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User Guide
AgGPS®252 Receiver
Version 1.00
Revision B
Part Number 55510-00-ENG
August 2005
ꢀ
OF THE POSSIBILITY OF ANY SUCH LOSS AND REGARDLESS OF
THE COURSE OF DEALING WHICH DEVELOPS OR HAS
DEVELOPED BETWEEN YOU AND TRIMBLE. BECAUSE SOME
STATES AND JURISDICTIONS DO NOT ALLOW THE EXCLUSION
OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR
INCIDENTAL DAMAGES, THE ABOVE LIMITATION MAY NOT
APPLY TO YOU.
Europe
This product has been tested and found to comply with the
requirements for the European Directive 75/322/EEC as
amended by 2000/2/EC thereby satisfying the requirements
for e-mark compliance for use in agricultural vehicles in the
European Economic Area (EEA).
NOTE: THE ABOVE LIMITED WARRANTY PROVISIONS MAY
NOT APPLY TO PRODUCTS OR SOFTWARE PURCHASED IN THE
EUROPEAN UNION. PLEASE CONTACT YOUR TRIMBLE
DEALER FOR APPLICABLE WARRANTY INFORMATION.
Notices
This product has been tested and found to comply with the
requirements for a Class A device pursuant to European
Council Directive 89/336/EEC on EMC, thereby satisfying the
requirements for CE Marking and sale within the European
Economic Area (EEA).
USA
NOTE – FCC Part 15 rules; paragraph 15.105
This equipment has been tested and found to comply with
the limits for a Class A digital device, pursuant to Part 15 of
the FCC Rules. These limits are designed to provide
reasonable protection against harmful interference when the
equipment is operated in a commercial environment. This
equipment generates, uses, and can radiate radio frequency
energy and, if not installed and used in accordance with the
instruction manual, may cause harmful interference to radio
communications. Operation of this equipment in a
residential area is likely to cause harmful interference, in
which case, you, the user, will be required to correct the
interference at your own expense.
Warning – This is a Class A product. In a
domestic environment this product may cause
C
radio interference in which case you may be
required to take adequate measures.
Notice to Our European Union Customers
For product recycling instructions and more information,
If this equipment does cause harmful interference to radio or
television reception, which can be determined by turning the
equipment off and on, the user is encouraged to try to correct
the interference by one or more of the following measures:
Recycling in Europe:
To recycle Trimble WEEE (Waste
Electrical and Electronic Equipment,
products that run on electrical power.),
Call +31 497 53 24 30, and ask for the
"WEEE Associate".
–
–
Reorient or relocate the receiving antenna.
Increase the separation between the equipment and the
receiver.
Connect the equipment into an outlet on a circuit
different from that to which the receiver is connected.
Consult the dealer or an experienced radio/TV technician
for help.
–
–
Or, mail a request for recycling
instructions to:
Trimble Europe BV
c/o Menlo Worldwide Logistics
Meerheide 45
Changes and modifications not expressly approved by the
manufacturer or registrant of this equipment can void your
authority to operate this equipment under Federal
Communications Commission rules.
5521 DZ Eersel, NL
Declaration of Conformity
This product conforms to the following standards, and therefore complies with the requirements of the R&TTE
Directive 1999/5/EC, which specifies compliance with the essential requirements of EMC Directive 89/336/EEC and
Low Voltage Directive 73/23/EEC.
EMC Emissions
EMC Immunity
Safety
BSEN 55022:1998 (W/A1:00) Class A
EN 55024:1998
EN 60950:2000
03
Mark First Applied
The technical file is maintained at Trimble Navigation Limited, 749 North Mary Avenue, PO Box 3642, Sunnyvale, CA
94088-3642, USA.
1
2
3
Optional extra . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Mounting the Receiver. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Choosing a location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Environmental conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Electrical interference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Connecting to an External Device . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
AgGPS 252 Receiver User Guide
v
Contents
4
Configuring the AgGPS 252 Receiver to Operate in RTK Mode . . . . . . . . . 31
5
Troubleshooting Flowcharts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
A
GPS Channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Receiver Default Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
B
Third-Party Interface Requirements . . . . . . . . . 57
Third-Party Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Third-Party Hardware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Index . . . . . . . . . . . . . . . . . . . . . . . . . . 61
vi AgGPS 252 Receiver User Guide
C H A P T E R
1
Introduction
1
Welcome to the AgGPS 252 Receiver User Guide. This manual:
•
•
•
Describes how to install and configure the Trimble® AgGPS® 252
receiver.
Provides guidelines for connecting the receiver to an external
device.
Provides guidelines for using the AgRemote utility to view and
configure the receiver correction sources and other operating
parameters.
Even if you have used other Global Positioning System (GPS) products
before, Trimble recommends that you spend some time reading this
manual to learn about the special features of this product.
If you are not familiar with GPS, go to the Trimble website at
www.trimble.com for an interactive look at Trimble and GPS.
AgGPS 252 Receiver User Guide
1
1
Introduction
1.1
Warnings
Always follow the instructions that accompany a warning.
WARNING – Indicates a potential hazard or unsafe practice that could
result in injury or property damage.
C
1.2
Related Information
Release notes describe new features, provide information that is not
included in the manuals, and identify changes to the manuals. You can
download release notes from the Trimble website.
1.3
Technical Assistance
If you have a problem and cannot find the information you need in the
product documentation, contact your local Trimble Reseller.
1.4
Your Comments
Your feedback about the supporting documentation helps us to
improve it with each revision. Email your comments to
2
AgGPS 252 Receiver User Guide
C H A P T E R
2
2
Q Standard Features of the AgGPS 252 Receiver
Q Receiver Connections
Q Receiver Input/Output
Q LED Indicator
Q GPS Positioning Methods
Q Sources of Error in GPS Positioning
This chapter describes the AgGPS 252 receiver and gives an overview of
GPS, DGPS, and related information. When used with a Real-Time
Kinematic (RTK) base station, the AgGPS 252 receiver provides RTK
positioning for high-accuracy, centimeter-level applications. For
physical specifications, see Appendix A, Specifications.
AgGPS 252 Receiver User Guide
3
2
Overview
2.1
Standard Features of the AgGPS 252 Receiver
A standard AgGPS 252 receiver provides the following features:
•
•
12 GPS (C/A-code) tracking channels, code carrier channels
Horizontal RTK positioning accuracy 2.5 cm (0.98 in) + 2 ppm,
2 sigma; vertical RTK positioning accuracy 3.7 cm (1.46 in)
+ 2 ppm, 2 sigma
•
Submeter differential accuracy (RMS), assuming at least five
satellites and a PDOP of less than four
•
•
•
Combined GPS/DGPS receiver and antenna
System level cable
AgRemote utility with four-button keypad to configure and view
system properties (download from the Trimble website at
•
•
LED status indicator
The receiver outputs a 1 PPS (pulse per second) strobe signal on
both ports. This signal enables an external instrument to
synchronize its internal time with a time derived from the very
accurate GPS system time.
•
•
•
•
•
WAAS differential correction compatibility
AgGPS 170 Field Computer compatibility
EVEREST™ multipath rejection technology
OmniSTAR VBS and HP positioning compatibility
Two ports that support both CAN 2.0B and RS-232:
CAN
–
J1939 and NMEA 2000 messages
Note – The AgGPS 252 is ISO 11783 compliant. It supports
some ISO 11783 messages.
RS-232
4
AgGPS 252 Receiver User Guide
Overview
2
–
NMEA-0183 output: GGA, GLL, GRS, GST, GSA, GSV, MSS,
RMC, VTG, ZDA, XTE (the default NMEA messages are
GGA, GSA, VTG, and RMC)
PTNLDG, PTNLEV, PTNLGGK, PTNLID, and
PTNLSM are Trimble proprietary NMEA output messages.
