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Surveying with ProMark2 63
Surveyi
ng
with Pr
oMark2
Known Point Initialization
The quickest method to initialize a kinematic survey is Known Point initialization. In most
situations, initialization on a known point can be accomplished in 10 seconds or less. It's very
important to note that the relationship between the kinematic base point and the known point to
be used to initialize must be very accurately established. For this reason, it is highly
recommended that you only initialize on a known point that has been previously established
with GPS either with a direct measurement between the base and known point or through a
network including both the base and known point.
The Known Point method is a little misleading in its name. It should truly be called the Known
Vector method. The initialization is performed on a known vector between 2 known points
(base point and rover point). Since the vector between the two points is already known,
initialization using this method requires very little time. In a normal static survey between two
points, the Integer Ambiguities must be found which then allows for the computation of a
precise vector. This takes an extended period of time. If the vector between the two points is
already known, the calculation of the Integer Ambiguities requires only a short observation
period.
Use the Known Point initialization method when your project area contains control points that
meet the requirements to perform a Known Point initialization. The requirements are stated
above a point whose position is known well with relation to the base point. Below are some
scenarios where Known Point initialization is best used:
• You are working on a landfill project where you are required to perform a topo
once a week for 2 months. In perparation, you establish 6 control points around the
landfill using the static survey method. You need then to occupy these points in
Stop-and-go mode and tag them as Control Points. With the kinematic base set up
on any one of these 6 control points, the remaining 5 points are available for a
Known Point initialization. For example, on the first day of your kinematic survey,
you place your base on point 0001. You want to start your kinematic survey at the
other end of the landfill near point 0003. So you drive to point 0003 and initialize
your kinematic survey using the Known Point method.
Don’t forget that any one of these 5 control points are also available for
reinitialization. For example, let’s say that after your successful initialization on
point 0003, you observe 53 new kinematic points. On your way to point 54, you
trip and fall causing the rover to trigger the Kinematic SV Alarm, indicating a loss
of initialization. At this time, you are very close to point 0004. Use the Known
Point method to re-initialize your kinematic survey on point 0004.
• You need to perform a kinematic survey in a project area with no control. You
initialize your kinematic survey using the Bar Point method. After initialization,
you successfully observe 16 new points. While attempting to position yourself for