Application Notes

for connecting the

Raven II and the

GPS Total Station® 5700

Base Station and Rover

October 16, 2001

AirLink Communications, Inc.

Confidential Material - Not For Redistribution

This document contains CONFIDENTIAL MATERIAL and

is NOT INTENDED FOR REDISTRIBUTION.

Information contained herein is the property of AirLink Communications, Inc. and is produced for the purpose of detailing technology developed by AirLink Communications, Inc. and its employees. Reproduction or distribution of this document without the express written consent of AirLink Communications, Inc. is strictly prohibited. This document is subject to change without notice.

 Copyright AirLink Communications, Inc, 2001. All rights reserved.

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AirLink Application Note

CONTENTS

1.Overview...... 2

2. profile: GPS Total Station® 5700...... 2

3. profile: Trimble TSC1 and TSCe Survey Controllers™...... 4

4. Using Cellular phones to connect a 5700 ROVER to a 5700 BASE...... 5

5. Using CDPD for connecting a single 5700 ROVER to a 5700 BASE...... 6

6. Using CDPD and the Internet to connect multiple 5700 rovers...... 13

7. AirLink Raven CDPD Modem Configurations...... 20

Rover Modem Configuration......

Base Modem Configuration......

1.Overview

This document describes how to connect the AirLink Raven CDPD Modem to the Trimble GPS TOTAL STATION® 5700 in both Base Station and Rover configurations to retrieve DGPS data using Cellular Digital Packet Data networks, TCP/Com, and the Internet.

Information about these and other Trimble products is available at Information on TCP/Com and other TAL Technologies products is available at Information on the AirLink Raven II CDPD Modem and other AirLink products is available at

2.PROFILE: GPS TOTAL STATION® 5700

The Trimble GPS Total Station® 5700 system is an all-Trimble integrated GPS survey system, with survey controller, office software and optional radios all custom developed by Trimble for a totally integrated workflow. As a modular survey instrument, the GPS Total Station 5700 system is a complete integrated surveying solution, including a receiver, a handheld controller, GPS antenna, RTK radio, and complete with Trimble Geomatics Office processing software designed for many applications, including Control, Measurement, Design, Stakeout or As-built work.

System Features:

  • 24-channel dual frequency advanced GPS receiver
  • Extremely rugged, waterproof metal alloy housing
  • eRTK technology extended real-time kinematic surveying
  • Fully-integrated internal Trimble radio modem
  • Everest™ multipath mitigation and high-performance low-elevation satellite tracking
  • Compact Flash data storage for up to 96MB or 2750 hours L1+L2 at 30 sec
  • Long battery life - 10 hrs receiver on 2 miniature camcorder batteries

Accuracy:

  • 10mm + 1ppm horizontal RMS
  • 20mm + 2ppm vertical RMS
  • Accuracy retained at long range with eRTK
  • 0.02 seconds (20 millisecond) latency
  • eRTK technology initialization time min 10secs + 0.5 baseline in km
  • VRS initialization time <30 seconds typical
  • Initialization Reliability >99.9%

Electrical:

  • DC input 10.5 to 28V
  • Over Voltage Protection
  • Power Consumption 2.5 Watts or 3.75 Watts including radio
  • Operates for up to 10 hours with two miniature camcorder batteries
  • Built-in battery charger for internal batteries

Mechanical & Environmental:

  • Rugged metal casing
  • Waterproof to IPX7 for submersion to 1 meter
  • Fully Sealed from sand, dust and moisture
  • Operating Temperature Range -40° to +65° C
  • Storage Temperature Range -40° to +65° C
  • Humidity: 100% non-condensing
  • Will survive a drop from 1m onto concrete
  • Weight as entire RTK rover in standard configuration:
  • Less than 4kg (8.8lb) including GPS receiver, GPS antenna, radio antenna, internal batteries, charger,
  • pole, controller, brackets, cable.

