GPS PRIMARY CONTROL
The primary control network for this project comprised two parts: (1) A
primary GPS network to obtain adequate ties to the existing National Geo-
detic Survey (NGS) control stations; and (2) a GPS network linking together
all new monuments along the corridor being surveyed.
Control Recovery
After completing field reconnaissance, it was concluded that seven control
monuments with NGS published values within the perimeter of the site
would provide an adequate network. Several other stations recovered within
the area were found not to be suitable for occupation via GPS due to
microwave disks, building obstructions, and access problems caused by se-
curity. The following stations were found suitable for GPS occupation:
Workman Hill WHR-LI Reset 2.89; Venice J-5G; Denker LAC C 1933;
Sawtell A-10; Hollywood L-5F; Divide USGS LAC C 1933; and LA L-2A
AUX ECC 1 (Fig. 2). Two California High Precision Geodetic Network
(HPGN) stations, namely HPGN 07-01 and HPGN 07-02, were also re-
covered and were included within this primary network. California HPGN
was completed in 1992 and positional values were published in June 1992.