Return to SSS Online home page
SSS Online is Your SS, RF & Wireless E-zine!

Topical Menus:

   SSS Online Ezine
   Spread Spectrum
   RF Topics
   Wireless Topics
   Design Topics
   Tech Notes & Tips
   Design Tools
   Software Downloads
   Reference Material
   Ham Topics
   Fun & Games
   Assorted Topics
   Community Topics
   Site Info

This site is managed by: Visit Pegasus Technologies
Pegasus Menu
Contact Us



Search site
Search Web
Leave a Comment

Sign our Guestbook

Visit our Sponsors:

Spread Spectrum Scene Online

Issue 9, Spring 2002

Special Issue on UWB


Inside This Issue:

Review our Previous Issues

SSS is proud to present our Ninth Online issue.

We are now soliciting ideas and articles for our tenth issue, which is tentatively scheduled for mid-summer. Please send your comments and suggestions to:

From the Editor's Perspective: The UWB Controversy

by Jim Pearce, Chief Technical Editor and Director, Pegasus Technologies

We have been following the UWB debate actively for several years. This is very interesting technology, and offers a host of interesting applications. In our December 2000 issue, we included an interview with Bob Fontana of Multispectral Solutions, Inc., a company that is one of the key players in the development of UWB communications devices. More recently, we have been closely following the UWB news on our UWB news page, where we covered the February 14, 2002 decision by the FCC to issue a First Report and Order (R&O) on UWB.

In the press release announcing the R&O, the FCC imposed some pretty conservative frequency limitations in order to address concerns from the military and airline industry (among others) about potential interference of UWB devices with the GPS system and other critical systems. You can see the FCC preliminary UWB emissions spectral templates that accompanied the press release here. We are all still anxiously awaiting the actual text of the R&O, which has not yet been issued as of the date of this page.

Like many other people, we were pleased that FCC had finally decided to permit UWB devices. We had some email correspondence with Dr. Fontana in which he stated that he was very pleased with the results, and thought the limits adopted were a good compromise that would ensure protection of vital systems while still allowing devlopment of lots of neat new applications. Discussions with some of the other people developing UWB systems indicated that they, too, thought that the R&O was a good first step and that they could operate within the limits proposed. So we were feeling pretty good about the entire process ...

Until we got the Letter to the Editor printed below.

It appears that the R&O, unless it has some loopholes that aren't shown in the sketchy information provided in the FCC press release and preliminary emissions spectral template slides, may sound the death knell for a small but already established and very important subset of UWB devices, namely Ground Penetrating Radar (GPR). Now, GPR is not something we had paid much attention to previously, as we are primarily interested in communications and this is just a bit out of our scope. But, it's certainly UWB and it certainly has some interesting applications that are important to all of us from a public safety, public interest, and educational standpoint. So we thought this would make a good subject for this edition of SSS Online -- we'd get educated putting it together, and hopefully you'd get educated reading it.

Please take some time to read the information and articles below, and think about what this situation says about our rulemaking process, particularly when pressure is on to do something in a hurry.

Return to Contents

Letter to the Editor

UWB and GPS: A Different Perspective

Dear Editors,

I have been reading the articles and papers posted on SSS Online about the impact of the new FCC rules for ultra-wideband (UWB) with interest. There is a "side story" that adds a new perspective on the issues.

In following the coverage on FCC licensing of UWB transmissions, my colleagues and I are surprised and dismayed by the lack of good data published about an important class of UWB device - ground penetrating radar (GPR). There seem to be some mistaken impressions about GPR technology and the GPR industry. Some of the news stories and submissions to the FCC treat UWB strictly as an emerging technology, when in fact GPR systems have been sold commercially for over 30 years.

Compared to many other players involved with UWB licensing, the thousands of companies in the GPR industry are small, but well established. The GPR industry has no lobbyists or PACs telling/selling its viewpoints in Washington (although a few companies have been actively persuasive on their own behalf). And, while news stories are generated by end results of GPR, the technology itself is rarely explained in any detail in the reporting. Many citizens have read or watched programs about the discovery of the wooly mammoth in Siberia, the largest emerald deposit in North America and the bones from the largest dinosaur, the Seismosaurus - all of which were found using GPR. But, with our low profile, we're just not an industry on the media's radar, if you'll pardon the pun.