–
RTCM SC-104 output
Trimble Standard Interface Protocol (TSIP) input and
output
2.2
Receiver Connections
Figure 2.1 shows the connector ports and the LED indicator on the
AgGPS 252 receiver.
Port A
Port B
LED indicator
Figure 2.1
AgGPS 252 receiver connector ports
The two connectors (Port A and Port B) can perform the following
functions:
•
•
•
•
accept power
accept TSIP, RTCM, ASCII, and (if enabled) CMR inputs
output RTCM, TSIP, and NMEA messages
output 1 PPS signals
AgGPS 252 Receiver User Guide
5
2
Overview
•
provide support for the J1939 (CAN) serial bus
For more information about the inputs, outputs, and LED indicators,
see the information in the rest of this section.
2.3
Receiver Input/Output
The AgGPS 252 receiver data/power cable (P/N 50166) connects to a
receiver connector port to supply power. It also enables the following
data exchanges:
•
TSIP, RTCM, and ASCII input from an external device
The receiver is able to receive ASCII data from an external
device, convert this data into an NMEA message, and export the
message to another device. TSIP command packets configure
and monitor GPS and DGPS parameters. The receiver is also able
to accept RTCM data from an external device, such as a radio.
•
•
CMR input from an external device
If the receiver is to be used in RTK mode, set the port that is
connected to the radio to the RtkLnk protocol. This protocol
enables the receiver to receive CMR messages.
TSIP and NMEA output to an external device
When you are using an external radio, the receiver can also
receive DGPS corrections.
TSIP is input/output when communicating with AgRemote.
NMEA is output when the receiver is exporting GPS position
information to an external device, such as a yield monitor, or to a
mapping software program.
For more information on the National Marine Electronics
Association (NMEA) and Radio Technical Commission for
Maritime Services (RTCM) communication standard for GPS
receivers, go to the following websites:
–
6
AgGPS 252 Receiver User Guide
Overview
2
document called NMEA-0183 Messages Guide for AgGPS
Receivers.
•
•
1 PPS output
To synchronize timing between external instruments and the
internal clock in the receiver, the connection port outputs a
strobe signal at 1 PPS (pulse per second). To output this signal,
the receiver must be tracking satellites and computing GPS
positions.
J1939 (CAN) bus
Both connection ports on the receiver support the J1939
Controller Area Network (CAN) bus protocol. This protocol
standardizes the way multiple microprocessor-based electronic
control units (ECUs) communicate with each other over the
same pair of wires. It is used in off-highway machines, such as
those used in agriculture, construction, and forestry.
For more information, go to the Society of Automotive Engineers
(SAE) International website at www.sae.org/servlets/index.
•
ISO 11783 messages
Both CAN ports support some ISO 11783 messages.
Position output format
The AgGPS receiver outputs positions in Degrees, Minutes, and
Decimal Minutes (DDD°MM.m'). This is the NMEA standard format
and is commonly used worldwide for data transfer between electronic
equipment.
AgGPS 252 Receiver User Guide
7
2
Overview
2.4
LED Indicator
The AgGPS 252 receiver has an LED light that shows the status of the
receiver. The following tables describe the light sequences for each
positioning method.
Table 2.1
LED sequences with Satellite Differential GPS or Autonomous
positioning
LED color LED flash
Status
Off
Off
No power
Green
Green
Solid
Slow
Normal operation: computing DGPS positions
No DGPS corrections: computing DGPS positions using old
corrections
Green
Fast
No DGPS corrections approaching DGPS age limit: computing DGPS
positions using old corrections
Yellow
Solid
DGPS corrections being received but DGPS positions not yet being
computed: computing autonomous GPS positions
Yellow
Yellow
Slow
Fast
No DGPS corrections: computing autonomous GPS positions
Not enough GPS signals: not tracking enough satellites to compute
position
Note – WAAS/EGNOS and OmniSTAR VBS use the Satellite Differential
GPS positioning method.
Table 2.2
LED sequences with RTK positioning
LED color LED flash Status
Off
Off
No power
Green
Green
Solid
Slow
Normal operation: computing fixed RTK positions
Receiving CMR corrections but not initialized: computing float RTK
positions
Green
Fast
No CMR corrections: computing RTK position using old corrections
8
AgGPS 252 Receiver User Guide
Overview
2
Table 2.2
LED sequences with RTK positioning (continued)
LED color LED flash Status
Yellow
Solid
Receiving CMR corrections but unable to calculate RTK position:
computing DGPS (if WAAS/EGNOS is unavailable) or autonomous
position
Yellow
Yellow
Slow
Fast
No CMR corrections: computing DGPS or autonomous position
Not receiving CMR corrections: not computing positions
Table 2.3
LED sequences with OmniSTAR HP positioning
LED color LED flash
Status
Off
Off
No power
Green
Green
Solid
Slow
Normal operation: computing converged OmniSTAR HP positions
Receiving OmniSTAR HP corrections, but only able to compute
unconverged position
Green
Fast
Receiving OmniSTAR HP corrections, but an HP error occurred
Yellow
Solid
Receiving OmniSTAR HP corrections but unable to calculate a
position: computing DGPS or autonomous solution
Yellow
Yellow
Slow
Fast
No OmniSTAR HP corrections: computing DGPS or autonomous
position
Not tracking OmniSTAR HP corrections: no positions
2.5
GPS Positioning Methods
GPS positioning systems are used in different ways to provide different
levels of accuracy. Accuracy is measured in absolute terms (you know
exactly where you are in a fixed reference frame).
AgGPS 252 Receiver User Guide
9
2
Overview
Table 2.4 summarizes the GPS positioning methods. Imperial units in
this table are rounded to two decimal places. The values shown are
2 sigma.
Table 2.4
Absolute accuracy of GPS positioning methods
GPS positioning
method
Corrections used
Approximate absolute accuracy
Real-Time Kinematic
(RTK) GPS
Trimble CMR corrections 2.5 cm (0.98 in) + 2 ppm horizontal
broadcast by a local
base station
accuracy,
3.7 cm (1.46 in) + 2 ppm vertical accuracy
Satellite Differential GPS OmniSTAR VBS
Satellite Differential GPS WAAS/EGNOS
78 cm (30.71 in)
95 cm (37.40 in)
OmniSTAR HP
Differential GPS
OmniSTAR HP
10 cm (3.94 in) after the signal has fully
converged
1
1
Convergence time can vary, depending on the environment. Time to the first fix (submeter
accuracy) is typically <30 seconds; time to the first high accuracy fix (<10 cm accuracy) is
typically <30 minutes.
For more information about each positioning method, see below.
25.1
RTK GPS positioning
The AgGPS 252 receiver uses the RTK positioning method to achieve
centimeter-level accuracy. To use the RTK method, you must first set
up a base station. The base station uses a radio link to broadcast RTK
corrections to one or more rover receivers. The AgGPS 252 receiver is a
rover receiver, so another compatible receiver, such as a Trimble
MS750™ or AgGPS 214 GPS receiver, must be used as the base station.
The rover receiver uses RTK corrections from the base station to
calculate its position to centimeter-level accuracy. As part of this
process, the rover receiver must calculate an initialization. This takes a
few seconds. While the receiver is initializing, an RTK Float solution is
generated. Once initialized, an RTK Fixed solution is generated. It is the
RTK Fixed solution that provides centimeter-level accuracy.
10 AgGPS 252 Receiver User Guide
Overview
2
The parts per million (ppm) error is dependent on the distance
(baseline length) between the base and rover receiver. For example, if
the distance is 10 km, a 2 ppm error equals 20 mm.
For more information about RTK positioning, go to the Trimble website
25.2
Differential GPS positioning (DGPS)
For differential positioning, the AgGPS 252 receiver uses corrections
from WAAS/EGNOS satellites or from OmniSTAR VBS or HP satellites.
These differential systems use special algorithms to provide differential
corrections that allow the rover receiver to calculate its position more
accurately.
