addition!
2red2white,
just remembered that for calculating TD (total drift),
u need to put ALL the presigns (ie. + or - in brackets otherwiese
u will get wrong answer!!!
Example:
a perfect gyro is set up to give 0 degrees drift when stationary
on the Ground at 54°N.
You are at Ground at 54°N!
Calculate rate of drift and state if reading is increasing or
decreasing.
TD= RW+LN + ER+TW
As there is no Real Wander in this Question,put a cero or/
below position of RW.Then u put + and then put LN with presign
+ or - in brackets! ( )
Means : RW= 0
LN=(+15°*sin 54°N)
ER=(-15°*sin54°N)
TW=0
PS: 15°are used nml for calculating those questions (its 15.04° to be precise) and gives the rate of drift of the earth in 1 hr!)
Result: 0 {RW} +(+15°*sin54°N) {LN} + (-15°sin 54°N) {ER}+0
=0+12.35° - 12.35°+0 ==cuz of presigns drift cancelles out!!
Remember the Northern and Southern Hemisphere Presigns !!!
for this example the LN in NH is + (in SH would be -)
ER in NH is - (in SH would be +)
Hope not to have confused u more my friend! let me know please
and good luck!!!