Is it possible to perform quaternion/Euler angle calculations from only accelerometer and gyroscope readings? I'd like to be able to detect orientation for a small pcb that I have which I designed and built with ICM-20689 but without a magnetometer. I can incorporate a magnetometer into the next revision, but I'd prefer not to if I can get away without it as it costs valuable PCB real estate on a wearable device which I'm trying to make very small. I've seen complimentary filters used to give 2 of 3 Euler angles in which no magnetometer is used, so I'd like to understand what the trade-offs are for not using a magnetometer.