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Please check http://jproc.ca/hyperbolic/loran_c_eloran.html

At the bottom of that page you will find a link to a dissertation in 
which, on page 122, the LF H-field antenna is described. This loop 
antenna is not an omni-directional antenna and, when used in a dual loop 
configuration, can be used as a heading device. On page 168 in fig 5-49 
a graph is shown that, after calibration, compass errors are smaller 
than 0.8 degrees. On page 175 it reads "With only factory calibration, 
the Loran-derived compass heading had an offset of 2.8�, a standard 
deviation of 3.9�, and a 95% error of 8.3� with respect to the Vector 
Pro GPS compass. After field-calibration, these errors reduced to an 
offset of -0.1�, a standard deviation of 0.5�, and a 95% heading error 
of 1.1�...". The eLoran heading was checked against a Vector Pro GPS 
heading device (which is a zero-baseline RTK heading device) with an 
accuracy of 0.5 degrees.

Nicol�s


Lu Abel wrote:
> A bit off topic, but ...
>
> A friend sent me an article (perhaps more accurately described as a 
> publicity release) about eLoran that claims its signal can be used in 
> electronic compasses.   The precise sentence in the article is:  
> "Moreover, eLORAN can do things GNSS cannot, such as acting as a static 
> compass."
>
> First of all, the statement about GPS is inaccurate, since one can buy 
> electronic compasses that work even when they are static by comparing 
> the phase differences between the receipt of GPS signals at two or three 
> antennas separated by a foot or less.
>
> What makes me very curious, though, is how an eLoran-based electronic 
> compass would work.  
>
> "GPS compasses" work by observing the phase differences between signals 
> received at two or three different receivers, these phase differences 
> give the direction to the satellite and by knowing its location in space 
> it's simple math from there to calculate the direction of true north.   
> But the phase difference method works only because GPS signals have such 
> a short wavelength that there are considerable phase differences between 
> signals received at antennas even a short distance apart.
>
> I have not been able to find any information on how eLoran-based 
> electronic compasses would work.   Loran signals are very 
> long-wavelength signals (25,000 times the wavelength of GPS signals), so 
> measuring their phase differences in any reasonably small electronic 
> compass setup would seem impractical.
>
> Maybe measure the bearing to each of the transmitters?   But I have a 
> hard time believing that could be done accurately enough to create an 
> electronic compass with sub-one-degree accuracy.
>
> Can anyone point me to an explanation, or is the sentence I quoted above 
> simply hyperbole from an eLoran supporter?
>
> Thanks
>
> Lu Abel
>
> >
>
>
>
>
>   


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