cartographer建图时，出现如下警告，求解

[ WARN] [1555592651.777067265]: W0418 21:04:11.000000 28585 sensor_bridge.cc:213] Ignored subdivision of a LaserScan message from sensor scan because previous subdivision time 621355968000000000 is not before current subdivision time 621355968000000000
[ WARN] [1555592651.979516436]: W0418 21:04:11.000000 28585 sensor_bridge.cc:213] Ignored subdivision of a LaserScan message from sensor scan because previous subdivision time 621355968000000000 is not before current subdivision time 621355968000000000
[ WARN] [1555592652.163651889]: W0418 21:04:12.000000 28585 sensor_bridge.cc:213] Ignored subdivision of a LaserScan message from sensor scan because previous subdivision time 621355968000000000 is not before current subdivision time 621355968000000000

这是配置文件

lua文件

include “map_builder.lua”
include “trajectory_builder.lua”

options = {
map_builder = MAP_BUILDER,
trajectory_builder = TRAJECTORY_BUILDER,
map_frame = “map”,
tracking_frame = “base_link”,
published_frame = “odom”,
odom_frame = “odom”,
provide_odom_frame = false,
publish_frame_projected_to_2d = true,
use_pose_extrapolator = true,
use_odometry = false,
use_nav_sat = false,
use_landmarks = false,
num_laser_scans = 1,
num_multi_echo_laser_scans = 0,
num_subdivisions_per_laser_scan = 1,
num_point_clouds = 0,
lookup_transform_timeout_sec = 0.2,
submap_publish_period_sec = 0.3,
pose_publish_period_sec = 5e-3,
trajectory_publish_period_sec = 30e-3,
rangefinder_sampling_ratio = 0.5,
odometry_sampling_ratio = 0.5,
fixed_frame_pose_sampling_ratio = 1.,
imu_sampling_ratio = 1,
landmarks_sampling_ratio = 1.,
}

MAP_BUILDER.use_trajectory_builder_2d = true

TRAJECTORY_BUILDER_2D.submaps.num_range_data = 35
TRAJECTORY_BUILDER_2D.min_range = 0.3
TRAJECTORY_BUILDER_2D.max_range = 8.
TRAJECTORY_BUILDER_2D.missing_data_ray_length = 1.
TRAJECTORY_BUILDER_2D.use_imu_data = false
TRAJECTORY_BUILDER_2D.use_online_correlative_scan_matching = true
TRAJECTORY_BUILDER_2D.real_time_correlative_scan_matcher.linear_search_window = 0.1
TRAJECTORY_BUILDER_2D.real_time_correlative_scan_matcher.translation_delta_cost_weight = 10.
TRAJECTORY_BUILDER_2D.real_time_correlative_scan_matcher.rotation_delta_cost_weight = 1e-1

POSE_GRAPH.optimization_problem.huber_scale = 1e2
POSE_GRAPH.optimize_every_n_nodes = 35
POSE_GRAPH.constraint_builder.min_score = 0.65

return options