Trimble DSM 132RS, DSM 132 User Manual

DSM™ 132/132RS Receiver

User Guide



Version 1.73

Revision A

Part Number 50979-00-ENG

December 2003

Contact Information

Trimble Construction Instruments Division
5475 Kellenburger Road
Dayton, Ohio 45424-1099
USA

800-538-7800 (toll free in USA)
[phone] Phone
[phone] Fax

www.trimble.com

Copyright and Trademarks

© 1999-2003, Trimble Navigation Limited. All rights
reserved.

Trimble, the Globe & Triangle logo, the Sextant logo
with Trimble, and AgGPS are trademarks of Trimble
Navigation Limited, registered in the United States
Patent and Trademark Of fice and other countries.

DSM, EVEREST, HYDROpro, and TMS are
trademarks of Trimble Navigation Limited.

Microsoft and Windows are ei ther registered trademarks
or trademarks of Microsoft Corporation in the United
States and/or other countries.

All other trademarks are the property of their respective
owners.

Release Notice

This is the December 2003 release (Revision A) of the
DSM 132 Receiver User Guide, part number
50979-00-ENG. It applies to version 1.73 of the
DSM 132 receiver.

The following limited warranties give you specific legal
rights. You may have others, which vary from
state/jurisdiction to state/jurisdiction.

Hardware Limited Warranty

Trimble Navigation Limited warrants that this hardware
product (the “Product”) will perform substantially in
accordance with published specifications and be
substantially free of defects in material and
workmanship for a period of one (1) year starting from
the date of delivery. The warranty set forth in this
paragraph shall not apply to software products.

Software License, Limited Warranty

This Trimble software product, whether provided as a
stand-alone computer software product, built into
hardware circuitry as firmware, embedded in flash
memory, or stored on magnetic or other media, (the
“Software”) is licensed and not sold, and its use is
governed by the terms of the relevant End User License
Agreement (“EULA”) included with the Software. In the
absence of a separate EULA included with the Software
providing different limited warranty terms, exclusions
and limitations, the following terms and conditions shall
apply. Trimble warrants that this Trimble Software
product will substantially conform to Trimble’s

applicable published specifications for the Software for
a period of ninety (90) days, starting from the date of
delivery.

Warranty Remedies

Trimble's sole liability and your exclusive remed y under
the warranties set forth above shall be, at Trimble’s
option, to repair or replace any Product or Software that
fails to conform to such warranty ("Nonconforming
Product") or refund the purchase price paid by you for
any such Nonconforming Product, upon your return of
any Nonconforming Product to Trimble in accordance
with Trimble’s standard return material authorization
procedures.

Warranty Exclusions and Disclaimer

These warranties shall be applied only in the event and
to the extent that (i) the Products and Software are
properly and correctly installed, configured, interfaced,
maintained, stored, and operated in accordance with
Trimble's relevant operator's manu al and specifications,
and; (ii) the Products and Software are not modified or
misused. The preceding warranties shall not apply to,
and Trimble shall not be responsible for defects or
performance problems resulting from (i) the
combination or utilization of the Product or Software
with hardware or software products, information, data,
systems, interfaces or devices not made, supplied or
specified by T rim ble; (ii) th e operation of the Product or
Software under any specification other than, or in
addition to, Trimble's standard specifications for its
products; (iii) the unauthorized, installation,
modification, or use of the Product or Software; (iv)
damage caused by accident, lightning or other electrical
discharge, fresh or salt water immersion or spray; or (v)
normal wear and tear on consumable parts (e.g.,
batteries). Trimble does not warrant or guarantee the
results obtained through the use of the Product.

