Remote control system for a locomotive

Abstract

A system for controlling a locomotive, including a plurality of portable communications units, each unit adapted to generate signals conveying commands indicative of functions to be performed by the locomotive. Each unit is also associated with an operational status; the signals generated by each unit have a characteristic dependent on the operational status associated with that unit. Also, the system includes a controller adapted to receive the signals generated by the plurality of portable communications units, to determine the commands conveyed by the received signals and to control the locomotive on the basis of the decoded commands. By making each portable transmitter unit aware of its operational status, battery power can be conserved and airwave congestion reduced by precluding the transmission of commands that are guaranteed to be rejected because of the lack of command authority of an originating unit. Meanwhile, the unit which holds command authority continues to be able to send a complete set of commands.

We claim:  
     
         1 . A system for controlling a locomotive, comprising: 
 a) a plurality of portable communications units, each said unit adapted to generate signals conveying commands indicative of functions to be performed by the locomotive, each said unit being associated with an operational status, the signals generated by each said unit having a characteristic dependent on the operational status associated with that unit;    b) a controller adapted to receive the signals generated by said plurality of portable communications units, to determine the commands conveyed by the received signals and to control the locomotive on the basis of the decoded commands.    
     
     
         2 . The system defined in  claim 1 , wherein the operational status associated with each portable communications unit is one of a command authority holder and a command authority non-holder.  
     
     
         3 . The system defined in  claim 2 , wherein the characteristic is bandwidth, the signals generated by a portable communications unit having command authority holder operational status occupying greater bandwidth than the signals generated by a portable communications unit having command authority non-holder operational status.  
     
     
         4 . The system defined in  claim 2 , wherein the characteristic is power level, the signals generated by a portable communications unit having command authority holder operational status consuming greater power than the signals generated by a portable communications unit having command authority non-holder operational status.  
     
     
         5 . The system defined in  claim 2 , wherein the characteristic is command word length, the signals generated by a portable communications unit having command authority holder operational status containing longer command words than the signals generated by a portable communications unit having command authority non-holder operational status.  
     
     
         6 . The system defined in  claim 2 , wherein the characteristic is a repetition rate at which the signals are transmitted to said controller, wherein the signals generated by a portable communications unit having command authority holder operational status are transmitted at a greater repetition rate than the signals generated by a portable communications unit having command authority non-holder operational status.  
     
     
         7 . The system defined in  claim 2 , wherein at any given time no more than one of said plurality of portable communications units has command authority holder operational status.  
     
     
         8 . The system as defined in  claim 2 , said controller being further adapted to inform each portable communications unit of changes in its associated operational status.  
     
     
         9 . The system defined in  claim 8 , each portable communications unit being adapted to produce a sensory signal indicative of its associated operational status.  
     
     
         10 . The system defined in  claim 9 , the sensory signal including at least one signal selected from the group consisting of an audio signal, a visual signal and a vibratory signal.  
     
     
         11 . The system defined in  claim 8 , each portable communications unit being adapted to produce a sensory signal indicative of a change in its associated operational status.  
     
     
         12 . The system defined in  claim 11 , the sensory signal including at least one signal selected from the group consisting of an audio signal, a visual signal and a vibratory signal.  
     
     
         13 . The system defined in  claim 1 , wherein each portable communications unit is adapted to send the signal commands generated by that unit via a radio frequency link.  
     
     
         14 . The system defined in  claim 8 , said controller being responsive to a first command received from a first portable communications unit having command authority holder operational status to relinquish command authority holder operational status.  
     
     
         15 . The system defined in  claim 14 , said controller being responsive to a second command received from a second portable communications unit having command authority non-holder operational status to assume command authority holder operational status.  
     
     
         16 . The system defined in  claim 15 , wherein said controller being responsive to the second command includes: 
 a) said controller assigning command authority non-holder operational status to the first portable communications unit;    b) said controller assigning command authority status to the second portable communications unit.    
     
     
         17 . The system defined in  claim 16 , wherein said controller being responsive to the second command further includes: 
 a) for each portable communications unit for which the associated operational status has undergone a change, notifying that portable communications unit of the change in its associated operational status.    
     