Communications: *

  • Integrated USB for 1 megabit per second data download
  • 2 external power ports, 1 internal power port, 3 serial ports, 1 USB port
  • Fully integrated, fully sealed internal UHF radio modem (20 MHz bands, receive only)
  • GSM, cell phone and CDPD modem support for wide area eRTK and VRS operation
  • eRTK UHF range pole antenna for wide area eRTK surveying, without interfering with GPS
  • Dual event marker inputs

* Now capable of wireless networking using AirLink Raven CDPD Modem & ‘Wireless IP’ Service

3.Profile: Trimble TSC1 and TSCe Survey Controllers™

The Trimble Survey ControllerTM line of handheld data collectors make working with combined GPS and conventional survey data simple and efficient. All survey project data is organized into a single Job file that can be loaded into a single office software package. Data can be readily transferred to and from third-party survey, design or GIS software packages via Trimble office software.

Innovative features and capabilities help speed up and improve the accuracy of every surveying operation, from establishing control to topographic measurements and stakeout, for both GPS and conventional instruments. All work is done from the real-time map display that shows all the points, lines, curves and roads in the database, as well as a background map for the site. The graphical display and touch-screen makes surveying more efficient.

The TSC1™ Controller is a rugged data collector:

  • that is a powerful, multitasking field computer
  • built for use in especially harsh environments
  • that can store an entire job in internal RAM, or use PC data cards for additional unlimited storage.

The Trimble TSCeTM Controller:

  • is a powerful, multitasking, touch-screen field computer
  • is built tough for use in harsh environments
  • built on Microsoft Windows CE operating system that can also run other third-party applications
  • comes with 32MB of data storage space
  • has a built in infra-red communications port

Both have support for:

  1. radio and cellular communication links
  2. Trimble's new extended RTK (eRTKTM) technology for single-base, multibase and virtual reference station (VRSTM) networks
  3. upcoming DGPS services around the world

4.Using Cellular ‘Dial-Up’ to connect a 5700 ROVER and BASE

The following section uses information from the Trimble Technical Tip entitled “Using Cellular and Cellular Digital Packet Data Modems for RTK work”. For more information on using Circuit Switched Cellular communications, please contact your Trimble dealer or Trimble Technical Support.

There are numerous advantages to using circuit-switched cellular communications to connect a 5700 ROVER to a 5700 BASE for RTK field applications. Some of those include:

  • No radio frequency allocation concerns
  • Stable and reliable public network
  • Little to no interference problems
  • Use of PSTN means no radio distance limitations
  • Low bandwidth cellular networks are perfect for RTCM and RTK applications

How conventional (circuit-switched) cellular works:

In order for the ROVER to communicate with a BASE using cellular networks, it would normally be connected to equipment enabling standard cell phone dial-up communications.

This requires equipment at the field ROVER such as:

  • Phones compatible with Trimble receivers
  • A cellular phone with a built-in Hayes-compatible modem and an RS-232 connection
  • A cell phone plan that allows for streaming data
  • An external power source or some spare phone batteries are needed
  • A NULL modem adapter or cable. Cable PN 37779 can be used to connect to a PC cable

This requires equipment at the BASE such as:

  • Modems that support cellular protocols
  • Modems that have the ability to accept multiple data calls in a row

The following demonstrates how to use cellular ‘Dial-up’ to connect a 5700 ROVER & BASE:

Example of a cellular phone being used for ‘Dial-up’ from a 5700 ROVER to a 5700 BASE

5.Using CDPD to connect a single 5700 ROVER to a 5700 BASE

It is possible to use 2 CDPD Modems to communicate between a 5700 ROVER and BASE. However, unlike the cellular ‘Dial-Up’ application, the best way to perform this task is to have the BASE send the data direct to a remote ROVER.

In this solution, the BASE CDPD modem makes a UDP connection to the ‘static’ CDPD modem address of the ROVER. This creates a persistent network connection between the two devices, allowing for the free flow of data between the BASE and ROVER via the CDPD network. No dialing strings are necessary. Just turning on the BASE and ROVER and starting up a survey on each device is enough.

