verifying tarball

[wis1]

I can't verify the 3.25 tarball using the instructions in "00README" on the
downloads page at https://download.savannah.gnu.org/releases/gpsd/

 I get:

     #gpg --verify gpsd-3.25.tar.xz.sig  gpsd-3.25.tar.xz
     gpg: Signature made Tue 10 Jan 2023 02:39:37 PM PST
     gpg:                using RSA key
0C898D47FDAF50A65928B1B42E6BC5DE2EE86A3E
     gpg: Can't check signature: No public key

What am I doing wrong?

Thanks,

-wis