Figuring out the GPS COM port on a ToughBook PC

I receive quite a few phone calls each year from ToughBook owners trying to figure out how to use the GPS receiver. A ToughBook with integrated GPS from the factory comes with a default COM port dedicated to the GPS, but which one? You need to know this COM port for using software, but also, in the event of a malfunction, you will need to test the GPS to make sure the defaults from the factory haven’t changed. To find out, the best route is to use the HyperTerminal program.

To get to HyperTerminal, start with the START button in the lower left corner:

START > All Programs > ACCESSORIES > Communications > HyperTerminal

Under “Connection Description” give any name to the New Connection, it won’t matter. The icon also doesn’t matter. In the next box, under “Connect Using” scroll down to COM 1. The properties screen will appear. Change to the following if set differently:

Bits per second: 9600; Data bits: 8; Parity: None; Stop bits: 1f; Flow control: None

Click OK.

On the main HyperTerminal screen, you should see a string of characters which are the NMEA sentences (e.g., $GPGGA, $GPGSA, etc., followed by comma-separated values). If not, chose “Disconnect” from the toolbar, then reconnect and start over but chose COM 2 this time. Keep working through the COM ports until one works. Record this COM port as it should not change. If you have the COM port correct in the software, but it still is not connecting to the GPS, make sure the Baud rate hasn’t changed. I have seen that happen and most times the software and GPS are not communicating, it is a mismatched Baud rate; the rest of the time, the GPS isn’t connected.

Super-cool field mineral analyzer from inXitu–check it out at AGU in San Francisco!

This week, I have been visiting the annual meeting of the American Geophysical Union (AGU) in San Francisco. This meeting, held each fall, showcases the latest in research on the Earth and space and the exhibit hall boasts lots of new technology. I had a great time speaking with folks at the NASA booth, visiting with booksellers, and chatting with the Google Earth crew. However, this year’s grooviest field device is a ruggedized rock and mineral analyzer from inXitu, Inc.

Image courtesy of the inXitu website. Note icy cold research ship in background! Where are the penguins?
Known as an XRD, this hefty box takes a powdered rock sample and bombards it with x-rays to produce a diffraction pattern. As we learned in Intro Geology, each mineral has a unique arrangement of atoms so each mineral will produce a unique diffraction pattern, like a fingerprint. Normally, you collect a sample in the field, bring it back to the lab, crush it to a fine powder, then put it in a large, humming box. The “TERRA” allows you to do this in the field as it comes with a handy metal mortar and screen. Simply crush a piece of the sample, put the powder in the sample holder, place it in the box, and in a very short time (~30 seconds in the demonstration I saw), a diffraction pattern is produced. As long as you have a database of known minerals (available from a variety of sources), identification is instantaneous.As this blog is about rugged field computers, I’ll mention this XRD amazingly has no moving parts so is field ready. It comes in a ‘Antarctic-orange’ rugged case and can operate from -10 to 40 degrees C. Slightly bulky, but not unmanageable. The battery claims 4 hours of field use and is hot-swappable. You don’t need a computer to run the XRD, but you can communicate via WiFi (802.11g) to control the start and stop, download data, and search stored data.

The suggested price is $64,500. Not cheap, but a reasonable price compared to lab-based units. If you were involved in a project where on-site mineralogic data is critical for saving time in planning the next day’s (or hour’s) investigation, you would quickly make up the cost. I anticipate that we will hear about use of these units from the major research schools, particularly the hot economic geology schools. U. M. Duluth grads, pool your money and donate one of these gems!

For more information, contact inXitu, Inc. My congratulations for the coolest field tool at AGU!

A marriage of convenience: GPS and cameras

What is the latest trend in GPS? For my money, there will be an expansion of ‘geocoded’ cameras; cameras that record the current longitude and latitude and affix this data onto the image. While the technology has been around for some time, both on the commercial market and as open-source software, the market demand seems to be increasing.

Camera with GPS or GPS with Camera?

Looking at the current market offerings there are two out-of-the-box solutions. First, there are a few cameras with GPS capabilities. For now, I am not overly impressed with cell phones that have cameras and GPS receivers as the quality does not seem that great. (Readers: if you have a cell phone that you are happy with, please let me know!) The leader is the Ricoh 500SE camera. This is a well-built, 8.0 megapixel SLR that comes with Bluetooth already installed and a GPS receiver. Simply take a photo and the location information is stored in the image tag (known as the EXIF header). I was not able to get details of the integrated GPS, but the camera does accept NMEA data from other GPS receivers. Therefore, you can use the camera with a top-quality sub-meter GPS like the SX Blue.

