I need to input raw formatted GPS coordinates into a spreadsheet i.e.
Latitude and Longitude.

Excel gives no options to allow the required formats, which can include
negative values. The formats I need a

Latitude: 00:00.000 to 89:59.999, plus 90:00.000

Longitude: 000:00.000 to 179:59.999, plus 180:00.000

Both value sets can be positive & negative values. I've tried using
hhh:mm.000 and Excel rejects it when I try to make the value. The only thing
I have been able to do is handle as text. Which ends any attempts to run
calculation.

The party that really stymies me is that apparently this never came up before.