Novatel GPSCard PC Configuration Instructions

WinFrog Device Group: GPS
Device Name/Model: NOVATEL CON (CONSOLE)

NOVATEL INC.

1120 - 68th Avenue N.E.

Device Manufacturer:

Calgary, Alberta, Canada, T2E 8S5
Tel: U.S. & Canada: 1-800-NovAtel
Fax: [phone]
E-mail: [e-mail]

Device Data String(s)
Output to WinFrog:
WINFROG DATA STRING(S)
Output to Device:
WinFrog Data Item(s) and their
RAW record:

Refer to Configuration Details Section
Configuration/Control Telegrams

RTCM (if turned on at Device Level)
POSITION 303

DEVICE DESCRIPTION:

The NovAtel GPSCard

TM

PC Series products are GPS receivers that are configured as
PC cards rather than as stand alone devices, allowing for the unit to be installed
internally in a host desktop computer. Instead of relying on a serial connection (and the
required cabling) to communicate with the computer, GPSCards utilize the PC ISA bus.
GPSCards are also configured with dual RS232 ports allowing for input and output of
data via serial connections, if so desired. These 2 DB9 male connectors allow you to
receive differential corrections from a DGPS receiver or output data to another
computer, with baud rates varying from 300 to 115,200 bps.

The GPSCard

TM

PC Series are 12 channel parallel tracking, C/A code GPS receivers,
utilizing the L1 (1575.42 MHz) frequency GPS signal. The NovAtel custom proprietary
correlater chip, combined with a high performance 20 MHz 32-bit CPU is capable of
measuring satellite code and carrier phase data to compute up to 10 position solutions
per second. Positional data (stand alone or differentially corrected) can be output at a
rate of up to 20 times per second.

For use with WinFrog, these cards are set to output raw Pseudorange and Ephemeris
data as well as internally calculated, differentially corrected positions. WinFrog’s
optional GPS Calculations extension module can combine the raw Pseudorange and
Ephemeris data with up to 5 differential GPS corrections to provide a Multi-Ref position
(See chapter 14 of the WinFrog Users Guide for more details).
The internally calculated position can utilize differential corrections received via the
serial ports or the PC ISA bus.

The GPSCards must be correctly installed and configured before they can be used with
WinFrog. This involves that you follow specific installation procedure, not just simply
installing the card into the computer. These instructions are listed below in the section
entitled Driver Installation.

This device can provide time synchronization using $--ZDA. See chapter 8.

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DEVICE CONFIGURATION INSTRUCTIONS

WINFROG I/O DEVICES > EDIT I/O:

The NovAtel CON (console) device is added to WinFrog from the GPS device group.
The Novatel PC Card dialog box (shown below) appears when the NovAtel CON

(console) device is selected. Within this dialog are various configuration options. The
settings are dependant on the GPSCard that has been installed in the PC.

Name: Enter the name of this GPSCard, or leave the default.
Re-Boot: Enable this option to re-start the GPSCard if it has been shutdown. The re-

boot will take place once you click OK to close this dialog box.
GPS Set: This section allows you to select which GPSCard to use. As detailed below,

you can add up to 3 GPSCards to a single PC. Each card is identified uniquely as
GPS1, GPS2 or GPS3. Select the appropriate radio button (usually GPS1).

Pseudorange Format: Most cards use the default RGEB (new) format.
Program: This window must display the correct .btl file name, as defined by the

GPSCard serial number. Note that all of the .btl files that were updated for the year
2000 week rollover should have the prefix Y2K.

Directory: Type in the appropriate folder name/location, or select the Browse button to
navigate to the appropriate directory where the .btl file is found. When you click Ok to
close this window, the GPS card is “booted” (i.e. started). A message will appear if there
is a problem with booting the card. A common error is experienced when WinFrog tries
to boot the GPSCard while it is already running. The card can be started when the
drivers are installed, and shutting down the card is often overlooked. To manually shut
down the card, go to Window’s Start > Settings > Control Panel > Devices. Highlight the
GPSCard device and select Stop.