Screen shot of Ricoh camera image (from Ricoh website).

The other option is to buy a GPS, or GPS-enabled computer, that has a built in camera. The photos will be of a lesser quality but could be ‘good enough’ for most jobs where you are recording field data for projects. For instance, you might be out checking on damaged trees for a county assessment and you are recording the tree data, including location. At some trees, you may want to take a picture and store this information as well. The advantage of this solution over the Ricoh is that you get the full computer benefits.

Finally, a third path is to use a software that allows you to integrate GPS data and photos. The ESRI folks already have a program, GPS-Photo Link (ArcPad Edition) that allows you to do this, and more will follow suit. I have also come across quite a few links online to folks that have created their own software, but I haven’t tested any. Again, if you know of other software, let me know.

Test of the new Nomad computer with GPS

Recently I tested the Trimble (nee Tripod Data Systems) Nomad Computer with integrated 2.0 megapixel camera. Firstly, I am very impressed with the computer and recommend it to folks who need a powerful and ultra-rugged handheld computer—particularly if you need USB-in capabilities. The camera option has a small camera in the top of the computer, under the weather-resistant see-through casing. The good news is that the camera is easy to use, and has the basic functions such as variable size and quality settings, white-balance, etc. Taking photos and later retrieving them was very straightforward. The bad news is that the photos are not geo-coded even though the computer comes with a decent, SiRF III embedded camera. In fact, I could not find software on the computer for creating geo-coded images. It would seem to me that a rugged field computer with GPS and camera from the factory would come with software for geo-coding standard. Trimble, when will this be available?

Photo from Nomad camera.  Setting was small-size and medium resolution.  Slightly overcast skies and using default settings.

Power levels and GPS receiver quality

Here’s one of the lessons you learn the hard way.   Sub-meter GPS receivers, like the popular SX Blue, keep an internal power source running so the computer can maintain clocks and other functions.  While personal computers do this as well, the drain is much more significant on the GPS receivers.  So, make sure you keep the receiver charged up!  I went to do some field collection and had a dead receiver.  Fortunately, the new SX Blue has a power level LED function so you can monitor the levels.

I haven’t seen this in press before, but my experience is that GPS receivers, whether commercial or high-grade, will not perform as well with low power.  This also includes GPS receivers driven via USB or CompactFlash slots on other computers.  You will have enough power to set the lights off, but the reception suffers.  This may have no scientific validity, and I haven’t conducted controlled tests, but it seems to be the case.  Regardless, keep the batteries charged!

Great free software for calculating your GPS accuracy (DOP)!

In the last blog, I gave an introduction to dilution of precision or DOP and explained when you need to know it and when you don’t. This time, I want to show you a very cool, free program to calculate your DOP values throughout the day. All you need to know is your latitude and longitude and day. The program is called “Planning” and is from Trimble. You can download it here.

To use this program, you need to first enter your position through File > Station. You can use the map feature to get ‘close’ but you really should use the correct latitude and longitude. On this screen, you also set the date and time and duration of observation. Then, you need the satellite almanac information. This is downloaded from the Trimble site as an ‘.alm’ file or you can use an ‘.ssf’ file.

Here we see a plot that shows the total DOP at 10 minute intervals for San Diego (where it is very lovely right now). Looks like 7:30 a.m. is the time to work.

That’s it! Now, play around with the different map features, it is surprisingly easy to navigate. Notice that you can use GPS (United States system) or Glonass (Russian system). WAAS is available but since those satellites don’t affect the DOP, they are not included in the almanac.

This cool screenshot shows the visibility of each satellite throughout the time period. You can turn satellites off and on to clean up the graph.

But wait…if the DOP is based on satellite positions, what happens if you cannot see a particular satellite because of mountains or buildings? Obviously, that satellite is no longer used in calculating the DOP. The “Planning” software doesn’t directly allow you to blank out areas of the sky (but you can turn off certain satellites). However, there is another great program that allows you to show the blocked view based on topography. Stay tuned…

 

What in blazes is ‘dilution of precision’ (DOP) and why should I care?

GPS receivers are so cool because you turn them on, wait a few minutes, click a button, and bingo—there is your location. For most applications, you don’t even need to care how accurate the location is because either accuracy isn’t important to you or you are using maps where the scale is so large, a sloppy error circle wouldn’t show up anyway. By example, the pencil here on my desk makes a mark about one millimeter in diameter. Let’s say you have a GPS receiver that is accurate to about 10 meters (not unrealistic for a Garmin or Magellan). That means that at a scale of 1:10,000 or larger, you wouldn’t see the error plotted on the map.