Customers for GPR represent a diverse community, with both government and commercial users operating the equipment in a variety of applications, many of them related to public safety. My company, Geophysical Survey Systems, Inc. (GSSI), has been a GSA supplier for 18 years selling systems to over 25 government agencies. We have 2000+ customers, half of these in the U.S.

GPR is the most effective technology for non-destructively investigating concrete and earth to . . .
  • Identify subsurface utilities prior to digging (a significant safety factor where gas and communication lines are concerned)
  • Survey roads and bridges to assess deterioration and cost effectively plan maintenance of the nation's aging infrastructure
  • QA and assess condition of concrete and concrete structures (e.g., airport runways, historical monuments)
  • Find rebar and live conduits in walls of nuclear power plants prior to drilling
  • Evaluate and delineate hazardous waste sites in preparation for cleanup
  • Find drug tunnels between borders and escape tunnels in war zones and under prison walls
  • Find bodies and mass burial sites, and a host of archeological artifacts

Also missing from coverage of UWB is any mention of the clear evidence that GPR does not interfere with GPS. By definition, GPR looks downward into the earth, water, ice and man-made materials to non-destructively detect anomalies. GPR is not intended for air transmission. GPR manufacturers go to some length to reduce unwanted air transmissions. A typical GPR antenna radiates into the ground 1/1000th the power a mobile phone radiates into the air. The range of GPR devices in air is typically a few meters, with power levels dropping off sharply after that distance. GPR represents no threat to aviation or military communications. GSSI systems, for instance, have been used at every major U.S. airport during flight operations without a single complaint. At no time in the past 30 years has the FCC recorded any GPR interference with other receivers. For the past 10 years, GPR manufacturers have sold GPS systems that work successfully in conjunction with their GPR systems.

By subjecting GPR to frequency limitations of less than 960MHz (3.1to10.6 GHz is impractical for GPR) and limiting operation to law enforcement, fire and rescue organizations, scientific research institutions, commercial mining companies and construction companies, thousands of GPR companies have become the metaphorical healthy baby that is getting thrown out with the bathwater - despite all evidence of peaceful coexistence between GPR and GPS. Speaking on behalf of the majority of the radar community, we would like to see FCC rules written that recognize GPR as a different category of UWB device.

As an important site covering UWB, my colleagues and I are hoping that you have an interest in informing your readers about GPR and its many useful applications. Given the diverse customer base and applications, it's certainly an interesting story ... as well as an opportunity to shine the spotlight on a group of small businesses that are battling to stay in business. If possible, I would like to write a position paper on behalf the GPR industry that could be posted on your UWB page. In the meantime, I am attaching some background material and would welcome the opportunity to talk about this situation ... or refer you to other experts and customers for their perspectives. Thank you very much for your guidance and consideration.

Dennis J. Johnson, President
Geophysical Survey Systems, Inc.
13 Klein Drive
North Salem, NH 03073
Tel: 800-524-3011; 603-893-1109, ext. 222

Please visit our website at where we are building a UWB/FCC information page.

Return to Contents

SSS Online Interview
with Dennis Johnson, President of Geophysical Survey Systems, Inc. (GSSI)

April 2002

by Karen Edwards, Pegasus Consulting Corporation

After reading the letter, we decided to give Mr. Johnson a call to talk about his concerns in more detail. This resulted in the interview below, a fascinating discussion with a very articulate and personable man who is extremely worried about how the FCC R&O will affect his industry.

