Two Phi values in the dataset?

[ryuchanhoe]

First of all, thank you for sharing the dataset.

The dataset includes two Phi values, Phi1 and Phi2. It states that both Phi1 and Phi2 correspond to yaw, with Phi1 having higher confidence than Phi2.

Questions:

1. Why do we have two Phi values? Could it be because we had two IMUs on the drone?
2. I am unclear about the purpose of providing two Phi values, with Phi1 having higher confidence. When should Phi2 be referenced instead of Phi1?

Thanks,