- SPECIAL REPORTS
- THE MAGAZINE
Magellan Navigation, Inc.
960 Overland Court
San Dimas, CA 91773
Suggested List Price: Pricing depends on options selected; a rover can be purchased for less than $14,000.
In his latest novel “Thirteen Moons,” Charles Frazier writes about the tools and farm implements of the early 19th century being “so simple their names rarely contained more than three or four letters. Plow, axe, hoe, adze, froe, maul.”
The names for the tools of the 21st century have become anything but simple. They are so much longer and complicated that we have reduced them to acronyms: GPS, GNSS, GPRS, RTK, WAAS, RTN, NTRIP, RTCM, VRS, FKP. Today we speak a new language of all capital letters and few vowels.
The new Z-Max.Net surveying system from Magellan (formerly Thales Navigation) seamlessly integrates all of these tools. It is comprised of a small number of components that allow the user to quickly configure the surveying system to perform under a wide variety of conditions. I tested a few of these configurations.
Conventional SetupThe first configuration I attempted was to operate the Z-Max.Net as a conventional onsite base and rover. I began configuration of the base by attaching the GNSS antenna module to the receiver module. The receiver has two lateral modules that attach to its side with a simple hinge motion that latches into place. For this configuration, I used a power module and a V-module (void module). A UHF radio transmitter was used for communication with the base.
Next, the rover was configured by inserting a UHF antenna module between the GNSS antenna and the receiver. In place of the V-module, a UHF communication module was snapped into place. Communication with the Bluetooth-enabled field terminal was established with both the base and rover, and the system was configured.
Operation in this mode was quick and easy to establish; the total time to configure the system was less than five minutes. Once configured, initialization was nearly instantaneous. Magellan reports RTK position performance of 0.010 m plus 1.0 ppm horizontal, and 0.020 m plus 1.0 ppm vertical with a minimum of five satellites and good conditions. The results I achieved compared very well with these specifications.
The only difficulty I encountered with this setup was the familiar problem of maintaining communication between the base and rover. Radio links have inherent limitations involving distance, terrain, power supply and noise. But these problems only served to highlight the versatility of the Z-Max.Net, as I next explored a configuration utilizing the rover with a RTN that relies upon a cellular modem delivering real-time kinematic (RTK) corrections from an NTRIP caster in place of the base and UHF radio.
RTN SetupThe first step was to configure the rover by attaching a GSM communication module in place of the UHF communication module. The UHF antenna module may be replaced by a void UHF antenna module. Next, communication with the Bluetooth-enabled field terminal was established.
Finally, the properties of the GPRS provider were entered, the appropriate NTRIP settings added and connection to the RTN initialized. Once the system was configured, it again took less than five minutes to switch to this mode of operation.
The principal challenge I encountered in this mode was finding a RTN that supplied useable data in southwestern Ohio. The geographic area in which the system operates needs to fall inside the network. After several hours of research on the Internet and a number of E-mails and phone calls, we received permission to connect to the Ohio Department of Transportation’s (ODOT) VRS system.
ODOT is in the process of implementing a statewide RTK GPS structure that will be available by subscription. David Albrecht, survey operations manager for ODOT’s Office of Aerial Engineering arranged for us to have a trial use of the system. He cautioned that currently the “coordinates for the base receivers are not correct and positions obtained should not be used for production survey work or GIS.” He also explained that the plan is to make it available for free for a few months until the system is fully operational and then to charge a small fee to help offset some of the annual maintenance costs. While not yet fixed, the price is expected to be approximately $500 to $800 per year.
Although the Z-Max.Net system configured in this manner could not be used to generate absolute positions, the relative positional tolerances we achieved in this mode compared favorably with those obtained while configured as an onsite base and rover. Communication through the cellular modem was not a problem in the areas in which we operated, although this could certainly be a problem in areas with poor coverage.
The rover, configured for UHF or GSM communication, was lightweight, well-balanced and cable free. The software was relatively easy to understand. Joe Sass, sales support engineer with Magellan, provided a half day orientation to the equipment. I then downloaded the Z-Max.Net Getting Started Guide (approximately 50 pages) and was off and running with little trouble.
Additional Setup OptionsThere are other modes of operation that, due to time and equipment constraints, I did not attempt. The Z-Max.Net is said to be capable of operating with NTRIP, VRS or FKP networks. Communication modes include GSM/GPRS, UHF, a unique combined UHF+GSM/GPRS and external sources. Data may be downloaded through a USB port, SD card or serial port; it can also be collected in static, rapid static, post-processed kinematic and real-time kinematic modes.
A Versatile SystemThe versatility of the configurations with a single piece of equipment that operates under a multitude of modes and conditions--and with the ease in which these transformations occur--is a definite advantage of the Magellan Z-Max.Net system. Couple this with accurate, fast results, and this is a system well worth investigating.
Special thanks go to Ruth’s survey crew members for their help in researching the Z-Max.Net. Additional credit and thanks are due to Tim Fielder, Charlie Campbell, Wendell Weimer, Derek Cinnamon and Jim Mickey.
Sidebar: Acronyms of TodayCORS – Continuously Operating Reference Station
DGPS – Differential GPS
FKP – Flächenkorretturparameter
GNSS – Global Navigation Satellite System
GPRS – General Packet Radio Service
GPS – Global Positioning System
GSM – Global System for Mobile Communications (cellular phone technology)
NTRIP – Networked Transport of RTCM via Internet Protocol
RTCM – Radio Technical Commission for Maritime Services
RTK – Real-Time Kinematic
RTN – Real-Time Network
SBAS – Satellite Based Augmentation System
UHF – Ultra High Frequency
VPN – Virtual Private Network
VRS – Virtual Reference Station
WAAS – Wide Area Augmentation Service