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If problems persist, refer to the Configuration Details section below for information on
setting up the GPSCard and installing the required files.

WINFROG I/O DEVICES > CONFIGURE DEVICE:

This device must be configured at the I/O Device window level. In the I/O Devices
window, click the device name to select it, then right-click and select Configure Device.
The GPSSET Configuration dialog box appears, as seen below. This configuration
dialog sets the internal calculation parameters of the NovAtel GPSCard.

Position:

An approximate initial position must be entered to provide the position calculations
with a reasonable starting point. This position should be within approximately 5
minutes in both Latitude and Longitude. Ensure that the “quadrant” signifiers are
correct: N/S or E/W.

Antenna Height:

Set the antenna height mode to one of the two provided options:

Calculated – Along with Latitude and Longitude, the NovAtel GPSCard will
calculate the GPS antenna Geoidal Height (Mean Sea Level). A minimum of four
satellites must be tracked in order to calculate both horizontal position and
height.

Fixed - Fixes the GPS antenna height to the Geoidal Height (Mean Sea Level)
value entered in the

provided entry box. In this mode, the NovAtel GPScard is

able to calculate horizontal positions using a minimum of three satellites.

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Auto\Last Height & Auto\Input Height – No Auto Height options are used by
the GPScard.

Note: Heights entered in the provided entry box must refer to the geoid (Mean
Sea level). In some other WinFrog dialog boxes, heights are displayed with
respect to the vehicle’s selected zero vertical reference point.

Undulation Model:

The Undulation Model can be set to the Internal Table, which uses the NovAtel’s
internal (OSU) geoid model, or Input Value in which case a specific Ellipsoid
separation value can be input. This Ellipsoid separation value is used to calculate
Ellipsoid height from the entered geoidal (Mean Sea Level) elevation, using the
following formula:

h = H + N Where: h = Ellipsoid height (of the antenna)

H = MSL (ie geoid) height (of the antenna)

N = Geoid height (undulation)

Unless you have accurate ellipsoid/geoid separation values from another source,
select the Internal Table radio button.

SV Tracking Elevation Cut Off:

Enter a mask angle value, in degrees. The GPSCard will not use measurements
from any satellites with elevation angles below the angular value input in the
Elevation (angle) Cut Off entry box.

DGPS:

This section of the dialog allows you to set the mode by which the GPSCard will
internally apply received differential GPS corrections.
There are four different DGPS modes: Auto, On, Off and Generate.

Auto: The GPSCard will automatically use differential corrections in its position
calculations, when available. If no corrections are available, the GPSCard will
compute a single point (aka autonomous) position solution.

On: The GPSCard will always attempt to use differential corrections. If no
corrections are available, no position will be computed.

Off: The GPSCard will not use differential corrections in its position
computations, even if they are available. Instead it will always compute a single
point GPS solution.

Generate: The GPSCard will generate differential corrections based on a fixed
reference position. This option is used for Base Stations only.

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Maximum Age (of Corrections): If the GPS mode is set to Auto or On, the
GPSCard will only apply the corrections if the received RTCM data is less than
the specified Max. Age (entered in seconds).

Code: This allows you to define which DGPS reference station will be used, as
defined by its Code. If you don’t know the code of the station being received,
select All, in which case the GPSCard will use any received RTCM data.

RTCM Source: Use the dropdown list to select which RTCM receiving device will
be used to provide the GPSCard with differential corrections. This RTCM
receiver must be interfaced to WinFrog before it will be listed. The RTCM data is
received via a serial connection, and is passed to the GPSCard via the ISA bus.

WINFROG VEHICLE > CONFIGURE VEHICLE DEVICES > DEVICE DATA ITEM >
EDIT:

Adding a NovAtel CONSOLE device to WinFrog provides you with three separate data
items: Position, Pseudorange and Ephemeris. The GPS, CONSOLE, POSITION data
item refers to the position data calculated and output by the GPSCard. The GPS,
CONSOLE, PSEUDORANGE and GPS, CONSOLE, EPHEMERIS data items provide
WinFrog with only raw measurement data. WinFrog’s GPS Calculations extension
module is required to combine these measurements to calculate a position.

