Gringo SoftwareGringo SoftwareIf you own an eMap, an eTrex Legend (or maybe another eTrex model), a GPS 76, a GPSMAP 76, a GPS V, or possibly another receiver, and have experienced CheckSum errors when logging Rinex data, try the new version, accessible from the download section.
Also new in Version 2.0.0:
Have you ever wondered if it would be possible to post-process the raw satellite measurements, to improve the positioning accuracy of your receiver ?
If so, then you've probably checked on the list of Frequently Asked Questions at the Garmin web site, or you might have posted a question to the sci.geo.satellite-nav news group. In either case, you will probably have found that post-processing is not possible with any current hand-held consumer-grade GPS receiver, since none of them is capable of logging the raw measurements.
Well GRINGO could be what you're looking for.
What is GRINGO?GRINGO (GPS RINEX Generator) is a program which records the raw receiver measurements (pseudoranges and, optionally, carrier phase measurements) from 12-channel Garmin GPS receivers in RINEX format.
It was developed using a Garmin GPS 12XL (software version 2.01), and
has since been found to work in the same manner with other
Garmin models and software versions. It is likely that it will work
in the same way with most models using the same 12-channel engine.
The output from GRINGO is a properly formatted RINEX file, containing the decoded data. This file is created in real-time, from data transmitted from the GPS receiver's data port to a serial port on your computer.
With the appropriate processing software, a RINEX pseudorange data file can be combined with data files from other receivers, to measure the vector between the receivers to a higher accuracy than would be possible using the stand-alone coordinates of the two receivers. Depending on the precision of the pseudoranges and the distance between the receivers, relative positioning accuracies of the order of 10 m or better can be achieved (The authors of GRINGO do not guarantee any level of precision for the decoded data, as many factors can influence the performance of a GPS receiver).
GRINGO can output the receiver's carrier phase measurements in addition
to the pseudoranges. Since version 1.3.1, the full (integer + fractional
part) carrier phase is logged, making centimetric positioning possible
under the right conditions.
What computers will GRINGO work on?
GRINGO is a Visual Basic 5 program, which was developed for the Windows 95 operating system. It will not run on earlier (16-bit) versions of Windows. It runs on Windows98, and probably works on Windows NT (see the note below).
NOTE: Since version 1.3.1, the probable reason why GRINGO would
not work on NT has been corrected, but I have not had a chance to test
it on an NT platform. If anyone is able to test the demo on an NT
platform, I would be very grateful to hear whether it now works.
(UPDATE: No reports yet from NT users, but Windows 2000 users have
reported success, so I am optimistic that the NT problem has gone)
GRINGO is a commercial product of the Institute of Engineering Surveying and Space Geodesy (IESSG) at the University of Nottingham. The downloadable program will run in demonstration/evaluation mode indefinitely, until it is fully activated by registering it with the IESSG. In demonstration/evaluation mode, the program will perform all of its normal functions, but will shut down after 1 minute of data logging. This mode of operation is provided to allow potential users to satisfy themselves that the program
Since the data from the Garmin receivers arrives on the computer's serial
port at a high rate, and since the decoding, checking and reformatting
in real time is computationally demanding, GRINGO will not work
on all computers. To give an indication, GRINGO was developed on a 133
MHz 486 'bitza' PC (roughly equivalent to a 90 MHz Pentium), and will work
quite satisfactorily on that platform. It has not been found to work on
any 66 MHz 486 PC to date. On the other hand, a 233 MHz Pentium II has
so much spare capacity that it hardly notices GRINGO! Some (older) Pentium
PCs, while appearing to have the processor speed to cope, have serial ports
which seem too 'slow' to keep up. It is therefore not possible to give
firm minimum requirements for a suitable PC system. For this reason, GRINGO
is provided in demonstration/evaluation mode to allow potential users to
verify that their hardware will run the program successfully. It is expected
that any PC which can keep up with the data decoding for 1 minute will
operate successfully indefinitely.
The data file produced by the demonstration/evaluation version of GRINGO
will contain up to 60 measurement epochs (if 1-second logging is selected).
