System and method for estimating and detecting speed

Abstract

A system for determining instances when a vehicle's indicated speed exceeds a governing speed includes a receiver to receive information from which a vehicle's location envelope, indicated direction of travel, and indicated speed can be derived, and a processor. The processor is configured to ascertain a location envelope in which the vehicle is located, an indicated speed of the vehicle, and a direction of travel of the vehicle at a sample time. It is also configured to and select the governing speed for the vehicle at the sample time, which includes ascertain possible road segments with at least a portion within the location envelope, eliminate road segments with a road segment direction of travel inconsistent with the indicated direction of travel, and select as the governing speed a speed associated with a remaining road segment. The processor will then determine if the indicated speed exceeds the governing speed.

1 . A system comprising:
 a controller that is operable to receive information for a mobile asset from which a location envelope in which the mobile asset is located, an indicated direction of travel of the mobile asset, and an indicated speed of the mobile asset can be derived, the controller also operable to derive, at a sample time, the location envelope, the indicated speed, and the direction of travel and to select a first governing speed for the mobile asset based at least in part on the derived location envelope and the direction of travel.   
     
     
         2 . The system of  claim 1 , wherein the controller is operable to select the first governing speed by generating a set of possible route segments that the mobile asset could be traveling on within the location envelope, examine a set of governing speeds associated with the possible route segments, and select the first governing speed from the set of governing speeds. 
     
     
         3 . The system of  claim 2 , wherein the possible route segments in the set of possible route segments are associated with allowed directions of travel, and the controller is operable to select the first governing speed by eliminating one or more of the possible route segments from the set of possible route segments based at least in part on the indicated direction of travel of the mobile asset being inconsistent with the allowed directions of travel associated with the one or more of the possible route segments. 
     
     
         4 . The system of  claim 3 , wherein the controller is operable to select the first governing speed from one or more governing speeds in the set of governing speeds that are associated with the possible route segments that remain in the set of possible route segments after eliminating the one or more possible route segments from the set of possible route segments. 
     
     
         5 . The system of  claim 1 , wherein the controller is operable to determine if the indicated speed of the mobile asset exceeds the first governing speed. 
     
     
         6 . The system of  claim 1 , further comprising a receiver operable to receive the information from which the location envelope, the indicated direction of travel, and the indicated speed are derived, and which is communicatively coupled to the controller. 
     
     
         7 . The system of  claim 1 , wherein the possible route segments in the set of possible route segments are associated with elevation data representative of respective altitudes of the possible route segments, the controller is operable to receive the information for the mobile asset from which an altitude of the mobile asset can be derived, the controller also operable to select the first governing speed by eliminating one or more of the possible route segments from the set of possible route segments based at least in part on the altitude of the mobile asset being inconsistent with the altitudes associated with the one or more of the possible route segments. 
     
     
         8 . A method comprising:
 receiving information for a mobile asset from which a location envelope in which the mobile asset is located, an indicated direction of travel of the mobile asset, and an indicated speed of the mobile asset can be derived;   deriving the location envelope, the indicated speed, and the direction of travel;   selecting a first governing speed for the mobile asset based at least in part on the derived location envelope and the direction of travel.   
     
     
         9 . The method of  claim 8 , wherein selecting the first governing speed includes obtaining a set of possible route segments that the mobile asset could be traveling on within the location envelope, examining a set of governing speeds associated with the possible route segments, and selecting the first governing speed from the set of governing speeds. 
     
     
         10 . The method of  claim 9 , wherein the possible route segments in the set of possible route segments are associated with allowed directions of travel, and selecting the first governing speed includes eliminating one or more of the possible route segments from the set of possible route segments based at least in part on the indicated direction of travel of the mobile asset being inconsistent with the allowed directions of travel associated with the one or more of the possible route segments. 
     
     
         11 . The method of  claim 10 , wherein the first governing speed is selected from one or more governing speeds in the set of governing speeds that are associated with the possible route segments that remain in the set of possible route segments after eliminating the one or more possible route segments from the set of possible route segments. 
     
     
         12 . The method of  claim 8 , further comprising determining if the indicated speed of the mobile asset exceeds the first governing speed. 
     
     
         13 . The method of  claim 8 , wherein the possible route segments in the set of possible route segments are associated with elevation data representative of respective altitudes of the possible route segments, and further comprising receiving information from which an altitude of the mobile asset can be derived and determining the altitude of the mobile asset, wherein the first governing speed is selected by eliminating one or more of the possible route segments from the set of possible route segments based at least in part on the altitude of the mobile asset being inconsistent with the altitudes associated with the one or more of the possible route segments. 
     
     
         14 . A system comprising:
 a receiver configured to receive information representative of a location of a mobile asset; and   a processor configured to derive a location envelope of the mobile asset, an indicated direction of travel of the mobile asset, and an indicated speed of the mobile asset from the information that is received, the processor further configured to obtain plural potential route segments on which the mobile asset could be traveling on in the location envelope, the potential route segments associated with respective governing speeds and respective directions of travel, the processor also configured to identify a first route segment from the potential route segments based at least in part on a comparison of the indicated direction of travel of the mobile asset with the directions of travel associated with the potential route segments and to determine a first governing speed associated with the first route segment,   wherein the processor is configured to determine whether movement of the mobile asset exceeds the first governing speed based at least in part on the indicated speed.   
     
     
         15 . The system of  claim 14 , wherein the processor is configured to identify the first route segment by eliminating the potential route segments that are associated with the directions of travel that do not match the indicated direction of travel of the mobile asset. 
     
     
         16 . The system of  claim 14 , wherein the information that is received by the receiver also represents an indicated altitude of the mobile asset and the potential route segments are associated with respective altitudes, and the processor is configured to identify the first route segment based at least in part on a comparison of the indicated altitude of the mobile asset and the altitudes associated with the potential route segments. 
     
     
         17 . The system of  claim 16 , wherein the processor is configured to identify the first route segment by eliminating the potential route segments that are associated with the altitudes that do not match the indicated altitude of the mobile asset. 
     
     
         18 . The system of  claim 14 , wherein at least one of the governing speeds associated with at least one of the potential route segments is a manually established governing speed that differs from a posted speed limit of the at least one of the potential route segments. 
     
     
         19 . The system of  claim 14 , wherein the processor is configured to obtain a pre-planned route that the mobile asset is to travel along and to identify the first route segment from the potential route segments by eliminating one or more of the potential route segments that are not included in the pre-planned route. 
     
     
         20 . The system of  claim 14 , wherein at least one of the governing speeds associated with at least one of the potential route segments changes based on a time of day, and the processor is configured to determine an indicated time at which the mobile asset was in the location envelope and was traveling at the indicated speed, further wherein the processor is configured to determine whether the movement of the mobile asset exceeds the first governing speed based at least in part on the indicated time of the mobile asset and the at least one of the governing speeds that changes based on the time of day. 
     
     
         21 . The system of  claim 14 , wherein, when at least one of the potential route segments is not associated with a respective governing speed, the processor is configured to designate an inferred governing speed for the at least one of the potential route segments based on the governing speeds of one or more of the potential route segments that are adjacent to the at least one of the potential route segments. 
     
     
         22 . The system of  claim 14 , wherein the processor is configured to determine a designated route for the mobile asset to travel along based on a history of previously identified instances of the indicated speed of the mobile asset exceeding the governing speed associated with one or more of the potential route segments. 
     
     
         23 . The system of  claim 22 , wherein the processor is configured to determine the designated route such that the mobile asset does not travel on one or more of the potential route segments for which the history includes at least a designated number of the previously identified instances of the indicated speed exceeding the governing speed.