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## Trimble GeoExplorer

### Mapping Procedures

Updated: July 18, 2000

[Getting Started:]{.underline}

1\. Turn unit ON, and wait for position fix.

-main menu, #2 \"POSITION\" to view current position

OR

-main menu, #3 \"GPS STATUS\", #1 \"SATELLITE TRACKING\"

The button at the bottom of the front of the receiver is the on/off
switch. Press it firmly and release to turn on the unit; press and hold
for five seconds to turn it off. To turn it off immediately, press the
on/off button, hold it down, and press the center button simultaneously.

The main menu appears the first time the receiver is turned on, but
subsequently it will display whichever menu was showing when the
receiver was turned off. The menus are nested. To enter a sub-menu,
press the center button. To exit back to the next menu up, press the Esc
button. Use the up and down arrow buttons to scroll through a particular
menu, or to select characters for text. Use the right and left arrow
buttons to move to a new position in a character string when entering
text. A quick reference guide, which comes with the receiver, explains
the buttons and menus in more detail. It's a small (approx. 2"x5"), thin
yellow spiral-bound booklet.

2\. Change configuration, if needed.

> -see \"Configuration Procedures\"

3\. From main menu, select #1 \"DATA CAPTURE\"

4\. From data capture menu, select #1 \"OPEN ROV. FILE\"

-to map a point, collect \"multiple positions\" standing in one place

-to map an area or line, begin walking (keep an eye on \# of positions)

-by default, file names begin with "r" for rover, followed by the month,
date, hour in Universal Coordinated Time (UTC), and a letter. The
letters start with "A" and increment with each new file within the hour.

5.  Select #3, \"CLOSE FILE\" and confirm when feature is completed.

To close the file, scroll to Close File (#3) and push enter. Confirm by
scrolling to yes and pushing enter. If you want to start another file,
push enter on Open Rov. File (this will then have file name: letter,
month, day, hour, B unless the next file is opened in the next hour, in
which case the letter will be A again).

6\. Record GPS FILE NAME & FEATURE TYPE (pt., line, or area) on data
sheet.

7.  Repeat procedures to map another feature.

8.  If collecting features with a data dictionary, it is not necessary
    to record the type of feature collected on a separate data sheet, as
    mentioned in step 6, since the receiver will do it automatically.
    Also, when using a data dictionary, it is not necessary to open a
    new file for each feature. However, you may want to create a new
    file every hour or so, just to prevent the accidental loss of all
    your data (say, if the file becomes corrupted).

9.  Other notes: The external antenna is attached with a cable. The
    receiver has an internal antenna, but using the external antenna
    will increase your chances for tracking four satellites. The antenna
    can be attached to a pole so that you can get the antenna as high as
    possible.

If you want to see if the receiver is tracking satellites, scroll to GPS
Status (#3). Push the diamond button (which is the enter key). Scroll to
Sat Tracking (#1) and push enter. This window will show you how many
satellites the receiver is currently tracking. The number of satellites
being tracked will show in the bottom left corner as figure-eight
symbols. There will be one symbol for each satellite being tracked.
There will be no symbols if there are no satellite signals being
received by the GPS unit. The numbers above the symbols also show which
satellites (identified by number) are being tracked. There will be an
arrow next to each satellite the unit is receiving signals from.

To get back to the main menu when a file is open, choose Main Menu (#4).
This will allow you to check the satellite positions and adjust the
receiver configuration as necessary without closing the file or
abandoning a feature.

The number of points being collected in a file is displayed in the upper
right corner. Points are usually collected at the rate of one per
second. If the number remains constant then there are not four
satellites being tracked or accuracy requirements are not being met. If
the number is going up, then at least four satellite signals are being
received within the specified accuracy settings. Collect points for 3 to
4 minutes. If the receiver loses one or more signals, or the accuracy
goes down, then the unit will cease collecting points. Try waiting until
the receiver picks up the signals again and begins collecting more
points. Try to get a minimum of 25 points if you are having trouble with
satellite signals fading in and out. The more points you collect, the
more accurate the position will be (this is because the points are later
averaged). DO NOT MOVE FROM YOUR LOCATION ONCE THE RECEIVER BEGINS
COLLECTING POINTS -- DOING SO WILL DECREASE THE POSITIONAL ACCURACY OF
THE FEATURE BEING COLLECTED.

