  Over the years, an enormous effort has been made to establish nitrogen
vacancy (NV) centers in diamond as easily accessible and precise magnetic field
sensors. However, most of their sensing protocols rely on the application of
bias magnetic fields, preventing their usage in zero- or low-field experiments.
We overcome this limitation by exploiting the full spin $S=1$ nature of the NV
center, allowing us to detect nuclear spin signals at zero- and low-field with
a linearly polarized microwave field. As conventional dynamical decoupling
protocols fail in this regime, we develop new robust pulse sequences and
optimized pulse pairs, which allow us to sense temperature and weak AC magnetic
fields and achieve an efficient decoupling from environmental noise. Our work
allows for much broader and simpler applications of NV centers as magnetic
field sensors in the zero- and low-field regime and can be further extended to
three-level systems in ions and atoms.
