It can be done. All Google Analytics seems to do is ultimately request an image file with analytic data appended to the URL. You can call that URL directly from your PHP or other server side code to achieve the same effect.
Yes, it is possible.
The parameters of Google Analytics .gif request are, surprisingly, documented at Google:
A similar, but more popular question, that discusses these issues is also available on StackOverflow: https://stackoverflow.com/questions/1027660/generate-google-analytics-events-utm-gif-requests-serverside