What is a GPS receiver that can receive both L1 and L2 frequencies called?

A GPS receiver that can receive both L1 and L2 frequencies is designated as a dual frequency receiver. The significance of this lies in the ability to utilize multiple frequency signals from GPS satellites, which enhances accuracy and reduces errors caused by atmospheric conditions like ionospheric delays.

The L1 frequency, which operates at 1575.42 MHz, is primarily used for civilian GPS services, while the L2 frequency at 1227.60 MHz is used for more precise applications, often benefiting military users and advanced surveying. By incorporating both frequencies, a dual frequency receiver can effectively mitigate errors that might occur when relying solely on one frequency, thus providing a more reliable and accurate positioning solution. This is particularly valuable in professional surveying and mapping, where precision is critical.

The other types of receivers mentioned do not possess this capability. For instance, a single frequency receiver can only use the L1 frequency, limiting its accuracy compared to dual frequency receivers. An autonomous receiver typically refers to those that operate without the need for additional correction data, and variable frequency receivers do not specifically align with the standard definitions within GPS technology.