[Creating a Data Dictionary]{.underline}

The Data dictionary editor is in Pathfinder Office under Utilities in
the command bar.

1\. In the Data Dictionary Editor window, select File / New.
Alternatively click on the New File tool.

2\. Enter a name for the data dictionary into the Name field.

3\. Enter a description of the dictionary into the Comment field.

4\. Press the New Feature button and create a feature. The feature
appears in the Features list box.

To create a new feature:

1\. Press F3 or click on the New Feature button. The New Feature dialog
appears.

2\. Enter a name for the feature in the Feature Name field.

3\. Optionally enter any comments you have into the Comment field.

4\. Select the appropriate feature classification (point, line, or
area).

> 5\. Press OK. You return to the main window and the feature you
> created is in the Features list box.
>
> 6\. If your GIS or CAD system only uses the first eight characters of
> feature names, select Options / Unique Feature Names to ensure that
> the Data Dictionary Editor checks for unique feature names.

You are now ready to add attributes to the feature.

5\. Press the New Attribute button and create an attribute. The
attribute appears in the Attributes list box, and information about it
appears to the right.

To create a new attribute:

1\. Select the feature that the attribute will belong to.

> 2\. Press F7 or click on the New Attribute button. The New Attribute
> Type dialog appears.

3\. Select the Type of attribute you want for the feature you
highlighted.

> 4\. Press OK. Enter the appropriate dialog for defining an attribute
> of the type selected. For example, if you selected Numeric, the New
> Numeric Attribute dialog appears.
>
> 5\. Define the new attribute by entering a name and values in the
> appropriate fields. For example, within a feature called "road", you
> may define an attribute of "surface" as a menu type, with possible
> values of "paved", "gravel", or "dirt". With menu attributes it is
> often desirable to have a category called, "other".
>
> 6\. Press OK. You return to the main window, and the attribute is
> added to the list of attributes for the current feature.

6\. Create the remaining attributes for the feature.

7\. Create the remaining features, creating attributes for each feature
in turn.

8\. Select File / Save or click on the Save File tool:

This saves the data dictionary you created. The Save As dialog appears.

9\. If desired, edit the default name in the File Name field to the name
you want.

10\. Press OK to save the file to disk. You return to the Data
Dictionary Editor window, which displays the data dictionary.

Use the Data Transfer Utility (described in more detail in the next
section) to transfer the data dictionary to the datalogger.

When collecting data while using a data dictionary, it is better to
configure the receiver not to collect positions outside of any features.
This option is under Main Menu, #6, Configuration; #1, Rover Options:
Set "Not in Feature Rate" to "Off".

[Using the Data Transfer Utility]{.underline}

To start the Data Transfer Utility from Windows 95:

1.  Press the \"Start\" button.

2.  Select *Programs/Pathfinder Office/Data Transfer* from the pop-up
    menu.

-If communication is established successfully, the Data Transfer user
interface appears. The *Status* field contains the name of the connected
datalogger.

-If communication could not be established, check that the cables are
properly connected and that the datalogger is in File Transfer mode, if
applicable.

Alternatively, to start the Data Transfer Utility from Pathfinder
Office:

1.  Select the Utilities menu.

2.  Choose Data Transfer.

If the cable is attached properly, the computer should then connect to
the GPS receiver.

Transferring Files

-   To transfer data files from a datalogger to an office computer:

1\. Select *Data* in the *Data Type* field.

2\. By default, data files are received by the current project
directory. Press **Destination**

**Directory** to change the directory if required.

3\. Select one or more files to be transferred by highlighting the file
names in the *Available Files* field. Press **Add** to add them to the
*Selected Files* field.

