We want to conduct highest-possible accuracy static surveys in accordance with:
NOAA Technical Memorandum NOS NGS-58. Guidelines for Establishing GPS-Derived
Ellipsoid Heights (Standards 2 cm and 5 cm) Version 4.3

We want to refresh our equipment and software with current state-of-the-art versions.
Listed below are my "quick takes" on possible choices for newer equipment.
I'll probably stick with Ashtech unless I hear compelling reasons to switch brands.
Any thoughts?

RECEIVERS:
Current: Z-12
Upgrade to: not sure (Z-Xtreme or uZ-CGRS?)

ANTENNAS:
Current: 700718 (B) ("Geodetic III")
Upgrade to: to be determined (Mfr./Model?)

TRIPODS:
Current: SECO adjustable height models
Upgrade to: fixed height models (Mfr./Model?)

POSTPROCESSING SOFTWARE:
Current: AOSS 2.0
Upgrade to: Ashtech Solutions (?)

Thanks,
Randy
Modified By Randy Van Steen on 2/12/2002 at 3:46 AM

If you really want to meet the NGS-58 guidelines, forget about Ashtech Solutions, or just about any other manufacturer's software. NGS-58 requires a multi-baseline processor; as far as I know, none of the receiver manufacturers offers one. If you're intent upon (or required to) chase down those last few millimeters, you'll have to rely upon something like OMNI, GAMIT/GLOBK, GIPSY, or Bernese. I'm told the learning curves for all of them are uncomfortably steep.

P.S. Don't forget barometers and hygrometers, as met data is required for observations at control and primary base stations. It almost certainly won't be used by anyone, but it's required under the guidelines nonetheless.

If control is all you're doing, keep the Z12 (best control box out there, just a bit clunky for rtk), get the latest v of AOSS (best control software), and upgrade antennas if you want. Oh yeah, fixed height poles are a must.

Processing and adjustment software (as well as procedure) are way more important than hardware, although for the tight stuff you'll want choke ring antennas. Gov't software or Bernese for processing...ick.

Randy,

Your Z-12's are still one of the best GPS receivers ever built. Your antennas and receivers don't really need to replaced. Unless you want to persue this.

Make sure you have the most current Firmware for your Z-12's.

Your GPS post-processing S/w could be upgraded. The AOSS V2.0 can be upgraded to the newer Ashtech Solutions V2.50+.
You can trade up to this newer Ashtech S/w.

Ashtech will soon release a version of Solutions that supports use of Precise Ephmeris (E18 & SP3 formats).

The NOAA #58 Guidelines specify use of Dual-frequency receivers, Fixed Height tripods, Precise Ephemeris, and 100 % double Baseline observations. Use of the various GPS manufactures GPS Post-Processing is acceptable. Blue Book format export is a bonus.

I tend to disagree with Jim's statement regarding the GPS Manufactures GPS post processing S/w. The long running debate over "Multi-Baseline" processors is an old warn out topic. Any of the current GPS Post-processing S/w can be used. NGS will not reject your data simply because you used the Manufacturer's S/w.

Before joining Ashtech, In my previous employ, I was directly involved in field testing the pre-released field procedures specified in NOAA #58 for NGS. For this project, the Manufacturer's GPS Post Processing S/w was used. This project was submitted to NGS.

The newer S/w's support Electrical Phase Center Variations and Precise Ephmeris.
There's where you'll chase down the "Millimeters"...

If your current SECO Adjustable Height Tripods have the Locking cotter-Pin mechanism, so the Height can be "Locked-in", your all set.

Just be sure to callibrate & adjust these Fixed Height tripods before your survey. Check them during & after the survey.

Further clarifications:

1. Dual-frequency receivers are advisable, but are only required on baselines longer than 10km. Since local network stations are required to be less than 10km apart, L1-only gear can be used. However, you may not be able to bluebook the project unless you use L1/L2 receivers.

2. Ground planes are required under the guidelines. These seem to be getting more and more scarce as demand for more compact gear increases.

3. As Bob pointed out, the guidelines can be "bent" some and still produce results acceptable to NGS.