Can I track my daughter's iPhone without her knowing?

My 15-year-old has been breaking curfew lately and spending time with a new crowd that has me really stressed out. I looked into the standard built-in location sharing settings on her device, but they all seem to send alerts and notifications to the user whenever someone checks their whereabouts. Does anyone know of a workable method to silently monitor her GPS coordinates so I can just make sure she is safe without starting a huge fight?