The fully activated program would produce an identical file for this minute.
Potential users can therefore use the outputs from the demonstration/evaluation
version to satisfy themselves that GRINGO output files are useable with
their chosen post-processing software, and that they produce the results
that are expected of RINEX data.
Garmin have provided a detailed description of most of the protocols supported by the Garmin Interface. However, GRINGO uses undocumented records, which the authors have attempted to interpret.
It should therefore be treated with caution!
Users should pay particular attention to the advice given by Garmin in the FAQ section of the Garmin GPS Interface Specification. Garmin state that undocumented protocols should not be considered safe, and are intended only as testing aids for their engineering and manufacturing departments. They go on to state that these testing aids are not necessarily implemented in the same way in every product. We should interpret that to mean that future software versions could cease to support the necessary records, or alter their format so that GRINGO will not work. It is also possible that GRINGO's authors have misinterpreted these records, and potential users should satisfy themselves that GRINGO performs as required, before purchasing the full product. As a final word of caution, Garmin state that some testing aids may have side effects which are undesirable for anything but testing.
Having noted all of that, it should be pointed out that numerous tests have been performed to validate the recorded data, and so far it appears to behave exactly as expected of pseudorange and carrier phase data, with no 'undesirable side effects'.
It is also interesting to note that Garmin's
answer, to the question of whether post-processing is possible with
Garmin handheld receivers, states that it is not possible, since
the receivers do not internally store the necessary pseudorange
data. This answer does not address the possibility that the necessary information
is output on the data port. So by reading between the lines, it could be
argued that Garmin have not officially denied this possibility.
P4 is a Pseudorange and Phase Post-Processor which is distributed free-of-charge to purchasers of GRINGO. Although the RINEX output from GRINGO should be recognised by any post-processing package capable of handling RINEX data, many GPS post-processing packages are intended for carrier phase computations and are unnecessarily sophisticated for the task of pseudorange post-processing. P4 was originally developed for the task of handling RINEX files of pseudorange data. It provides all the options necessary to compute Differential (DGPS) or stand-alone positions, whether the receiver is static or mobile. It provides a statistical and graphical analysis of the resulting positions, as well as providing details of the observations used in the computations (such as the DGPS corrections and the range residuals). Since the development of a carrier phase version of GRINGO, P4 has been developed to cope with carrier phase data. The option to use the phase data to smooth the pseudorange data, and thereby improve the precision of the pseudoranges, has been added. More significantly, the option to process a single static baseline using purely the carrier phase data has also been added. The program has retained its simple interface, but the carrier phase functionality offers the possibility of measuring baselines to a decimetre or better.
Although distributed free of charge, unless P4 is installed in the same directory as an activated copy of GRINGO, it will only run in demonstration mode. In this mode you can process 1 minute of pseudorange data, and the carrier phase options will be disabled. If P4 finds an activated copy of GRINGO, it will be fully functional.
P4 is a Windows 95/98/NT/2000/XP program, with an easy-to-use graphical
interface.
How do you obtain the Demonstration/Evaluation version of GRINGO?
If you have not previously downloaded GRINGO, you should download the full GRINGO setup disk. This should be unzipped to a temporary location. To install GRINGO, run SETUP.EXE from within Windows.
If you have not previously installed a Visual Basic 5 program, you will probably need to download the VB5 Runtime files (download to a temporary location, then run the .EXE to install the runtime files).
If you have already installed a copy of GRINGO, you can obtain the latest
version by downloading just the GRINGO
Executable, which should be unzipped and copied to your GRINGO installed
directory,
eg. C:\Program Files\GRINGO.
The setup program for P4, the Pseudorange and Phase Post-Processor, is configured on the basis that you already have an installed copy of GRINGO, and it leaves out installation files which are common to both programs. Unless you have installed GRINGO already, P4 may not work, even in demonstration mode. Download this file and unzip it to a temorary location. Run SETUP.EXE, and BE SURE TO SPECIFY THE DIRECTORY CONTAINING YOUR COPY OF GRINGO AS THE INSTALLATION DIRECTORY FOR P4. If you have already installed P4, you can obtain the latest version (1.2.11) by downloading just the P4 Executable, which should be unzipped and copied to the directory containing your installed copies of GRINGO and P4.
