Going wirelessly geomatic (Part I)

December 2005 » Columns » GEOMATICS
For geomatics professionals, wireless technologies have opened up a host of ways to innovate in gathering, accessing, analyzing, acting upon, and delivering information.
Joseph V.R.Paiva, Ph.D., P.S., P.E.

Whether it is wi-fi, Bluetooth, cellular, or some other radio technology, most professionals in almost any discipline today use one or more of these in their business lives. For geomatics professionals, these wireless technologies have opened up a host of ways to innovate in gathering, accessing, analyzing, acting upon, and delivering information.

The real time kinematic (RTK) GPS application probably is the great-granddaddy of them all. It requires the transfer of position correction information from a carrier phase tracking GPS satellite receiver base station to a similar receiver acting as a rover (hence kinematic). The radio technologies most used at the time it was released in the early 1990s and later were the ultra high (UHF) and very high frequency bands of the electromagnetic spectrum. Probably the next application to use wireless technology was so-called robotic total station technology. By adding servo motors to the horizontal and vertical axes of the total station, and by including target recognition and tracking technology to the telescope, it became possible for a total station to track the prism as it moved from point to point. It was an easy transition from there to enable the person at the prism pole to trigger the measurement. This was accomplished by a two-way radio link, most commonly using UHF and 900-MHz spread spectrum radios.

These were significant first steps in the wireless arena that facilitated new surveying technologies. The newer wireless computing technologies that have pervaded society, however, redefine the workflow of the affected geomatics activities, regardless of the position sensor that is used.

Bluetooth technology is a short-range, cable-free solution to connect various surveying system components. Sometimes it only serves to replace cables, but it also can enhance connectivity through a small network, called a piconet. One example is using Bluetooth to connect a handheld controller with a mapping/GIS data-collection system so that the GPS receiver and antenna can be located on a handheld or body harness-supported pole or mast on a vehicle. This solution requires the integration of a lowpower, high-performance receiver with the antenna (to eliminate the antenna cable) and sufficient capacity to output serial data.

Output includes the GPS-determined position and other key operational information such as satellites-in-view; dilution of precision values; and other error, warning, and status indications.

A further enhancement is independently powered receivers for GPS differential correction signals that use Bluetooth technology to transmit corrections to the GPS receiver or controller so that higher precision positions can be calculated. The net result? More streamlined field gear, much better ergonomics for the user, and less worry about damaging or tangling cables, thereby enabling more focus on mapping activities.

A similar situation can be seen with products designed for RTK GPS surveying and construction layout, monitoring, and supervision. These high-precision positioning systems use Bluetooth to connect a self-powered receiver/antenna combination with a controller. Depending on the configuration, a third component—the radio receiver for RTK corrections—may be used and connected to the rest of the system with Bluetooth.

A further application of Bluetooth technology may be used with the previously described systems. A Bluetooth-enabled mobile phone that is data-enabled may be used to connect an office, or some remote data repository, with the field system. The phone may be used to send data from an office location or to initiate receiving data from the field. Similarly, the field system operator may initiate sending data to the office or download files residing on the office database.

For mapping projects, data from the office can help with team management in the field. For example, by allocating geographical boundaries for several teams, gaps and overlaps in mapping coverage can be eliminated. Additionally, field crews can receive portions of base maps or databases that cover the areas to be mapped; data about existing features and attributes to be found, identified, and re-inventoried; and information about additional areas needing to be mapped or investigated.

Information that may be sent from the field to the office includes updates on features and attributes that already exist in the office database. Also, mapped information that can be used to create or update new maps and databases can be submitted, as well as data to help managers identify cost and billing quantities; schedule and plan new work (or rework); and coordinate other teams, tasks, and disciplines.

These examples describe applications of Bluetooth technology for surveying and mapping, indicating that the basic nature of necessary low-level tasks haven't changed, but that the accuracy of information from the field and the speed at which that information can be received have improved. Now managers can more tightly integrate tasks. Additionally, field crews can significantly reduce time in the office uploading and downloading data, which translates into more time to work on mapping tasks, less confusion, and better control of the quality of field data being collected.

Joseph V.R. Paiva, Ph.D., P.S., P.E., is a geomatics consultant. He can be reached at paiva@cenews.com.


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