Campbell GPS16X-HVS User manual

INSTRUCTION MANUAL
GPS16X-HVS GPS Receiver
March 2014
Copyright © 2008 - 2014
Campbell Scientific Inc.

1
Table of Contents
PDF viewers: These page numbers refer to the printed version of this document. Use the
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1. Overview......................................................................3
2. Wiring ..........................................................................3
3. GPS Data .....................................................................7
4. CRBasic Programming...............................................8
4.1 Read GPS Data.........................................................................................8
4.1.1 SerialOpen.......................................................................................8
4.1.2 SerialIn............................................................................................8
4.1.3 SerialFlush ......................................................................................9
4.2 Parsing and Data Storage Options ............................................................9
4.2.1 SplitStr ............................................................................................9
4.2.2 Converting Strings to Floating Point Numbers ...............................9
5. Troubleshooting........................................................11
5.1 GPS Setup and Function.........................................................................11
Appendices
A.1 Programming..........................................................12
A.1.1 Program Execution Interval ................................................................12
A.1.2 Reading GPS Data ..............................................................................12
A.1.3 Filters ..................................................................................................13
A.1.4 Managing the Data..............................................................................14
A.1.5 Program Discussion ............................................................................15
A.1.6 Troubleshooting..................................................................................19
B.1 Replacement Parts.................................................20
B.2 Specifications.........................................................20

GPS16X-HVS GPS Receiver
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Figures
Figure 0—1 GPS16X-HVS GPS Receiver...........................................................................................................3
Figure 2—1 RJ45 with Flying Leads, Part Number L17217..............................................................................4
Figure 2—2 CR1000 to GPS16X-HVS Using the L17218 Adapter..................................................................4
Figure 2—3 RJ45 to DB9 Serial Adapter, Part Number L17218.......................................................................5
Figure 2—4 GPS16X-HVS Receiver Mounting Kit, Part Number C1737........................................................6

GPS16X-HVS GPS Receiver
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GPS16X-HVS GPS Receiver
Figure 0—1 GPS16X-HVS GPS Receiver
1. Overview
The GPS16X-HVS is a complete GPS receiver manufactured by Garmin
International, Inc. The GPS16X-HVS has been configured by Campbell
Scientific (Canada) Corp. (CSI) to work with CSI dataloggers.
The CR1000, CR3000, CR800, and CR850 dataloggers use serial input
instructions and string handling functions to read, parse and store GPS data.
The CR23X, and other dataloggers that support P15 or the SDM-SIO4 four
channel serial interface can be used with the GPS16X-HVS. Note that the
GPS16X-HVS is not compatible with the CR510, CR10X, or CR200.
The GPS16X-HVS includes the GPS receiver and antenna in the same housing
with one cable for the power supply and communications. The GPS antenna
must have a clear view of the sky. Generally the GPS antenna will not work
indoors.
The GPS16X-HVS is a 12-channel GPS receiver that supports FAA Wide Area
Augmentation System (WAAS) or RTCM differential GPS. Also supported is
the 1 Pulse Per Second (PPS) timing signal. The cable connections provided
with the GPS16X-HVS do not support differential GPS correction. The cable
can be modified by the user if differential correction is required.
2. Wiring
Wiring for the GPS16X-HVS can be done with or without the RJ45 connector.
When shipped from Campbell Scientific, the GPS16X-HVS has an RJ45
connector attached to the cable end. The GPS16X-HVS can be purchased with
an RJ45 adapter with flying leads, an RJ45 to DB9 RS-232 adapter, and the
C1737 mount. Table 2-1 is the wiring description for the RJ45 adapter with
flying leads. To use Table 2-2, the RJ45 connector must be cut off the cable.