The current version of GRINGO is 1.3.3 (see history file). The current version of P4 is 1.2.11 (see history file).
***Beta Release***
A Beta release of GRINGO 2.0.0 is also available (see the history file). To use this version, you must first download and install the full GRINGO setup disk above (unless you've already done so). The executable (DGRINGO) should be unzipped into the same folder as your existing copy of GRINGO, and you should then add a shortcut to DGRINGO.EXE as necessary. If you have activated an earlier version of GRINGO, this Beta release will work with your existing activation files. A brief description of the new features is given here.
To process data from this version, you will also need a new version of P4. This version adds support for the changes to Rinex 2.10, as well as a large number of other improvements (see the history file). If you've never installed a copy of P4 before, you will first need to install the full P4 setup disk. Then simply unzip the executable (DP4) into the same folder as GRINGO and P4, and add a shortcut to DP4.EXE. It will work with your existing activation files. With this release there is also now a User Guide (Adobe Acrobat 5 PDF) at long last!
Please try out these beta versions and e-mail any comments that you have. Please pass on any comments about the P4 User Guide as well.
How do you obtain the full version?
The demonstration/evaluation version of GRINGO can be 'activated' to turn it into an unrestricted version by registering it with the IESSG (e-mail). Activation costs £65 (UK pounds), excluding VAT, for the Pseudorange version, or £100 excluding VAT for the full Carrier Phase and Pseudorange version. For these amounts you will receive a unique password. Entering this password will result in an 'activated' installation, which will be locked to a single disk. Although GRINGO provides options to permit its transfer to other disks (eg to a laptop for use in the field), a single activation will only work on one computer at any one time. When the necessary activation files are transferred to another computer, the original installation will revert to demonstration/evaluation mode, until such time as the activation files are transferred back.
VAT at 17.5% will be charged to all UK purchasers. Purchasers from the rest of the EU will be charged VAT unless you can provide a company VAT registration number at the time of purchase. Purchasers outside the EU will not be charged VAT.
Payment can be made by Cheque, drawn in UK £, payable to the University of Nottingham, for the sum of £65 + VAT (or £100 + VAT for the Carrier Phase version), which should be sent to
'GRINGO'
IESSG
The University of Nottingham
University Park
Nottingham
NG7 2RD
United Kingdom
Alternatively, the University can accept credit card transactions (VISA and Mastercard only) and, for UK buyers, Switch cards. If you wish to pay this way, please send the name and address of the cardholder, the card number and the expiry date. For Switch transactions, please also send the Issue Number.
The instructions in this section should show you how to get GRINGO started
as quickly as possible, once you have downloaded the setup disk. The program
interface should be reasonably intuitive, but on the first run you may
find it useful to follow these instructions. More details on each of the
options are provided elsewhere in this document, and are linked to from
the relevant points below. You don't need to follow these links for a quick
start.
Software Activation
The downloadable version of GRINGO will run in demonstration/evaluation mode until it is 'activated'. To activate your copy, there are 2 steps that you must follow.
Click on the button next to '1. Registration'. This step will generate a unique serial number for your installation, but your copy of GRINGO will still only run in demonstration mode. GRINGO will then display a message advising you of the serial number it has generated, and giving the name of a log file where the serial number has been recorded.
This step is necessary so that a unique password can be generated by the program authors to activate your installation. The password will ONLY activate the ONE copy of the software which has the unique serial number generated by this step. If you subsequently reinstall the software, or install the downloaded file on another computer, a different serial number will be generated by the Registration process, so the activation password will NOT work on this new installation.
You should now contact the authors with the serial number of your installation. Once payment has been received, you will be sent a Password to activate your installation. This password will only work ONCE (so you will not need make a permanent record of it), and it will not be any use to anyone else (so you don't need to keep it secure). With this password, you can now proceed to step 2.