THE WARRANTIES ABOVE STATE TRIMBLE'S ENTIRE
LIABILITY, AND YOUR EXCLUSIVE REMEDIES,
RELATING TO PERFORMANCE OF THE PRODUCTS
AND SOFTWARE. EXCEPT AS OTHERWISE
EXPRESSLY PROVIDED HEREIN, THE PRODUCTS,
SOFTWARE, AND ACCOMPANYING
DOCUMENTATION AND MATERIALS ARE PROVIDED

“AS-IS” AND WITHOUT EXPRESS OR IMPLIED

WARRANTY OF ANY KIND BY EITHER TRIMBLE
NAVIGATION LIMITED OR ANYONE WHO HAS BEEN
INVOLVED IN ITS CREATION, PRODUCTION,
INSTALLATION, OR DISTRIBUTION INCLUDING, BUT
NOT LIMITED TO, THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A
PARTICULAR PURPOSE, TITLE, AND
NONINFRINGEMENT. THE STATED EXPRESS
WARRANTIES ARE IN LIEU OF ALL OBLIGATIONS OR
LIABILITIES ON THE PART OF TRIMBLE ARISING
OUT OF, OR IN CONNECTION WITH, ANY PRODUCTS
OR SOFTWARE. SOME STATES AND JURISDICTIONS

DO NOT ALLOW LIMITATIONS ON DURATION OR
THE EXCLUSION OF AN IMPLIED WARRANTY, SO
THE ABOVE LIMITATION MAY NOT APPLY TO YOU.

TRIMBLE NAVIGATION LIMITED IS NOT
RESPONSIBLE FOR THE OPERATION OR FAILURE OF
OPERATION OF GPS SATELLITES OR THE
AVAILABILITY OF GPS SATELLITE SIGNALS.

Limitation of Liability

TRIMBLE’S ENTIRE LIABILITY UNDER ANY
PROVISION HEREIN SHALL BE LIMITED TO THE
AMOUNT PAID BY YOU FOR THE PRODUCT OR
SOFTWARE LICENSE. TO THE MAXIMUM EXTENT
PERMITTED BY APPLICABLE LAW, IN NO EVENT
SHALL TRIMBLE OR ITS SUPPLIERS BE LIABLE FOR
ANY INDIRECT, SPECIAL, INCIDENTAL OR
CONSEQUENTIAL DAMAGES WHATSOEVER UNDER
ANY CIRCUMSTANCE OR LEGAL THEORY RELATING
IN ANY WAY TO THE PRODUCTS, SOFTWARE AND
ACCOMPANYING DOCUMENTATION AND
MATERIALS, (INCLUDING, WITHOUT LIMITATION,
DAMAGES FOR LOSS OF BUSINESS PROFITS,
BUSINESS INTERRUPTION, LOSS OF BUSINESS
INFORMATION, OR ANY OTHER PECUNIARY LOSS),
REGARDLESS WHETHER TRIMBLE HAS BEEN
ADVISED 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.

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

Class B Statement – Notice to Users. This equipment
has been tested and found to comply with the limits for a
Class B digital device, pursuant to Part 15 of the FCC
rules. These limits are designed to provide reasonable
protection against harmful interference in a residential
installation. This equipment generates, uses, and can
radiate radio frequency energy and, if not installed an d
used in accordance with the instructions, may cause
harmful interference to radio communication. However,
there is no guarantee that interference will not occur in a
particular installation. 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:

– 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.

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.

Contents

1 Welcome . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Related Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Technical Assistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Your Comments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

2 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

The DSM 132 Receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Standard features. . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Standard Features DSM 132RS . . . . . . . . . . . . . . . . . . . 17

Receiver enhancements . . . . . . . . . . . . . . . . . . . . . . . 17

Receiver input / output . . . . . . . . . . . . . . . . . . . . . . . 18

Differential GPS (DGPS) . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Sources of GPS error. . . . . . . . . . . . . . . . . . . . . . . . . 19

DGPS accuracy. . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Position Output. . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Receiving beacon DGPS . . . . . . . . . . . . . . . . . . . . . . . 22

Receiving satellite DGPS . . . . . . . . . . . . . . . . . . . . . . 23

Receiving DGPS Corrections from Other Sources . . . . . . . . . 24

Generating DGPS Corrections . . . . . . . . . . . . . . . . . . . . 24

3 Installing the Receiver. . . . . . . . . . . . . . . . . . . . 25

System Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Optional extras (if ordered) . . . . . . . . . . . . . . . . . . . . . 27

Mounting the Receiver and Antenna . . . . . . . . . . . . . . . . . . . . 27

Choosing a location . . . . . . . . . . . . . . . . . . . . . . . . . 27

DSM 132/132RS Receiver User Guide v

Contents

The receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

The antenna . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Environmental conditions . . . . . . . . . . . . . . . . . . . . . . 29