GPS16X-HVS GPS Receiver
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If the GPS16X-HVS is to be connected to a computer for setups, an RJ45 to
DB9 adapter is needed.
TABLE 2-1. Wiring the RJ45 Connector with Flying Leads
GPS16X-HVS
Datalogger Connection
Function
Blue
12 volts
Power
Orange
Ground
Power Ground
Black
Ground
Remote on/off
Green
Data in
RS232 TX out of GPS
Yellow
None
1 Pulse Per Second
Figure 2—1 RJ45 with Flying Leads, Part Number L17217
Figure 2—2 CR1000 to GPS16X-HVS Using the L17218 Adapter

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TABLE 2-2. Wiring without the RJ45 Connector
(Garmin Wiring)
GPS16X-HVS
Pin
Color
Function
1
Red
Power in, 6.0 to 40 volts DC
2
Black
Power ground
3
Yellow
Remote power on/off switch, ground for on, float
for off
4
Blue
Port 1 Data in, RS232 or TTL levels OK
5
White
Port 1 Data out, RS232 Levels
6
Gray
PPS
7
Green
Port 2 Data in, RS232 or TTL levels, DGPS input
8
Violet
Port 2, Data out, RS232, reserved for future use
TABLE 2-3. RJ45 to DB9 RS-232 Adapter
Pin
Color
Function
NA
Red
Power in, 12 volts
NA
Black
Ground
NA
Yellow
PPS
5
NA
GPS, power and remote on/off ground
3
NA
GPS data in
2
NA
GPS data out
Figure 2—3 RJ45 to DB9 Serial Adapter, Part Number L17218

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Figure 2—4 GPS16X-HVS Receiver Mounting Kit, Part Number
C1737

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3. GPS Data
The GPS16X-HVS has several data formats available. The GPS16X-HVS is
configured to output the NMEA $GPGGA time and position string. It is
possible to configure the GPS16X-HVS to output other NMEA strings
including the $GPVTG track made good and ground speed string.
Sample NMEA $GPGGA data string:
$GPGGA,hhmmss,llll.lll,a,nnnnn.nnn,b,t,uu,v.v,w.w,M,x.x,M,y.y,zzzz*hh<CR><LF>
TABLE 3-1. NMEA $GPGGA String Definition
Field
Description
0
$GPGGA
NMEA string identifier
1
hhmmss
UTC of Position: Hours, minutes, seconds
2
1111.111
Latitude: Degrees, minutes, thousandths of minutes
3
a
N (North) or S (South)
4
nnnnn.nnn
Longitude: Degrees, minutes, thousandths of minutes
5
b
E (East) or W (West)
6
t
GPS Quality Indicator: 0 = No GPS, 1 = GPS, 2 =
DGPS
7
uu
Number of Satellites in Use
8
v.v
Horizontal Dilution of Precision (HDOP)
9
w.w
Antenna Altitude in Meters
10
M
M = Meters
11
x.x
Geoidal Separation in Meters
12
M
M = Meters. Geoidal separation is the difference
between the WGS
-84 earth ellipsoid and mean-sea-
level.
13
y.y
Age of Differential GPS Data. Time in seconds since
the last Type 1 or 9 Update
14
zzzz
Differential Reference Station ID (0000 to 1023)
15
*
Asterisk, generally used as the termination character
16
hh
Checksum
17
<CR><LF>
Carriage return, line feed characters.
Sample $GPGGA output strings:
Cold Start
No satellites acquired, Real Time Clock and Almanac invalid:
$GPGGA,,,,,,0,00,,,,,,,*66
Warm Start
No satellites acquired, time from Real Time Clock, almanac valid:
$GPGGA,235032.0,,,,,0,00,,,,,,,*7D

