The question of offboard control with pixhawk

Hey, We are using a VICON system + Pixhawk +Odroid XU4 on our uav. We have configured the Firmware, and are able to get the mocap data on the local_position/pose topic. However, when I using the command rostopic hz /mavros/local_position/pose to looking at the publishing frequency of the topic’s data ,it is found to continue to decrease even lower than 1HZ.Meanwhile, the situation of data loss occurs.It will brings the effect that the UAV will not get real-time location information and leave the offboard mode. I am very confused. ****Then I commented out the code which is subscribe to the image topics and the function that handles it.The topic 's publishing frequency is 10Hz and the data will not be lost.****I guess that the callback function may run for too long.Because it involves dealing with real-time images.But, it has been opened a new thread for processing. Today,on github, Daniel Agar told me you can asking for a higher rate via mavlink, or the command line. mavlink stream -d /dev/ttyS1 -s LOCAL_POSITION_NED -r 100.
I would like to ask is if the publishing frequency to increase this topic, whether to publish and subscribe to other topics affected. Thank you.