def METHOD_NAME(self, data, name="nav1", unit=None, nav_plot=False):
    """Adds in a navigation signal to the metadata.  Any type of navigation signal is acceptable.
    Parameters
    -------------------
    data: np.array
        The data for the navigation signal.  Should be the same size as the navigation axis.
    name: str
        The name of the axis.
    unit: str
        The units for the intensity of the plot. e.g 'nm' for thickness.
    """
    dict_signal = {}
    dict_signal[name] = {
        "data": data,
        "unit": unit,
        "use_as_navigation_plot": nav_plot,
    }
    if not self.metadata.has_item("Navigation_signals"):
        self.metadata.add_node("Navigation_signals")
    self.metadata.Navigation_signals.add_dictionary(dict_signal)