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Warm Start
One satellite in use, time from GPS Real Time Clock (not GPS), no position:
$GPGGA,183806.0,,,,,0,01,,,,,,,*7D
Valid GPS Fix
Three satellites acquired, time and position valid:
$GPGGA,005322.0,4147.603,N,11150.978,W,1,03,11.9,00016,M,-
016,M,,*6E
If the almanac and ephemeris data are not stored in the non-volatile data, GPS
acquisition time is less than 5 minutes. If only the ephemeris data are unknown,
acquisition time is less than 45 seconds. If all data are known (warm start),
GPS acquisition time is less than 15 seconds.
4. CRBasic Programming
CRBasic is used to write programs for the CR1000, CR3000, CR800, and
CR850 dataloggers. These dataloggers use several instructions to read GPS
output, which is asynchronous serial data. As shipped from Campbell
Scientific, the GPS receiver will output data once a second, 4800 baud, 8 data
bits, no parity, and 1 stop bit. Only the GPGGA string is output. See Section 3
for details on the GPGGA string. See Appendix C for specifics on changing
the GPS receiver setups, including using higher baud rates, which the CR1000,
CR3000, CR800, and CR850 support.
In the following program example please note that both output tables may not
be required, and are only examples. The output intervals of the data tables are
also of concern. These items must be considered when determining the output
data required for individual applications and any potential data storage
constraints. Finally, the use of the PPS line is not addressed for the CR1000,
CR3000, CR800, and CR850 dataloggers. Typically this is not required due to
these dataloggers’ ability to execute tasks concurrently.
4.1 Read GPS Data
4.1.1 SerialOpen
SerialOpen is used to open the appropriate serial port, specify the baud rate,
data format, etc. Any of the six serial ports may be used, but option codes 3
and 4 are not used in this application. Data format is zero, TX delay is zero,
buffer size should be about 2000, which is large enough to prevent the GPGGA
string from overrunning the buffer before data is read by the SerialIn
instruction. If memory is limited, the buffer size can be smaller.
Example: SerialOpen (com1,4800,0,0,2000)
4.1.2 SerialIn
The SerialIn instruction removes data from the buffer declared in the
SerialOpen instruction and places the data in a variable of type string. Use a
timeout of 20, a termination character of 13, and maximum number of
characters of 100, or 1 less than the size of the destination variable. Declare a
string variable of size 101 before using SerialIn.

GPS16X-HVS GPS Receiver
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Example: Public GPSdata as string * 101
Example: SerialIn (GPSData,com1,20,13,100)
4.1.3 SerialFlush
The SerialFlush instruction is used to clear all data from the buffer associated
with the serial port.
4.2 Parsing and Data Storage Options
The CR1000, CR3000, CR800, and CR850 can store data as a string or as a
number. Every time the datalogger stores a string, the size of the string
determines the number of bytes used. If the string was declared to be 101 bytes
long, every time the string is written to memory, 101 bytes are used.
Depending on the application, the entire GPGGA string can be stored to
memory or just specific parts. When storing specific parts, some numbers can
be converted to floating data points.
To parse the GPGGA string, first read the entire string into 1 large string (see
Section 4.1). Next parse the string into a group of smaller strings (see Section
4.2.1). Determine which of the smaller strings to keep and which to convert to
floating point number, then store the data.
4.2.1 SplitStr
Use the SplitStr instruction to parse the GPGGA string into an array of strings.
Declare an array of 18 strings of 15 characters.
Example: ParseStr(18) as string * 15
The SplitStr instruction uses the result string, search string, filter string, number
of splits and split option to parse the search string and store the results in the
result string. The GPGGA string uses the comma character (chr(44)) between
each parameter. The comma makes a nice marker to parse on.
Example: SplitStr (ParseStr(1),GPSData ,chr(44),18,5)
4.2.2 Converting Strings to Floating Point Numbers
Strings can be converted to floats with the simple assignment operator, but
Latitude and Longitude require more precision than the CR1000, CR3000,
CR800, or CR850 will store as a floating point number.
' Sample CR1000 program to read GPS NMEA GPGGA string
Public location, bytes
public GPSData as string * 101 ' $GPGGA string about 57 characters
PUBLIC ParseStr(18) as string * 15
' Aliases allow proper labels in output data tables,
' and when viewing public variables
alias ParseStr(1) = GPGGA
Alias ParseStr(2) = Time
Alias ParseStr(3) = Latitude
Alias ParseStr(4) = Hemisphere_NS
Alias ParseStr(5) = Longitude
Alias ParseStr(6) = Hemisphere_WE