When you clear the message advising you of the installation's serial number, another screen will appear that will allow you to enter the activation password given to you by the program's authors. If you have not yet obtained a password, you may click on the button next to 'Continue in Demonstration Mode'. Each time you start GRINGO again, this screen will reappear, to prompt you for the activation password.
When you enter the password, your copy of GRINGO will be activated, and will now log RINEX data without any time restrictions.
The password you are given will, depending on the payment received, activate either a Pseudorange-only copy of GRINGO, or a Carrier Phase and Pseudorange version. The functionality of P4 will be matched to your copy of GRINGO. If you purchase the Pseudorange-only version, P4 will not perform phase smoothing or carrier phase solutions. If you purchase the carrier phase option, both of these functions will be enabled.
Things you should know about an activated copy of GRINGO
The 'Activation' process generates a hidden subdirectory underneath the installation directory (named GRINGO.745). This subdirectory contains the 'activation files' for your installation. Think of these activation files as a software 'Dongle'. If GRINGO finds valid activation files it will run without restriction. If the files are not present, or are invalid, GRINGO will run in demonstration mode.
These activation files are unique to the hard disk itself, and to the location of the installation within that hard disk. You cannot use normal DOS or WINDOWS commands to move your GRINGO installation.
Do NOT delete, move, rename, or otherwise change this subdirectory, as you will LOSE your activation files, and your installation will revert to demonstration/evaluation mode. The only way to reinstate your activation files would then be to re-register your copy, and purchase another password.
You can backup your hard disk without affecting the installation, but restoring your hard disk WILL NOT reinstate lost activation files.
The ONLY way to transfer your copy of GRINGO to another location on your hard disk, or to another computer, is to use the built in functions to 'Export' and 'Import' your activation files. These functions do not perform a simple DOS copy of the GRINGO.745 subdirectory. They carry out a number of steps which create a new installation, activate it, and then deactivate the original installation. Since version 1.3.3, a new option, 'Generate Password' has been added. This will create an activation password for another installation, and will deactivate the original installation. This could be useful if you wish to transfer your installation to a remote machine, where it is impractical to send a floppy disk. For instance, if you set out to gather data in the field, but forget to bring your activation floppy disk with you, you can 'register' the field copy (to generate a serial number', then phone the office to get someone to generate a password from your office installation.
The Export function is available under the 'File' menu option on the main GRINGO screen (for an inactive installation, this option is greyed out, naturally). You will be prompted to locate a drive and (optionally) a directory for the exported files. GRINGO will create the hidden GRINGO.745 directory as a subdirectory of the location you choose.
The Import function is available on the Registration screen for any installation which has either not been registered, or which has been deactivated by exporting the activation files. You will be prompted to locate a drive and (optionally) a directory to import the activation files from. GRINGO will assume that the hidden GRINGO.745 directory is a subdirectory of the location you select.
When the Import or Export function is successfully completed, GRINGO generates a message to confirm the new location of the Activation Files.
The main purpose of these functions is to give you the option to transfer your activation files, via a floppy disk, to another PC, such as a laptop for use in the field. If you select a floppy disk as the export destination, you should be aware that
NB. The Import function is also available on the serial number entry
screen. However, if you have already requested a password for the serial
number of your installation, you should NOT select the Import function
at this stage, as it will destroy the password for your installation. This
would mean that when you receive the password for that serial number, it
would not be able to activate your copy. The Import function is provided
at this stage for one reason only. As described above, for users who have
previously activated a copy of GRINGO, and subsequently exported the Activation
Files, the correct procedure to reactivate their copy is to Import the
Activation Files at the Registration Screen. However, if the user ACCIDENTALLY
registers his copy again at that stage, GRINGO would then jump straight
to the serial number entry screen each time the program is started. The
Import function on that screen can then be used to destroy the accidental
registration. If you select the Import function at this stage, GRINGO will
warn
you that the Registered Serial Number will be destroyed, and ask you to
confirm the action.
Accessible from 'File', 'Program Options', this screen allows you to setup the parameters of the serial interface between your computer and the Garmin receiver, and allows you to set some logging options. Once GRINGO has started to log data, this screen is not available, so to change these options you must stop logging data.
