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Why is the default update rate for costmap2d only 5Hz, not the sensor rate?

asked 2015-09-17 08:45:59 -0500

ingo

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The default costmap configuration in the ROS navigation stack updates the costmap every 200ms (at 5Hz). I wonder why it is not updated at the sensor's rate, or at least at the local planners rate (which is 10Hz by default). Wouldn't this make the robot react faster to new obstacles?

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answered 2015-09-19 11:54:21 -0500

David Lu

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It's a tradeoff of reaction time and amount of work. The time required to update the costmap does not scale exactly linearly with the amount of sensor data. Updating more frequently involves overhead. You are free to configure it to be faster.

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I guessed it is to reduce work, but I've been wondering about this particular number. Did anybody do experiments and/or optimizations to arrive at the figure of 5Hz, or is it just a number chosen from experience?