Electrical interference . . . . . . . . . . . . . . . . . . . . . . . . 29

Routing and Connecting the Antenna Cable . . . . . . . . . . . . . . . . 30

Connecting to an External Device . . . . . . . . . . . . . . . . . . . . . 32

Laptop Computer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

4 Getting Started. . . . . . . . . . . . . . . . . . . . . . . . 35

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Front Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Installing AgRemote . . . . . . . . . . . . . . . . . . . . . . . . . 37

The AgRemote Menu System. . . . . . . . . . . . . . . . . . . . . . . . 40

Using AgRemote . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

The AgRemote keys . . . . . . . . . . . . . . . . . . . . . . . . . 41

Navigating the Menus and Screens . . . . . . . . . . . . . . . . . . . . . 42

Menu System Fields . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

Display-only fields . . . . . . . . . . . . . . . . . . . . . . . . . . 44

Multiple-choice fields . . . . . . . . . . . . . . . . . . . . . . . . 44

Alpha, numeric, and alphanumeric fields . . . . . . . . . . . . . . 45

The Home Screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Satellite DGPS mode. . . . . . . . . . . . . . . . . . . . . . . . . 47

Satellite and WAAS/EGNOS DGPS mode . . . . . . . . . . . . . 47

Beacon DGPS mode . . . . . . . . . . . . . . . . . . . . . . . . . 50

Updating the Firmware . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

5 Configuring the Receiver . . . . . . . . . . . . . . . . . . 53

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

Display Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

Configuring the Communication Ports . . . . . . . . . . . . . . . . . . . 57

Configuring input / output communication . . . . . . . . . . . . . 59

Configuring Differential GPS. . . . . . . . . . . . . . . . . . . . . . . . 62

Paid Subscription Services . . . . . . . . . . . . . . . . . . . . . . . . . 63

vi DSM 132/132RS Receiver User Guide

Contents

OmniSTAR. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

Thales . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

WAAS/EGNOS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

Configuring Beacon DGPS . . . . . . . . . . . . . . . . . . . . . . . . . 70

Configuring Other DGPS Corrections . . . . . . . . . . . . . . . . . . . 73

Configuring DGPS Base Station . . . . . . . . . . . . . . . . . . . . . . 73

Configure base station output settings . . . . . . . . . . . . . . . . 75

Base location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

View location. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

Set from here . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

Edit base position . . . . . . . . . . . . . . . . . . . . . . . . . . 77

Set from averaged positions . . . . . . . . . . . . . . . . . . . . . 77

Setting the base station mode . . . . . . . . . . . . . . . . . . . . 78

Setting the PRC mode . . . . . . . . . . . . . . . . . . . . . . . . 78

6 Activating Firmware Options . . . . . . . . . . . . . . . . 81

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

Installing an Option . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

Enter a password . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

FlashLoader100 . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

Using an Option. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

Fast Rate Output . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

A Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . 85

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Problems and Solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Troubleshooting Flowcharts . . . . . . . . . . . . . . . . . . . . . . . . 92