But what about when location is critical because you are monitoring changes over time, or you have found Flint’s treasure and you don’t want to be digging three feet away and suffering the same fate as Ben Gunn? In that case, you want to record the accuracy as well as the location and that is the DOP factor.

DOP, or ‘dilution of precision’ is a unitless value that relates the accuracy of the satellite measurements based on their positions to the computed solution. Therefore, the lower the DOP, the more similar the two values are and the more ‘accurate’ the value. Since the satellites are constantly in motion relative to your position, the DOP changes as well. The more widely spaced the satellites, the lower (and better) the DOP. The best situation is one satellite directly overhead and several others spread out on the horizon, giving you a wide spread. There are several DOP values commonly reported: PDOP is the position DOP and is based on three coordinates, HDOP is the horizontal DOP based on two coordinates, and VDOP is the vertical DOP which is only based on height.

The DOP value acts as a multiplier to the error of the measurement (the calculated position). That is, with a DOP of 2 and an error of 5 meters, the accuracy would be 10 meters. Because of this, many programs will allow you to set a minimum DOP for data collection. Usually, the default is a value of 6. To get sub-meter resolution, you would need a DOP of 4.

Let’s say you are planning a mapping project and want to increase the DOP of your measurements, there are several things you can do in preparation. The simplest method is to set a minimum DOP and only collect data during those times. Again, the shift in value occurs because the relative spread of satellites is changing. Second, you can occupy one location for a longer time, gathering more data points to average. This usually results in a lowered DOP, though you could increase your average if the satellites get worse. Third, you can chart the satellites for your area and plan on collecting data during the best times. Because the satellites are in geostationary orbits, they will be in roughly the same positions each day for several weeks.

In my next blog, I will discuss a fantastic free program that charts your DOP for you.

The costs and benefits of using field computers and GPS receivers

Recently, I ran into an old professor of mine and we chatted about the use of computers in field geology. Both of us were trained using little more than compasses, 1:24,000 topographic maps and aerial photo interpretation. And we both agreed that students need to be trained in these methods. “So,” he asked me, “when do you decide to spend several thousands of dollars for good field computers?”

The answer I gave is that you bring a computer in the field if you need data handy. Data to read in the field or data to collect in the field. There is a real advantage to processing data in the field so you can shift priorities as you are working. Of course we are always collecting data, but not all data needs to be digested with a computer processor. One advantage I have seen recently is recording repetitive data. If you use a database program with drop-down lists, you are less likely to incorporate spelling errors and you can have the program prompt you for data so you won’t miss key features.

It is also standard these days to use a GPS receiver to locate key locations, but it is not as common to use the devises to track lines or areas. However, with a good receiver, you can often track your moving position directly onto a digitized map, saving time later.

Sounds great, but what is the catch? The obvious answers are that field computers are costly, take up space and add weight, and are totally useless if the battery dies. A less obvious answer is that we run the risk of creating a virtual ideal, even when we are outdoors. I have seen students rely directly on GPS receivers even when the receiver shows them in a gulley when they are standing on a ridge! Or you turn the world into a binary playing field when we know reality is probably more fuzzy.

The bottom line is that field computers and GPS receivers are fantastic tools, but we still need to teach the underlying fundamentals of location and data collection and interpretation. In future blogs, I will outline specific research and teaching projects I have done to illustrate successes with field computers—successes that justify the cost of bringing these tools in the field.

Free GPS software for the rugged handheld PDA

When you buy a Garmin or a Magellan, you are getting a computer + GPS receiver + software. Ready to go! However, if you choose to use a rugged PDA and attach a GPS receiver, you will need some sort of software to read the data and / or store the data and / or plot the data on a map. Today, I will mention two of the many freeware options out there that I actually use and recommend.

There are several add-on features to note when comparing GPS programs, whether freeware or purchased: 1) display position on a map, 2) store individual locations, 3) store tracks, and 4) display other information from the GPS receiver such as the accuracy or location of satellites. In addition, you should also be clear on how the data is stored. Unfortunately, most software stores the data in proprietary format. Fortunately, there are many programs available to convert these formats to a more usable format (such as GPS Babel). So, when you are comparing programs, keep in mind your needs.

