Schematron using XPath 2.0
The attribute rings:occultation_type must be equal to one of the following values 'Radio', 'Solar', 'Stellar'.
The attribute rings:frequency_band must be equal to one of the following values 'C', 'D', 'E', 'F', 'G', 'H', 'K', 'Ka', 'Ku', 'Q', 'R', 'S', 'U', 'V', 'W', 'X', 'Y'.
The attribute rings:ring_occultation_direction must be equal to one of the following values 'Both', 'Egress', 'Ingress', 'Multiple'.
The attribute rings:ring_profile_direction must be equal to one of the following values 'Egress', 'Ingress', 'Multiple'.
The attribute rings:planetary_occultation_flag must be equal to one of the following values 'N', 'Y'.
The attribute rings:occultation_type must be equal to one of the following values 'Radio', 'Solar', 'Stellar'.
The attribute rings:frequency_band must be equal to one of the following values 'C', 'D', 'E', 'F', 'G', 'H', 'K', 'Ka', 'Ku', 'Q', 'R', 'S', 'U', 'V', 'W', 'X', 'Y'.
The attribute rings:ring_occultation_direction must be equal to one of the following values 'Both', 'Egress', 'Ingress', 'Multiple'.
The attribute rings:ring_profile_direction must be equal to one of the following values 'Egress', 'Ingress', 'Multiple'.
The attribute rings:planetary_occultation_flag must be equal to one of the following values 'N', 'Y'.
The attribute rings:occultation_type must be equal to one of the following values 'Radio', 'Solar', 'Stellar'.
The attribute rings:ring_occultation_direction must be equal to one of the following values 'Both', 'Egress', 'Ingress', 'Multiple'.
The attribute rings:ring_profile_direction must be equal to one of the following values 'Egress', 'Ingress', 'Multiple'.
The attribute rings:planetary_occultation_flag must be equal to one of the following values 'N', 'Y'.