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Z-Xtreme GPS Receiver System Guide for Post-Process Surveying Magellan Corporation Ashtech Precision Products 471 El Camino Real Santa Clara CA 95050-4300 Phone and Fax Numbers • Main • Voice: 408-615-5100 • Fax: 408-615-5200 • Sales • US: 800-922-2401 • International: 408-615-3970 •...
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Printed in the United States of America. Part Number: 630045-01 Revision A November, 2000 Trademarks Z-Xtreme, Instant RTK, Z-Tracking, and the Ashtech logo are trademarks of ® Magellan Corp. Ashtech is a registered trademark of Magellan Corp. All other prod- ucts and brand names are trademarks or registered trademarks of their respective holders.
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SOFTWARE LICENSE AGREEMENT IMPORTANT: BY OPENING THE SEALED DISK PACKAGE CONTAINING THE SOFTWARE MEDIA, YOU ARE AGREEING TO BE BOUND BY THE TERMS AND CONDITIONS OF THE LICENSE AGREEMENT (“AGREE- MENT”). THIS AGREEMENT CONSTITUTES THE COMPLETE AGREEMENT BETWEEN YOU (“LICENSEE”) AND MAGELLAN CORPORATION (“LICENSOR”).
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Should you have any questions concerning the License Agreement or the Limited Warranties and Limitation of Lia- bility, please contact Magellan Corporation in writing at the following address: 471 El Camino Real, Santa Clara, CA 95050-4300 Z-Xtreme Operations and Reference Manual...
Static data collection..................4 Kinematic data collection................4 Post-process data processing ................5 Applications ......................5 Limitations ......................6 Ashtech Z-Xtreme Survey System ............... 6 System Components..................9 Hardware ......................9 GPS Receiver....................9 Z-xtreme Receiver ..................9 GPS Antenna....................10 Geodetic IV....................
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Continuous Kinematic................41 Stop&Go Kinematic ................... 41 Troubleshooting ....................43 GPS receiver does not track satellites ............. 43 1. Is the GPS receiver powered up?............. 44 2. Is the GPS antenna connected to the receiver?........45 3. A component may be malfunctioning............45 4.
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Internal Power Source with External Conversion Kit ...... 15 Figure 3.1 GPS Antenna Cable with TNC Connectors ........19 Figure 3.2 Cable Connected to Z-Xtreme Receiver & Geodetic IV Antenna ... 20 Figure 3.3 Computer Connection Cable ............21 Aero Handheld Pouch..............22 Figure 3.4...
Introduction to Post-Process GPS Surveying Although difficult to believe, it has been nearly 20 years since precise positioning using the Global Positioning System (GPS) was demonstrated. In a relatively short time, this capability was put to commercial use with the introduction of the Macrome- ter V-1000 GPS receiver.
Even with the introduction of RTK GPS surveying in the mid 1990s, post-process GPS surveying has continued to be the most popular method of surveying with GPS. It remains the most accurate and reliable method to survey with GPS. The Global Positioning System (GPS) Let’s take a quick look at what makes this all possible, the Global Positioning System (GPS).
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It’s important to remember that GPS observations result in vectors defining the rela- tionship between the points observed. That is, a vector is the result of a GPS obser- vation, not the coordinates of the surveyed points. To determine coordinates of surveyed points, a set of coordinates must first be supplied for one of the points.
Post-process GPS Surveying Post-process GPS surveying can be broken down into two primary tasks, data col- lection and data processing. Let’s examine each task in detail. Post-process data collection Data collection can be performed using two different methods; static and kinematic. Following is a description of each method.
ing along the centerline and instructing the rover system to store a position every five seconds, for example. The result is a trail of points defining the centerline. To facilitate the mobility required to utilize the kinematic method of data collection, the rover system is designed to be man-portable, usually carried in a backpack.
The Z-Xtreme Survey System is built around the Ashtech Z-Xtreme dual- frequency GPS receiver. Being a dual-frequency receiver (utilizes satellite signals on both L1 and L2 frequencies), the Z-Xtreme makes your GPS system more versatile and productive compared to a post-process GPS system based on a single-frequency GPS receiver.
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20 kilometers or more. There is no more advanced post-pro- cess survey system than one based on the Z-Xtreme dual-frequency GPS receiver.
Choosing the right component will depend on the users needs and environment in which the system is to be used. In this section, each of the major components of the Z-Xtreme system is presented. If options exist for a specific component, each option is discussed.
