To unlock the trophy, you will need a new “Imperial Navy I" key, which can be purchased on the Market for GJN.
How to get?
The "Imperial Navy" trophy drops periodicity (with a specific probability) in random battles of all modes (except for the cooperative PvE “Assault” and “World War” modes).
The minimum requirements to earn the trophy will be to participate in a battle, in a vehicle of rank III or higher, while achieving a battle-activity of at least 50%.
Along with the new trophy, two old ones will also have the chance to drop, but the probability of obtaining the new trophy is much higher.
For PlayStation 4® and Xbox One players, the key and trophy will be available for Golden Eagles in the in-game item shop.
More about the Market and GJN
The Market is a place where players can buy and sell various in-game items. Items are bought and sold using a special currency called Gaijin Coins which allow you to gain access to most War Thunder premium content.
In other words, you can not only spend here, but also earn money! Now you can go to the Market directly from the game by selecting the appropriate link in the menu.