How can dual frequency code and carrier measurements be optimally combined to enhance position solution accuracy?
The smoothing of GPS code pseudorange measurements with carrier phase measurements to attenuate code noise and multipath is a well-established GPS signal processing technique. Unlike carrier phase real time kinematic (RTK) techniques, carrier-smoothed code (CSC) positioning solutions do not attempt to resolve carrier phase ambiguities. As a result, they offer a number of design and operational advantages for those applications that do not require RTK accuracies. Ionospheric effects are a limiting factor in how much smoothing of pseudorange errors can be accomplished with single-frequency measurements. The use of dual-frequency code and carrier measurement combinations in CSC processing to attenuate pseudorange errors and as a precursor for carrier phase ambiguity resolution has gained increasing importance, particularly with the availability of all-in-view dual-frequency GPS receivers in the survey and military markets. Interest in these techniques will increase with the advent of addi
