- SPECIAL REPORTS
- THE MAGAZINE
Santa Clara, Calif.
Suggested Listed Price: $3,645 to $6,795
It was, I suppose, inevitable that once the "marriage" between GPS and GIS technologies was consummated there would be an increasing demand for improvements in the quality of the products that supported them. Such is frequently the case in a marriage.
Submeter accuracy has been the de facto standard for what has euphemistically been referred to as "mapping-" or "resource-" grade GPS receivers. But there have been rumblings of a cost-effective method of getting "survey-accurate" data into a GIS as well. GPS developers and manufacturers have been introducing a "new generation" of products designed to increase both accuracy and efficiency for users.
The ProMark3 from Thales is of that genre. The ProMark series has an interesting pedigree. The Magellan ProMark V (indicating a five-channel receiver) was the first serious attempt at a moderately priced, submeter accurate receiver. That was in 1993 when Selective Availability was active. Fifteen minutes or so of occupation could get users to attain a meter or less on a good day with post-processing. And users could attribute their point identifiers.
Several generations of continuing im-provements have resulted in the Thales ProMark3. The "3" combines all the best features of the Thales product line-the data collection capability of the MobileMapper Pro compact handheld GPS receiver, the precision capability of the ProMark2 survey system and the durability of the MobileMapper CE handheld GPS mapping device.
The submeter Mobile Mapping module is identical to the MobileMapper Pro, but now the user has the option to easily add the external antenna and use the rover rod for a more defined placement during point collection. And as with the MobileMapper Pro, there are two modes of collection available: WAAS (Wide Area Augmentation System)/EGNOS (European Geospatial Navigation Overlay Service), and post-processing submeter.
Additionally, the display on the ProMark3 has far better definition and utility than its sister products. The touch screen is big, bright and bold, and it has integrated options. The user can select with a stylus on the touch screen, or use the compass rose arrow keys or the alphanumeric keypad. There are also command keys for the "LOG" and "NAV" functions. Because the ProMark3 operating system is based on Windows CE, a "virtual" keypad can be used. But what is particularly powerful is that all of the input devices are seamlessly integrated, allowing the user to move between any and all of them for a single entry sequence.
Unlike some CE devices, the ProMark3 does not require Microsoft ActiveSync to download or transfer files. As is the case with the MobileMapper Pro, ProMark3 data can be downloaded via a USB cable or directly from the SD (Secure Digital) Flash card. Unlike the MobileMapper Pro, the I/O (Input/Output) module connected to the charger must be attached to the unit in order to use the USB cable.
Static SurveyingThe ProMark3 immediately informs the user he isn't ready to proceed if he double taps the "Surveying" icon and doesn't already have the external antenna attached to the GPS unit. But that is about as complex as it gets in Surveying mode. The user just needs to enter the point identifier and the recording interval (epoch), and then press the "LOG" key.
The screen reports the battery strength and remaining storage capacity continuously during the session. The screen has a "sleep" mode to conserve battery strength but the display instantly returns with a tap of the screen. The Lithium batteries are said to be rechargeable and "hot swappable" (exchangeable without disturbing the current collection session). With an overnight charge they seem to easily make it through an eight-hour workday. The "standard issue" 32 Mb SD card easily handles a full day of submeter data collection. An all-day static job might push the envelope but seems doable. Larger cards are recommended for storing base map data.
Two or more ProMark3 units enable "stop-and-go" or kinematic surveying. One unit mounted on a tripod serves as the base station, the other(s) is mounted on the rover antenna bar. This seems to work best (easiest) when the base station is occupying a known point. The user also has the option of running the initialization routine to produce seed coordinates.
The ProMark3 SoftwareThe ProMark3 kit includes both MobileMapper Office software and GNSS Solutions software (minus the password for accessing dual-frequency post-processing).
MobileMapper Office Software (Release 2.77)
MobileMapper Office-as its name implies-views and processes data collected in the Mobile Mapping module. If the data was collected in the "real-time" mode, the collected points show up in the map window. The point metadata is displayed in the window on the right side of the graphical user interface. To review the data on a point the user simply selects it.
To enable post-processing, the user must do two things. He must select the "Post-processing" option on the unit when he creates a new job. When he downloads his data he needs to use the "Download from GPS" command and drag the job file from the left pane to the project file in the right pane of the transfer screen. This step is necessary even when transferring copies of job files from the SD card because the job file (*.mmj) contains compressed files.
In post-processing mode, MobileMapper Office displays a time bar below the map window showing the occupation times of the sessions and a tool bar with a line of triangle icons. The yellow triangle on the far left, "Add Reference Station," takes the user to the CORS interface "RINEX Download Screen." The user simply loads and selects a reference station and the desired date and time, and downloads the compressed correction file. The "Process Data" triangle icon on the right can then be clicked to display the corrected values.
MobileMapper Office makes it particularly easy to work in a variety of different coordinate systems as well as import AutoCAD drawings and ESRI Shape files to use as background. I was able to load my existing control point Shape files and use them to plan my test projects and create a new feature library in just a few minutes. Users can also export data collection files as Shape files, .mif, .dxf or ASCII.
GNSS Solutions Software
GNSS Solutions software shares some features with MobileMapper Office. One is the way it handles compressed project files. The user must choose the "Import" button on the left side of the project window. The import screen is identical to the one in MobileMapper Office, but the files are .MLM with the GPS day (numerical representation of the calendar date) as the extension. GNSS Solutions creates a folder named "My Projects" where it places the uncompressed files. The import button has several options. One is "Internet Download" (identical to the MobileMapper screen) where the user can download collection and correction files from CORS and other base stations.
Though GNSS Solutions has many of the same windows as MobileMapper Office and uses the same or similar terms, it is a far more full-featured and nuanced product. There is no single click adjustment button. In the "Workbook" window, a row of tabs allows the user to look at an overview of his collection files and set the processing parameters. GNSS Solutions also has a full array of utility programs including mission planning and RINEX conversion.
AccuracyThe ProMark3 produced all the results for me that Thales claims for the product. Mobile Mapping real-time with WAAS consistently produced at or near submeter results. Post-processing always improved the horizontal results. I typically collected one or two minutes of data with at least four satellites tracked. Most of the testing was performed under near optimum conditions.
In static (surveying) mode it took about 20 minutes of collection to approach the centimeter level in the horizontal plane. Thales recommends "about 15 seconds" of collection time in the "stop-and-go" (kinematic) mode for "survey accuracy." I used one-, two- and five-minute occupations with the rover rod on some known points in about a 3 km radius and received excellent results.
The DocumentationThe "Getting Started" .pdf files were very useful for the receiver operation. And the documentation for the MobileMapper Office has been enhanced. The GNSS Solutions software documentation is still at best a "work in progress." But for additional assistance, the Thales support page http://products.thalesnavigation.com/en/support is only a few mouse clicks away. I find the customer support for all of these products to be excellent.
For Mapping and SurveyingThe Thales ProMark3 is marketed in one- or two-receiver kits ranging from under $4,000 to under $7,000 depending on the number and type of accessories purchased. The dual kit (about $6,800) gives the user quite a few deployment options. For mapping applications, two receivers are available, allowing simultaneous data collection on different projects or even the same project to increase efficiency. The MobileMapper Office software makes it easy to merge output files. For surveying applications, the ProMark3 deploys the same as the ProMark 2.
The ProMark3 also has the same navigational capability of the MobileMapper along with the ability to upload background maps in the most popular formats including ESRI Shape files.