Free corrections
WAAS/EGNOS corrections are free in North America and Europe. For
more information about WAAS, go to the Federal Aviation
Administration website at
For more information about EGNOS, go to the European Space Agency
website at
Subscription-based corrections
The AgGPS 252 receiver uses OmniSTAR HP or OmniSTAR VBS
differential corrections in the same way that it uses WAAS/EGNOS
corrections.
OmniSTAR corrections are provided on a subscription basis.
The corrections that are produced by OmniSTAR HP algorithms are
more accurate than the corrections that are produced by OmniSTAR
VBS algorithms. The accuracy of the positions reported using
OmniSTAR HP increases with the time that has elapsed since the
AgGPS 252 Receiver User Guide 11
2
Overview
instrument was turned on. This process is called convergence.
Convergence to where the error is estimated to be below 30 cm
influence the time to convergence include the environment, the
geographical location, and the distance to the closest OmniSTAR
corrections base station. OmniSTAR is continually improving the
service.
For more information about OmniSTAR, go to the OmniSTAR website
subscription, see OmniSTAR, page 29.
25.3
Autonomous GPS positioning
Autonomous GPS positioning uses no corrections. The rover receiver
calculates its position using only the GPS signals it receives. This
method does not have high absolute accuracy, but the relative accuracy
is comparable to the other methods.
12 AgGPS 252 Receiver User Guide
Overview
2
2.6
Sources of Error in GPS Positioning
The GPS positioning method influences the accuracy of the GPS
position that is output by the AgGPS 252 receiver. The factors described
in Table 2.5 also affect GPS accuracy.
Table 2.5
Condition
Factors that influence the accuracy of GPS positions
Optimum Description
value
Atmospheric
effects
GPS signals are degraded as they travel through the
ionosphere. The error introduced is in the range of 10 meters.
The error is removed by using a differential or RTK positioning
method.
Number of
satellites used
> 5
To calculate a 3D position (latitude and longitude, altitude, and
time), four or more satellites must be visible. To calculate a 2D
position (latitude and longitude, and time), three or more
satellites must be visible. For RTK positioning, five satellites are
needed for initialization. Once initialized, four or more
satellites provide RTK positions. The number of visible satellites
constantly changes and is typically in the range 5 through 9.
The AgGPS receiver can track up to 12 satellites simultaneously.
Note – To see when the maximum number of GPS satellites are
available, use the Trimble Planning software and a current
ephemeris (satellite history) file. Both files are available free
Maximum PDOP < 4
Position Dilution of Precision (PDOP) is a unitless, computed
measurement of the geometry of satellites above the current
location of the receiver. A low PDOP means that the positioning
of satellites in the sky is good, and therefore good positional
accuracy is obtained.
Signal-to-noise
ratio
> 6
Signal-to-noise ratio (SNR) is a measure of the signal strength
against electrical background noise. A high SNR gives better
accuracy.
Normal values are:
• GPS6
• WAAS3+
• OmniSTAR HP/VBS6+
AgGPS 252 Receiver User Guide 13
2
Overview
Table 2.5
Condition
Factors that influence the accuracy of GPS positions (continued)
Optimum Description
value
Minimum
elevation
> 10
Satellites that are low on the horizon typically produce weak
and noisy signals and are more difficult for the receiver to track.
Satellites below the minimum elevation angle are not tracked.
Multipath
environment
Low
Multipath errors are caused when GPS signals are reflected off
nearby objects and reach the receiver by two or more different
paths. The receiver incorporates the EVEREST multipath
rejection option.
RTCM-
These corrections are broadcast from a Trimble AgGPS 214,
compatible
corrections
MS750, or equivalent reference station.
RTK Base station
coordinate
accuracy
For RTK positioning, it is important to know the base station
coordinates accurately. Any error in the position of the base
station affects the position of the rover; every 10 m of error in a
base station coordinate can introduce up to 1 ppm scale error
on every measured baseline. For example, an error of 10 m in
the base station position produces an error of 10 mm over a
10 km baseline to the rover.
For more information about how to make sure the position of
your base station is accurate, refer to the manual for your base
station receiver.
Multiple RTK
base stations
If you are using several base stations to provide RTK corrections
to a large site area, all base stations must be coordinated
relative to one another. If they are not, the absolute positions
at the rover will be in error. For more information about how to
use several base stations to cover your site, contact your local
Trimble Reseller.
26.1
Coordinate systems
Geographic data obtained from different sources must be referenced to
the same datum, ellipsoid, and coordinate format. Different formats
provide different coordinate values for any geographic location. In
North America, the datums NAD-27 and NAD-83 are commonly used in
Agricultural mapping applications.
14 AgGPS 252 Receiver User Guide
Overview
2
The AgGPS 252 receiver outputs position coordinates in several datums
and ellipsoids depending on the GPS positioning method being used.
See Table 2.6.
Table 2.6
DGPS coordinate systems
GPS positioning method
None – Autonomous mode
OmniSTAR VBS North American Beams
OmniSTAR VBS Rest of World Beams
OmniSTAR HP
Datum
WGS-84
NAD-83
Ellipsoid
WGS-84
GRS-80
1
2
3
ITRF
GRS-80
ITRF 2000
WGS-84
WGS-84
ITRF 2000
WGS-84
WGS-84
WAAS Beams
RTK
1
World Geodetic System (WGS) 1984. Datum and ellipsoid.
2
North American Datum (NAD) 1983. Equivalent to WGS-84 in North
America.
3
International Terrestrial Reference Frame (ITRF). Contact the DGPS provider for details.
For more information, go to the National Geodetic Survey website at
AgGPS 252 Receiver User Guide 15
2
Overview
16 AgGPS 252 Receiver User Guide
C H A P T E R
3
3
In this chapter:
Q System Components
Q Mounting the Receiver
Q Connecting to an External Device
Q Connectors and Pinouts
This chapter describes how to check the equipment that you have
received, set up the receiver, and connect the receiver to another
device.
AgGPS 252 Receiver User Guide 17
3
Installing the Receiver
3.1
System Components
Check that you have received all components for the AgGPS system
that you have purchased. If any containers or components are
damaged, immediately notify the shipping carrier. Components are
listed in the following tables.
Table 3.1
AgGPS 252 receiver (P/N 55500-XX)
Quantity
Description
1
1
1
1
1
AgGPS 252 DGPS receiver (P/N 55500-01)
System level cable (P/N 50165 or 50166)
Mounting plate assembly (P/N 51312-00)
Port B plug (P/N 51062)
AgGPS 252 Receiver User Guide
(this manual, P/N 55510-00-ENG)
1
1
Warranty Activation Card (P/N 25110-00)
OmniSTAR Activation Card (P/N 33965)
31.1
Optional extra
You may also have ordered the following item:
Table 3.2
Receiver option
Quantity
Description
1
RTK capability (P/N 51264)
18 AgGPS 252 Receiver User Guide
Installing the Receiver
3
3.2
Mounting the Receiver
WARNING – For continued protection against the risk of fire, the power
source (lead) to the model AgGPS 252 receiver should be provided with a
10 A (maximum) fuse.
C
Secure the AgGPS 252 receiver directly to the mounting plate assembly
(P/N 51312-00) and insert three bolts through the holes that are in the
housing and in the mounting plate assembly. Torque the bolts to 75–
80 inch pounds.
32.1
Choosing a location
When choosing a location, consider the following:
Mount the receiver:
•
•
on a flat surface along the centerline of the vehicle
in any convenient location that is within 5.5 meters (18 ft) of the
port on the external instrument; if necessary, use the optional
extension cable to connect the receiver and external device
Note – If you are using a Trimble AgGPS Autopilot system,
please refer to the installation instructions that are provided
with the Autopilot.
