I don't follow what you mean by E being slightly heaver than W.

Hi W,
If the earth was cut in half through the Greewich meridian, I think the East side would be heavier than the West side. If you cut the earth along the 102M meridian, the West would be farther round it's 1/2 circumferance, than the East.
Do you agree?
C

 

Hi W,
If the earth was cut in half through the Greewich meridian, I think the East side would be heavier than the West side. If you cut the earth along the 102M meridian, the West would be farther round it's 1/2 circumferance, than the East.
Do you agree?
C

You're reading too much into it.

 

Hi C,
This may help clarify.

A rule of thumb for the Equator, of say 40,000km.

360deg * 60min * 60sec = 1296000secs

40,000,000mtr/1296000sec = 30.864mtr/sec

Example: dd mm.mmmm

Move from, Lat 37 23.2475 to 37 23.2476
Sub the degrees gives, 23.2575 to 23.2476 min
Sub the integer minutes gives, 0.2475 to 0.2476 min
Sub the decimal parts gives =0.0001 min
Convert to seconds 60 * 0.0001min = 0.006sec.

Which means 30.864mtr per sec * 0.006sec = 0.18518 mtrs

E

Hi E,
I've just noticed, that there are 5x digits after the decimal point: e,g, 11111.11111.W

does this mean that the 'steps' are 10x more accurate than your smallest step?
C.

 

Hi E,
I've just noticed, that there are 5x digits after the decimal point: e,g, 11111.11111.W

does this mean that the 'steps' are 10x more accurate than your smallest step?
C.

It doesn't really say anything about the accuracy. It is merely the resolution to which the position estimate is reported. For instance, I might design a system that reports the value of pi to 8 digits after the decimal point and it might get reported as 3.14286744. That does NOT mean that it is accurate to that resolution.

The accuracy of a GPS position fix is dependent on a lot of things, some of which the receiver can adjust for and some of which it has no knowledge of. But regardless of how good the fix is, a given receiver generally reports the position fix to the same resolution to make the processing easier for whatever consumes the data.

One way to estimate the precision (as opposed to the accuracy -- they are not the same thing) of your system is to record many measurements while the receiver is stationary. The amount of variation in the measurements is an indication of how repeatable they are (which is the precision). To determine the accuracy, you would need to do something similar, but with the receiver located at a point whose position is well known.

 

It doesn't really say anything about the accuracy. It is merely the resolution to which the position estimate is reported. For instance, I might design a system that reports the value of pi to 8 digits after the decimal point and it might get reported as 3.14286744. That does NOT mean that it is accurate to that resolution.

The accuracy of a GPS position fix is dependent on a lot of things, some of which the receiver can adjust for and some of which it has no knowledge of. But regardless of how good the fix is, a given receiver generally reports the position fix to the same resolution to make the processing easier for whatever consumes the data.

One way to estimate the precision (as opposed to the accuracy -- they are not the same thing) of your system is to record many measurements while the receiver is stationary. The amount of variation in the measurements is an indication of how repeatable they are (which is the precision). To determine the accuracy, you would need to do something similar, but with the receiver located at a point whose position is well known.

Hi W,
Yes, I should have 'said' resolution, not accuracy.

In U-center, there is a deviation chart, that shows the accuray of the unit. It can be zoomed in and out.

The GPS's I use, have 1Mtr or so, accuracy, but perhaps later I will get CM accuray types.
C