|PRODUCTS AND SERVICES|
The Chain+Level - A True Alternative to Total Stations for Topographic Surveys
Advantages of the Chain+Level over Total Stations
The new GDD Chain+Level is lighter, up to 3 times more accurate, immune to temperatures fluctuations, and has been built with applications software such as gravity, profiles and probing. Profile readings are memorized and transferred daily to a PC.
Using the Chain+Level, some field crew like Geosig Inc., have been able to cut gravity survey cost substantially while keeping a good precision per station. For example, in October 2005, Geosig Inc. reported that on traverses of 3 to 4 km, the error per station was less than one cm.
GPS can loose satellite signal over significant daytime periods, especially
in northern areas because of the poor satellite coverage, the craggy
areas and forest cover. This can reduce GPS crew survey time by more than
50%. GDD Chain+Level is not affected by these inconvenients, neither by
water, snow, fog, etc. Therefore, the Chain+Level provides lower costs
with comparable precision to a high end GPS configuration.
Geosig Inc. gravity crew at work with the latest GDD gear
Labrador, Canada, 2005
The Chain+Level is really fast and simple to operate
The GDD Chain+Level consists of a digital reading unit and two pressure sensors connected by a flexible 25 or 50-meter chaining cable containing a special fluid. Three other sensors measure temperature and density variations in the fluid. Readings are quick, and the meter indicates true elevation differences with high precision at any outside temperature.
The sensor rods at each end of the cable are placed on the points to be measured. The digital reading of the difference of elevation, V, is obtained instantly just by pressing one key. The rods are then transferred to new positions to read successive differences in elevation. No visual contact is ever needed between the points to be measured.
The operator presses the slope distance button and is given the exact slopedistance (S) he must chain for a preset horizontal interval (H).
The slope distance (S) is chained. The two stations are now exactly H meters or feet apart horizontally. The pickets are driven in or a reference point is marked on the ground.
With sensor supports on top of the pickets, the exact elevation difference between the two points is read instantly by pressing the vertical distance button.
Whether it is used by itself or jointly with a GPS or a total station, the Chain+Level is designed to suit your own requirements. You just have to choose between these options:
For a one-kilometer profile, typical closure errors are less than 10 cm. The error on each station is less than 2 cm (0.1 foot).
For sections or profiles, the Chain+Level can measure a difference of elevation of ~15 meters in millimetres in a single reading with a precision of 0.2 %. The reading precision gives an immediate feedback of the reading quality to the operator.
The reading unit with a cable, combined to the optional datalogger and
the Multi-Carnet software for advanced surveys, allow to relate total
station data or transform the data obtained to make them compatible with
any COGO software. Users can use the datalogger with the Multi-Carnet
software, choose the Chain+Level driver and later change the driver to
work with almost any total stations on the market.
Instrumentation GDD Inc.
Products and specs are subject to change without notice
Instrumentation GDD Inc.
860 boul. de la Chaudiere, Suite 200
Phone: +1 (418) 877-4249 - Fax: +1 (418) 877-4054