Processing Modes and Solutions

Processing Modes

The following are the types of processing modes:

Static Mode

Static processing involves the determination of a single coordinate for an entire static session. There are two types of static solutions supported by GrafNav: float and fixed solutions.

Kinematic Mode

When processing kinematic data, it is of interest to optimize the entire trajectory. This is in contrast to static processing, which solves one coordinate for the entire session.

In order to quickly achieve cm-level accuracy in kinematic processing environments, ARTK is used to resolve integer carrier phase ambiguities.

Processing Solutions

ARTK solution

AdVance RTK is NovAtel's industry leading RTK engine which provides rapid centimeter level positioning. ARTK is used in Waypoint products to resolve integer carrier phase ambiguities.

With short baseline lengths (several kilometers), open sky conditions and dual frequency data, ARTK often requires only several seconds of data to fix ambiguities. Although ARTK needs at least 5 satellites to resolve, in practice it is most robust when 7 or more satellites are available. ARTK may resolve at baseline lengths as long as 70 km, however it is most reliable at distances of 30 km and less provided dual frequency data.

Fixed static solution

The fixed static solution uses ARTK with static constraints to resolve integer carrier phase ambiguities. New ambiguities are automatically fixed whenever there is a change in satellite geometry (i.e. a new satellite rises or a satellite drops out). A history of ARTK solutions over the static session is kept and GrafNav/GrafNet allows you to choose which is accepted as the final solution based on estimated error, lowest RMS, highest reliability, or an average of all fixes.

Float solution

Float solutions, unlike fixed static and ARTK solutions, do not resolve carrier phase ambiguities as integer values. As such, they are associated with lower accuracy applications than fixed solutions. Provided good data, float solutions improve with time and can still achieve centimeter-level accuracy, depending on factors such as baseline length, number of satellites and geometry, raw measurement data quality, etc.