Q. Dennis, tell us a little bit about your background and your company, please.

A.  Geophysical Survey Systems, Inc. (GSSI) is a New Hampshire company that is one of the biggest players in the manufacture of ground penetrating radar systems. It was founded in 1970 by a couple of guys who were working for EG&G, doing some contracts for the Department of Energy monitoring nuclear explosions in the 50s and 60s. They noticed that the pulse from the nuclear explosion went through earth, reflected off things underground, and came back out of the earth. Using this knowledge, they built and sold the first commercial GPR systems. And we've been going strong ever since. We have sold equipment to 50 different foreign countries, and have about 1,000 customers in the United States.

I started with the company 5 years ago as its President. Before that, I was involved in doing management buyouts of companies and that's where I had become involved with the Oyo Group, which is the parent company of GSSI. Oyo is a Japanese company that specializes in various geophysical and environmental services areas. Previously, I was the Director of Manufacturing at a company with $3 billion in sales of downhole gas and oil equipment that provides information on how much gas and oil there was and how recoverable it was. I went to the Naval Academy and had some years in nuclear submarines as an operations officer, then went back to Harvard for an MBA. For the last 20-25 years I've done primarily engineering business management.

Q. What's the history of GPR, and what are the changes in the technology and uses during the last 30 years?

A.  During the 70s and 80s, the equipment was all analog with a strip chart as output. It was used to find water tables, bedrock, and other geophysical structures. During the 1980s, GPR was used at nuclear power plants to find rebar and pipes before drilling a new hole. Those were the primary markets.

In the last 5 years, there has been a big change in GPR equipment, because of the availability of faster, cheaper, smaller computers with more memory. GPR equipment is primarily digital now, and this has resulted in improved post processing of the results. You can input the survey data into a hard drive and get a real time image on the computer screen as the data is collected. 3D images are available minutes after data collection. Before, the output was single line surveys - a pipe looked like a hyperbola on the output, so a lot of experience was needed to read the results. With a 3D image, the interpretation is much easier. Things like tree roots and pipes can be distinguished much more easily.

3D image of underground pipes

3D Quickdraw image of 3 pipes at various depths. Note the sloping angle of the pipe on the right.

So, although this is a relatively new technology, it's pretty well established in a lot of different uses. It's unequaled for doing nondestructive testing and inspection of earth and concrete. A lot of the applications, the bread and butter, are for things like finding flaws in highway pavement and locating embedded structures to make drilling, replacement, and repairs a lot safer, easier and cheaper.

airport pavement GPR picture

Plan view of airport runway thickness in cm. QA inspections and void detection can prevent the unexpected.

There are also some neat applications in archaeology. For example, our equipment was used to find a crypt underneath the Sphinx about 10 years ago -- no one knew it was there. Also, during World War II there were some planes that had to land on the ice pack up near the Arctic Circle. The flyers were all rescued, but they left the planes there. When they went back to get them some time later, they were buried under ice and snow. About 12 years ago, our equipment was used to locate these planes, and one of them was dug up from under 200 feet of ice, repaired, and flown out. I think it's in a museum in Kentucky now. National Geographic did a 1-hour TV special on this.

Forensics is another area where our GPR equipment is used a lot. Police departments at the local and state level and the Royal Canadian Mounted Police use our equipment to find things like drug caches and buried bodies. We also donate our services in this area from time to time. There was one case where our equipment was able to locate a body under a concrete pool deck -- this one resulted in a first degree murder conviction.

2D GPR data collected in 1994, showing physical remains of a murder victim beneath a concrete pool deck.

GPR equipment is also used for search and rescue operations, for finding people trapped under avalanches. Also, if you remember the plane crash in the Everglades a few years ago, we donated our services to help find parts of the airplane and the black boxes so the NTSB could investigate the causes of that crash.

Q. Tell us some about GSSI's GPR products.

A.  We sell five different basic systems. Three of these have fixed antennas that are set up for specific types of applications. Two of these are for utility detection, and one of these is our high-end model PathFinder. This system can be bought with an attached high resolution differential GPS system, so as you're collecting data you know where it is to within one inch. This system is used for utility mapping in very complex urban street intersections with lots of pipes and other structures crossing each other at different depths. We've sold this system all around the world -- Taiwan, Israel, Italy, Germany, and Argentina, for example.

