Add check for channel positions

[sappelhoff]

PR Description

closes #129

Merge Checklist

• [ ] the PR has been reviewed and all comments are resolved
• [ ] all CI checks pass
• [ ] (if applicable): the PR description includes the phrase closes #<issue-number> to automatically close an issue
• [ ] (if applicable): bug fixes, new features, or API changes are documented in whats_new.rst
• [ ] (if applicable): new contributors have added themselves to the authors list in the CITATION.cff file