Intel aero // Mavros - Clock skew detected

[ChriSil]

Hi all,

when establishing a mavros connection between my Laptop (Ubuntu 16.04 LTS , running ros), and the Intel Aero RTF via UDP

$ roslaunch mavros px4.launch fcu_url:="udp://0.0.0.0:14550@192.168.0.73:14556" (IP of drone in local network)

the console yields the following

[ INFO] [1505308969.287351579]: MAVROS started. MY ID 1.240, TARGET ID 1.1 [ WARN] [1505308969.372640545]: TM: Clock skew detected (-1505308694.417684555 s). Hard syncing clocks. [ INFO] [1505308969.393820707]: IMU: High resolution IMU detected! [ INFO] [1505308969.393991552]: IMU: Attitude quaternion IMU detected! [ INFO] [1505308969.727654561]: CON: Got HEARTBEAT, connected. FCU: PX4 Autopilot [ INFO] [1505308970.051755980]: IMU: High resolution IMU detected! [ INFO] [1505308970.052007967]: IMU: Attitude quaternion IMU detected! [ INFO] [1505308970.740422861]: VER: 1.1: Capabilities 0x00000000000024ef [ INFO] [1505308970.740548486]: VER: 1.1: Flight software: 01060500 (000000000181F900) [ INFO] [1505308970.740654226]: VER: 1.1: Middleware software: 01060500 (000000000181F900) [ INFO] [1505308970.740712155]: VER: 1.1: OS software: 000000c0 (0000000000000000) [ INFO] [1505308970.740770259]: VER: 1.1: Board hardware: 0000a4a7 [ INFO] [1505308970.740831751]: VER: 1.1: VID/PID: 0525:a4a7 [ INFO] [1505308970.740884032]: VER: 1.1: UID: 3335511839343335 [ WARN] [1505308970.740974275]: CMD: Unexpected command 520, result 0 [ WARN] [1505308979.375366479]: TM: Clock skew detected (7718063342.435769081 s). Hard syncing clocks. [ INFO] [1505308979.728118434]: HP: requesting home position [ INFO] [1505308984.735264665]: WP: mission received [ WARN] [1505308989.471157623]: TM: Clock skew detected (-7718063342.437295914 s). Hard syncing clocks. [ INFO] [1505308989.728430551]: HP: requesting home position [ WARN] [1505308999.473095008]: TM: Clock skew detected (7718063342.437585831 s). Hard syncing clocks. [ INFO] [1505308999.728594636]: HP: requesting home position

Executing the mavros topic "time_reference"

$ rostopic echo /mavros/time_reference

yields the following:

header: seq: 201 stamp: secs: 1505309160 nsecs: 267349839 frame_id: '' time_ref: secs: 1505309160 nsecs: 265019000 source: fcu

header: seq: 202 stamp: secs: 1505309161 nsecs: 304928103 frame_id: '' time_ref: secs: 1505309161 nsecs: 265189000 source: fcu

now, my question: what is the reason for the Clock skew, and how can I fix it, as I believe it prevents my /mavros/mocap/pose data to be transfered to the drone, and thus, to appear in the RTFs logfiles.

regards, Christopher

Issue has also been posted on the "Intel® Aero Platform for UAVs", https://communities.intel.com/thread/117934

[shakthi-prashanth-m]

Hi Christopher, could you set conn/timesync_rate to 0 in px4_config.yaml ? Its path should be mavros/launch/px4_config.yaml.