. Each slot has second predetermined time duration. The first predetermined time duration is less than the second predetermined time duration.

Claims

1. A unidirectional telemetry system comprising:

a monitoring receiver operative to receive transmitted packets over successive frames, each frame being constituted by a plurality of equal length time slots, without acknowledging receipt of any of said transmitted packets; and

a plurality of beacons, 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;

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.

2. The telemetry system of claim 1, further including a plurality of sensors, each respective sensor being operative to periodically perform a predetermined measurement and each respective sensor being operative to supply a signal representative of performed measurement data to one of said plurality of transmitters whereby information relating to a performed measurement may be transmitted to said monitoring receiver.

3. The telemetry system of claim 1, wherein at least one transmitter receives measurement data from multiple sensors.

4. The telemetry system of claim 2, wherein at least one of said plurality of sensors has a tolerance range wherein a transmitter associated with said at least one sensor repeats a transmitted packet representative of data measured by said at least one sensor more frequently during a frame than if data measured is outside of said tolerance range.

5. The telemetry system of claim 2, wherein each sensor has a priority level assigned thereto which is known by an associated transmitter and wherein an associated transmitter adaptively repeats data from a sensor having a higher priority level more often over a frame than data from a sensor having a lower priority level.

6. The telemetry system of claim 1, wherein each transmitter is operative to transmit each packet within approximately one-half of a time slot.

7. 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.

8. The telemetry system of claim 7, wherein at least one transmitter receives measurement data from multiple sensors.

9. The telemetry system of claim 7, wherein at least one of said plurality of sensors has a tolerance range wherein a transmitter associated with said at least one sensor repeats a transmitted packet representative of data measured by said at least one sensor more frequently during a frame than if data measured is outside of said tolerance range.

10. The telemetry system of claim 7, wherein each sensor has a priority level assigned thereto which is known by an associated transmitter and wherein an associated transmitter adaptively repeats data from a sensor having a higher priority level more often over a frame than data from a sensor having a lower priority level.

11. The telemetry system of claim 7, wherein each transmitter is operative to transmit each packet within approximately one-half of a time slot.

12. The telemetry system of claim 7, further including a locomotive control unit, said locomotive unit being operative to receive signals representative of said sensor measurements from each of a plurality of car control units, each respective car control unit being associated with a corresponding locomotive car and being operative to report sensor measurements associated with said corresponding locomotive car.

13. 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.

14. The method of claim 13, further including a step of receiving from the monitoring receiver, at a locomotive control unit, signals representative of measurements associated with the at least one car.

15. The method of claim 14, further including a step of generating an alarm to alert maintenance personnel to a need to service a component monitored by one of the sensors.