Origin of GPS

[Cliff Mugnier]

First geodetic satellite that transmitted signals was the SECOR (Sequential Collation of Ranges). Receiver neatly fit into one 18-wheel trailer. Diesel generator was extra. I was a Army Company Commander for a short while when I was first assigned to Army Map Service. Had to process an Article 15 to a soldier that was involved in a fist fight at a SECOR site in Chiang Mai, Thailand. The guy was shipped back to me in leg irons for disciplinary action. SECOR observations usually took 4-6 months at one location since there was only one satellite … then another 6 weeks or so for data reduction from 9-track magnetic tapes. Position was good to within a few meters.

[beau1941]

We used Bache’s equipment, in 1980 to measure an 1862 baseline (Originally surveyed by Jefferson Davis), and got 5-6 cm, the first time we used it. After much tinkering with the mathematics, we got that down to 2-3 cm. Not bad for that time in history. Years later (1985), we went back with “Trimble” equipment and proved the results to within 2 cm. Not bad…

[Unknown Member]

Sounds as though that was what the “Black Box” was called. yes we have come a very long way!!

[jud]

73-74 is when I started hearing about GPS, “Black box’s”, In 73 we were using a Geodometer 6A and it was kind of a magic box itself. Heavy, preferred to work in the dark because it used a white light then post processing of the data. It would measure lines that would have taken much time and effort to chain. Seemed that those early GPS units were usually government owned. At that time professors were all excited about EDMs and were spending much teaching wave theory so we would not be using those EDMs in the wrong manner for lack of understand such things. The units themselves came with a cook book that seemed good enough to keep us out of trouble, but the grid to true became an issue. Haven’t we gone through the same with GPS and now are just getting to the point that local minimally distorted grids actually are much better for the common use of those units and the old EDMs than SPC can ever be.
jud

[foggyidea]

Thank you for all your hard work…. i was first introduced to Surveyor quality GPS in Tenn. at the annual convention in 1982

[Daniel S. McCabe]

Glad to see you posting again.
:good:

[northernsurveyor]

I had Richard Collins bring some Macrometer gear for my first GPS survey in 1987, or so. Then TI-4100’s was our first production. $160k a box, and you need 3 to be productive at all (generate 2 independent baselines), and there were 2 windows a day for an hour observation. Neet as bees knees though. The “bleeding edge” of GPS.

When Javad created Ashtech and released the LXII, we finally had a first productive commercially viable receiver. They looked like a steal at #35k a box! Head to head with the Trimble 4000SX which we used too.

[beau1941]

The very saddest part of the new technology, was the hundreds (Thousands?) of hours that went into triangulating all those mountaintop stations, in order to project wing-points down along highways and such. Only to have GPS come along and make them obsolete. Now, it is just set 2 points, observe for 20 minutes and you have coordinates to do your survey. How neat is that. Still sad though. I still will always have the memories of the “old days”, the “Bilby” tower, the “Laser Geodimeter”, T-3 and all the other things that made surveying a great job. God, do I have memories. You haven’t lived until you have climbed to the top of a 250 foot microwave tower to check hill clearances (Recon) and built, in one day, a 90 foot Bilby tower. (Five man crew). We could tear down two in one day. Thanks for letting me babble on.

[David Absher]

Dear Prof. Mugnier: So good of you to post, thank you. Hope all is well.

Thank you all for the history.

dla

[jhframe]

There’s a 2-part article titled Origins of GPS in the May and June issues of GPS World that I found both interesting and enjoyable. It covers a lot of techno-trivia that only a GPS geek can appreciate.

Part 1 can be found here, and Part 2 here.

[David Absher]

thanks Jim – got those now copied into a MS 2010 OneNote Notebook that i’m building for GPS. i’ve lost track of GPS World the last few months even though i get their magazine, emails, and attend their webinars; i need to bear down there again. Thanks for reminding me. It’s a great resource –

thanks!
david

[SteveKerseyPLS]

I worked on a survey control network on Yuma Proving Grounds the summer of 1976 making T3 observations. The network was being set up for a test of railroad box car sized receivers for the ground segment. The concrete slab to rest each unit on was the size of a box car. I returned to Ft. Hood for another project before the test took place, but the work on YPG was unforgettable. Night observations, sixteen positions, direct and reverse within three seconds of the mean on two separate nights. We used EDM prism for sights and an aircraft landing light at the instrument to light them up. Point Red Mountain was on peak too high to hike up to, so the Army would fly us up in a helicopter the afternoon before observations and come back to get us in the morning. I remember losing a jeep for three weeks in the rough terrain when I walked away from it at dusk to get a target on a hill.