System Hardware and Power Troubleshooting Flowchart . . . . . . . . . 93

GPS Reception Troubleshooting Flowchart . . . . . . . . . . . . . . . . 94

OmniSTAR Troubleshooting Flowchart . . . . . . . . . . . . . . . . . . 95

Thales Troubleshooting Flowchart . . . . . . . . . . . . . . . . . . . . . 96

DSM 132/132RS Receiver User Guide vii

Contents

B Cables and Connectors . . . . . . . . . . . . . . . . . . . 97

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

Port A and Port B Connectors . . . . . . . . . . . . . . . . . . . . . . . 98

Standard Power/Data Cable. . . . . . . . . . . . . . . . . . . . . . . . . 99

C NMEA-0183 Messages. . . . . . . . . . . . . . . . . . . 101

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

NMEA-0183 Message Structure . . . . . . . . . . . . . . . . . . . . . 104

Symbols and delimiters . . . . . . . . . . . . . . . . . . . . . . 105

Checksum values. . . . . . . . . . . . . . . . . . . . . . . . . . 105

Field formats . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

Null fields . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

Talker ID codes. . . . . . . . . . . . . . . . . . . . . . . . . . . 106

Latitude and longitude values . . . . . . . . . . . . . . . . . . . 107

Time values. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

Reading NMEA string format . . . . . . . . . . . . . . . . . . . 107

NMEA Message Summary . . . . . . . . . . . . . . . . . . . . . . . . 107

GGA (GPS Fix Data) . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

GLL (Position Data) . . . . . . . . . . . . . . . . . . . . . . . . . . . .111

GRS (GPS Range Residuals) . . . . . . . . . . . . . . . . . . . . . . . .112

GSA (GPS DOP and Active Satellites) . . . . . . . . . . . . . . . . . . .113

GST (GPS PRN) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .114

GSV (GPS Satellites in V iew) . . . . . . . . . . . . . . . . . . . . . . .115

MSS (Beacon Receiver Signal Status) . . . . . . . . . . . . . . . . . . .116

RMC (Recommended Minimum Specific GPS Data) . . . . . . . . . . .117

VTG (Course Over Ground and Ground Speed) . . . . . . . . . . . . . .119

XTE (Cross-Track Error) . . . . . . . . . . . . . . . . . . . . . . . . . 120

ZDA (Time and Date). . . . . . . . . . . . . . . . . . . . . . . . . . . 120

PT NLEV Proprietary (Event Marker). . . . . . . . . . . . . . . . . . . 121

P T NLID Proprietary (Trimble Receiver ID) . . . . . . . . . . . . . . . 122

P T NLDG Proprietary (Trimble DGPS Receiver Status) . . . . . . . . . 123

P T NL,GGK (Time, Position, Position Type, and DOP) . . . . . . . . . 124

viii DSM 132/132RS Receiver User Guide

Contents

PT NLSM Proprietary (RTCM Special). . . . . . . . . . . . . . . . . . 125

D Navigation Maps. . . . . . . . . . . . . . . . . . . . . . 127

DSM132 Menu System . . . . . . . . . . . . . . . . . . . . . . . . . . 128

Navigation map for DSM 132 Receiver — Home,

Field Operations, and Status menus. . . . . . . . . . . . . 129

Navigation map for DSM 132 Receivers — Configuration

menu. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130

E Specifications . . . . . . . . . . . . . . . . . . . . . . . 131

DMS 132 Receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132

Combined Antenna . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132

GPS Channels. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133

Beacon Channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133

L-Band Satellite Differential Correction Receiver . . . . . . . . . . . . 134

Receiver Default Settings . . . . . . . . . . . . . . . . . . . . . . . . . 134

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137

DSM 132/132RS Receiver User Guide ix

Contents

x DSM 132/132RS Receiver User Guide

CHAPTER

1

Welcome 1

This manual describes how to install and configure the DSM™ 132
receiver. It provides guidelines for u sing the AgRemote utility to view
and configure receiver DGPS and communication operating
parameters. The manual also provides guidelines for connecting the
receiver to a variety of external devices, information about NMEA
messages supported by the receiver, and pin-out diagrams for data
cable connections.

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
(www.trimble.com) for an interactive look at Trimble and GPS.

1.1 Related Information

Other sources of related information are:

• Release notes – the release notes describe new features of the
product, information that is not included in the manuals, and
any changes to the manuals. You can download release notes
from the Trimble website.

DSM 132/132RS Receiver User Guide 11

1 Welcome

1.2 Technical Assistance

If you have a problem and cannot find the information you need in the
product documentation, contact your local dealer. Alternatively, do
one of the following:

• Request technical support using the Trimble website at

www.trimble.com/support.html

1.3 Your Comments

Your feedback about the supporting documentation helps us to
improve it with each revision. E-mail your comments to

[e-mail] you have a problem and cannot find

the information you need in the product documentation, contact your

local Trimble Reseller.

12 DSM 132/132RS Receiver User Guide

CHAPTER

2

Overview 2

In this chapter:

■ Introduction

■ The DSM 132 Receiver

■ Differential GPS (DGPS)

DSM 132/132RS Receiver User Guide 13

2 Overview

2.1 Introduction

This chapter describes the DSM 132 receiver and gives an overview of
GPS, DGPS, and related information. For details of the receiver
physical specifications, see Appendix E, Specifications.

