Ramsden Surveying Instrument

RAMSDEN SURVEYING INSTRUMENTS:

The Ramsden surveying instruments are those constructed by Jesse Ramsden and used in high precision geodetic surveys carried out in the period 1784 to 1853. This includes the five great theodolite great in name, great in size and great in accuracy—used in surveys of Britain and other parts of the world. Ramsden also provided the equipment used in the measurement of the many base lines of these surveys and also the zenith telescope used in latitude determinations.

Gyrotheodolite

GYROTHEODOLITE:

In surveying, a gyro theodolite is an instrument composed of a gyroscope mounted to a theodolite. It is used to determine the orientation of true north. It is the main instrument for orientation in mine surveying and in tunnel engineering, where astronomical star sights are not visible and GPS does not work.

HISTORY:

In 1852, the French physicist Léon Foucault discovered that a gyro with two degrees of freedom points north. This principle was adapted by Max Schuler in 1921 to build the first surveying gyro. In 1949, the gyro-theodolite – at that time called a "meridian pointer" or "meridian indicator" was first used by the Clausthal Mining Academy underground. Several years later it was improved with the addition of auto collimation telescopes. In 1960, the Fennel Kassel company produced the first of the KT1 series of gyro-theodolites. Fennel Kassel and others later produced gyro attachments that can be mounted on normal theodolites.

 

PRICE:

$2000-2500 or 140000-180000 PKR

Vernier Theodolite

VERNIER THEODOLITE:

The vernier theodolite is also known as a transit. In a transit theodolite or simply transit the telescope can be rotated in a vertical plane. Earlier versions of theodolites were of the non-transit type and are obsolete now. The function of vernier theodolite is same as other theodolites. It is used to measure angles.

PARTS OF INSTRUMENT:

1. Levelling head
2. Limb or lower plate
3. Spindles
4. Upper plate
5. Standards or A-frame
6. Level tube
7. Compass
8. Telescope
9. Vertical circle
10. Plumb bob
11. Tripod

  

PRICE:
$300 USD or 42000 PKR

Plane Table

PLANE TABLE:

A plane table is a device used in surveying and related disciplines to provide a solid and level surface on which to make field drawings, charts and maps.

USES:

In use, a plane table is set over a point and brought to precise horizontal level. A drawing sheet is attached to the surface and an alidade is used to sight objects of interest. The alidade, in modern examples of the instrument a rule with a telescopic sight, can then be used to construct a line on the drawing that is in the direction of the object of interest.

METHOD OF USING:

1. Radiation Method
2. Intersection Method

Blog Links

Blog Links

• http://instruments.simplesite.com
• https://ahmm65177.wixsite.com/eng-sur
• https://nediansurveyor.wixsite.com/surveying
• http://ehtishamsiddiqui3.wixsite.com/surveyhelper

links

Links for further detail.

•                 https://www.orbitals.com/self/survey/chain/chain.htm 
•                   https://civilseek.com/tacheometric-surveying/
•           https://www.merriam-webster.com/dictionary/cosmolabe
•           http://www.finedictionary.com/Graphometer.html
•           https://www.engineersupply.com/theodolites.aspx
•          //www.gim-international.com/content/article/robotic-theodolites-rts
•           http://www.johnsonlevel.com/News/TheodolitesAllAboutTheodo
•            http://kotsanas.com/gb/exh.php?exhibit=1301002
•            http://lensaticcompass.blogspot.com/2008/09/what-is-lensatic-compass.html
•            https://theconstructor.org/surveying/electronic-distance-measurement-               instrument/6576/
•           https://theconstructor.org/surveying/how-to-use-planimeter-parts/14821/
•           https://www.engineersupply.com/automatic-levels.aspx
•           https://www.aboutcivil.org/what-is-phototheodolite

Gunter Chain

                               GUNTER'S CHAIN 

DEFINATION:

 It is a distance measuring device used for chain surveying. 

Chain survey is the simplest method of surveying. In this survey only measurements are taken in the field, and the rest work, such as plotting calculation etc. are done in the office. This is most suitable adapted to small plane areas with very few details.

Market Value:

Its price in US dollar is $20 to $25 in PKR 3000 to 4000.

TACHEOMETER:

Tacheometry, is a system of rapid surveying, by which the horizontal and vertical positions of points on the earth's surface relative to one another are determined without using a chain or tape, or a separate levelling instrument and the instrument used for tacheometry is known as tacheometer.

USES: 

• Its convenient is due to the fact that it does not need chaining or horizontal distance.
• It  is used to prepare counter map in case when both horizontal and vertical distance needed.
• It is very useful to triangulation surveying also

Method: 

 Its method of using is shown below in video.

Market Value:

Its price in US dollar is $570 to $720 in PKR 80000 to 100000.

Graphometer

DEFINITION:
A Graphometer is a surveying instrument which is used to measure angles. It consist of semicircle limb which is divided into 180 degree and sometime sub-divided into minutes.

• The term graphometer was introduced by Phillipe Danfrie in 1597.
• 19th century graphometer had telescope rather than open sight.   

Components

•  It consist of a limb which is subtended by the diameter with two sights at its ends.
• The device is mounted in a staff via a ball and socket joint.
• The whole device is circumfentor.                  

Cosmolabe

DEFINITION:

An instrument resembling the astrolabe formerly used for measuring angular distances between heavenly bodies.

• Cosmolabe is the old instrument used in surveying resembles to astrolabe used since 15th century.
• 
  
• 
  
• Astolabe means 'the one that catches the heavenly bodies'. Astrolabe is used for astronomers and navigaters to find inclined position of celestial body.