Figure 2.1 Z-Xtreme GPS Receiver The Z-Xtreme supports an integral battery, removable PC card memory, and optional internal radio. It is capable of functioning as the base or rover in RTK and post-pro- cessed surveys. The integrated display and control panel supports the ability to per- form some survey tasks without a handheld computer.
tion conditions will dictate which antenna is appropriate. Geodetic IV The Geodetic IV antenna, Figure 2.2, is the standard antenna offered. Figure 2.2 Geodetic IV Antenna without and with Groundplane The Geodetic IV is small, lightweight, and meets the needs of most users. It is avail- able with an optional groundplane attachment, which is effective in reducing noise created by satellite signals reflecting off of nearby obstructions.
A handheld computer is an optional component of the Z-Xtreme Survey System. It serves as a more advanced interface to the Z-Xtreme GPS receiver. Although the Z- Xtreme has a built-in interface, it is limited in its capabilities. The handheld computer, running field application software (discussed below), expands on the receiver inter- face, providing more control and functionality.
Compaq Aero Pocket PC The Z-Xtreme Survey System offers, as an option, the Compaq Aero Pocket PC, Fig- ure 2.4, a low-cost yet reliable handheld computer. Although not designed for use in harsh environments, the Aero comes with an environmental pouch that protects the computer, allowing it to be used in rain.
cient. Figure 2.5 shows a typical internal battery. Figure 2.5 Typical Internal Power Source External Power For extended operation, an external power source is available as an option with the Z- Xtreme System. Internal to External Power Conversion Kit A kit can be purchased that allows the use of an internal battery as an external power source.
Figure 2.6 Internal Power Source with External Conversion Kit Cable-to-User-Supplied Power Source In addition to the external power source, an optional cable is available to allow use of a vehicle battery for extended operation periods. Also available is a cable to power the GPS receiver from a cigarette lighter port.
As with hardware, a GPS survey system includes a number of software components used both in the office and in the field. The Z-Xtreme Survey System offers options for some of the software components. Each component, including options, is dis- cussed below.
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This concludes the presentation of hardware and software components which make up the Z-Xtreme Survey System. Next, we will examine the relationship between the hardware components.
System Hardware Connectivity At this point, you should have an understanding of the function of each hardware com- ponent of a GPS survey system and how the components relate to each other. In order for the different components to function as a system, they must communicate. This requires that the components be connected for both communication and power.
Figure 3.3. The computer communication cable connects to the Z-Xtreme via one of the three serial ports on the back panel of the receiver. These three ports are grouped together and labeled SERIAL PORTS. Although any one of the three ports will accept the connection to the handheld, it is recommended that the handheld be connected to port A.
Connection of the computer communication cable to the handheld is made via a stan- dard 9-pin serial connector. The Compaq Aero must be in its environmental pouch in order to connect it to the Z-Xtreme receiver (Figure 3.4). The handheld can be connected to the receiver at any time during the equipment...
(Figure 3.5). External power is applied to the Z-Xtreme by either connecting the battery cable con- nected to the optional external power kit, or the cable for a user-supplied power...
POWER port on the back of the receiver. Figure 3.5 Z-Xtreme Connected to External Power The external power source can be connected at any time without concern of the inter- nal battery. This concludes our review of the hardware component connectivity for the ZX Super- Station.
This chapter will step through the general process of preparing for and executing a survey with the Z-Xtreme Surveying System. Specific details on how to utilize the Z- Xtreme interface or the field application software to perform these steps are not pre- sented here.
The shoulder straps are also useful when a short hike is required to access the location of a survey point. The Z-Xtreme receiver is mounted in the kit bag is such a way as to make it possible to leave cables, such as antenna and handheld cables, connected to the receiver.
Figure 4.2 Inside View of Kit Bag Static Survey Prior to leaving the office to perform a GPS survey, check the following items: 1. Check through the GPS system to ensure all components are present to successfully perform the survey. 2.
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With the previous checklist completed, field data collection can begin. When collecting data using the Static method, each Z-Xtreme receiver will follow pre- cisely the same steps in equipment setup and survey execution. These steps are pre- sented below.
incorrectly determining the instrument height of the antenna Conventional Fixed-Height Figure 4.3 Conventional and Fixed-Height Tripods 3. Measure and record instrument height (HI) of GPS antenna Remember that measurements of satellite data are made at the center (hori- zontally and vertically) of the GPS antenna. Yet the location of the point to be surveyed is not at the center of the antenna but below it on the ground.
