Geodetic (GPS) Horizontal & Vertical Control Surveys
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 so 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.
Our GPS/geodetic surveys are supervised by Dr. Shanlong Kuang, a frequently-published geodetic expert who is internationally recognized as a pioneer in surveying with GPS. Dr. Kuang has a PhD in Surveying Engineering. Before coming to work for ASE 16 years ago, Dr Kuang was involved in high-profile geodetic projects around the world. He was responsible for establishing the project geometry for the Superconducting Supercollider in Texas and designing the deformation survey and analysis of the Gezhou Generating Station constructed on the Yangtze River, the largest of its kind in China. Dr. Kuang has also designed and programmed project-specific software applications that are useful to us in our work on high-order geodetic surveys. Dr. Kuang takes the lead in most of our Blue Booking efforts with NGS. We are proud to have Dr. Kuang on our staff.
American Surveying & Engineering has the expertise, personnel and equipment to handle any horizontal and/or vertical control survey. Virtually all modern control surveys are now completed using GPS exclusively or in conjunction with some supporting work using conventional methods. Our crews are equipped with the most up-to-date DGPS and GPS/RTK equipment. For high order vertical control surveys, we have digital levels and invar bar code rods that are necessary to perform this work within the strict confines of NGS requirements for NGS Second Order, First Class precision leveling.
We have performed some of the most challenging and technically complex control surveys in the Midwest. When the Illinois Department of Transportation District 4 decided to establish its own district-wide high order control network, it turned to ASE for the solution. We established a control network that integrated existing NGS control stations into a network that spanned 9 counties and included 250 new horizontal monuments. This project was so successful in allowing the District to reference all of its projects to one network that we were selected to do a similar control project for IDOT District 3 over 11.
We do a great number of projects that require high precision and accuracy over large distances. We have included several examples of these types of projects in this response, including the Prairie Parkway Study (36 miles), the US 20 Freeway Study (48 miles of ROW boundary surveys), and the Cook County Aerial Photo/LiDAR Project (covering Cook County and the 5 collar counties). Most of these large projects and many of our smaller-scale jobs require the establishment of geodetic control for continuity across the length of the project. High-order GPS control surveys are routine for ASE, and we have Blue Booked much of this work with NGS.
We are knowledgeable in all varieties of control surveys for any type of control need, including aerial photo control, project control for all types of land acquisition and engineering needs, and published geodetic control networks. The newest type of control project that has evolved over the past few years is the establishment of CORS (Continuously Operating Reference Station) networks, and we have been active in this type of work. A CORS network is a network of permanently installed GPS receivers that log data which can be accessed in real time (or by post processing) by GPS rover receivers, so that the rover has access to state plane coordinates that are highly accurate across the network. In effect, the network becomes a new datum that is accepted by all users.
When the Illinois State Toll Highway Authority wanted to centralize its old monument-based control network because of errors and inconsistencies, it turned to ASE to install a CORS network that would span its entire system (Over 275 miles of roadways), ASE established the high-order survey for the base receivers and adjusted the network across the system of 9 stations in 7 counties according to strict NGS criteria. When this system was completed in late 2006, it broadcast GPS position data over the Tollway radio frequencies or through a website and across a cell phone network that could be used by any licensed user. Since the Network has gone on line, all new Tollway design projects are referenced to the CORS datum, and now these projects can be integrated seamlessly into one coordinate system.
ASE is also a leader in high-order vertical control work. We have been selected to perform a 43-mile line of 2nd Order, Class 1 leveling for the Illinois Height Modernization project. This project will ultimately result in the ability to get higher vertical accuracy from GPS across the state. When we discovered that some of the specified equipment was so specialized that it is not commercially available, we designed and created our own equipment that meets NGS criteria. All of the results from the high-accuracy vertical survey will be Blue Booked with the NGS.