•
•
at the highest point on the vehicle, with no metal surfaces
blocking the receiver’s view of the sky
in such a way that it is not damaged when you drive the machine
into a shed or storage area
Do not mount the receiver:
•
close to stays, electrical cables, metal masts, CB radio antennas,
cellular phone antennas, air-conditioning units (machine cab
blower fan), or machine accessory lights
•
near transmitting antennas, radar arrays, or satellite
communication equipment
AgGPS 252 Receiver User Guide 19
3
Installing the Receiver
•
near areas that experience high vibration, excessive heat,
electrical interference, and strong magnetic fields
Note – A metal combine grain tank extension can block
satellites.
32.2
Environmental conditions
Although the receiver has a waterproof housing, you should install it in
a dry location. To improve the performance and long-term reliability of
the receiver, avoid exposure to extreme environmental conditions,
including:
•
•
•
•
•
water
excessive heat (> 70 °C or 158 °F)
excessive cold (< –30 °C or –22 °F)
high vibration
corrosive fluids and gases
32.3
Electrical interference
As far as possible, when you install the receiver, you should avoid
placing it near sources of electrical and magnetic noise, such as:
•
•
•
•
•
•
•
•
gasoline engines (spark plugs)
computer monitor screens
alternators, generators, or magnetos
electric motors (blower fans)
equipment with DC-to-AC converters
switching power supplies
radio speakers
high-voltage power lines
20 AgGPS 252 Receiver User Guide
Installing the Receiver
3
•
•
•
CB radio antennas
cellular phone antennas
machine accessory lights
3.3
Connecting to an External Device
After installing the receiver and connecting the appropriate cabling,
you can connect the receiver to various external devices. For example:
To connect the AgGPS 252
use the cable ...
receiver to ...
an Autopilot system
P/N 50165
(this cable has no DB9 connector)
a Field computer
a Yield monitor
P/N 50166
P/N 50166
P/N 49801
a Trimble SiteNet™ radio, for RTK
positioning
To convert the AgGPS 252 receiver to a Trimble 12-pin conxall cable,
use the adapter cable (P/N 50581).
Plug the ...
into ...
Deutsch 12-pin connector
straight DB9-pin connector
power connectors
Port A on the back of the receiver
the external device
a power supply
Note – Do not bend the cable at the Deutsch connector. When you secure
the cable, use the supplied P-Clip. The P-Clip provides additional support
to the connectors and reduces the risk of damage.
AgGPS 252 Receiver User Guide 21
3
Installing the Receiver
Figure 3.1 shows how to connect the receiver to an external device
using the system level cable (P/N 50166).
LED indicator
AgGPS 252 receiver
Port A
Port B
Deutsch 12-pin
System level
cable (P/N 50166)
DB9
To external
device
Ground –ve
Power +ve
Figure 3.1
Standard power/data cable connections
When routing the cable from the receiver to the external device, avoid:
•
•
•
•
•
sharp objects
kinks in the cable
hot surfaces (exhaust manifolds or stacks)
rotating or moving machinery parts
sharp or abrasive surfaces
22 AgGPS 252 Receiver User Guide
Installing the Receiver
3
•
•
door and window jams
corrosive fluids or gases
Note – Do not bend the cable at the Deutsch connector. When you secure
the cable, use the supplied P-Clip. The P-Clip provides additional support
to the connectors and reduces the risk of damage.
tie-wraps to secure it at several points, particularly near the base of the
receiver, to prevent straining the connection. Coil any slack cable,
secure it with a tie-wrap, and tuck it into a safe place.
The external device may have to be configured to work with the AgGPS
252 receiver. The configuration tools for the external device should be
provided with the device. For more information about configuring the
receiver, see Chapter 4. For information about connecting a particular
external device, refer to the manual for that device or contact your local
Trimble Reseller.
Note – Use a connector plug (P/N 51062) to cover Port B when that port is
not in use. For example, cover Port B when you are using the receiver in a
non-RTK mode.
AgGPS 252 Receiver User Guide 23
3
Installing the Receiver
3.4
Connectors and Pinouts
Use the following pinout information if you need to wire a cable for use
with the AgGPS 252 receiver.
1
2
3
4
9
5
8
6
7
12
11
10
Figure 3.2
AgGPS 252 receiver port pinout
34.1
Port A
Port A on the receiver has a 12-pin Deutsch DTM connector. For cables,
use the mating connector, Deutsch part number DTM06-12SA.
Viewed from outside the receiver, the Port A connector is on the left. It
is the port that is typically used to connect to an Autopilot system.
Table 3.3
Port A pinout
Pin
1
Name/Function
CAN A High I/O
Comments
2
Port 1 RS232 Tx OUT
When held to ground during power up,
puts unit into Monitor mode
3
4
Port 1 RS232 Rx IN
PPS OUT
24 AgGPS 252 Receiver User Guide
Installing the Receiver
3
Table 3.3
Port A pinout (continued)
Pin
Name/Function Comments
5
Signal GND
Used for RS232 and other signals. Should
not be connected to
V– (battery negative)
6
Port 1 RTS OUT
Event OUT / Alarm OUT
Port 1 CTS IN
Event IN
7
8
9
10
11
12
V+ IN
V- IN
CAN A Low I/O
34.2
Port B
This port has the same connector as Port A, see above. Viewed from
outside the receiver, the Port B connector is on the right. It is the port
that is typically used to connect to the SiteNet 900 radio.
Table 3.4
Port B pinout
Pin
1
Name/Function
CAN B High I/O
Port 2 RS232 Tx OUT
Port 2 RS232 Rx IN
PPS OUT
Comments
2
3
4
5
Signal GND
Used for RS232 and other signals.
Should not be connected to V–
(battery negative)
6
Port 2 RTS OUT
or Port 3 RS232 Tx OUT
7
8
Event OUT / Alarm OUT
Port 2 CTS IN or Port 3
RS232 Rx IN
AgGPS 252 Receiver User Guide 25
3
Installing the Receiver
Table 3.4
Port B pinout (continued)
Pin
9
Name/Function Comments
Event IN
10
11
12
V+ IN / OUT
V– IN / OUT
CAN B Low I/O
Maximum output current = 1.25 A
Maximum output current = 1.25 A
26 AgGPS 252 Receiver User Guide
C H A P T E R
4
In this chapter:
Q AgRemote Home Screen
Q Configuring Differential GPS
Q Configuring the AgGPS 252 Receiver to Operate in RTK Mode
Q Configuring the Communication Ports
Use either the Autopilot interface or the Trimble AgRemote utility to
change configuration settings in the AgGPS 252 receiver. You will need
to configure the receiver if you connect to a third-party device, for
example.
•
If a Trimble AgGPS Autopilot system is configured to use an
AgGPS 252 receiver, and the port on the receiver is set to
receiver.
•
The AgRemote utility is available from the Trimble website
(www.trimble.com). This chapter describes how to use the utility
to perform some common configurations.
Note – OmniSTAR VBS and HP are subscriber services that need to be
activated. For more information, see OmniSTAR, page 29.
AgGPS 252 Receiver User Guide 27
4
Configuring the Receiver
4.1
AgRemote Home Screen
Figure 4.1 shows the AgRemote Home screen when WAAS corrections
are being received.
Number of GPS satellites being tracked
Position type
Current PDOP value
GPS indicators
D/3D í07 DOP03
WAAS 122 ÷ø04
Correction
indicators
Correction type
Signal-to-Noise ratio
of DGPS satellite
DGPS satellite name or ID
Figure 4.1
AgRemote Home screen
For more information about these fields and how they change as you
change GPS mode, refer to the document called AgRemote Software on
Reseller.
4.2
Configuring Differential GPS
For the receiver to output GPS position coordinates of submeter
accuracy, you must first select a differential signal from one of the
following sources:
•
WAAS/EGNOS – free service, limited availability
The Wide Area Augmentation System (WAAS) augments GPS
with additional signals for increasing the reliability, integrity,
accuracy, and availability of GPS in the United States. The
European Geostationary Navigation Overlay System (EGNOS) is
the European equivalent of WAAS.
