Drawbacks of the previous method: when writing to the SD card, there are
high delays in the write() call of several 100ms, every now and then. The
frequency and length of these events depend on:
- SD card
- used logger bandwidth
- bandwidth of gps data (RTCM)
Since the whole gps thread was blocked during this period, it lead to
gps timeouts and lost module.
What we do now is: publish an orb topic with queuing. This makes it async
and the logger takes care of buffering. This means it's best to:
- use high logger rate
- use large logger buffer
- reduce logger bandwith by disabling unused topics
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