4\. Press **Transfer**.

# Transferring Data Dictionaries

The default Data Dictionary file extension is \*.DDF.

*Important:*

*Before sending a data dictionary to a GeoExplorer I, you must delete
all rover files in the receiver. This is not a problem with the
GeoExplorer II or III.*

-   To transfer a data dictionary from an office computer to a
    datalogger:

1\. Select *Data Dictionary* in the *Data Type* field.

> 2\. By default, data dictionary files are sent from the same directory
> form which the last
>
> data dictionary file was sent. Press **Source Directory** to change
> the directory if required.

**Note** - Source and destination directories always refer to the
**office** computer.

3\. Select the data dictionary file to be transferred by highlighting
the file name in the

*Available Files* field. Press **Add** to add it to the *Selected Files*
field.

**Note** - You can only send one data dictionary to a GeoExplorer. An
existing data dictionary will be overwritten.

4\. Press **Transfer**.

5.To verify that the dictionary is properly loaded, under Main Menu,
select #1, Data Capture; then #6, Dictionary. It should show the name of
the dictionary just transferred from your PC.

[Differential Correction:]{.underline}

1.  You will need to retrieve base files from a GPS base station within
    300 miles of where you collected your data. A good site for finding
    base station files on the Web is *www.fs.fed.us/database/gps/.* The
    clickable map of community base stations (CBS) is especially easy to
    use for downloading base files. Be sure to download all the hourly
    base files covering the time during which you collected data. Note
    that all times recorded in your receiver (and the base files, too)
    are in UTC time.

2.  You will probably find it easier to manage your data if it's
    separated into several directories. Put your rover SSF files in one
    directory, and the base SSF files in another. When you create
    differentially corrected files (COR) place them in a third
    directory, with export files (see next section) in a fourth
    location. Get in the habit of placing all your data in a directory
    path outside the Pathfinder default data.

3.  Run the differential correction utility in Pathfinder Office under
    the Utilities menu. Select the appropriate rover and base files, and
    output directory for the corrected file(s). This utility will not
    run without the dongle (hardware key) in the parallel port of the
    computer.

[Export:]{.underline}

Select an export setup under Utilities, Export. For output to shapefiles
(recommended) use the Sample ArcView Shapefile Setup as a starting point
and choose Change Setup Options. Under the Coordinate System tab, be
sure to set the coordinates to the correct UTM zone (see table below),
and the datum to NAD27 or NAD83 (whichever your park is using). Under
the Format tab, select Features - Positions and Attributes as the Type
of Data to Export. Take all other defaults. Alternatively, to output GPS
positions rather than features, choose Positions Only.

> zone 10 longitude 126°W to 120°W
>
> zone 11 longitude 120°W to 114°W
>
> zone 12 longitude 114°W to 108°W

The shapefiles can be viewed and edited in ArcView. Spikes are sometimes
a result of multipathing (when a reflected satellite signal interferes
with the direct signal), sometimes from poor PDOP. Regardless of the
cause, these anomalies should be removed, but with caution to avoid
creating fictitious data.

[Changing Batteries:]{.underline}

1\. Remove back cover and replace batteries.

-return used batteries

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-data will not be lost if batteries are replaced within 2-3 minutes

2\. From main menu, select #6 \"CONFIGURATION\"

3\. From configuration menu, select #10 \"BATTERY USAGE\"

4\. Select \"RESET TIMER\" and ESC back to main menu.

Use this procedure to check battery status, don\'t select \"RESET
TIMER\", ESC instead. (batteries last 3-4 hours)

There are two battery choices; four AA batteries or a camcorder batter.
The AA battery pack slides into the back of the GPS receiver. They do
not last as long as the camcorder battery (about 3 or 4 hours for AA
batteries and about 7 or 8 for a camcorder battery). The camcorder
battery is attached by a clip at the end of a cable. The other end of
the cable attaches to the outlet on the bottom left side of the
receiver. A green light next to the connection should be on if the
camcorder battery is providing power to the receiver. Make sure the
receiver is always receiving power, even when the unit is not on. Your
data could be lost if the unit is without power for a number of hours.