28 AgGPS 252 Receiver User Guide
Configuring the Receiver
4
•
OmniSTAR – paid subscription, available worldwide
You can use this paid service as an alternative to WAAS/EGNOS.
It provides over-the-air DGPS activation.
For more information, see Differential GPS positioning (DGPS),
page 11.
42.1
OmniSTAR
The AgGPS 252 receiver can use OmniSTAR corrections. To do this, you
need to configure the receiver and purchase an OmniSTAR
subscription.
Note – To track the OmniSTAR satellite, the receiver must be outside with
a clear view of the sky, turned on, and configured to receive OmniSTAR
VBS or HP corrections.
To use the AgRemote utility to activate an OmniSTAR subscription:
1. Connect the AgGPS 252 receiver to the computer. Turn on the
receiver and start the AgRemote utility. For instructions on how
to use AgRemote, refer to the AgRemote documentation.
2. In AgRemote, select Configuration / DGPS Config.
3. Set the Source Select field to one of the following:
–
–
Omnistar HP
Omnistar VBS
4. Set the EZ Sat: Omni* field to the area you are operating in. For
example, if you are working in California, select N. America West.
5. Press 4 then 5 to complete the procedure.
6. Obtain an OmniSTAR licence from OmniSTAR. All licenses are
activated over the air. Contact OmniSTAR on
1-888-883-8476 (USA or Canada) and provide the following
details:
–
your billing information
AgGPS 252 Receiver User Guide 29
4
Configuring the Receiver
–
–
serial number
satellite beam name
OmniSTAR will activate the receiver. Activation can take
5–30 minutes.
40.1
WAAS/EGNOS
WAAS is a free satellite-based DGPS service that is available only in
North America; EGNOS is a free satellite-based DGPS service that is
available only in Europe.
To use the WAAS/EGNOS DGPS signal, you must first configure the
receiver.
1. Connect the AgGPS 252 receiver to the computer. Turn on the
receiver and start the AgRemote utility.
2. In AgRemote, select Configuration / DGPS Config.
3. Set the Source Select field to WAAS.
4. Press 4 then 5 to complete the procedure.
To enable WAAS reception in the field:
1. Take the receiver outside. Make sure that it has a clear southeast
and southwest view of the sky.
2. Turn on the receiver. WAAS activation can take two or more
minutes. Once activation succeeds, the Home screen displays
D/3D.
30 AgGPS 252 Receiver User Guide
Configuring the Receiver
4
4.1
Configuring the AgGPS 252 Receiver to
Operate in RTK Mode
Use the AgRemote utility to configure the AgGPS 252 receiver for
operation in RTK mode. To configure the receiver:
1. Connect the AgGPS 252 receiver to the computer. Turn on the
receiver and start the AgRemote utility.
2. In AgRemote, select Configuration / DGPS Config.
3. Set the Source Select field to RTK.
4. Press 4 then 5 to complete this part of the procedure.
5. For RTK operation, connect the radio to a port. Change the port
input settings for that port to RtkLnk.
4.1
Configuring the Communication Ports
If the AgGPS 252 receiver is to be connected to an external device,
configure Ports A and B so that the proper data type is input to and
output from the receiver.
AgGPS 252 Receiver User Guide 31
4
Configuring the Receiver
To configure Port A:
1. Connect the AgGPS 252 receiver to the computer. Turn on the
receiver and start the AgRemote utility.
2. In AgRemote, select Configuration / Port A Config.
3. Use the menu commands to configure the communication
ports. Ensure that the receiver outputs the correct GPS position
data type for the hardware device or software program that is
connected to the receiver.
•
Repeat the above steps but in Step 2 select Configuration / Port B
Config.
40.1
Configuring input/output communication
The port input and output settings appear in the first screen. In
Figure 4.2, the port is set to accept TSIP inputs at a baud rate of 115,000
with a parity of 8-Odd-1. The outputs are TSIP, also at a baud rate of
115,000.
Figure 4.2
Communication settings
32 AgGPS 252 Receiver User Guide
Configuring the Receiver
4
Configure the Port Input/Output communication settings for
communicating with the AgGPS Autopilot, other external hardware
devices, and software programs. Table 4.1 describes the input settings.
Table 4.1
Port input settings
Setting
None
Description
Inputs nothing to the receiver.
TEXTB
The receiver can accept ASCII data from an external device, such
as a chlorophyll meter, on Port A, merge it with NMEA GPS data,
and output the combined data on Port B. The incoming data
must be limited to 66 ASCII characters and terminated by a
carriage return and line feed (hex characters 0x0D 0x0A). The
NMEA string outputs as $PTNLAG001,<up to 66 ASCII
characters>*<2 digit checksum><CR><LF>. For the receiver to
output the combined NMEA string, NMEA must be selected as
the output protocol on Port B.
TEXTA
See the description for the TEXTB setting (above). TEXTA input
outputs text on Port A. The default port settings are 8-N-1 TSIP
38.4 K. These may vary by product.
RTCM
TSIP
The receiver can accept RTCM data from an external DGPS device,
such as an external radio.
The receiver can accept or output TSIP data packets from the port
when using the optional AgRemote program or using the AgGPS
170 Field Computer.
RtkLnk
The receiver can accept real-time corrections (CMR data) from an
external device such as a Trimble radio.
The default port settings are:
Port A
Port B
Baud rate
In
TSIP 38,400
TSIP 38,400
Out
TSIP 38,400
TSIP 38,400
Data bits
Parity
8
8
None
1
None
1
Stop bits
AgGPS 252 Receiver User Guide 33
4
Configuring the Receiver
Note – The AgRemote utility, when connected to an AgGPS 252 receiver
receiver, automatically resets the receiver port communication settings to
8-O-1 TSIP 115 K. This enables optimal communication with an office
computer. If the receiver is to work with an Autopilot system, however, the
receiver port communication settings must be 8-N-1 TSIP 38.4 K. To work
with some other devices and software programs, the receiver port
communication settings must be 8-N-1 NMEA 4800. If AgRemote has
changed the settings, you will need to change them back manually.
When using a Trimble SiteNet 900 radio, make sure that the
communication settings are correct in the receiver.
The default settings to use with the SiteNet radio are:
Setting
Baud rate
Data bits
Parity
Description
38,400
8
None
1
Stop bits
Changing the input or output port settings
1. From the Port A Config screen, press 2 until the Port-A
Input/Output screen appears:
åæ I RTCM 9600
8N1 0 NMEA 4800
2. Press 3 to activate the cursor.
3. Press 1 or 2 to change the value.
4. Press 3.
5. Repeat Steps 3 and 4 until you have set all the required values.
6. Press 4 to save all the changes.
7. Press 2 to move to the next screen.
34 AgGPS 252 Receiver User Guide
Configuring the Receiver
4
NMEA settings
Three screens (NMEA1, NMEA2, and NMEA3) show what NMEA
messages are output from the port. Message types shown in upper case
are being output; message types shown in lower case are not.
For more information about NMEA message types, refer to the
document called NMEA-0183 Messages Guide for AgGPS Receivers on
the Trimble website (www.trimble.com).
Port output rate
This setting can be used to vary the NMEA and TSIP output rate. A
setting of 1 outputs one position each second.
ASAP equals the rate selected on the Filter and Position Rate screen
under the GPS Config menu. A setting of ASAP outputs positions five or
ten times every second. The default ( factory) setting is 1 Hz.
AgGPS 252 Receiver User Guide 35
4
Configuring the Receiver
36 AgGPS 252 Receiver User Guide
C H A P T E R
5
5
In this chapter:
Q
Q Problems and Solutions
Q Troubleshooting Flowcharts
This chapter describes some problems that can arise and explains how
to solve them. It includes a series of flowcharts to help with
troubleshooting.
As you work through this chapter, you may need to view the receiver
status or change values in some fields. For information on how to do
this, refer to the document called NMEA-0183 Messages Guide for
AgGPS Receivers. This document is on the Trimble website
5.1
Problems and Solutions
If you encounter a problem, try the following solutions.