In the 'Serial Port' frame, you can select the serial port to match the socket that your receiver is connected to. For instance, if your mouse is connected to Com1, you could connect your Garmin to Com2, and select Com2 on this screen. When you try to log data on the selected com port, GRINGO will check to see whether any other software, such as a mouse driver or a modem driver, already has control of the port. If it does, you will receive a message that the selected port is unavailable. Once a port is selected, the chosen port is recorded in the GRINGO.INI file, and is used as the default port the next time the program is launched.
The Serial Port Buffer size specifies, in bytes, the number of characters that can be received on the serial port without having to be processed by the computer. Depending on the number of satellites visible, the Garmin receiver may be transmitting up to 2 mb per hour, so the default (and maximum) buffer size of 32 kb will allow something of the order of 1 minute of data to accumulate on the serial port before it needs to be read and processed. If the computer does not retrieve the data on the serial port before this buffer fills, you will lose data. This means that you should only lose data if some process on your computer takes over the processor completely and prevents GRINGO from executing for more than 1 minute. In practice, you will probably never need to change this value from the default of 32 kb. It may be useful as a means of getting certain serial ports to work properly under 'difficult' situations.
GRINGO uses a double buffering technique, so that whenever characters arriving on the serial port trigger a response from GRINGO, the first thing it does is to read the contents of the serial port (hardware) buffer into a secondary (software) buffer. This secondary buffer is then the data source for all of GRINGO's processing. The Port Receive Threshold tells GRINGO how often it should divert its attention from processing the data already in the software buffer, and retrieve the data from the hardware buffer. The default value of 20 means that every time more than 20 characters have arrived in the hardware serial port buffer, GRINGO must stop whatever it is doing, and go and empty the hardware buffer into the secondary software buffer. If this value is too low, GRINGO will spend all of its time going backwards and forwards to the serial port to collect data. If this value is too high, GRINGO becomes less efficient at emptying the hardware buffer into the software buffer (the process takes more time, byte-for-byte), so the overall program speed is reduced. The default value of 20 has proven to be a good compromise on computers tested to date.
It should be noted that these two parameters are only likely to be significant on (older) computers which are marginal in terms of hardware performance. On a 200 MHz Pentium for instance, you will probably not notice any difference in performance by changing these parameters. If you make changes to either of these parameters, they are recorded in the GRINGO.INI file, and are then used whenever GRINGO is run.
In the 'Data Logging Options' frame, you can choose not to record pseudorange observations which have a signal-to-noise ratio below a certain threshold. RINEX uses a scale of 1 (worst) to 9 (best) to describe the quality of the measurements, as determined by the received signal-to-noise-ratio. The RINEX-recommended minimum is 5, which means that observations with a signal-to-noise indicator below 5 should not be used in data processing. The default value for this parameter is therefore 5, but there is no reason why you should not set this to 1, record everything, and use your processing software to filter out the poorer observations.
Garmins do not output a value in this RINEX scale. They do however output a value which corresponds to the signal strength bars displayed on the Garmin screens. An analysis of these values, and their correspondence with the height of the signal strength bars, was carried out to determine an empirical scale for the determination of the RINEX quality indicator. The value of 5 was chosen, somewhat arbitrarily, to match signals which reach the second horizontal grid line on the GPS12XL signal strength display.
Synchronise PC Clock and Local Offset
These parameters allow you to use your Garmin receiver to keep your PC's internal clock aligned to UTC within a second or so. If 'Synchronize PC Clock' is checked, then whenever GRINGO starts to log data, your PC's internal clock will be set to UTC, plus or minus the number of hours specified in 'Local Offset'. So, for instance, if your local time zone is British Summer Time, which is one hour ahead of GMT (UTC), you should select +1 in the 'Local Offset' box. There is no provision for non-integer offsets as yet. Please note that GRINGO will not continually synchronize your PC's clock, but will set the clock once, at the beginning of the data logging session. During long data logging sessions, experience has shown that the PC clock may jitter by a second or more from the initial setting. Furthermore, the Garmins do not output a precise and accurate 1 pps signal. GRINGO is simply using a data timetag which appears to be output within a second or so of real time.
