What is true static pressure? How do we define it? Is it same as corrected static pressure for installation and errors? ARINC 429P1-18 defines Static pressure as corrected and uncorrected where in few places I have heard this term "True static pressure".
From what I can see, the "true" static pressure is the measured static pressure corrected for airspeed & position (Static Source Error Correction).
In my copy of ARINC 429 (May 2004) I don't see a label definition that fits this "true static pressure". Label 171 can be used for manufacturer defined data, so I would see if you can get a better answer from the manufacturer of your data source.