Static files BaseUrl in singleSpa

My cesium app host is localhost:8002, static file likes "Assets ", “Widgets” are hosted on this sever
for example, "cesium_credit.png" real URL is “http://localhost:8002/Assets/Images/ion-credit.png”.

But my main app host is localhost:3000, this image and the earth globe are not display, I find "cesium_credit.png" request url is “http://localhost:3000/Assets/Images/ion-credit.png”.

I try to set window.CESIUM_BASE_URL = “http://localhost:8002”, it didn’t work. what should i do ?