AgGPS 252 Receiver User Guide 37
5
Troubleshooting
Global Positioning System (GPS)
Problem
Possible solution
Poor accuracy
The accuracy of GPS positions is poor
because the receiver is picking up
poor quality signals from the
satellites.
Change some or all of the following GPS settings:
• Minimum elevation – Increase the setting
(the default is 8°).
• Minimum Signal Strength – Increase the System Mask AMU
setting (the default is 3).
• Maximum PDOP – Decrease the setting
(the default is 13).
• GPS Mode – Change to Manual 3D
(the default is Auto 2D/3D).
The receiver always calculates the
most accurate position it can, given
the current GPS satellite differential
operating conditions.
• DGPS Mode – Change to DGPS
(the default is DGPS Auto/On/Off).
GPS signals are reflecting off nearby
trees and/or metal buildings and
horizontal surfaces.
To reduce multipath noise, mount the GPS receiver
must be away from trees and large metal objects.
Intermittent loss of lock on
satellite
The receiver loses the satellite signal
from time to time.
Make sure that the receiver is mounted on the
highest point of the vehicle and is clear of metal
surfaces.
Check Maximum PDOP and Minimum Signal
Strength settings (see Poor accuracy, above).
Intermittent DGPS signal
The correction signal strength can
drop to unusable levels. Causes
include tree canopy cover between
the receiver and the differential
satellite, radar sets, and microwave
transmitters.
Move the receiver away from the tree cover and/or
from sources of electromagnetic interference.
38 AgGPS 252 Receiver User Guide
Troubleshooting
5
Problem
Possible solution
Tracking but not receiving a
differential signal
The receiver is tracking satellites and
tracking an OmniSTAR satellite
beam, but is not receiving DGPS
signals. The Home screen indicates
how many satellites are being
tracked, and whether a differential
source is being tracked.
Check that your DGPS service subscription is still
current and enabled.
For OmniSTAR service:
following screens, depending on what you are
using:
•
the Omni HP Info
You see:
h-3D for HP not converged
H-3D for HP converged
r-3D for RTK float
R-3D for RTK fixed
D-3D for DGPS
Omni VBS Info
2. Press 4 until Stop Date
If the message Access Unknown appears, contact
OmniSTAR to reactivate your subscription. For more
information, see OmniSTAR, page 29.
HP and RTK also give an indication
of positional accuracy on the Home
screen (AgRemote).
The receiver must be switched on and configured to
track the correct satellite coverage beam before it
can be reactivated.
The receiver automatically tracks the correct beam
based on receiver geographic location. If the receiver
is manually changed, automatic tracking is
deactivated until you perform a hard reset or
firmware flash.
When a satellite subscription is activated, the Home
screen displays D/3D.
AgGPS 252 Receiver User Guide 39
5
Troubleshooting
Problem
Possible solution
No GPS position output from the
receiver after connecting to
AgRemote
When the receiver is connected to
the AgRemote utility, AgRemote
automatically resets the port
communication settings on the
receiver to 8-O-1 TSIP 115 K for both
input and output. This enables
optimal communication with an
office computer.
Connect AgRemote. Then reset the port
communication settings to NMEA output. For more
information, see Configuring the Communication
Ports, page 31.
If the receiver is to work with an
Autopilot system, however, the
receiver port communication
settings must be 8-N-1 TSIP 38.4 K.
To work with some other devices
and software programs, the receiver
port communication settings must
be
8-N-1 NMEA 4800. If AgRemote has
changed the settings, you will need
to change them back manually.
Long time to initialize
In RTK mode, longer baselines
require longer initialization times.
(The baseline is the distance
between the base receiver and the
rover receivers.)
Wait for the receiver to initialize or consider
repositioning the base receiver to shorten the
baseline. Make sure the rover is in a clear area.
Loss of initialization
In RTK mode initialization can be
lost when the rover receiver is close
to trees or buildings and the number
of satellites falls below four.
Additionally, initialization may be
lost if the receiver has not been
tracking RTK corrections for some
time. For more information, see the
next item.
Move away from trees and obstructions to initialize.
Once initialized, approach the obstructed area
again. If the obstructions are severe, GPS positioning
may not work in that area.
Because the GPS satellites move, there may be times
of the day when you are working in an area with
obstructions. For more information, see the Trimble
Planning software on the Trimble website
40 AgGPS 252 Receiver User Guide
Troubleshooting
5
Problem
Possible solution
Not tracking RTK corrections
The radio link is down or
intermittent.
• Ensure that the line-of-sight between the base and rover
receivers is not obstructed.
• Ensure that the rover receiver is within range of the radio.
• Ensure that the radio power supply is on.
AgGPS 252 Receiver User Guide 41
5
Troubleshooting
Interference
Problem
Possible solution
Strong magnetic fields
Strong magnetic fields have no
effect on GPS or satellite DGPS
signals.
If you suspect interference from a local magnetic
field, move the receiver away from, or turn off, the
suspect electronics while observing the number of
satellites being tracked on the receiver or the signal-
to-noise ratio (SNR) of the satellite. If the SNR goes
up when the electronics are turned off, there may be
interference from the local electronics.
However, some computers and other
electric equipment radiate
electromagnetic energy that can
interfere with a GPS receiver.
FM 2-way radios
Transmitting FM 2-way radios can
interfere with OmniSTAR, WAAS,
and GPS signal reception.
Make sure that there is at least 1 m (3 ft) between
the FM 2-way radio antenna and the receiver.
Engine noise
An unshielded ignition system can
cause enough noise to block
Use resistor spark plug wires on the vehicle ignition
system.
reception of a differential signal.
An alternator can cause noise that
interferes with a differential signal.
Use bypass capacitors, commonly available in
automotive stores for cleaning up interference to CB
and other radios. If the problem persists, shield
engine components with aluminum foil.
Relocate the antenna on the machine.
Determine the optimal antenna location by
watching the SNR value on the AgRemote Home
screen.
Note – Before replacing engine parts in an attempt
to solve this problem, make sure that the problem is
not caused by a computer or power source near the
receiver. Some computers and their power sources
cause noise that disrupts GPS and satellite DGPS
signals.
42 AgGPS 252 Receiver User Guide
Troubleshooting
5
GPS receiver
Problem
Possible solution
Mounting location
The receiver is not picking up a clear
signal.
Mount the receiver on the centerline of the vehicle,
away from any sources of interference and with a
clear view of the sky (see Choosing a location,
page 19).
Cables
One of the cables seems faulty.
Use an ohmmeter to check the cable. The resistance
of a good cable between connector pins at each end
of the cable is zero.
If the cable is sound, but the problem persists, try
exchanging the cable with one that you know is
working.
If the cable is defective, contact your local Trimble
Reseller for an RMA number (if the Trimble product
is still under warranty), or to purchase a replacement
cable.
Real-time clock battery
A lithium-ion battery in the receiver
powers the internal real-time clock
and so enables the receiver to get a
first fix faster. The battery has a life
of 7.5 years. When the battery fails,
the internal clock cannot keep
Please contact your local Trimble Reseller to get
the batteries replaced. You cannot replace the
battery yourself.
accurate time and the receiver may
take longer to output GPS positions.
Factory defaults
You need to restore the receiver
factory defaults.
To restore receiver factory default settings:
Connect the receiver to a computer. Turn on the
receiver.
2. Run the AgRemote utility.
3. Navigate to the Clear BB RAM
4. Press 2 until Yes appears.
5. Press 4.
The factory default settings are restored. The DGPS
service subscription is not lost.
AgGPS 252 Receiver User Guide 43
5
Troubleshooting
AgRemote utility
Problem
Possible solution
AgRemote cannot communicate
with the receiver. All you see is a
blank screen.
