A signal is a device which is capable of determining exact location of station. In order to exhibit this property, it must be free from phase. But it can be allowed to have some phase in it.

The formula for correction of temperature can be given as C = ? (T_m ? T₀) L, where ? determines value of coefficient of rmal expansion, T_m = mean temperature, T₀ = temperature during standardisation, L = length measured.

The grid system involves formation of framework with primary triangulation but filling parallel and perpendicular with secondary and tertiary triangulation systems. It is widely used process in India and central system is adopted in U.K.

The main purpose of satellite station is to act as an eccentric station or a false station. For securing well conditioned triangle some of objects like flag poles, towers, were chosen as satellite station.

Due to its high accuracy and high order presence, primary triangulation is adopted for important works like measuring earth?s figure and also for or government related works.

The length of base chosen will depend upon grade of triangulation adopted. Generally, in India, ten bases were adopted off which tenth base is having a length of 1.7 miles.

A tower is generally made of masonry, timber and steel. For small heights, masonry structure is adoptable, which makes m economical for range of work y do.

Reconnaissance is a process which helps on determining elevations in terrain and also peak points in terrain which help in determining slope which is a secondary thing.

The correction for absolute length can be given as
C_a = L*c / l. On substitution, we get
C_a = 20*2 / 30
C_a = 1.34.

For applying triangulation system, certain parameters will be assumed and length of base line is one among m. It is assumed as 5-15 km in primary, 1.5-5 km in secondary, 0.5-3 km in tertiary triangulation system.