WinFrog can use either or both position solutions. Adding the Position data item is
simpler but provides the vehicle with only a single GPS or DGPS position. Using the
Pseudorange/Ephemeris option provides the ability to set up a multiple reference
solution - you can add DGPS correction data from up to 5 different RTCM stations,
which are then combined resulting in 1 weighted mean solution.

No matter which positioning method is selected, you must edit the device to suit the
application, as detailed below. (Note that the Ephemeris data item requires no editing).

GPS, CONSOLE, POSITION
In the appropriate vehicle’s Configure Vehicle - Devices dialog box, highlight the
POSITION data item and click the Edit button. The Configure Position dialog box
appears as seen below:

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The following items are available for configuration:

Calculation:

Set the Calculation selection to Primary or Secondary. Devices set to Primary
calculation are used to provide a vessel position. Note that more than one Primary
positioning device can be added to a vehicle’s device list; data from these devices
will be combined in a weighted mean solution. (See the paragraph on Accuracy
below for more on the weighting of Primary calculation device data).

If the Calculation type is set to Secondary, WinFrog will simply monitor the device’s
data. WinFrog will not use the data from a secondary device in the final solution of
the vehicle’s position.

If auto switching is enabled (see below) a secondary may automatically become a
primary should all the primaries fail.

Use For Heading Calculations:

Select this checkbox if this GPS position is to be used in conjunction with another
GPS device for determination of the heading of the vessel. The vessel’s heading will
be derived by the inverse of the GPS antenna coordinates.

Graphics:

If On is selected, a labeled square will be made visible in the Graphics and Bird’s
Eye displays, depicting the raw (unfiltered) location of the GPS antenna. This
provides a means of comparing raw and filtered positions between different sources.

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Elevation:

If On is selected, the elevation determined by the GPS will be used as the elevation
of the antenna with respect to the WGS84 Ellipsoid. Do not enable this option unless
you are utilizing high accuracy (centimeter level) RTK type GPS positioning.

Accuracy:

The Accuracy value is the expected accuracy (i.e. standard deviation) of the
positioning device. This value is used in the weighting of this device relative to other
primary positioning devices, and in the vehicle’s kalman filtering. The default values
should be changed only if you have confidence that newly entered accuracy values
are more correct than the default values.

You must also be cautious of setting both a Multi-Ref position and a single source
DGPS position as primary positioning devices. This will weight the single position
equal to the 5 positions combined to create the Multi-Ref position.

Code:

Set the Code to coincide with the code parameters that may be associated with the
GPS unit being used, as required when using telemetered GPS data. This is usually
set to 0.

Multiple Position Source Options:

This group box allows you to enable automatic switching of a secondary to primary
should the data from all POSITION and PSEUDORANGE data items set to primary
timeout. The Age entered is the length of time that the secondary will wait in the
absence of data from all primaries, before taking over as primary. This age is only
entered for the secondary.

For example, if the POSITION or PSEUDORANGE data items associated with two
GPS receivers were set to primary and the POSITION or PSEUDORANGE data
item of a third GPS receiver was set to secondary, both primary GPS receivers must
time out before the secondary will become the primary. Upon the recovery of either
of the original primary data items, the original primary will be reset to primary and the
original secondary will be reset to secondary.

Note for the auto switching feature to work, there must be at least one primary and
one secondary enabled. For example, given two data items, one set to primary with
the auto switching disabled and the other set to secondary with the auto switching
enabled, if the primary fails the secondary is not set to primary and the vehicle
positioning stops until the primary data item recovers.

Disable Auto Switching of Primary:

If this data item is not to be involved in the auto switching process, check this
box. As stated above, this data item is then not involved in the auto switching
process in any way.

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