The other two systems we sell are designed to be used with any of our antennas, which means they can be used for a variety of applications. One is a 1-channel system and the other has 2 channels. We sell 12 different antennas for different types of applications. Higher frequency ones are for shallow, high resolution applications, and low frequency ones go deeper and find larger objects.

SirVeyor system
the SIRveyor SIR-20 System

Q. Now let's get into the regulatory arena. What was the regulatory situation before the issuance of the FCC First Report and Order?

A.  GPR hasn't really fit in FCC's rule structure up till now. The Part 15 Rules were written for frequency domain transmitters back in 20s and 30s to prevent transmitters from interfering with each other. GPR is in the time domain area, using UWB. As far as I know, GPR is the only transmitter of EM waves that does NOT transmit into air and doesn't want to! We want to transmit only into the ground -- if it goes into the air, it can cause reflection problems. So any air transmission is unintentional. In the majority of cases, we've been under the class B part 15 emission limits for unintentional radiators, and there has not been a single report to my knowledge of any interference coming from a GPR device.

Several times over the years, FCC has had discussions with the GPR community, and they certainly knew we were there - GSSI has been on the GSA supply list for 18 years and has sold equipment to more than 25 different government agencies including every branch of the military. I think FCC left us alone since the GPR industry was so small - it's not a consumer product, exactly! But over the years, the industry has certainly become well established. Services and uses of the product are very beneficial and relate to public safety in very fundamental ways, like the delineation of toxic waste dumps and looking for pavement voids in highways.

FCC decided to come out with rules covering UWB not because of us, but because of the new UWB industry, the air transmitters, who wanted to develop and sell unlicensed UWB communications devices. This has a huge market potential, with lots of consumer applications, so there's a lot of money at stake here. FCC has been under a lot of pressure to get these rules issued.

Q. Were the original proposed UWB rules OK with GPR?

A.  The rules originally proposed back in 2000 would have been OK with us with a few minor exceptions or clarifications. They specifically allowed GPR to operate at any frequency under the Part 15 Rules.

Q. Did GSSI make any comments to the FCC on the proposed UWB Rulemaking?

A.  Yes, we made several comments and several responses to others' comments, and we also provided testing data showing that there were no interference issues with operation of GPR systems. Data from 2 systems was submitted.

Editor's Note: Below are links to pdf copies of the documents GSSI has filed with FCC on the UWB Rulemaking:

Q. What impact will the new rules have on GPR?

A.  In the press release and the frequency charts FCC issued on February 14, GPR is lumped in with through- wall and medical imaging. Equipment must be operated below 960 MHz or from 3.1-10.6 GHz (which isn't practical for GPR); licensing appears to be required except for medical imaging; and every use appears to require 2-week advance notification. Also, there are limits on who can operate GPRs - law enforcement, construction companies, fire and rescue organizations, scientific research institutions, and commercial mining companies. Pulse repetition frequency is also an issue.

This will put GPR out of business. We just can't live with it. Depending on the antenna, GPRs operate from 40 MHz to 2.2 GHz. So the part of the spectrum we use is outside the proposed regulatory limits. The advance notification is impossible to meet if you're a company that uses this stuff on a daily basis like many of the GPR users do. And putting requirements on who can operate it - there are a lot of geophysical consulting/contracting operations out there that are apparently banned from using GPR, as well as GPR users in transportation, agriculture, utility location and other areas. And there are problems with manufacturers having to figure out whether a company falls into one of these categories.

Go On to Page 2
The Interview with Mr. Johnson Continues Here

Return to Contents

Spread Spectrum Scene Online is managed by Pegasus Technologies. We can help you get your quality RF products to market!
Visit Pegasus Technologies
Meet Pegasus Technologies!

Contents SS Glossary Pegasus Tech Navigation Home

  Tel: 865-717-9339   ||   FAX: 865-717-9904    ||   E-Mail:
This site © 1995-2008 by SSS Online, Inc. All rights reserved.
Revised November 26, 2008