Dioptra

DEFINITION:

Dioptra is also an old astronomical and surveying instrument. The dioptra is a sighting tube or a rod with sight at both ends.

• Greek astronomers used this dioptra to find out the positions of stars.
• The dioptra was replaced by theodolite in surveying instruments.
• A book is also written for the usage of dioptra in surveying by Hero of Alexandria.
• Dioptra is also known as diopter which is also the unit of power of lens.
• It was the suitable instrument used for the precise measurement of horizantal,vertical and angular distances between two celestial or terrestrial objects

Robotic Theodolite

DEFINITION:
Robotic theodolites, the new generation of the well-known surveying theodolite, are used to measure deflections in short-span bridges with millimeter accuracy.

• Robotic theodolite is a new version of total station.
• They are able to track a moving reflector with a frequency of measurement up to between 5-10 Hz.
• Robotic theodolite are widely used in numerous surveying and engineering projects.
• It also measure zenith and horizantal angles of sighting point.
• Market value of this theodolite is very high.

Military Compass

DEFINITION:
A compass is a instrument usually used for navigation and orientation to  aligned north,south,west or east. But in military compass we aligned magnetic north to find out bearings in direction of north.
TYPES
There are multiple parts to a lensatic compass.
.The biggest part is the base, the compass itself.

.There will be a floating needle and a bunch of information around the outside of the dial.

.Those are the 360 degrees you’ll use to figure out directions.

.There’s also a movable bezel with a mark painted on it or etched into it.

ELECTRONIC DISTANCE MEASURING INSTRUMENT:(EDMI)

Electronic distance measuring instrument is a surveying instrument used to measure distance electronically between two points through electromagnetic waves.

Components of EDMI

Figure 2.1 and the list given below indicates major components constitututing a typical EDMI (Wolf and Ghilani, 2001):

carrier signal modulation signals and modulator signal transmitter and signal receiver beam splitter reflector filter Operations with EDMI Measurement with EDMI involves four basic steps:  Setting up: The instrument is centered over a station by means of tribrach or by mounting over a compatible theodolite. Reflector prisms are set over the remote station either on tribrach or on a prism pole. Observations related to height or instrument and prism are recorded. These are usually kept the same to avoid any additional corrections. Aiming: The instrument is aimed at prisms by using sighting devices or theodolite telescope. Slow motion screws are used to intersect the prism centre. Some kind of electronic sound or beeping signal helps the user to indicate the status of centering. Measurement: The operator presses the measure button to record the slope distance which is displayed on LCD panel. Recording: The information on LCD panel can be recored manually or automatically. All meteorological parameters are also recorded ERRORS SOURCES: Measurement with EDMI has the following error sources which have to be accounted for while reporting the distance (Kennie and Petrie, 1990):  (i) Instrument operation errors One has to be careful for precise centering at the master and slave station pointing/sighting of reflector entry of correct values of prevailing atmospheric conditions (ii) Atmospheric errors Meteorological conditions (temperature, pressure, humidity, etc.) have to be taken into account to correct for the systematic error arising due to this. These errors can be removed by applying an appropriate atmospheric correction model that takes care of different meteorological parameters from the standard (nominal) one. (iii) Instrument error: Consists of three components - scale error, zero error and cyclic error. These are systematic in nature. Market Value: Its price in US $600 to $800 in PKR 85000 to 111000.

TOTAL STATION:

A total station (TS) or total station theodolite(TST) is an electronic/optical instrument which is used for surveying and construction of buildings.It is an electronic transit theodolite which is integrated with ELECTRONIC DISTANCE MEASURENT (EDM) to measure both vertical and horizontal angles and the slope distance from the instrument to a particular point, and an on-board computer to collect data and perform triangulation calculations.

PARTS OF TOTAL STATION ITS WORKING:

It has some same components like theodolite but four of them are main components;

1.     EDM determine distance from total station to a reflector by measuring the time of travel of EM signal, it also uses signal structure and determine phase shift. The EM wave has sinusoidal wave form which repeats every 360°.

2.     ELECTRONIC THEODOLITE measures the horizontal and vertical angles and works by combining the optical plummet, level bubble and calibrated circles to find the said angles.

3.MICROPROCESSOR: Before accompanying microprocessor to a total station

   the surveyor had to do all the calculations on their hands which results in errors. But now total station has been provided with microprocessor which saves a lot of work which the surveyor has done eliminate the chances of maximum errors. It typically performs the following functions but the inherent program varies widely from manufacturer to manufacturer;

·        Averages multiple angle measurements

·        Averages multiple distance measurements

·        Computes horizontal and vertical distances

·        Provides corrections for temp, pressure and humidity

·        Computes inverses, polars and resections

·        Computes X, Y and Z coordinates

 

4.ELECTRONIC DISPLAY  provide a visual of what is happening in the total station. Depending on the button pressed it helps the user navigate to the various menu items. It also enables input of instrument and reflector heights as well as access to the stored data. It displays horizontal distance, vertical distance, horizontal and vertical angles, difference in elevations of two observed points and all the three coordinates of the observed points (XYZ).

APPLICATIONS:

Total stations are mainly used by land surveyor and civil engineers, either to record features as in topographic surveying or to set out features (such as roads, houses or boundaries). They are also used by archaeologists to record excavations and by police, crime scene investigators, private accident reconstructionists and insurance companies to take measurements of scenes.

Market Value:

Its price is US $1000 to $1600 which is in PKR 139883.82 to 223814.11 .