The two programs I recommend are GPS Viewer and VisualGPSce (both available from the Walcott Scientific resources website). Neither can store waypoints or tracks or upload background maps. GPS Viewer is a good, simple program to check to see if your GPS receiver is working, and get a location and information on the quality of the signal [dilution of precision (DOP) and percent dilution of position (PDOP)]. In the opening screen, you can scan your device’s COM ports to find the GPS receiver.

Then, you can begin receiving data and follow the data as a stream. Toggling to the other screen shows a map of the satellites, the date and time, latitude, longitude, DOP, and PDOP. Again, I use this program to warm up my GPS receivers and test them. Remember to turn the program off if switching to another program or the COM port will remain in use!

VisualGPSce is a wonderful program that adds much more options, such as a navigation screen and a statistics screen that shows you the standard deviations of your data points. Also, you can save the NMEA codes as a text file if you want the raw format.

Unless I am mapping, these two programs suffice to allow me to use a GPS receiver and test the quality of the data. Neither program takes up much memory or requires a steep learning curve.

Creating databases on a handheld field computer (PDA): Part 2…Monkey Mapper!

In an earlier blog, I discussed some options for building a database for a rugged handheld. If you have no interest in creating a program, but just want to buy a pre-configured database, quit reading. Otherwise, I will lay out an example of a program I created using Visual CE for a researcher who is monitoring monkeys in South Africa with his graduate students. Welcome to Monkey Mapper!

To begin, I sketched out the different types of data so I could plan the table. He wanted from the GPS latitude and longitude and I added date and time. Then, we decided the best route was to create drop down lists of the monkey names and activities. My first step was to set up a table for these attributes. It is o.k. to add extra fields at this point as you can always tap into these later. (This is like what Sean Carroll recently published about DNA and evolution—oops, wrong blog!)

Next, I outlined a logical route for the program to follow. The basics are: 1) operator sees a monkey and pushes a button, 2) the computer snatches the current location and time from the GPS receiver’s stream of data in NMEA format, 3) the operator chooses a monkey name and behavior, and 4) the record is stored in the table. To make the basics work, the troubleshooting begins. In order for the GPS to work, you need to be able to open the COM port. Then, make sure there is a way to close it as well. But, the GPS receiver is constantly streaming out information so how do you control the flow? With databases you use ‘global variables’ to temporarily store data. It is like the barstool next to a loquacious drunk. The patrons may come and go (=stream of data), but to the drunk, all he knows is that there is a warm body next to him, eager to hear his philosophies. The conversations are the snapshots stored in the global variable. Any time you want to store the data, grab it from the global variable. When all is finished, you can go about making the screen look nice, add pictures, etc. Here is the entry screen from Monkey Mapper (*note that the name and behavior of the monkey has been changed to protect the simian).

For ease of use, I set this particular program to save the data as a .txt file. Other options are to synch directly into a database program on the PC, such as Microsoft Access. As I mentioned, I used Visual CE to create this program and have been happy with it. Others have used PenDragon and it is also popular. If you know of another program, please let me know so I can post the info. If you want to see more details, let me know.

Why is importing waypoints into mapping programs so hard?

One of the more frustrating tasks I deal with is figuring out how mapping programs import data. Most will allow for you to hook up a commercial GPS, like a Garmin, and work live or download saved waypoints. But what if you just wanted to bring in a set of known locations? You would think the software manufacturers would make this most obviously useful task easy. The problem is that there isn’t really a standard data format for storing waypoint information.

Underlying all of the mapping software is some sort of geographical reference system. Therefore, each of the data points must have longitude and latitude (or some other referencing). Next, the points will have some identifying tag, like the name or waypoint number. Then, there might be coded information about attributes like elevation or time of record. Finally, there could be information on how the point is displayed (color, icon, etc.). The software should be able to parse this information once it is input.

The logically way for this to work is as a text (.txt) or comma-separated-values (.csv) file. In this format, the data for each site (=record) exists as a line with different information bits separated by commas. The software uses the commas when it is reading the text to gain the information. However, many applications use a proprietary format and therein lies the rub. (I have noticed, many will accept the ESRI standard shape file, so this is an option.)

So, how do you do it? Here is my method: 1) First, figure out the acceptable geographic format. For example, do you need decimal-degrees or UTM or some other standard? 2) Then, within the program make a few random waypoints. 3) Download these points to a file. Typically, the software will download as a text file. 4) Open up this file and *format your data points exactly!* Make sure you have the same number of spaces and any column-header information. 5) Save your file in the same format as the one you downloaded. 6) Go for the input!

This is a bit cumbersome, but I have used it successfully in National Geographic TOPO! and other software. Soon, I will post my favorite software page and I will link some conversion software.