Description: <DIV STYLE="text-align:Left;"><DIV><DIV><P STYLE="margin:0 0 0 0;"><SPAN>The values for the City of Richardson GPS Control Network were established using Static data collection procedures during the month of February 2020. </SPAN><A href="http://www.cpyi.com/"><SPAN>CP&Y, Inc</SPAN></A><SPAN>., in conjunction with the City of Richardson set all 3-1/4 inch domed aluminum monuments throughout the City at designated key areas. All fieldwork and post processing were performed by CP&Y, Inc. Final data sheets were published after consultation with the City of Richardson. </SPAN></P><P STYLE="margin:0 0 0 0;"><SPAN /></P><P STYLE="margin:0 0 0 0;"><SPAN>Horizontal State Plane Coordinates (SPC) are on the Lambert Projection System — NAD83 (CORS96) — Texas Coordinate System (Texas North Central Zone 4202). A position was derived using the National Geodetic Service (NGS) Online Positioning User Service (OPUS) position for Monument No. 116 (previously City of Richardson Monument H7) near the center of Richardson, as a base point. All other monuments within the City of Richardson were tied to a constellation of multiple observations (baselines) using 3 GPS receivers from this base point location. The vectors were assembled into a three-dimensional network least squares model using the Trimble Business Center® software. A minimally constrained adjustment proved the integrity of the vector data. The positions of four Continuously Operating Reference Stations (CORS) in the NGS network were included in the project as control and the vectors from each of these stations were used to develop coordinates for Monument No. 116. The resulting coordinate values for all stations matched the OPUS solution and separate vector data corrected from the Trimble RTKNet. The dual-frequency vectors were added to the project to obtain coordinates for all stations for publication. </SPAN></P><P STYLE="margin:0 0 0 0;"><SPAN /></P><P STYLE="margin:0 0 0 0;"><SPAN>Vertical values are NAVD88 elevations and validated by the City of Richardson Control Network generated in 1990, OPUS, and Trimble RTKNet datums. The 1990 City of Richardson Control Network was previously adjusted to the Federal Emergency Management Agency (FEMA) with GPS Static observations on U.S. Coast & Geodetic Survey Monuments M923 and S923. All GPS derived elevations were computed using a Geoid Model (GEOID12B). </SPAN></P><P STYLE="margin:0 0 0 0;"><SPAN /></P><P STYLE="margin:0 0 0 0;"><SPAN>In summary, CP&Y, Inc. provided the City of Richardson with a GPS Control Network based on the position of Monument No. 116 and its elevation verified from the City of Richardson 1990 Control Network. All data sheets will show State Plane Coordinates in both Geodetic and Grid formats. The horizontal data is referenced to NAD83 Texas North Central Zone- 4202, in both U.S. Survey feet and meters. Vertical data is referenced to NAVD88 elevations. </SPAN></P></DIV></DIV></DIV>