  Magnetic field couples the solar interior to the solar atmosphere, known as
the corona. The coronal magnetic field is one of the crucial parameters which
determines the coronal structures and regulates the space weather phenomena
like flares, coronal mass ejections, energetic particle events, and solar
winds. Measuring the magnetic field at middle and higher coronal heights are
extremely difficult problem and to date there is no single measurement
technique available to measure the higher coronal magnetic fields routinely.
polarization measurements of the low-frequency radio emissions are an ideal
tool to probe the coronal magnetic fields at higher coronal heights
($>1R_\odot$). To date, most of the low-frequency polarization observations of
the Sun were limited to bright solar radio bursts. Here we developed a novel
algorithm for performing precise polarization calibration of the solar
observations done with the Murchison Widefield Array, a future Square Kilometer
Array (SKA) precursor. We have brought down the instrumental polarization
$<1\%$. We anticipate this method will allow us to detect very low-level
polarised emissions from coronal thermal emissions, which will become a tool
for routine measurements of the global coronal magnetic fields at higher
coronal heights. This method can be easily adapted for future SKA and open a
window of new discoveries using high fidelity spectro-polarimetric snapshot
imaging of the Sun at low radio frequencies.
