RF ID Technology in Geospatial

April 6, 2010 By: Eric Gakstatter

For field locating technology, GPS/GNSS has taken the cake and baked a multi-billion dollar business over the past two+ decades, there’s no denying it. In the geospatial industry, it has been so dominant that it has shadowed other technologies that are worthy of discussion.

Back in the early '90s, I worked for a company that designed handheld data collectors. As such, I was involved in other identification technologies, outside of GPS, such as bar-coding and some other specialized sensor technology.

One technology that I looked at a bit, but never had experience with, was RF ID (radio frequency identification). Even though I never had experience with it, I saw it had great potential. In fact, it did and it’s implemented worldwide today.

What is RF ID (Radio frequency identification)?

An RF ID tag (or referred to as a chip) is essentially a very small radio device that stores digital information that can be read by an RF ID scanner. The tag consists of a digital chip and a very small antenna. When you think about RF ID tags, you may think of something the size of a luggage tag. However, they are much smaller. In fact, they can be incorporated into a thin label such as in the examples below.

Courtesy: ADASA, Inc. RFID Innovation

If you've received a U.S. passport within the last couple of years, there's an RF ID tag in it. Passports issued by the United States as well as many other countries incorporate RF ID chips. These are referred to as E-Passports. Essentially, the RF ID chip inside the passport contains all of your information printed in the passport as well as a digital photo of you. It is a non-contact technology, meaning that the reader doesn’t have to touch the passport to read the information, but rather just be within a certain distance. In fact, I read a story (and I see it’s in the Wikipedia description also) that the original U.S. passport design could be read from 30 feet away. For security reasons, designers had to reduce the performance of the RF ID chips in the passports so they could only be read by scanners a few inches away so no unsavory individuals would sit in the airport and "scan" passport data of the surrounding people.

When traveling internationally in 2008, I recall arriving at airport customs in Moscow, Russia. The E-Passport line was very short and very fast compared to those carrying a traditional passport.

There are many other applications of RF ID such as electronic tollbooths, animal tracking, retail inventory tracking, and tracking books in libraries. These types of uses have been mainstream for many, many years.

A few years ago, I heard about a product line from 3M where they had designed RF ID technology specifically for underground locates. This isn’t an advertisement for 3M, but their technology is a good example of what can be accomplished with RF ID in utility locating. When I first heard of 3M’s product, I could see an application for this in golf course construction where a lot of underground utilities are installed (irrigation, drainage, electric). The concept, as explained to me, was simple. If you want to mark the location of a pipe, throw the tag into the pipe trench and you’ll be able to read it after the trench has been filled in.

Of course, it might get complicated with multiple pipes in a trench, especially if they are small, although each RF ID tag has a unique identification number. Not only would this technology be useful for utility locates, but also for creating construction as-built drawings, which are notoriously poor in many construction projects.

RF ID in construction is a natural extension of GPS mapping technology. It’s easy to envision an irrigation contractor having an inventory of RF ID tags as they are trenching and installing irrigation mainline. They would drop a tag into the trench at each change in direction (or every few feet), piping intersections and at the gate valves. After the trench is backfilled, the RF ID tags would be very useful in locating the mainline while accurately mapping it using GPS.

Back to the technology

There are generally two types of RF ID tags: active and passive. The active tags have a battery and are generally higher performing and can broadcast their own signal. Passive tags do not require a battery and simply reflect a signal that is broadcast from a RF ID scanner. Of course, that’s oversimplifying, but I think you understand my point.

3M offers a range of active and passive RF ID tags. Some are designed for near-surface locating (2 ft.) and some are designed for deeper locating (8 ft.). They vary in size and form factor.

15" dia., up to 8 ft. deep 8.25" dia., up to 6 ft. deep 4" dia., up to 5 ft. deep 3.5" long, up to 2 ft. deep

(Courtesy: 3M)

Not all RF ID tags are measured in inches or centimeters. In 2009, it was widely reported that Bristol University successfully mounted a tiny RF ID tag on the body of an ant.

Courtesy: Bristol University

RF ID tags aren’t useful without an RF ID scanner which is used to locate the RF ID tags. The RF ID scanner isn’t small. Similar to a metal detector, the sensing unit is placed close to the ground while the operator monitors the measurements on the LCD screen.

Courtesy: 3M

RF ID Tags on Surveying Monuments?

In the February 2010 issue of the ACSM (American Congress on Surveying and Mapping) Bulletin, surveying marker manufacturer Berntsen International, Inc. published an article about smart surveying monuments using RF ID technology. Berntsen is one of the largest surveying monument manufacturers in the world.

According to Bill Rushing, vice president of product development, “durable, environment-proof, and updatable RF ID chips attachable to stable, world-class, magnetically-detectable monumentation is a game-changing technology.” I think I’m going to agree with him on this. Following is a concept drawing from Berntsen communicating their vision if RF ID for smart monumentation:

Imagine an RF ID chip on a monument that includes an NGS datasheet, visit history, datum info, photos, etc. That technology is not available today, but it will be in the not-so-distant future. What’s available today is a device that will hold 512 bits of information. That is more than enough to contain a unique ID number that could be used to reference a county database accessible from a laptop computer in the field. The county database would contain as much information as anyone would need including drawings, photos, datasheets, related surveys, etc.

Berntsen International's InfraMarker RF ID Markers

How many construction as-built drawings get filed away forever and have to be re-constructed when the structure renovation is planned? Imagine the construction as-built drawing set being included in a chip on each site monument?

I can guarantee the adoption of this technology is going to happen in the geospatial industry in a big way. It just makes too much sense.

Thanks, and see you next week.

Be sure to catch up with me at the GITA/ACSM conference later this month in Phoenix, AZ.

I'll be speaking at both the GITA (Sunday, April 25, 8:00am) and the ACSM (Wednesday, April 28, 9:45am) technical sessions as well as blogging while I'm there.

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