cartographer_rosbag_validate

cartographer_rosbag_validate -bag_filename 2019-07-31-10-34-40.bag 
E0731 14:19:08.877801 15014 rosbag_validate_main.cc:350] frame_id "laser_link" on topic /lslidar_point_cloud has serialization time 1564540480.822384623 but sensor time 1.286553000 differing by -1.56454e+09 s.
E0731 14:19:08.879762 15014 rosbag_validate_main.cc:350] frame_id "laser_link" on topic /lslidar_point_cloud has serialization time 1564540480.907164046 but sensor time 1.386593000 differing by -1.56454e+09 s.
E0731 14:19:08.882105 15014 rosbag_validate_main.cc:350] frame_id "laser_link" on topic /lslidar_point_cloud has serialization time 1564540481.008895614 but sensor time 1.486632000 differing by -1.56454e+09 s.
E0731 14:19:08.924367 15014 rosbag_validate_main.cc:160] Sensor with frame_id "laser_link" is not sequential in time.Previous range message ends at time 621355968042913260, current one at time 621355968000963990
E0731 14:19:08.924422 15014 rosbag_validate_main.cc:315] Sensor with frame_id "laser_link" jumps backwards in time. Make sure that the bag contains the data for each frame_id sorted by header.stamp, i.e. the order in which they were acquired from the sensor.
E0731 14:19:08.987812 15014 rosbag_validate_main.cc:160] Sensor with frame_id "laser_link" is not sequential in time.Previous range message ends at time 621355968042938560, current one at time 621355968000989280
E0731 14:19:08.987860 15014 rosbag_validate_main.cc:315] Sensor with frame_id "laser_link" jumps backwards in time. Make sure that the bag contains the data for each frame_id sorted by header.stamp, i.e. the order in which they were acquired from the sensor.
E0731 14:19:09.050433 15014 rosbag_validate_main.cc:160] Sensor with frame_id "laser_link" is not sequential in time.Previous range message ends at time 621355968041975440, current one at time 621355968000026150
E0731 14:19:09.050483 15014 rosbag_validate_main.cc:315] Sensor with frame_id "laser_link" jumps backwards in time. Make sure that the bag contains the data for each frame_id sorted by header.stamp, i.e. the order in which they were acquired from the sensor.
W0731 14:19:09.125984 15014 rosbag_validate_main.cc:203] Sensor with frame_id "laser_link" range measurements have longest overlap of 4.19553 s
I0731 14:19:09.126125 15014 rosbag_validate_main.cc:398] Time delta histogram for consecutive messages on topic "/imu" (frame_id: "imu"):
Count: 1702  Min: 0.009999  Max: 0.010000  Mean: 0.010000
[0.009999, 0.009999)	                    	Count: 1 (0.058754%)	Total: 1 (0.058754%)
[0.009999, 0.009999)	                    	Count: 0 (0.000000%)	Total: 1 (0.058754%)
[0.009999, 0.009999)	                   #	Count: 54 (3.172738%)	Total: 55 (3.231492%)
[0.009999, 0.010000)	                    	Count: 0 (0.000000%)	Total: 55 (3.231492%)
[0.010000, 0.010000)	               #####	Count: 411 (24.148062%)	Total: 466 (27.379553%)
[0.010000, 0.010000)	                    	Count: 0 (0.000000%)	Total: 466 (27.379553%)
[0.010000, 0.010000)	           #########	Count: 749 (44.007050%)	Total: 1215 (71.386604%)
[0.010000, 0.010000)	                    	Count: 0 (0.000000%)	Total: 1215 (71.386604%)
[0.010000, 0.010000)	              ######	Count: 473 (27.790834%)	Total: 1688 (99.177437%)
[0.010000, 0.010000]	                    	Count: 14 (0.822562%)	Total: 1702 (100.000000%)
E0731 14:19:09.126168 15014 rosbag_validate_main.cc:382] Point data (frame_id: "laser_link") has a large gap, largest is 0.100639 s, recommended is [0.0005, 0.05] s with no jitter.
I0731 14:19:09.126209 15014 rosbag_validate_main.cc:398] Time delta histogram for consecutive messages on topic "/lslidar_point_cloud" (frame_id: "laser_link"):
Count: 169  Min: -4.195527  Max: 0.100639  Mean: -0.001645
[-4.195527, -3.765910)	                    	Count: 4 (2.366864%)	Total: 4 (2.366864%)
[-3.765910, -3.336294)	                    	Count: 0 (0.000000%)	Total: 4 (2.366864%)
[-3.336294, -2.906677)	                    	Count: 0 (0.000000%)	Total: 4 (2.366864%)
[-2.906677, -2.477061)	                    	Count: 0 (0.000000%)	Total: 4 (2.366864%)
[-2.477061, -2.047444)	                    	Count: 0 (0.000000%)	Total: 4 (2.366864%)
[-2.047444, -1.617827)	                    	Count: 0 (0.000000%)	Total: 4 (2.366864%)
[-1.617827, -1.188211)	                    	Count: 0 (0.000000%)	Total: 4 (2.366864%)
[-1.188211, -0.758594)	                    	Count: 0 (0.000000%)	Total: 4 (2.366864%)
[-0.758594, -0.328978)	                    	Count: 0 (0.000000%)	Total: 4 (2.366864%)
[-0.328978, 0.100639]	####################	Count: 165 (97.633133%)	Total: 169 (100.000000%)