ASE was the first firm in the Midwest to use GPS for surveying applications. In the early 1990s we offered training classes for our peers and leased GPS equipment to them, because we felt strongly that this technology was going to revolutionize the surveying profession. As the technology matured into kinematic and RTK, we stayed ahead of the curve and were consistently testing equipment for manufacturers (Trimble) before the equipment was commercially available. We have the latest RTK/DGPS equipment available for every one of our crews in the field, and it is integrated into every aspect of our performance.
We do a great number of projects that require high precision and accuracy over large distances, and we have performed some of the most challenging and technically complex control surveys in the Midwest including:
  • GPS for Continuously Operating Reference Station (CORS) Networks
  • Illinois Height Modernization Program
  • Ground Control for Large-Scale Mapping and Photogrammetric Projects 

We have also done extensive Control Survey work on these selected projects:

More examples of Control Survey projects are available upon request.

  • CORS Network Stations, ISTHA
  • Illinois Height Modernization, Second Order Class 1 Level Lines
  • Illinois Height Modernization, Flood Risk Survey, U17081
  • Aerial Control for Various Counties in Illinois
ISTHA, Establish CORS (Continuously Operating Reference Stations) Network Stations, Authority-wide, PSB 04-05, Item 28/RR-05-5483   
The Illinois State Toll Highway Authority’s (ISTHA) CORS (Continuously Operating Reference Stations): Reference Network Stations are located in 7 different Counties, including Boone, Cook, DuPage, DeKalb, Lake, Lee, and Winnebago of Northern Illinois, covering an area of about 100 miles (West-East) by 50 miles (North-South).  Selection of locations and monumentation for each ISTHA CORS station was done according to the National Geodetic Survey (NGS) criteria in effect at the time when the stations were constructed.  LEICA GRX1200 Pro dual frequency GPS receivers with LEIAT504 antennas were installed on all the 9 new ISTHA CORS stations to log GPS data continuously.
Horizontal Positioning
Using four national CORS stations nearby as reference ties to the ISTHA’s CORS network, ASE successfully accomplished baseline processing, network error analysis and adjustment, and bluebooking the CORS network to NGS.  The FGCS B-order Standards and Specifications for relative GPS surveys were used in this analysis.  The final adjusted geodetic coordinates of the new stations will be used as reference coordinates for surveying applications in the future.
Vertical Positioning
Due to the extensive range of the ISTHA’s CORS network, in order to obtain accurate orthometric height for each CORS station, an extensive search was made to find a minimum of 2 existing NGS benchmarks within 10 km radius of each CORS station.  A GPS field campaign was then performed for each CORS station.  The existing benchmarks together with the CORS station make up a “mini- GPS network”.  By combining GPS , the NGS Geoid Model Geoid03 and existing NGS benchmarks, the orthometric heights of ISTHA’s CORS stations have been derived with an accuracy of about 2 to 3 cm.
Illinois Height Modernization, Second Order Class 1 Level Lines
ASE conducted Second Order First Class Levels lines across Illinois as part the Illinos Height Modernization program managed by the Illinois State Geological Society. ASE installed new marks as prescribed by the NGS standars. This contract included purchasing all of the materila for the monuments, setting the marks, running the levels, and compiling data in a format suitable to be submitted to NGS for inclusion into the NSRS. It was ASE's responsibility to check and obtain any and all needed permits to perform the tasks. 
Illinois Height Modernization, Flood Risk Survey
ASE surveyed top priority areas in Rock Island County, a total of 2,851, as part of flood risk structure inventory for the Illinois State Geological Society (ILGS) and the Illinois State Water Survey (ISWS). The information obtained was not intended for use in preparing “Flood Insurance Elevation Certifications,” but could be used as an initial screening tool for that course of action. ASE surveyed First Finished Floor Elevations, Low Entry Elevations, and Typical Ground Elevation for each structure. ASE took photos of each structure and uploaded information into GIS. ASE crews also noted the general occupancy class (residential, commercial, industrial, agriculture, religion, government, and education), the number of stories, and the foundation type. ASE performed 85 miles of control surveys to establish control for the entire project. ASE provided all survey points as shapefiles compatible with ArcGIS 10.3. Federal Geographic Data Committee (FGDC) compliant metadata was provided.
Aerial Control for Various Counties in Illinois

ASE provided ground control for Cook County’s Orthoimagery project.  ASE provided photo control points for aerial photogrammetry in support of the County’s mission to acquire aerial imagery of approx 4,160 square miles, including all or portions of the following northeastern Illinois counties: Cook, DuPage, Grundy, Kane, Kendall, Lake, McHenry and Will.  Incorporate recoverable  Mission photo-id points to establish  photo-id points, locate base station points, tie photo-id control points to base stations, capture digital photo of each point, prepare network design, plan configuration and duration of observations, determine optimum observation schedules, prepare session design on master observation schedules. Horizontal control accurate to Second Order, Vertical control accurate to Third Order; using Horizontal Datum - NAD 83 and NSRS 2007; Vertical Datum – NAVD 88. Deliverables: Final control / GPS report including narrative, field notes, sketches;  ASCII file of all checkpoint control conforming to FDGC Metadata standards, digital photos.

Request a Consultation!

American Surveying & Engineering, P.C. (ASE) offers a variety of professional services. Please contact us with any question you may have and one of our representatives will get back to you shortly.


American Surveying & Engineering, Ltd. (ASE) offers a variety of professional services. ASE, which was established in 1978 as American Surveying Consultants, has its corporate office in Chicago and branch offices in Naperville and Dixon, Illinois.

Read more


Let ASE work with you to provide project solutions that exceed your expectations. We offer unique solutions to every project that saves time and money.
Innovative approaches to everday tasks allow you to get your data sooner at less cost.  


  • 312-277-2000
  • 200 N. LaSalle St., Suite 2630, Chicago, IL 60601


  • Surveyors
  • Engineers
  • Geodesists
  • Mapping Scientists
  • Appraisers, Negotiators
Copyright 2024 by American Surveying & Engineering, Ltd. Terms Of Use Privacy Statement
Back To Top