2.2 The DSM 132 Receiver

The DSM 132 receiver combines high-performance GPS reception
with a DGPS-capable receiver in a lightweight, durable, waterproof
housing. The DSM 132 receiver also contains technology which
enables WAAS/EGNOS, OmniSTAR, Thales, or Coast Guard Beacon
(MSK) real-time differential capabilities. See Figure 2.1.

When the connections described above are not available, the
DSM 132RS receiver has the capability to be used as a base station for
the generation of Differential GPS (DGPS) corrections. A radio link is
needed to broadcast the corrections to rover DSM 132 units.

14 DSM 132/132RS Receiver User Guide

Overview 2

Figure 2.1 DSM 132 receiver

As part of a marine construction or survey system, the receiver
provides submeter (less than 3.28 ft) precision whenever differential
corrections are applied. You can use a 1 PPS (pulse per second) strobe
signal to synchronize time for logging event markers when you are
using external instruments.

You can use the receiver with a variety of marine survey equipment,
including office software such as HYDROpro™, which also interfaces
with echo sounders and magnetometers, for use on waterborne
projects.

DSM 132/132RS Receiver User Guide 15

2 Overview

22.1 Standard features

A standard DSM 132 system provides:

• 12-channel L1 1575.42 MHz (C/A code) GPS receiver with
carrier phase filtering

• Combined L1 GPS, Satellite differential, and beacon antenna

• L-Band satellite differential correction capable receiver

Note – For the DSM 132 to operate with the L-Band
corrections, the client must subscribe to a satellite differential
service.

• Dual-channel digital medium frequency beacon receiver

• EVEREST™ technology for multipath rejection (firmware
version 1.73 and greater)

• Differential correction input from other RTCM SC-104 sources

• WAAS (U.S.A.) and EGNOS (Europe) differential capable

• Sub-meter differential accuracy

• 2 line, 16 character liquid crystal display

• 4 button keyboard

• 1, 2, 5, and 10 Hz (10 positions per second) output messages

• Operation manual

• 15m antenna cable

• GPS receiver to PC cable

• Magnetic mount for antenna

• Two programmable RS-232 serial ports:
– NMEA-0183 output
– RTCM SC-104 input
–TSIP I/O
– Baud Rate 2400-38400
– 1 PPS (pulse per second) output

16 DSM 132/132RS Receiver User Guide

22.2 Standard Features DSM 132RS

A DSM 132RS system provides all the features of the DSM 132
except:

• the L1 Geodetic antenna with ground plane is supplied

• the 30 meter antenna cable is supplied

• the RTCM SC-104 output (base station corrections) is available

22.3 Receiver enhancements

Table 2.1 lists the receiver options that you can purchase with the
DSM 132 receiver.

Table 2.1 Receiver enhancement options

Option (PN) Description Use

Overview 2

Differential
Base Station
(36429-30)

EVEREST
Technology
(36429-20)

RTS/CTS
Flow Control
Negotiation
(36429-50)

Outputs RTCM differential
corrections. (This option is installed
in the DSM 132RS.)

Reduces multipath interference.
(This option is installed in receivers
with firmware version 1.73 and
greater.)

Provides hardware flow control When attached to third-party modems,

If a radio link is attached, enables the
receiver to broadcast corrections for
use by other DGPS receivers. This
provides submeter positioning.

Improves DGPS receiver accuracy.

provides RTS/CTS flow control for
correct operation.

DSM 132/132RS Receiver User Guide 17

2 Overview

22.4 Receiver input / output

The DSM 132 standard power/data cable (PN 30945) connects to the
receiver ports to supply power. It also enables the following data
exchanges:

• ASCII, TSIP, and RTCM 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
that 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 pager.

• RTCM, TSIP, and NMEA to an external device.
The receiver is able to output RTCM in base station mode

(requires the base station option). When you are using an
external radio, it can also receive DGPS corrections. TSIP is
input/output when communicating with HYDROpro. NMEA is
output when the receiver is exporting GPS position information
to an external device or navigation software.