The following demonstrates how to use CDPD for connecting between a 5700 ROVER & BASE:

ROVER SETUP:
The following description and graphics detail the steps to enable a 5700 ROVER to receive data from a BASE via a CDPD connection using a UDP connection.

  1. Connect the Raven CDPD Modem to the ROVER station using the Trimble Null Modem cable. (Part number #37779)

  1. Connect the Survey Controller, GPS Antenna, CDPD modem and power supply to the tripod

The following demonstrates connecting a Raven II CDPD modem to a Trimble 5700 ROVER:

  1. Start the Survey Controller
  1. Set the Survey Style as RTK

  1. Setup the Rover for communicating as Rover radio and select Custom radio as Radio Type

  1. Configure the ‘Custom radio’ option using the following configuration parameters:

BASE SETUP:
The following description and graphics detail the steps to enable a 5700 BASE to send data to a ROVER via CDPD using a UDP connection.

  1. Connect the Raven CDPD Modem to the ROVER station using the Trimble Null Modem cable. (Part number #37779)
  1. Connect the handheld Trimble Survey Controller, GPS Antenna, and CDPD modem power supply
  1. Start the Survey Controller
  2. Set the Survey Style as RTK
  1. Setup the Base for communicating as Base radio and select Custom Radio as Radio Type
  1. Configure the ‘Custom radio’ option using the following configuration parameters:

INITIATING A SESSION:

Step 1:Power up the BASE CDPD Modem.

Step 2:Power up the Trimble Survey Controller and 5700 BASE, and start a survey.

Step 3:Once the BASE starts sending data, the modem will begin forwarding packets.

Step 4:Power up the ROVER CDPD Modem.

Step 5:Power up the Trimble Survey Controller at the ROVER.

It will start to receive data immediately.

Step 6:The TSC screen should immediately display a Radio Link icon, indicating it is receiving data from the BASE. Start a survey. The radio icon should continue to display a link during the connection process.

6.Using CDPD and the Internet to connect Multiple 5700 ROVERS

While connecting one ROVER unit to a BASE is a useful solution, it sometimes necessary to connect multiple ROVERS to one BASE simultaneously. This is not possible using the previous solution, as the HOST CDPD Modem cannot support multiple simultaneous TCP sessions. However, there are tools that can enable these connections to take place. One of these is TCP/Com from Taltech Software. (More info on TCP/Com and other TAL Technologies products is available at

What is TCP/Com?

TCP/Com is a software solution for Windows® computers designed to make RS232 serial data available to a network IP address or make TCP/IP network data available on a serial port of the computer. TCP/Com makes a serial (RS232) port on a PC to interface directly to a TCP/IP network, making it possible for any other computer on the same network to send and receive serial data through a remote serial port on the PC where TCP/Com is running. You connect to the remote serial port by connecting to a TCP/IP port.

Using TCP/Com, you can attach a data collection device such as a bar code scanner, sensor, gauge, meter, lab instruments, (or DGPS server such as a 5700 BASE) - to the serial port of a Windows® PC and have that data available anywhere over any TCP/IP based network - including the Internet. Given that CDPD networks are all connected to the Internet, connecting a 5700 BASE to a PC with an Internet connection running TCP/Com can make that data available to 5700 ROVERS equipped with CDPD Modems.

Diagram illustrating a ROVER connecting to a BASE using CDPD and TCP/Com

How TCP/Com makes the TCP/IP connection:

One of the questions that may come up is just how Serial/IP servers like TCP/Com work. TCP/Com can be described as a software based terminal server. Much like a physical terminal server, TCP/Com acts as middleware laying in-between a physical serial port and a TCP/IP network. Data that comes into the serial port is passed to connections made to the TCP side. TCP/Com can accept connections from multiple TCP clients, allowing data from a device connected to the serial port to be sent to more than one client at the same time. In this case, the clients for the TCP/Com are handheld Trimble Survey Controllers.