As with all other Program Options, if these parameters are changed,
the new values are recorded in GRINGO.INI,
and are used whenever GRINGO is run.
The GRINGO.INI file is a plain text file which is located in the GRINGO software directory. It stores the last-used values of a number of key parameters, which are subsequently used as default values when the program is next started. An INI file is used in preference to entries in the Windows Registry, to allow you to copy these settings to another computer without the inconvenience of having to export and import sections of the Registry. The GRINGO.INI file which is distributed with the downloadable program is as follows:
[gringo]
ObservingAgency=My Agency
MarkerName=My Marker
MarkerNumber=1
Observer=My Name
ReceiverSerialNumber=00000000
AntennaSerialNumber=00000000
AntennaType=My Antenna
CommPort=1
SerialPortBuffer=32760
LoggingInterval=1
ReceiveThreshold=100
DataDirectory=C:\Program Files\GRINGO\logs
SNRThreshold=5
SyncClock=0
The following sections describe the entries in GRINGO.INI.
These entries are accessed and updated by the RINEX Header Information screen. They provide information which is reproduced at the top of the output RINEX file, to describe the observer, the equipment used, and the observation session. GRINGO reads these values in whenever the RINEX Header Information file is displayed. Whenever you type new values into the RINEX Header Information screen, the changes are immediately incorporated into the GRINGO.INI file. This way, if you always use the same receiver and antenna, then you only need to enter their serial numbers once, and GRINGO will remember them for the next time.
Station identification string. The first 4 non-blank characters of the string are used in the creation of the default filename for the logged RINEX data. This string is displayed in the RINEX header screen when the logging session is started, and any changes made to the displayed string will be written back to the INI file.
Syntax
MarkerName=60-character string
If MarkerName is not present in the INI file, the parameter defaults
to a blank string.
Station identification number. This number is written to the header of the RINEX file. This number is displayed in the RINEX header screen when the logging session is started, and any changes made to the displayed number will be written back to the INI file.
Syntax
MarkerNumber=20-character string
If MarkerNumber is not present in the INI file, the parameter defaults
to a blank string.
Observer's identification string. This information is written to the header of the RINEX file. This string is displayed in the RINEX header screen when the logging session is started, and any changes made to the displayed number will be written back to the INI file.
Syntax
Observer=20-character string
If Observer is not present in the INI file, the parameter defaults to
"My Name".
Observer's Agency identification string. This information is written to the header of the RINEX file. This string is displayed in the RINEX header screen when the logging session is started, and any changes made to the displayed number will be written back to the INI file.
Syntax
ObservingAgency=40-character string
If ObservingAgency is not present in the INI file, the parameter defaults
to "My Agency".
Serial number of GPS receiver. This information is written to the header of the RINEX file. This string is displayed in the RINEX header screen when the logging session is started, and any changes made to the displayed number will be written back to the INI file.
Syntax
ReceiverSerialNumber=20-character string
If ReceiverSerialNumber is not present in the INI file, the parameter
defaults to a blank string.
Serial number of GPS antenna. This information is written to the header of the RINEX file. This string is displayed in the RINEX header screen when the logging session is started, and any changes made to the displayed number will be written back to the INI file.
Syntax
AntennaSerialNumber=20-character string
If AntennaSerialNumber is not present in the INI file, the parameter
defaults to a blank string.
Description of Antenna. This information is written to the header of the RINEX file. This string is displayed in the RINEX header screen when the logging session is started, and any changes made to the displayed number will be written back to the INI file.
Syntax
AntennaType=20-character string
If AntennaType is not present in the INI file, the parameter defaults
to a blank string.
These parameters control serial port characteristics, and are described in Program Options. They have the following syntax in the INI file:
Syntax
CommPort=Integer value (maximum value 4)
SerialPortBuffer=Integer value (maximum value 32767)
ReceiveThreshold=Integer value (maximum value
1000)
These parameters control other aspects of data logging and program operation.