For more information on the NMEA (National Marine
Electronics Association) and RTCM (Radio Technical
Commission for Maritime Services) communication standard
for GPS receivers, go to the following websites:

– www.nmea.org
– www.rtcm.org

• 1 PPS output
To synchronize timing between external instruments and the

receiver’s internal clock, either one of the connection ports
outputs a strobe signal at 1 PPS (pulse per second). To output
this signal, the receiver must be tracking satellites and
computing GPS positions.

18 DSM 132/132RS Receiver User Guide

2.3 Differential GPS (DGPS)

The DSM 132 receiver uses DGPS to achieve high accuracy. You can
have a DSM 132RS (this is called the reference or base station)
located at a known point. This receiver is used to determine GPS
signal measurement errors. One or more mobile receivers (called
rovers) collect data at unknown locations, while remaining within
range of the reference station. The reference station broadcasts
correction values, which are applied to the receiver positions. In this
way , errors common to the reference and rover receivers are corrected.

For more information about DGPS and the different DGPS signals
available, visit the Trimble website
(www.trimble.com/gps/dgps.html).

23.1 Sources of GPS error

Autonomous (GPS only) horizontal accuracy for the Trimble
DSM 132 receiver ranges from approximately 2–9 meters (about 6–
30 ft).

The errors that cause this reduced accuracy are produced mainly by
atmospheric conditions, multipath error (that is, GPS signals bouncing
off objects before reaching the antenna), and electronic or GPS
frequency noise interference.

Overview 2

DGPS removes most of the errors caused by atmospheric conditions,
errors which are further minimized by the advanced design of the
DSM 132 receiver. For more information, see the section on Error
Correction on the Trimble website at

www.trimble.com/gps/errors1.html

DSM 132/132RS Receiver User Guide 19

2 Overview

23.2 DGPS accuracy

Submeter accuracy from the DSM 132 receiver utilizing differential
correction is best achieved under the conditions described in
Table 2.2.

Table 2.2 DGPS accuracy

Condition Optimum

Value

Number of
satellites used

Maximum
PDOP

Signal to Noise
Ratio

Minimum
Elevation

Multipath
environment

RTCM­compatible
corrections

> 5 To calculate a 3D position (latitude and longitude, altitude,

< 4 Position Dilution of Precision (PDOP) is a unitless, computed

> 6 Signal-to-Noise ratio (SNR) is a measure of the satellite

> 7.5 Satellite that are low on the horizon typically produce weak

Low Multipath errors are caused when GPS signals are reflected

Description

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.
The number of visible satellites constantly changes and is

typically in the range 5–9. The DSM 132 receiver can track
up to 12 satellites simultaneously.

Note – To see when the maximum number of GPS satellites are
available, use the Quickplan utility and a current ephemeris
(satellite history) file. Both files are available free from:

www.trimble.com/support_trl.asp?Nav=Collection-3627

measurement of the geometry of satellites above the
receiver’s current location.

Note – In some agricultural applications that do not require high
accuracy, a maximum PDOP of 12 or more can be used.

signal strength against electrical background noise. A high
SNR gives better accuracy.

and noisy signals and are more difficult for the receiver to
track. Satellites below the minimum elevation angle are not
tracked.

off nearby objects and reach the receiver by two or more
different paths. The receiver incorporates the EVEREST
multipath rejection option.

These corrections are broadcast from a DSM 132RS or
equivalent reference station.

20 DSM 132/132RS Receiver User Guide

23.3 Position Output

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 marine applications.

The DSM 132 receiver outputs position coordinates in several datums
and ellipsoids depending on the source of DGPS being used. See
Table 2.3.

Table 2.3 DGPS source

Differential Source Datum Ellipsoid

None – Autonomous mode
OmniSTAR 3 North American Beams NAD-83
OmniSTAR Rest of World Beams ITRF
Thales Beams ITRF GRS-80
WAAS Beams WGS-84 WGS-84

1

World Geodetic System 1984. Datum and ellipsoid.

2

North American Datum 1983. Equivalent to WGS-84.

3

International Terrestrial Reference Fr ame. Contact the DGPS provider for details.

WGS-84

3

Overview 2

1

2

WGS-84
–
GRS-80

For more information, go to the National Geodetic Survey website:

www.ngs.noaa.gov/faq.shtml#WhatDatum.

