This is how competent sci-fi writers that I've read have done it. In Jack Campbell's books, his fleets automatically designate one side of the star's equatorial plane as "up" and the other as "down" upon arriving in a new system, while port and starboard are based on turning away from or toward the star. There's moment in one book where the protagonist's fleet enters a binary star system for the first time ever, the protagonist starts giving maneuvering orders, and then someone goes "wait, which star do we use for reference?" and he has to stop and pick one. It's a nifty little scene of the kind that Pat would never think to write.