This option allows you to record one epoch of data every 'n' seconds, where 'n' is the logging interval. The default of 1 second records one epoch of data every second, and is the fastest possible with the Garmin receivers. The drop-down selection box on the RINEX Header Information screen lists commonly used intervals, although other values can be entered either on the RINEX Header Information screen, or in the GRINGO.INI file. When a value is selected or entered on the RINEX Header Information screen, the new value is recorded in GRINGO.INI.
A note on how GRINGO implements this logging inteval: GRINGO tests each received epoch of data to see whether the number of seconds since the last whole minute is divisible by the selected logging interval. If it is, the epoch is recorded, and if not, the epoch is discarded. Thus, intervals which divide exactly into 60 (seconds) will produce regular, evenly spaced intervals in the output file. For instance, if a logging interval of 30 seconds would produce recorded epochs at 0:00, 0:30, 1:00, 1:30, 2:00 etc. Other intervals will produce less satisfactory results. For instance, a logging interval of 25 seconds would produce recorded epochs at 0:00, 0:25, 0:50, 1:25, 1:50, 2:25 etc.
Syntax
LoggingInterval=integer value
This parameter is described in Program Options.
Syntax
SNRThreshold=integer value (between 1 and 9)
Default location of the RINEX data file. If this string represents a valid path on the host computer, the dialog box which prompts the user for the location and name of the RINEX log file will initially start in this named directory. If a new location is selected for the output file, either by navigating within the dialog box or by directly typing a full valid path for the filename, the new path will be written back to the INI file.
Syntax
DataDirectory=80-character string
If DataDirectory is not present in the INI file, the parameter defaults
to a null string.
Parameter to allow setting of the PC's internal clock, based on the GMT time reported by the GPS receiver.
Syntax
SyncClock=20-character string
If the supplied string can be interpreted as a valid numeric constant or time value, it will be used as the offset between local time and GMT, and the PC's internal clock will be set to local time. If the supplied string can not be interpreted as a valid numeric constant or time value, the program will not set the PC clock. Three formats are permitted for the local time offset:
Format 1 SyncClock=integer value (-12 to +12)
The integer value will be interpreted as the integer offset in hours between local time and GMT. The integer may be preceded by a -ve or (optionally) +ve symbol, to denote the direction of the local time offset.
Example: SyncClock=+1 Local time will be set 1 hour ahead of GMT.
Format 2 SyncClock=decimal value
If the supplied offset contains a decimal point, any digits after the decimal point will be ignored, and the resulting integer value will be interpreted as in format 1 above.
Examples: SyncClock=1.0 Local time will be set 1 hour ahead of GMT.
SyncClock=-8.3 Local time will be set 8 hours behind GMT.
SyncClock=-8.7 Local time will be set 8 hours behind GMT.
Format 3 SyncClock=time value
This format is supplied to allow this program option to be used in time zones which do not have an integer offset in hours from GMT. If the supplied string contains a colon (":"), the string will be interpreted as a time value, where the digits before the colon represent the hours in the local offset, and the digits after the colon represent the minutes. The time value may be preceded by a -ve or (optionally) +ve symbol, to denote the direction of the local time offset (the direction symbol will apply to both the hours and minutes).
Examples: SyncClock=9:30 Local time will be set 9.5 hours ahead of GMT.
SyncClock=-5:00 Local time will be set 5 hours behind GMT.
NB. If Format 3 is used to enter a value in GRINGO.INI, the value displayed in the Program Options panel will not be correct. Furthermore, the Program Options panel cannot be used to enter a non-integer value. Therefore, if you wish to use a non-integer local time offset, you must enter a suitable time value in GRINGO.INI, and must not attempt to modify the displayed value in the Program Options panel.
Format 4 SyncClock=False
This format is used to specify that the PC clock should not be synchronised with UTC. In fact, this setting simply makes use of the fact that 'False' will not be interpreted as a valid numeric constant or time value, so the program will not attempt to set the clock.
If SyncClock is not present in the INI file, the program will not set the PC clock.
For further information please email.
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Last edited 2008-07-14
