I'm assuming that you want to know if this maybe is a sleep-breathing problem. Since one sleep cycle is about 90 minutes, it's not surprising that she take short naps well, but keeps waking up at the same time every night. At around 90 minutes, muscles start to relax and breathing problems can happen. There are variation with younger children, however. Do either you or her father have any sleep-breathing issues (snoring, sleeps on side/stomach, chronically tired, etc.)? Have you talked to your pediatrician? I won't give you a long list of things to try (I'm sure you've already tried them). Worse case scenario, a consultation with a pediatric sleep specialist may be your next step.