The units of measurement mentioned in the series can be divided into two main categories: those produced by civilisations either at their pre-spacefaring or spacefaring stages, before or after they reached the stage of using space flight, by themselves or through others, as a regular means of communication with other civilisations.
In the case of civilisations of Earth origin, such as the Terran Federation, this division was not difficult to see, many units mentioned being familiar to a late twentieth century inhabitant of Earth, such as many time units, and imperial or metric ones. In the case of other civilisations, this division was more difficult. It was compounded by the fact that, not only did other spacefaring civilisations know the units of measurement of others; they might have adopted and used certain ones, whatever their origins, either by custom or by international agreement.
To conclude, many of the units of measurement referred to in the series, including colloquial references, would have been familiar to an inhabitant of late twentieth century Earth. This was logical, given that Earth was the Federation's capital, and most of the characters heard using such units were either Federation or ex-Federation, including the computers they interacted with: Zen, Orac, and Slave. Also in this category would have been inhabitants of worlds colonised by people of Earth origin. For example, Avandor, an inhabitant of Hellotrix in Traitor, used both yards and metres.
With other measurements, however, it was not so easy to identify their origins. While some could have been of pre-spacefaring origin, such as the 'cobar' used as a unit of weight by the Thaarn's people, and others were of spacefaring origin, such as faster than light speeds, it is difficult to say which civilisations the latter in particular originated from, as some spacefaring civilisations might have adopted those measurements from others.
There was also a problem regarding the use of time units, in terms of which ones were being used, particularly when characters of non-Earth origin were concerned. However, those from spacefaring civilisations appeared, when dealing with people of Federation origin, to translate things into Federation measurements.
To give a few examples, Saymon, in The Web, told Blake that the Liberator needed to sustain their maximum power for 160 hours to break out of orbit, presumably Federation or Earth hours. In Sarcophagus, the alien told Avon that she had been waiting 'Centuries', presumably centuries of Federation or Earth years. Later, Pella, in Power, told Vila that the 'forty eight hours' referred to by her was in 'Earth Standard Time'.
See also FEDERATION, SPACIAL, TIMELINE, SUBSEC.