[TowerTalk] Measuring Terrain Slope / Elevation

[Eric Gustafson]

Well, the high cost idea is correct.  But the post processing
software step is unnecessary.  We locate shovel bucket positions
to an RMS error sphere with a radius of tens of centimeters in
real time.  The GPS data is not the largest source of our error.
But the receiver (even just as an OEM module) costs about $2400.
To that must be addded the cost of the reference station and the
data link to get the differential corrections to the field unit.

73, Eric  N7CL


>Date: Tue, 22 Dec 1998 18:26:05 -0800 (PST)
>From: Pat Barthelow <aa6eg@hh.tmx.com>
>
>HI Brian,
>
>Yes, it is possible to get millimeter accuracy using
>sophisticated techniques in GPS, but it is not trivial, or
>cheap.  Such accuracy requires Surveying grade GPS receievers,
>simultaneous measurement, fancy data stream integration (from
>the users GPS receiver, and the Differential Reference receiver)
>and application of post processing software.  I believe that a A
>cheap, handheld, real time Differential receiver using simple
>techniques should resolve to 30 ft horizontal, and less than
>that horizontal...
>
>73, DX, de Pat, AA6EG/N6IJ; 
>
>aa6eg@hh.tmx.com
>
>599 DX Drive, Marina CA 93933
>"The Contest Station from the Government"
>
>On Tue, 22 Dec 1998, alsopb wrote:
>
>> Pat,
>> 
>> My understanding is that differential GPS is capable of millimeter
>> resolution.  Is that accurate enough?  Among other things it is used by
>> geologists to track extremely small changes in seismic areas which may
>> indicate possible future activity.
>> 
>> 73 de Brian /K3KO
>> > ((D GPS), which provides higher accuracy than raw GPS,) probably will not
>> > provide the accuracy you need to for terrain
>> > profiles used in antenna modelling...especially the elevation readings,
>> > which are quite innacurate unless sophisticated equipment  is used....
>> >
>> 
>

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