Simply means "Location statistic". In Borneo ; the place was so mountainous and difficult that it often became necessary to do a fire mission to confirm location. Pick a feature; shoot a bearing; convert it to a back bearing, get the radio; call" 1, this is 122 alpha;" fire mission over". back would come "122 alpha, send mission over ; then 1," this is 122 alpha"; fire mission  and give the locstat and target; then "1 round, fire for effect, over" then watch where the round hit; then get a protractor  and draw line a line from it . My position was on that line.