Make sure that:
• the receiver is connected to a 12–32 V DC power source
• all cable connections between the receiver and the
computer are secure
• you are using the correct COM port
Select File / Connect
FlashLoader 200 upgrade utility
Problem
Possible solution
The FlashLoader 200 upgrade utility
cannot detect the receiver or
download the firmware.
Make sure that:
• Other programs, such as AgRemote and Microsoft®
ActiveSync® technology, are not using the COM port that the
computer is using.
• The receiver is connected to a 12–32 V DC power source.
• All cables are connected correctly between the device and
the computer.
• The receiver is connected to the correct computer COM
port. To do this:
From the FlashLoader 200 menu, select
Settings
Select the check box for a serial link.
3. At Port, select Auto. Click OK.
4. Select the Upload firmware to receiver
Proceed
6. From the Auto Port Select dialog,
receiver on port... OK
Use
Once you have checked this, turn off the receiver
then turn it on again. Try again to connect
FlashLoader 200.
44 AgGPS 252 Receiver User Guide
Troubleshooting
5
5.1
Troubleshooting Flowcharts
These flowcharts describe how to troubleshoot problems in the
following areas:
•
•
•
•
•
system hardware and power
GPS reception (no third-party device attached)
GPS reception (third-party device attached)
OmniSTAR positioning
RTK (using the AgRemote utility)
In addition, you may find it useful to review Chapter 3, Installing the
Receiver.
AgGPS 252 Receiver User Guide 45
5
Troubleshooting
46 AgGPS 252 Receiver User Guide
Troubleshooting Flowcharts
52 AgGPS 252 Receiver User Guide
A P P E N D I X
A
Specifications
A
A.1
AgGPS 252 Receiver
Table A.1 lists the physical characteristics of the AgGPS 252 combined
GPS/DGPS receiver and antenna:
Table A.1
AgGPS 252 receiver
Item
Description
Size
300 mm (11.7 in) wide x 309 mm (12.05 in) deep x 70 mm
(2.73 in) high
Weight
Power
2.1 kg
Nominal 350 mA at 12 V DC
Operating temperature
Storage temperature
Humidity
–30 °C (–22 °F) through +70 °C (+158 °F)
–40 °C (–40 °F) through +85 °C (+185 °F)
Complies with Mil 810E Method 507.3 Procedure III Aggravated
Cyclic Humidity.
Ten 24 hour cycles of constant 95% RH, with cycling
temperature and dwells +30 °C (+86 °F) and +60 °C (140 °F).
Unit sealed to +/- 5 PSID
Casing
Low-profile UV-resistant plastic. Dust-proof, waterproof, shock
resistant, with recessed protected connectors.
Connectors
12-pin Deutsch connectors
AgGPS 252 Receiver User Guide 53
A
Specifications
Table A.1
AgGPS 252 receiver (continued)
Item
Description
Ports
Two connection ports, both of which support RS-232 and CAN
Mounting
Compliance
Three holes for 10 mm (0.39 in) bolts
FCC Part 15 Class A, C-Tick, E-mark,
CE-mark
A.2
GPS Channels
Table A.2 lists the performance characteristics of GPS channels.
Table A.2
GPS channels performance
Description
Item
General
12-channel, parallel tracking L1 1571.42 MHz and L2
1227.60 MHz. C/A code and carrier phase filtered measurement.
Update rate
1, 5, 10 Hz
RTK speed accuracy
0.16 kph (0.10 mph)
RTK position accuracy
Horizontal 2.5 cm (0.98 in) + 2 ppm, 2 sigma, and vertical 3.7 cm
(1.46 in) + 2 ppm, 2 sigma, if all of the following criteria are
met:
• At least 5 satellites
• PDOP <4
• CMR corrections
• Standard format broadcast from a Trimble MS750, AgGPS 214,
or equivalent reference station
Differential speed accuracy
0.16 kph (0.1 mph)
Differential position
accuracy
Less than 1 m (3.28 ft) horizontal if all of the following criteria
are met:
• At least 5 satellites
• PDOP <4
• RTCM SC-104 corrections
• Standard format broadcast from a Trimble MS750, AgGPS 214,
or equivalent reference station
OmniSTAR HP speed
accuracy
0.16 kph (0.1 mph)
54 AgGPS 252 Receiver User Guide
Specifications
A
Table A.2
Item
GPS channels performance (continued)
Description
OmniSTAR HP position
accuracy
10 cm (3.94 in) after convergence, 2 sigma, if all the following
criteria are met:
• At least 5 satellites
• PDOP <4
• OmniSTAR HP corrections
Convergence time can vary, depending on the environment.
Time to the first fix (submeter accuracy) is typically <30 seconds;
time to the first useable fix (<10 cm accuracy) is typically
<30 minutes.
Time to first fix
<30 seconds, typical
Multipath mitigation
EVEREST technology
Satellite differential
compatibility
OmniSTAR, WAAS, and EGNOS
1
NMEA messages
GGA 1 1 , GLL, GSA1, GST, GSV, GST, MSS, PTNLDG, PTNL PJK,
PTNL PJT, PTNL VGK, PTNL VHD, PTNLEV, PTNLID, PTNLSM,
RMC1, VGK, VTG1, XTE, ZDA
1
By default, the receiver is configured to output GCA, GSA, RMC, and VTG messages at a 1 Hz
(1 position per second) update rate.
A.3
L-Band Satellite Differential Correction
Receiver
Table A.3 lists the characteristics of the L-band satellite differential
correction receiver with OmniSTAR support.
Table A.3
L-Band satellite differential correction receiver with
OmniSTAR support
Item
Description
-5
Bit error rate
10 for Eb/N of >5.5 dB
Acquisition and reacquisition time
Frequency band
<5 seconds, typical
1525–1559 MHz
0.5 kHz
Channel spacing
AgGPS 252 Receiver User Guide 55
A
Specifications
A.4
Receiver Default Settings
Table A.4 lists the receiver default settings.
Table A.4
Receiver default settings
Item
Description
DGPS source
Dynamics
WAAS/EGNOS
Land
Minimum elevation
AMU mask
8°
3
PDOP mask
13
PDOP 2D/3D switch
DGPS mode
11
Auto On/Off
250 seconds
1 Hz
DGPS correction age limit
Pos fix rate
56 AgGPS 252 Receiver User Guide
A P P E N D I X
B
Requirements
B
B.1
Third-Party Software
Table B.1 lists the interface requirements for connecting an AgGPS
receiver to third-party software.
Use cable P/N 50166, or 30945 plus 50581, when connecting to the
third-party software products listed.
Table B.1
Third-party software interface requirements
Software
AgView
Company
GIS Solutions
Red Hen
Protocol NMEA messages Baud
Other Pos rate
NMEA
NMEA
VTG, GLL
4800
4800
4800
8-N-1
8-N-1
8-N-1
1Hz
1Hz
1Hz
FarmGPS
Field Rover
GGA, GSA, VTG
SST Dev Group NMEA
GGA, GSA, GSV,
VTG
FieldLink DOS
Agris
NMEA
NMEA
NMEA
GGA, GSA, VTG
4800 or 8-N-1
9600
1Hz
1Hz
1Hz
FieldLink
Windows
Agris
GGA, GSA, VTG
4800 or 8-N-1
9600
Field Worker
Pro
Field Worker
GGA, GLL, RMC,
VTG
4800 or 8-N-1
9600
AgGPS 252 Receiver User Guide 57
B
Third-Party Interface Requirements
Table B.1
Third-party software interface requirements (continued)
Software
Company
Protocol NMEA messages Baud
Other Pos rate
HGIS
Starpal
NMEA
NMEA
NMEA
GGA, RMC
4800 or 8-N-1
9600
1Hz
1Hz
1Hz
1Hz
Instant Survey
Pocket Survey
Sitemate
Agrilogic
(Case-IH)
GGA, GSA, RMC
GGA, GSA, RMC
GGA, VTG
4800
8-N-1
8-N-1
8-N-1
Agrilogic
(Case-IH)
4800
4800
Farmworks
B.2
Third-Party Hardware
Table B.2 lists the interface requirements for connecting an AgGPS
receiver to third-party hardware.
