I am looking into the available error state filters for aided inertial navigation, particularly insfilterErrorState.
There is one part of the code that I am having a hard time understanding, which is the usage of rf.LinAccelSign on line 98 of ErrorStateIMUGPSFuserBase.m. This is used to invert the sign of the acceleration measurements from the accelerometer before they are used in the prediction routine, the comment above reads
rf = rfconfig(obj.ReferenceFrame);
accelMeas = rf.LinAccelSign.*accelMeas;
Looking at ReferenceFrame.m I can see that the LinAccelSign parameter is given as negative for both ENU and NED frames, can this really be the case? I would have guessed that they would have been the opposite of one another.
Edit: Just noticed, in NED.m
the exact same is written in the ENU.m file, perhaps this is an error?