The upcoming technology to measure any given point is the Global Navigation Satellite System, also called GNSS. In many fields of science and technology, satellites are used to provide autonomous Geo-spatial positioning. It discovers their location (Latitude, Longitude, and Altitude) to high precision using time signals transmitted. This research is to find out the effect of the magnetic field and the accuracy of GNSS receivers. In this context, have a preliminary study on the magnetic field’s outcome to the GNSS observation. The primary purposes are to analyze the magnetic field surveys on the positional accuracy of GNSS, the event of the magnetic field on GNSS signal, and examine the effect of a geomagnetic substorm on GNSS observation. This research contains the qualitative analysis conducted using the selected studies. The magnetic field effect on the GNSS antenna performance, observation, and GNSS signals as studied and stated by the authors of the reviewed previous research activities. All the analyses that the magnetic field changes contain a specific effect over the key GNSS observations. And for the specifications of point accuracy and millimeter level precision, this research gives us the impact of the magnetic field that cannot be neglected. This study recommended considering the external and the internal areas, magnetic and metal item effect when using GNSS notice for land surveying and construction surveying activities. And also recommended getting pre-knowledge about heavy substorm and other magnetic fields are effect weather before starting any GNSS observation to harvest the maximum output with limited errors through the successful project.