Dic: fix as a noun meaning a clear determination or understanding

a fix (noun):

• (a) something that solves a problem
• (b) something that has been dishonestly arranged. (cf. predicament and its synonyms)
• (c) a clear determination or understanding. 
• etc.

* * *

As a noun meaning (c) in the above:

• a briefing that gave us a fix on the current situation.
• It's been hard to get a steady fix on what's going on.
• He peered out, trying to get a fix on the enemy's position.
• I couldn't seem to get a fix on the situation.

△ If you get a fix on someone or something, you have a clear idea or understanding of them. (informal)

△ get a fix on sb/sth:

1. to find out exactly where someone or something is.
2. to understand what someone or something is really like.

... COBUILD, LDOCE, American Heritage