The following command is used to adjust the heading time constant. 
$JATT,HTAU,htau<CR><LF> 
Where ‘htau’ is the new time constant that falls within the range of 0.0 to 
3600.0 seconds. 
Depending on the expected dynamics of the vessel, you may wish to adjust 
this parameter.  For instance, if the vessel is very large and is not able to turn 
quickly, increasing this time is reasonable.  The resulting heading would have 
reduced ‘noise’, resulting in consistent values with time.  However, artificially 
increasing this value such that it does not agree with a more dynamic vessel 
could create a lag in the heading measurement with higher rates of turn.  A 
convenient formula for determining what the level of smoothing follows.  If 
you are unsure on how to set this value, it’s best to be conservative and 
leave it at the default setting. 
htau (in seconds) = 10 / maximum rate of turn (in °/s)  
You may query the Vector for the current heading time constant by issuing 
the same command without an argument. 
$JATT,HTAU<CR><LF> 
Note - If you are unsure of the best value for this setting, it’s best 
to be conservative and leave it at the default setting of 0.5 seconds. 
8.10  $JATT,PTAU 
The pitch time constant allows you to adjust the level of responsiveness of 
the pitch measurement provided in the $PSAT,HPR message.  The default 
value of this constant is 0.5 seconds of smoothing.  Increasing the time 
constant will increase the level of pitch smoothing.   
The following command is used to adjust the pitch time constant.