The method of disclosure in numerous separate files makes it a rather time-consuming and tedious business to compile a comprehensive overview across government over a long period, but the material is there.
The ancient civilization of Mayans lived in Mesoamerica since 2, 600 BC and had an extremely complicated and accurate method of keeping track of time based on three separate calendars.
Conveniently, more modern spacecraft than the Pioneers include separate range-finding hardware, which can be used to test the accuracy of the Doppler method.
Hansen offers a method that in other contexts would have seemed reserved for the truly paranoid: use a separate browser to connect to secure sites, setting the browser to load directly to secure URLs rather than click through from an unprotected site.