$a_x = $latllastval;
$a_y = $lonllastval;
$b_x = $latlastval;
$b_y = $lonlastval;
$alpha = acos ( ($b_x - $a_x) / sqrt( ($b_x - $a_x)**2 + ($b_y - $a_y)**2 ) );
$x_x = 50 * cos ( (3 * pi)/4 + $alpha ) + $b_x;
$x_y = 50 * sin ( (3 * pi)/4 + $alpha ) + $b_y;
$y_x = 50 * cos ( (5 * pi)/4 + $alpha ) + $b_x;
$y_y = 50 * sin ( (5 * pi)/4 + $alpha ) + $b_y;
#$X = ($x_x, $x_y);
#$Y = ($y_x, $y_y);
#$B = ($b_x, $b_y);
#$A = ($a_x, $a_y);