GPS16X-HVS GPS Receiver
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Alias ParseStr(7) = GPS_Quality
Alias ParseStr(8) = Num_Satellites
Alias ParseStr(9) = HDOP
Alias ParseStr(10) = Altitude
Alias ParseStr(11) = Altitude_units
Alias ParseStr(12) = Geoidal_Sep
Alias ParseStr(13) = Geoidal_units
Alias ParseStr(14) = DGPS_Age
Alias ParseStr(15) = Diff_Ref_ID
Alias ParseStr(16) = Asterisk
Alias ParseStr(17) = Check_Sum
Alias ParseStr(18) = CRLF
' Store the ParseStrd elements of the $GPGGA string as
' short strings.
DataTable(Parsed,1,-1)
DataInterval (0,5,sec,10)
Sample(1,GPGGA,String)
Sample(1,Time,String)
Sample(1,Latitude,String)
Sample(1,Hemisphere_NS,String)
Sample(1,Longitude,String)
Sample(1,Hemisphere_WE,String)
Sample(1,GPS_Quality,String)
Sample(1,Num_Satellites,String)
Sample(1,HDOP,String)
Sample(1,Altitude,String)
Sample(1,Altitude_units,String)
Sample(1,Geoidal_Sep,String)
Sample(1,Geoidal_units,String)
Sample(1,DGPS_Age,String)
Sample(1,Diff_Ref_ID,String)
Sample(1,Asterisk,String)
Sample(1,Check_Sum,String)
Sample(1,CRLF,String)
EndTable
' Store GPS $GPGGA string as a complete string
DataTable (GGA,1,-1)
DataInterval (0,5,Sec,10)
Sample (1, GPSData, String)
EndTable
'Main Program
BeginProg
SerialOpen (com1,4800,0,0,2000)
Scan (5,Sec,0,0)
bytes = SerialInChk (com1)
SerialIn (GPSData,com1,20,13,100)
SplitStr (ParseStr(1),GPSData,CHR(44),18,5)
SerialFlush (com1)
CallTable GGA
CallTable Parsed
NextScan
SerialClose (com1)

GPS16X-HVS GPS Receiver
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EndProg
5. Troubleshooting
Testing and evaluation of serial communications is best done by reducing the
whole system to small manageable systems. Usually some portions of the
whole system are working. The first steps involve finding what is working.
During this process you may find parts of the system that are not working or
mistakes that can be easily corrected. Fix each subsystem before testing others.
5.1 GPS Setup and Function
Test the GPS16X-HVS for proper operation including the baud rate and output
string. Use a computer, terminal emulator software, a serial port (RS232), and
a 9-pin to 9-pin serial cable. The computer and serial port can be the same as
used to communicate with the datalogger. Terminal emulation software is
pretty common. Hyperterm is supplied as part of Windows ™ and works.
Procomm ™ is another communication software package that works well.
Set up the software for the correct serial port, 4800 baud, 8 data bits, 1 stop bit
and no parity. Flow control should be off. Using the serial cable, connect the
GPS16X-HVS to the computer serial port. Power up the GPS16X-HVS. The
GPS antenna should have a clear view of the sky. Don’t expect the GPS
antenna to work indoors. The $GPGGA string should be displayed once a
second. Make sure the $GPGGA string is showing a valid GPS fix. A valid
GPS fix will display time, position and have a GPS quality number greater than
zero. Part number L17218, RJ45 to DB9 adapter, is needed to connect the
GPS16X-HVS to the computer serial cable.

