High Precision Single Surveying Reflector Prism Total Station
Accessory
Model: AK16
Item Overview:
Plastic frame.
Leica type of connector (no threads).
Does not have a 5/8 x11 thread.
Single tilt prism with soft bag
Circular prism sealed in red polymer holder. Large integrated
target plate provides good visibility.
Specifications
| Prism Constant | Range | Centering Accuracy | Effective Diameter |
| 0mm | 2500m | 2.0mm | 65mm |
Lifetime
High quality prisms have longer lifetime. In contrast to many
conventional prisms, the reflective copper coating on the reverse
side of high quality prisms consists of a support coating, a
vacuum-metallised copper coating, a protective coating and an
overlying coat of lacquer. The special adhesive lacquer protects
the underlying layers from corrosion and detachment. Working
together, the copper coating and the lacquer increase the life of
the prism significantly. An additional anti-reflex coating on the
sensitive front surface of the prism provides a tough resistance to
scratches. The production process of these coatings is so complex
that only a very few manufacturers worldwide meet the requirements
of high standard prisms.
Survey Prism Offsets
Retro-reflectors (or corner cube prisms) used with electronic
distance measuring (EDM) instruments have an offset because the
transmitted light beam from the EDM takes longer to enter and exit
the prism. This longer time translates to a longer distance
measured. This distance is corrected by using an 'offset' and
positioning the prism in relationship to the plumb line of the
prism holder. The offset is determined by multiplying the height of
the prism by the refractive index of the glass used. Common offsets
are 0, -17.5 mm, -30 mm, -34 mm, and -40 mm.
A nodal offset on a surveying prism is defined by the relationship
of the prism holder and prism that places the optical center of the
prism on the plumb line of the holder. This offset is the most
advantageous at close range work when the apex or center of the
prism is used as a pointing target for vertical and horizontal
angle measurement. Every surveying prism has a nodal offset.
Surveying Prisms and holders that are not in the nodal position
however, can cause angular errors when using the prism apex as a
target if it is not perfectly pointed toward the measuring
instrument.
For high accuracy surveying it is recommended to use a round prism
instead of a 360o prism if you are using a robotic total station. A
Nodal Point prism should be used for high accuracy traversing and
layout work.
Optical Surveying Reflector Prism Applications
Surveying reflector prisms are used by surveyors and engineers to
measure the change in position of a target that is assumed to be
moving. Survey prisms are used for a wide range of monitoring
applications including:
- Rail Monitoring
- Settlement Monitoring
- Displacement Monitoring
- Deformation Monitoring
- Convergence Monitoring
Packing and Details