Figure 4.4 Measuring HI (Height of Instrument) of GPS Antenna Different GPS antennae will have different HI measurement points. For the Geodetic IV, the HI measurement point is the top of the ground plane. 4. Connect system components With the remaining system components residing in the field pack, connect all components as listed below.
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For static survey method, recording intervals of 5 to 30 seconds are commonly used. The interval can be changed either through the interface on the Z-Xtreme receiver or by using the handheld computer running the field application software. Refer to the appropriate manuals for details on how to perform this task.
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GPS receiver and others collecting data simultaneously), whether single or dual-frequency receivers are being used, etc. A conservative occupation time for the Z-Xtreme receiver is 10 minutes plus 1 minute for very kilometer of vector length. For example, if three receivers are collecting data simulta- neously and the longest vector being observed is approximately five kilome- ters, observation time would be 15 minutes for each receiver.
Figure 4.5 Z-Xtreme Survey System Performing a Static Survey Kinematic Survey When using the kinematic method of GPS data collection, one of the GPS receiver systems is designated as the base. This system remains stationary throughout the survey while the other GPS receiver system, the rover, moves about the project area positioning objects of interest.
able to easily move around the project site with the rover system in order to position objects of interest. This requires that the rover system be set up in a man-portable configuration, as described below. 1. Mount GPS antenna on Rover pole For kinematic data collection, the rover antenna is mounted on a fixed-height pole carried by the operator, as shown in Figure 4.6.
held is included in the rover system. Figure 4.7 Compaq Aero Handheld Mounted on Rover Pole 4. Connect system components The remaining system components reside in the Kit bag. The Kit bag is designed to function as a backpack when used as a rover in kinematic mode. Connect all components in the system as listed below.
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changed is the recording interval. The recording interval is set to 20 seconds by default. As stated earlier, an interval of 1-5 seconds is normally used for kinematic data collection. The recording interval can be set using the field application software running on the handheld computer. Note: It is very important that the recording interval on the rover is set to the save interval as the base.
Figure 4.8 Rover System Ready to Survey Now that the base and rover systems are configured, point location can begin. Using the rover system, you will move about the project area collecting data on points of interest in order to determine their position. This process involves two primary func- tions that you must execute repeatedly.
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enough data to calculate a set of parameters termed integer ambiguities. During the initialization process, you are collecting the data required to calculate the integer ambiguities. Once the integer ambiguities have been calculated, your current location can be determined very precisely. Solving for the integer ambiguities is the most time consuming part of GPS data collection.
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3. Initialize on-the-fly When using a dual-frequency GPS system such as the Z-Xtreme, there is no requirement that initializations be performed while standing still at one loca- tion. It is possible to initialize your kinematic survey while moving about the project site (thus the term on-the-fly).
You have a landfill that you need to topo. Being that the project site is a landfill, most of the area has no obstructions with the possible exception of trees along the perimeter. You set up your base station in an open area. You then set up your rover system.
level positions. If you are walking around the project site, a position is calculated every 2 seconds producing a crumb-trail of where you walked. If you stop and observe a feature of interest for 10 seconds, five data samples are observed for this feature, producing a more precise position than those produced while walking.
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ture. With Stop&Go Kinematic, you can expect positions at the 0.01 – 0.03 meters (0.03 – 0.10 ft) level. If your linear features require the level of accuracy produced by the Stop&Go Kine- matic method, this method can be used to position your linear features by used multi- ple Stop&Go observations to delineate the feature.
Troubleshooting So, you followed all the steps to prepare the Z-Xtreme Survey System to perform a survey and the system is not working. Why? Well, the problem is usually due to one of two things: a component is malfunctioning, or the system is not set up properly.
Receiver Is Not Powered Up a. Turn on the receiver. Press and hold the power switch on the left side of the Z-Xtreme front panel. The button must be held for a few seconds since there is a delay in power on.
Antenna Is Not Connected Connect the GPS antenna to the receiver. On the back panel of the Z-Xtreme, connect the antenna cable to the port labeled ‘GPS’. Ensure the connection is snug and not cross-threaded. At the antenna, connect the antenna cable to the antenna. Ensure the connection is snug and not cross-threaded.
GPS receiver in order for the receiver to log data. Check to ensure that the data card is installed. If the Z-Xtreme is powered on without a data card, a warning message should appear across the receiver display.
You may have a malfunctioning GPS receiver. Call your local dealer or Ash- tech customer support for assistance. This concludes the troubleshooting section. If the tips given here did not help you to resolve your problem with your Z-Xtreme Survey System, please call your local dealer or Ashtech customer support for assistance.
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