Star Wars: The Last Jedi introduced the concept of hyperspace tracking, which also fixed a plot hole from A New Hope. It's always been odd that the Empire tracked Leia's ship, the Tantive IV, to Tatooine, given that lightspeed was the go-to escape option throughout the original Star Wars trilogy. This was made even more confusing when the sequel trilogy established that hyperspace tracking was new technology, suggesting that the Tantive IV should've been able to escape by going to lightspeed.

Although The Last Jedi's fully-explained hyperspace tracking wasn't developed until the sequel era, the original Star Wars trilogy showed that the Empire did have some techniques at its disposal. Darth Vader and Grand Moff Tarkin found the rebel base in A New Hope by placing a homing beacon on the Millennium Falcon, allowing them to track the ship through hyperspace. This still doesn't explain how the Empire followed the Tantive IV,...