Note – To convert GPS positions in the NAD-83 datum to backgr ound
maps for the old NAD-27 datum, use the conversion program
Corpscon. This is available free from the Topographic Engineering
Center (http://crunch.tec.army.mil/software/corpscon/corpscon.html).

DSM 132/132RS Receiver User Guide 21

2 Overview

Position Output Format

The DSM 132 receiver outputs positions in Degrees, Minutes, and
Decimal Minutes (DDD°MM.m'). This is the NMEA (National
Marine Electronic Association) standard format and is commonly
used worldwide for data transfer between electronic equipment.

23.4 Receiving beacon DGPS

To obtain free radiobeacon differential signals, the DSM 132 receiver
uses dual-channel, fully-automatic beacon receiver electronics and
tracks broadcasts that conform to the IALA (International Association
of Lighthouse Authorities) Standard. When you use beacon DGPS, the
receiver selects the closest of the 10 most powerful radiobeacons in
the vicinity. You can configure the receiver to search for particular
station frequencies, or use the EZ beacon feature to select local
beacons.

The receiver continuously monitors the integrity of the data received
from the differential radiobeacons. If it finds unacceptable errors in
the data stream, the receiver automatically switches to a different
radiobeacon, if one is available.

Radiobeacon signal reception is generally not affected by:

• hilly or mountainous terrain

• tree canopy

• location of the receiver inside a canyon (the signal reception
depends on the proximity of the receiver to the transmitter)

Radiobeacon signal reception is affected to varying degrees, by:

• natural “noise”, such as lightning

• human-made “noise”, such as alternators, electric fan motors,
radio speakers, and high voltage power lines

• Sky wave interference with ground wave

22 DSM 132/132RS Receiver User Guide

During darkness, when the beacon tower is more than
240–480 kilometers (150–300 miles) from the receiver, the sky
wave beacon signal may be reflected off the ionosphere. This
causes interference with the ground wave beacon signal. Self­jamming at night may be a problem with stronger beacon
stations.

• Geographic de-correlation
This phenomenon causes radiobeacon signal accuracy to

decrease as the distance between the beacon tower and the base
station increases. Ionospheric conditions can affect accuracy by
as much as 1 meter (3 feet) for every 100 km (60 miles).

23.5 Receiving satellite DGPS

The DSM 132 receiver supports subscription-based OmniSTAR, and
Thales, satellite differential technology. Contact the service provider
for service activation or an encrypted activation passcode.

Note – For the DSM 132 to operate with these corrections, you must
subscribe to one of these services. The service provider may set
geographic limits on the use of its service.

Overview 2

In addition, the WAAS/EGNOS service is available free in North
America and Europe. For more information, see Configuring
Differential GPS, page 62, or go to the following websites:

• OmniSTAR (www.omnistar.com)

•Thales (www.landstar-dgps.com)

•WAAS (http://gps.faa.gov/Programs/WAAS/waas.htm)

• EGNOS (www.esa.int/export/esaSA/)

DSM 132/132RS Receiver User Guide 23

2 Overview

23.6 Receiving DGPS Corrections from Other Sources

The DSM 132 can also receive RTCM SC-104 corrections from
sources such as:

• AM/FM carrier services

• Your own radio data link (from a DSM 132RS reference
station)

23.7 Generating DGPS Corrections

In locations where MSK beacons or WAAS/EGNOS are not available,
or if you decide not to subscribe to L-band correction services, you
can install your own reference station and broadcast your own
corrections. The DSM 132RS or the firmware option for the DSM 132
allow corrections to be generated. A radio data link (UHF, VHF, and
so on) is required to transmit the corrections.

24 DSM 132/132RS Receiver User Guide

CHAPTER

3

Installing the Receiver 3

In this chapter:

■ System Components

■ Mounting the Receiver and Antenna

■ Routing and Connecting the Antenna Cable

■ Connecting to an External Device

■ Laptop Computer

DSM 132/132RS Receiver User Guide 25

3 Installing the Receiver

3.4 System Components

Check that you have received all the appropriate components for the
DSM 132 system that you have purchased. If any containers or
components are damaged, immediately notify the shipping carrier, or
Trimble Construction Division at the address given in the front of this
manual. Components for each system are listed in the following
tables.

