Consider using vonmises KDE to estimate head direction rate

```python
def vonmises_kde(data, kappa=100, n_bins=100):
    from scipy.special import i0
    bins = np.linspace(-np.pi, np.pi, n_bins)
    x = np.linspace(-np.pi, np.pi, n_bins)
    # integrate vonmises kernels
    kde = np.exp(kappa * np.cos(x[:, None] - data[None, :])).sum(1) / (2 * np.pi * i0(kappa))
    kde /= np.trapz(kde, x=bins)
    return bins, kde
```