Configuring TCP/Com Software:
TCP/Com System Requirements

TCP/Com will run on any Windows 95/98/ME or NT/2000/XP system and uses roughly 2 Mb of disk space. 16 or more Mb of RAM is recommended.

Configuring TCP/Com

The following description and graphics detail the steps to configure TCP/Com.

  1. Start TCP/Com – You will see the TCP/Com icon show up in the Windows Task Bar.
  1. Right mouse clicking on the Task Bar icon will open the TCP/Com menu.

Select ‘Open TCP/Com’

  1. The main screen is where you do most of the configuration.

Configure the Com Port to match the settings of the RS232 port on the 5700 BASE.

Select TCP Server, and Configure the Public IP Address and the desired TCP Port.

In this example, the TCP Port chosen is 12345, but you can set this to any port #.

  1. Select I/O Options from the main screen. The following screen pops up. Select these options:
  • Allow multiple client connections will allow for multiple ROVERS to connect to a single BASE
  • Ignore Inbound TCP/IP data
  • Sending inbound serial data to all TCP/IP clients is the key to distributing the data to every ROVER.
  1. Select OK to return to the main screen.

From here select the Activate button to start.

  1. You should see the main screen change to the following:
  • The IP Address and TCP Port will shade;
  • You should see the De-Activate button will be displayed;
  • In the bottom left corner you should see COM Status: Open
  • In the bottom right corner you should see TCP/IP Status: Listening…

Select FileSave As to save the profile settings as a .T2C file for future recall.

Final Steps:

  • Minimize the application, and TCP/Com will drop into the Windows Task Bar.
  • TCP/Com is now ready and running.
  • You can connect to it from anywhere on the CDPD network or the Internet.

When a successful connection is made from a remote ROVER via CDPD, you will see the number of connections displayed in the Status area shown above.

ROVER SETUP for TCP/Com Solution:

The setup to communicate via CDPD to a TCP/Com connection is very much like a ROVER using a cellular phone to call into a BASE connected to a phone line.

The controller should be configured for using a Cellular modem, however the phone number to be dialed is not a phone number, but an IP Address and TCP Port – specifically those of the TCP/Com server as shown in the example above. You simply replace the phone number (555) 555-5555 with the IP Address followed by a “/” and the TCP Port. Example: “166.148.11.123/12345”

The following steps show how to set up the ROVER to ‘dial’ into TCP/Com.

  1. Start the Survey Controller
  2. Set the Survey Style as RTK
  3. Setup the Rover radio as a Cellular modem as the Radio Type
  1. Configure the ‘Cellular modem’ option using the following configuration parameters:


BASE SETUP for TCP/Com Solution:

The 5700 BASE setup to communicate to a PC running TCP/Com is exactly the same as the setup for the CDPD–to–CDPD solution. It is simply an RTK Survey Style using a Custom radio as a BASE radio.

Connecting the ROVER BASE to the PC:

Simply connect the 5700 BASE to the PC using the Trimble ‘straight-through serial cable’. (Part #32960)

Once connected, the 5700 BASE will be passing data out of Port 3 and into the serial port of the PC. TCP/Com will listen on the Com Port for the data, taking it and passing it into the TCP stack. The data is then made available to any ROVER making a TCP connection to the TCP/Com server.

INITIATING A TCP/COM SESSION:

Step 1:Start TCP/Com as described in Section 6 / Page 14.

Step 2:Power up the Trimble Survey Controller and 5700 BASE, and start the survey.

The BASE will start sending data into the TCP/Com server.

You are now ready to connect any ROVER unit.

Step 3:Power up the ROVER CDPD Modem.

Step 4:Power up the Trimble Survey Controller at the ROVER.

Step 5:Start the Survey and Dial the TCP/Com server. You will see the connection being made.

The controller screen should display the following dialing steps:

  • Start Survey
  • Connecting to radio…
  • Connecting to modem...
  • Dialing 166.148.11.123/12345
  • Waiting for carrier…
  • Connected