[GeoExplorer Configuration Procedures:]{.underline}

It is critical to map accuracy that GPS units be configured properly.
Factors such as time of day and forest canopy can have a dramatic effect
on GPS accuracy. To help ensure optimum results, **[consult GPS charts
daily under the Quick Plan utility and check GPS configurations
throughout the day.]{.underline}**

**To change GPS configuration:**

1.  From main menu, select #6 \"CONFIGURATION\"

2.  From configuration menu, select #1 \"ROVER OPTIONS\"

3.  From rover options menu, select the parameter to change:

> Pos Mode
>
> 2D Alt
>
> Elev Mask
>
> SNR Mask
>
> PDOP Mask
>
> PDOP Switch
>
> Antenna Ht
>
> Also, use Not in Feature Rate: Off, if collecting features)

4.  From rover options menu, Esc to main menu and wait for position fix.

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What if I can\'t get enough satellites?

>  Use Quick Plan GPS charts and collect data during best times.
>
> Lower \"SNR Mask\" to 4, 3, or 2.
>
> Lower \"Elev Mask\" to as low as 8.
>
>  Change \"Pos Mode\" to \"Auto 2D/3D\"
>
> and set \"2D Alt\" to current elevation.

What if I get satellites but I still can\'t log positions?

This is probably because the PDOP is higher then the

PDOP mask. Check main menu, #3 \"GPS STATUS\", #1

\"SATTELITE TRACKING\" to check current PDOP.

>  Use GPS charts and map during best times.
>
> Raise the \"PDOP Mask\" and \"PDOP Switch\" to 10, 12, or higher.
>
>  Change \"Pos Mode\" to \"Auto 2D/3D\" and set \"2D Alt\" to
> current elevation.

Examples of Possible Configurations:

** Configuration 1:**

Pos Mode 3D

2D Alt (default)

Elev Mask 15

SNR Mask 5

PDOP Mask 6

PDOP Switch 6

** Configuration 2:**

Pos Mode 3D

2D Alt (default)

#  Elev Mask 10

SNR Mask 4

PDOP Mask 9

PDOP Switch 9

** Configuration 3:**

Pos Mode 3D

2D Alt (default)

Elev Mask 8

SNR Mask 2

PDOP Mask 15

PDOP Switch 15

** Configuration 4:**

Pos Mode Auto 2D/3D

2D Alt(best estimate of elevation in feet)

Elev Mask 12

SNR Mask 3

PDOP Mask 10

PDOP Switch 10

[Other Information:]{.underline}

1.  The receivers may be set up to display data in a variety of
    coordinates. However, this does not affect the coordinates in which
    the output data is stored. That is determined when exported GPS
    files (say, to a shapefile).

2.  Data collected in files need to be corrected in order to calculate
    an accurate position. Uncorrected positions can be up to 100 meters
    off, although since Selective Availability (the random error in the
    civilian signal) has been set to 0 (zero) since May, 2000,
    uncorrected data is usually within 5-10 meters.

3.  The receivers are not waterproof.

4.  Do not block the external antenna when trying to record a file. You
    may have to move around to try to get the most unobstructed view of
    the sky. Heavy canopy, or areas blocked by steep slopes can make
    collecting points difficult.

5.  Use Quick Plan, the mission planning program with Pathfinder Office,
    to print planning charts showing when the greatest number of
    satellites are available in the area.

6.  To set the local time on the receiver, subtract the appropriate
    number of hours difference between your time zone and UTC time. (The
    latter doesn't change with daylight time.) This is under Main Menu,
    Configuration, Date & Time. For example, Pacific Daylight Time is -7
    hours from UTC. See the Web page at
    *www.marineweather.com/utcgmt.htm* to determine the correct hour
    differential for your time zone.