     
         18 . The system defined in  claim 14 , said controller rejecting at least one command received from a portable communications unit having command authority non-holder operational status that is not rejected if received from a portable communications unit having command authority holder operational status.  
     
     
         19 . The system defined in  claim 18 , said controller accepting at least one command received from a portable communications unit having any one of command authority non-holder operational status and command authority holder operational status.  
     
     
         20 . The system defined in  claim 15 , said controller rejecting the second command unless said controller has previously received the first command.  
     
     
         21 . The system defined in  claim 8 , wherein said controller is adapted to inform each portable communications unit of changes in its associated operational status includes said controller being operative to determine when the operational status associated with a given portable communications unit has changed and to signal the change in operational status to that unit.  
     
     
         22 . A portable communications unit for use in a remote control system that includes a controller instrumental in controlling a locomotive, said portable communications unit comprising: 
 a) a user interface for allowing a user to specify functions to be performed by the locomotive;    b) a command generator adapted to generate commands indicative of the functions specified by the user via said user interface, said command generator being further adapted to determine an operational status is assigned to said portable communications unit;    a) a transmitter connected to said command generator, the transmitter adapted to send signals conveying the commands generated by said command generator to the controller, the signals generated by the transmitter having a characteristic dependent on the operational status associated with the portable communications unit.    
     
     
         23 . The portable communications unit defined in  claim 22 , wherein the operational status associated with the portable communications unit is one of a command authority holder and a command authority non-holder.  
     
     
         24 . The portable communications unit defined in  claim 23 , wherein the characteristic is bandwidth, the signals generated by the portable communications unit when having command authority holder operational status occupying greater bandwidth than the signals generated by the portable communications unit when having command authority non-holder operational status.  
     
     
         25 . The portable communications unit defined in  claim 23 , wherein the characteristic is power level, the signals generated by the portable communications unit when having command authority holder operational status consuming greater power than the signals generated by the portable communications unit when having command authority non-holder operational status.  
     
     
         26 . The portable communications unit defined in  claim 23 , wherein the characteristic is command word length, the signals generated by the portable communications unit when having command authority holder operational status containing longer command words than the signals generated by the portable communications unit when having command authority non-holder operational status.  
     
     
         27 . A controller for controlling a locomotive, comprising: 
 a) a transceiver for receiving commands from a plurality of remote communications units and for sending messages to the plurality of remote communications units;    b) a processing unit connected to the transceiver, the processing unit being operative for: 
 i) assigning to each remote communications unit in the plurality of remote communications units either one of a command authority holder operational status and a command authority non-holder operational status;  
 ii) controlling the locomotive on the basis of the commands received from the remote communications units and on the basis of the operational status of each remote communications unit from which commands are received;  
 iii) allowing transfer of command authority holder operational status between the remote communications units;  
 iv) upon a transfer of command authority from a first remote communications unit to a second remote communications unit in the plurality of remote communications units, the processing unit being adapted to send a message to the first and second remote communications units indicative of the change in the operational status.  
   
     
     
         28 . A method implemented by a portable communications unit used for instructing a locomotive controller to control a locomotive, comprising: 
 a) determining an operational status associated with the portable communications unit;    b) assembling commands indicative of functions to be performed by the locomotive;    c) generating signals conveying the commands, the signals having a characteristic dependent on the operational status associated with the portable communications unit.    
     
     
         29 . The method defined in  claim 28 , wherein the operational status associated with the portable communications unit is one of a command authority holder and a command authority non-holder.  
     
     
         30 . The method defined in  claim 29 , wherein the characteristic is bandwidth, the signals generated by the portable communications unit when having command authority holder operational status occupying greater bandwidth than the signals generated by the portable communications unit when having command authority non-holder operational status.  
     
     
         31 . The method defined in  claim 29 , wherein the characteristic is power level, the signals generated by the portable communications unit when having command authority holder operational status consuming greater power than the signals generated by the portable communications unit when having command authority non-holder operational status.  
     
     
         32 . The method defined in  claim 29 , wherein the characteristic is command word length, the signals generated by the portable communications unit when having command authority holder operational status containing longer command words than the signals generated by the portable communications unit when having command authority non-holder operational status.