New Scientist articleThe link above shows just how susceptible GPS is to jamming even now.BTW, the site has some excellent coverage of the unfolding e...

Yes that's right. Should have provided more information. See:for site details.

Yup. It was a 4000SST. Those units actually had displays showing all sorts of parameters as well as SV conditions including DOPs. It gave you someth...

Howdy,Here are two colleagues from the Chilean government and I in 1994. We are atop a small summit in the background is Santiago and the mountains b...

Howdy,I had a chuckle when I saw this caption for the planetable in the surveying instrument case at the British National Maritime Museum in Greenwich...

Study materials for upcoming webinarHowdy,For those wanting to study up for the upcoming webinar, check out this NGS report to the FGCS:Status update ...

Detailed Information on ITRF2008 in JofG (open access)This message was copied from a recent IGSMail:For your information, a detailed article on ITRF20...

Howdy,I happened to come across this image of the screen of the TAGS meter within a presentation. I copied it and post it here. Resolution is not gr...

Howdy,Absolute meters are used to provide the tie absolute gravity at the aircraft parking spot. See the following link: GRAV-D Alaska Survey 2008 Re...

I believe the meter used by NGS is the one described in the following file: Micro g LaCoste Romberg TAGS meter

Howdy,Sounds like fun. I hope that the airborne gravity observations go well and the data is made available to researchers soon. There is an interes...

FWIW,The NGS has a venerable package ADJUST that is free, rigorous and is distributed with sample data and guidelines. I consider it a good tool to l...

FWIW,I cannot definitively tell from the picture BUT IF the monument was undermined by nearby construction/excavation the monument lost its value as a...

Howdy,I am almost sure (95%) of the following:Since the point is located on an airport and has a copper washer with USC&GS stamped in it, it was e...

Howdy,The following was copied from the NGS web site. I changed the key statement to bold. To the best of my knowledge this is still current. Page ...

Howdy,As usual, very good information. Accounting for the differences in gravity along the line of leveling allows for the determination of a unique ...

Invar tape for baselines adopted in early 20th CenturyHowdy,I do not intend to be obnoxious (though I am perhaps infected by the degeneration of this ...

Howdy,FWIW, when I disparaged SPCS as 2D I did not acknowledge that the measurements used are inherently 3D. I do not doubt that accurate work can be...

Howdy,I do consider the SPCS to be important. Computations using the SPCS is usually covered in other course. The notion that SPCS and geodetic coor...