Which frequency is considered survey grade for GPS signals?

Survey-grade GPS signals are typically associated with the L1 and L2 frequencies. However, the L2 frequency is specifically used for high-accuracy applications and is often employed by survey-grade receivers. This frequency provides a signal that can be used to correct for certain types of errors that can affect positioning accuracy, such as ionospheric delays.

Survey-grade GPS receivers often utilize both L1 and L2 signals to enhance positioning precision. By using the L2 signal, users can apply techniques such as differential GPS (DGPS) or real-time kinematic (RTK) positioning, which are crucial for high-accuracy requirements in surveying.

While L1 is commonly used and serves many applications, it is the L2 frequency that plays a vital role in achieving the high accuracy characteristic of survey-grade equipment, making it essential for applications like land surveying and geodetic measurements.