GPS16X-HVS GPS Receiver
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Appendix A. CR23X Programs
A.1 Programming
Program instruction 15 (P15) is used to read the NMEA $GPGGA string of
time and position data. Each iteration of P15 can either read the numeric fields
or read everything. When reading the numeric fields, such as time, latitude,
longitude and elevation, P15 requires non-numeric delimiters between data
points. The only available format of GPS data with delimiters is the NMEA
0183 format. Program instruction 15 (P15) reads serial data and discards non-
numeric values. All non-numeric values act as delimiters between numbers,
and decimal points can also act as delimiters. P15 can be used to import
everything in the string, character by character, and convert it to the decimal
equivalent. The decimal equivalent method is seldom used, and only when the
general area (hemisphere) is not known.
A.1.1 Program Execution Interval
Due to the sequential program instruction execution of the CR23X the Port
Interrupt Subroutine 98 is useful in synchronizing the GPS16X-HVS
measurement via the Pulse Per Second output. When the PPS signal is used to
trigger the read data function (P15), the program table execution interval does
not matter. Otherwise the timing between the GPS16X-HVS output and the
datalogger read must be considered. Generally the execution interval can not
be less than 2 seconds when the PPS signal is not used. This is discussed
further in Section A.1.5.
A.1.2 Reading GPS Data
Table A-1 is a sample CR23X P15 instruction for reading NMEA $GPGGA
data string. The second parameter has two dashes indicating data buffering has
been turned off.
TABLE A-1. P15 for NMEA $GPGGA Data String
Parameter
Data
Description
1
1
Repetitions
2
63 --
Configuration code for RS232 ASCII data at 4800 baud
with data buffe
ring turned off. The -- indicates data
buffering turned off. Decimal delimiter
3
1
Delay before sending data out
4
05
Control ports. Two digit format AB. A is for
handshaking and set to zero. B in this example is control
port 5 (datalogger RCV).
GPS16X-HVS
communication
cable: GPS transmit to control port 5 in this example
5
1
Input location where first character to transmit is stored.

GPS16X-HVS GPS Receiver
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Note: nothing is actually transmitted
6
0
Number of consecutive input locations to send
7
42
Termination character, 42 is ASCII equivalent of the
asterisk
8
100
Maximum number of characters to receive.
9
80
Delay in mS. How long to wait for $GPGGA string
10
1
Starting input location for time and position data
11
1
Multiplier, always 1.
12
0
Offset, always 0.
P15 parameters 4, 5, and 10 are somewhat variable. When using a CR23X,
parameter 4 can be set to 05, 06 or 07 depending on what control ports are
used. Wiring of the communication cable depends on the selection for
parameter 4. With a CR23X the GPS transmit wire is connected to the control
port selected in parameter 4.
P15 is executed when the PPS signal drives control port 8 high. P15 will wait
until one of three conditions is met: the time-out listed in parameter 9 has
expired, the maximum number of characters in parameter 8 have been read, or
the termination character listed in parameter 7 has been read.
P15 parameter 10 is the first input location you wish to store GPS data in.
Fifteen sequential input locations will be used to store time and position.
Example A-1. Program Instruction 15 (P15) for CR23X
Port Serial I/O (P15)
1: 1 Reps
2: 62 -- ASCII/RS-232, 4800 Baud, decimal delimiter
3: 1 Delay (units = 0.01 sec)
4: 5 Control Ports
5: 1 Output Loc [ Bulk ]
6: 0 No. of Locs to Send
7: 42 Termination Character
8: 100 Maximum Characters
9: 80 Time Out Delay (units = 0.01 sec)
10: 1 Loc [ Raw_time1 ]
11: 1 Mult
12: 0 Offset
Communication cable wiring for:
CR23X/Example A-1 —PPS to C8, GPS transmit to C5.
A.1.3 Filters
Filters can be used to make sure P15 reads the correct data string. Filters also
ensure P15 starts to read the string at the beginning of the string. To use a
filter, follow P15 with instruction P63 (extended parameters). P63 is used to
define the filter. Enter the desired filter in P63.
NOTE