Table 3.4 DSM 132 Receiver (PN 49086-00)

Qty P/N Description

1 33302-33 132 Receiver
1 33580-00 132 Antenna
1 12920-00 Magnetic Mount for Antenna
1 21555 15 m (50 ft) Ruggedized Antenna Cable
1 30945 Power/data Cable
1 50984-00 DSM Support CD (manuals, utilities)

Table 3.5 DSM 132RS Receiver (PN 49086-10)

Qty P/N Description

1 33302-33 DSM 132RS Receiver
1 36654-00 Compact L1 Antenna
1 11820-10 30 m (10 ft) Antenna Cable (N-N)
1 30945 Power/data cable
1 50984-00 DSM Support CD (manuals, utilities)

26 DSM 132/132RS Receiver User Guide

34.1 Optional extras (if ordered)

Table 3.6 DSM 132 Receiver options

Qty P/N Description

1 36429-30 DGPS Base station Capability
1 36429-20 EVEREST Multipath Rejection Technology
1 36429-50 RTS/CTS Flow Control

3.5 Mounting the Receiver and Antenna

Mount the antenna in a clear position free from obstructions.
For some short term installations you can place the antenna upright

with the magnetic base on a flat metal surface.

35.1 Choosing a location

When choosing a location, consider the following:

Installing the Receiver 3

Do mount the antenna:

• on a flat surface along the centerline of the vessel.

• in any convenient location within 15 meters (50 feet) of the
GPS receiver.

• at the highest point of the vessel with no metal surfaces
blocking its view of the sky. Trimble recommends that you
position the antenna on the top of a mast or pole.

• in such a way that it is not damaged when you sail under a
bridge.

Do not mount the antenna:

• close to stays, electrical cables, metal masts, CB radio antennas,
cellular phone antennas, air-conditioning units, active TV
antennas, or machine accessory lights.

DSM 132/132RS Receiver User Guide 27

3 Installing the Receiver

• near transmitting antennas, radar arrays, or satellite
communication equipment.

• near areas that experience high vibration, excessive heat,
electrical interference, and strong magnetic fields.

35.2 The receiver

To mount the DSM 132 receiver:

4. Drill four holes in the mounting surface. Use the slotted holes in
the mounting brackets as a template.

5. Use screws to secure the brackets to the mounting surface.

Note – If you use machine screws, tap the mounting holes to
fasten the receiver to the mounting surface. Trimble
recommends that you use 8-32 UNF socket head cap screws.
Alternatively, use self-tapping screws.

30.1 The antenna

Mount the GPS antenna so that it has a clear view of the sky even
when the vessel is rolling. Ensure that it is safe from damage during
normal operation; that is, mount the antenna solidly for the worst-case
pitch, roll, and heave of the vessel.

The base of the rover antenna has a 1" UNC female thread. A steel
pipe with a male 1" UNC thread is a suitable pole mounting for the
antenna.

28 DSM 132/132RS Receiver User Guide

30.2 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 (> 65°C or 149°F)

• excessive cold (< –20°C or –4°F)

• high vibration

• corrosive fluids and gases

30.3 Electrical interference

As far as possible, when you install the receiver and antenna, you
should avoid placing them near sources of electrical and magnetic
noise, such as:

• gasoline engines (spark plugs)

Installing the Receiver 3

• PC monitor screens

• alternators, generators, or magnetos

• electric motors (blower fans)

• equipment with DC-to-AC converters

• switching power supplies

• radars

• active marine TV antennas

• CB radio antennas

• cellular phone antennas

• machine accessory lights

DSM 132/132RS Receiver User Guide 29

3 Installing the Receiver

3.1 Routing and Connecting the Antenna Cable

A 15 m (50 ft) antenna cable (PN 21555) is included with the receiver.
One end is pre-terminated with a straight connector. The other end of
the antenna cable is not terminated, so that it can be routed in the
vessel through a minimal-sized hole (gland). If excess cable remains,
the cable can be cut to size before fitting the right-angle TNC
connector. See Figure 3.2.

Antenna cable
PN 21555

Figure 3.2 Antenna cable connections

30 DSM 132/132RS Receiver User Guide