Table B.2
Hardware
Third-party hardware interface requirements
Company
Protocol NMEA
messages
Baud
Other Pos
rate
Cable P/N
AMS
Raven
NMEA
RTCM
NMEA
GGA, VTG
9600
9600
8-N-1 1Hz
8-N-1 10Hz
Ag Navigator Springhill
Aim
Case Tyler
GGA
19200 8-N-1 5Hz
50166, or
30945 plus
50581
Navigator
Contour
Marker
Position Inc.
NMEA
NMEA
GGA
GGA
19200 8-N-1 5Hz
19200 8-N-1 5Hz
RDS or
Position Inc.
Falcon
Ag Chem
NMEA
GGA, VTG
4800
8-N-1 1Hz
58 AgGPS 252 Receiver User Guide
Third-Party Interface Requirements
Third-party hardware interface requirements (continued)
B
Table B.2
Hardware
Company
Protocol NMEA
messages
Baud
Other Pos
rate
Cable P/N
Falcon w/
Falcon Track
LBAR
Ag Chem
NMEA
GGA, VTG
19200 8-N-1 10Hz
Swath Smart Raven, Starlink NMEA
GGA, VTG
or RMC
19200 8-N-1 10hz
or RGL 500
(LB-5 for
Raven)
manufactured
50166, or
30945 plus
50581
LB-3, LB-4,
and LB-5
Starlink
NMEA
NMEA
GGA, VTG
or RMC
19200 8-N-1 10hz
YM2000
Yield
Ag Leader
GGA, VTG
4800
8-N-1 1 Hz
39903 plus
50581
1
Monitor
PF3000 Yield Ag Leader
Monitor
NMEA
NMEA
GGA, VTG
GGA, VTG
4800
4800
8-N-1 1 Hz
8-N-1 1 Hz
39903 plus
50581
1
PF3000Pro
Monitor
without
Ag Leader
39903 plus
50581
internal GPS
2
AFS Yield
Monitor
Case-IH
(Ag Leader
YM2000)
NMEA
GGA, VTG
GGA, VTG
4800
4800
8-N-1 1 Hz
8-N-1 1 Hz
32609 plus
50581
AFS Yield
Monitor
Case-IH YMIU NMEA
(yield monitor
interface unit)
manufactured
by Ag Leader
32609 plus
50581
for Case-IH
GreenStar
Yield
Monitor
John Deere
NMEA
NMEA
GGA, GSA, 4800
RMC
8-N-1 1 Hz
8-N-1 1 Hz
34189 plus
50581
3
New Holland New Holland
Yield
Monitor
GGA, VTG
4800
39903 plus
50581
(Ag Leader
PF3000)
AgGPS 252 Receiver User Guide 59
B
Third-Party Interface Requirements
Table B.2
Hardware
Third-party hardware interface requirements (continued)
Company
Protocol NMEA
messages
Baud
Other Pos
rate
Cable P/N
VCD (Vision
Display
Controller)
Rockwell
NMEA
NMEA
NMEA
NMEA
GGA, GLL,
VTG, ZDA
4800
8-N-1 1 Hz
50166, or
30945 plus
50581
Swath XL
Midtech
Claus
GGA
GGA
19200 8-N-1 5 Hz
50166, or
30945 plus
50581
Caterpillar
Cebis Yield
Monitor
4800or 8-N-1 1 Hz
9600
50166, or
30945 plus
50581
AGCO
FieIdStar
Yield
AGCO
GGA, VTG, 4800
GSV, GSA
8-N-1 1 Hz
39903 plus
50581
4
Monitor
1 P/N 39903 replaced old Ag Leader cable P/N 30660.
2 Connect to Aux port.
3 Older GreenStars with version 5.3P mapping processor software require 9600 baud. Older GreenStars
with version 5.3R mapping processor software require 4800 baud.
4 AGCO unit requires a null modem RS-232 connection. Ag Leader cable P/N 39903 is wired correctly for
connection.
60 AgGPS 252 Receiver User Guide
Index
ASCII input 6
Numerics
1 PPS output 7
A
accuracy 4, 10
adapter cable 21
Ag Navigator 58
cables 6
routing 22
SiteNet radio 21
centimeter-level accuracy 10
changing
troubleshooting 44
AgView 57
Aim Navigator 58
altitude 13
battery 43
AMS 58
antenna
correction source 29
port setting and protocol 33
characteristics 53
electrical interference 20
location of 19
Class A digital device, FCC notice iii
mounting 20
AgGPS 252 Receiver User Guide 61
Index
CMR
enhancements 18
COM port 44
components 18
environmental conditions for receiver 20
European Geostationary Navigation Overlay
configuring
RTK 31
connectors 6
specification 53
Contour 58
Controller Area Network bus protocol see
CAN bus protocol
convergence 12
factory defaults 43
Falcon 58
Field Rover 57
D
FieldLink Windows 57
data/power cable 6
Declaration of Conformity iii
default settings, receiver 56
Differential GPS (DGPS) positioning
method 11
free corrections 11
GPS Mode 38
GPS positioning methods 9
GPS positions
E
EGNOS
output format 7
output of 14
accuracy 10
DGPS, configuring 30
website 11
electrical interference, sources of 20
62 AgGPS 252 Receiver User Guide
GPS reception
troubleshooting 48
longitude 13
Marker 58
H
hardware
third-party 58
troubleshooting 47
HGIS 58
GPS channels 55
Home screen
NMEA
New Holland Yield Monitor 59
NMEA
I
information, more 2, 7, 28
inputs 6
output 6, 35
protocol 5
Instant Survey 58
ISO 11783 4
web document 7
J
HP Differential GPS positioning
method 9, 10, 11
satellite beam 39
troubleshooting 50
VBS Differential GPS positioning
method 10, 11
L
latitude 13
LB-3, LB-4, LB-5 59
LED indicator 8
location of antenna 19
location of receiver 19
website 12
optional extras 18
AgGPS 252 Receiver User Guide 63
Index
output 6
TSIP 5
overview 3
P
P-clip 21
PDOP 13
PDOP Mask 38
physical characteristics 53
Pocket Survey 58
ports 4
number of satellites 13
radio connection 21
troubleshooting 51
CAN, ISO 11783 support 7
setting output rate 35
troubleshooting (third-party
positioning method
power
release notes 2
RS-232 4, 54, 60
specification 53
troubleshooting 47
protocol
RTCM
input 6
output 6
CAN bus 7
NMEA 5
protocol 5
website 6
RTCM 5
RtkLnk 6
RTK see Real-Time Kinematic (RTK) GPS
positioning method
64 AgGPS 252 Receiver User Guide
RtkLnk protocol 6
troubleshooting
battery 43
cables 43
GPS reception 48
intermittent DGPS 38
S
Satellite Differential GPS positioning
method 8
satellite history (ephemeris) file 13
settings 33
Sitemate 58
size, specification 53
software
positioning method 51
receiver location 43
restoring defaults 43
RTK 41
AgRemote 27
third-party 57
input 6
output 6, 35
specifications 53
standard features 4
Swath Smart 59
Swath XL 60
utility
AgRemote 27
FlashLoader 200 44
T
temperature, operating and storage
specification 53
V
vertical accuracy 4
Vision Display Controller 60
third-party
hardware 58
software 57
time 13
time to output positions 43
Trimble Standard Interface Protocol see TSIP
Trimble website 1
AgGPS 252 Receiver User Guide 65
Index
W
WAAS
accuracy 10
warnings
websites
NMEA 6
OmniSTAR 12
RTCM 7
SAE International 7
Trimble 1
WAAS 11
weight, specification 53
Wide Area Augmentation System see WAAS
Y
YM2000 Yield Monitor 59
66 AgGPS 252 Receiver User Guide
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