GPS16X-HVS GPS Receiver
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TABLE A-2. Filter
ASCII Equivalent
Character
36
$
71
G
80
P
71
G
71
G
65
A
A.1.4 Managing the Data
Several of the data values in the $GPGGA string are too large to view or write
to final storage. Some simple math is used to parse the data.
The UTC time is in the format hhmmss where hh is the hours, mm is the
minutes and ss is the seconds. Six digits are too many to view with the
datalogger display and some software. Add 0.3 to the raw time field. Multiply
the raw time input location by 0.01 to reduce the magnitude and place the
seconds in the fractional portion of the number. Next use P45 to write the
integer portion (hours/minutes) to a new input location, then use P44 to write
the fractional portion to another input location (seconds) and multiply that
location by 100. The last step is to use P45 again to take the integer portion of
the input location for seconds. The result is hour/minutes in one input location
and seconds in another.
The latitude and longitude can be parsed with the P15 instruction when decimal
delimiter is on. If P15, parameter 2 is 6x, where the x selects the baud rate,
every non-numeric value and decimal point will act as a delimiter. The
Degrees and Minutes will be placed in one input location, and the minute
fractional portion will be placed in the next input location. The decimal
delimiter preserves the resolution of the original measurement.
Further parsing of the latitude and longitude may be necessary. Longitude
degrees and minutes can range in value up to 18059, which exceeds the low
resolution format of the dataloggers final storage area. Either parse the latitude
and longitude degrees and minutes the same way the time was parsed, or store
the data in high-resolution format.
The GPS quality number can be used to determine if you have a valid GPS fix
and if the datalogger received the data properly. Use P89 to test if the GPS
quality number is greater than or equal to one. There is a catch to using the
GPS quality number to verify your data. P15 will write to fifteen input
locations if everything works correctly. If P15 fails to read the GPS data, only
the first input location is written to. The GPS quality number will be
unchanged. If P15 fails to read the GPS data, the value displayed in the first
input location will be 99999. The datalogger actually stores FFFFFFFFh, a
very large number. The time field includes six digits, which can be greater than
99999. This limits the usefulness of the time field as a test for a valid GPS fix.
A better approach is to overwrite the GPS quality location with zero before
executing P15. Use P30 to overwrite one input location.
If the GPS time is used to set the datalogger clock, the GPS time must be
parsed into three input locations: Hour, Minutes, Seconds. P114 is used to set

GPS16X-HVS GPS Receiver
15
the datalogger clock to match values in input locations. Some time will have
passed between the GPS fix and when the program table reaches the P114
instruction. Adjustments can be made by adding a second or two. Be careful
about setting seconds to a number greater than 59. You can also correct the
UTC time to local time. Table based dataloggers require year, day, hour,
minute, and seconds to use P114. Only hour, minutes, and seconds are
available from the $GPGGA string. The PGRFM string includes the month,
day and year, but is difficult to use.
A.1.5 Program Discussion
Wiring when using RJ45 adapter:
Function Color Datalogger Connection
Power in Blue 12 volts
Power ground Orange Ground
Power switch Black ground
TXD Green C5
PPS Yellow C8
The GPS16X-HVS should be setup for 4800 baud, 8 data bits, 1 stop bit and no
parity. The GPGGA string should be output. The 1 pulse per second signal
should be output with a pulse duration of 100 milliseconds.
The code required to read the GPS information and store it to final storage is in
Subroutine 98. Subroutine 98 is interrupt driven and triggered when a rising
edge is detected on Control port 8. The GPS16X-HVS has a 1 PPS signal
which is wired to control port 8. The transmit data line of serial port 1 on the
GPS16X-HVS is wired to control port 5. The GPS16X-HVS serial port 2
generally is not used.
When the 1 PPS signal triggers subroutine 98, P15 is executed. P15 is setup to
read ASCII serial data. Each data point is separated by a non-numeric
character or a decimal point. Fifteen input locations are used as temporary
storage for the $GPGGA string. Table 3.1 explains the $GPGGA string.
The input locations used for the $GPGGA string are:
1) Raw_Time, Time in hours, minutes, and seconds
2) LatDegMin, Latitude degrees and minutes
3) Lat_Frac, Latitude fractions of minute
4) LngDegMin, Longitude degrees and minutes
5) Lng_Frac, Longitude fractions of minute
6) Quality, GPS quality indicator
7) NumSats, Number of satellites in use
8) HDPWhole, Horizontal Dilution of Precision
9) HDPFrac, Horizontal Dilution of Precision, tenths
10) Elevation, Elevation in meters
11) Geoidal, Geoidal separation in meters
12) Geoidalth, Geoidal separation in meters, tenths
13) Age, Age of differential GPS data
14) Agetenth, Age of differential GPS data, tenths
15) DiffID, Differential reference station ID
Additional input locations used in the example program are:
18) Orig_TM, Copy of original time

GPS16X-HVS GPS Receiver
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19) Int1, Place holder for math
20) Hours, formatted hours
21) Minutes, formatted minutes
22) Seconds, formatted seconds
23) remainder, place holder for math
Before writing any datalogger code, it’s best to enter all the input locations
needed. In Edlog, open the input location editor (F5) and enter names for the
input locations listed above. When an input location is needed, use the input
location pick list (F6).
;{CR23X}
;
*Table 1 Program
01: 60 Execution Interval (seconds)
; Instruction to eliminate warning about unused subroutine, not needed
1: If Flag/Port (P91)
1: 11 Do if Flag 1 is High
2: 98 Call Subroutine 98
*Table 2 Program
02: 0.0000 Execution Interval (seconds)
*Table 3 Subroutines
1: Beginning of Subroutine (P85)
1: 98 Subroutine 98
;--- read serial data non-buffered
2: Port Serial I/O (P15)
1: 1 Reps
2: 62 -- RS-232 ASCII (decimal delimiter), 4800 Baud
3: 1 Delay (0.01 sec units) before TX
4: 5 No RTS/DTR, C5 TXD/RXD
5: 1 Start Loc for TX [ Raw_Time ]
6: 0 Number of Locs to TX
7: 42 Termination Character for RX
8: 100 RX Buffer Size or Max Chars to RX if Par 2 indexed (--)
9: 80 Time Out for CTS (TX) and/or RX (0.01 sec units)
10: 1 Start Loc for RX [ Raw_Time ]
11: 1.0 Mult for RX
12: 0.0 Offset for RX
;--- filter for $GPGGA
3: Extended Parameters (P63)
1: 36 Option ;$
2: 71 Option ;G
3: 80 Option ;P
4: 71 Option ;G
5: 71 Option ;G
6: 65 Option ;A
7: 0 Option
8: 0 Option
; Test for valid GPS fix and string read
4: If (X<=>F) (P89)

GPS16X-HVS GPS Receiver
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1: 6 X Loc [ Quality ]
2: 3 >=
3: 1 F
4: 30 Then Do
; Make a copy of time
5: Z=X (P31)
1: 1 X Loc [ Raw_Time ]
2: 18 Z Loc [ Orig_TM ]
; Add 0.45 to time stamp to eliminate complications with
; floating point math, P44, and P45
6: Z=X+F (P34)
1: 18 X Loc [ Orig_TM ]
2: 0.45 F
3: 18 Z Loc [ Orig_TM ]
; Move minutes and seconds right of decimal
7: Z=X*F (P37)
1: 18 X Loc [ Orig_TM ]
2: .0001 F
3: 19 Z Loc [ Int1 ]
; Pluck off hours
8: Z=INT(X) (P45)
1: 19 X Loc [ Int1 ]
2: 20 Z Loc [ Hours ]
; Subtract hours out
9: Z=X-Y (P35)
1: 19 X Loc [ Int1 ]
2: 20 Y Loc [ Hours ]
3: 19 Z Loc [ Int1 ]
; Move decimal left 2 places
10: Z=X*F (P37)
1: 19 X Loc [ Int1 ]
2: 100 F
3: 19 Z Loc [ Int1 ]
; Pluck off minutes
11: Z=INT(X) (P45)
1: 19 X Loc [ Int1 ]
2: 21 Z Loc [ Minutes ]
; Subtract out minutes
12: Z=X-Y (P35)
1: 19 X Loc [ Int1 ]
2: 21 Y Loc [ Minutes ]
3: 19 Z Loc [ Int1 ]
; Move decimal left 2 places
13: Z=X*F (P37)
1: 19 X Loc [ Int1 ]
2: 100 F