Magellan’s BLADE processing is a proprietary GNSS processing solution that provides centimetre-level accuracy for real-time and post processing surveys and mapping operations. Magellan developed BLADE to enable its receivers to outperform single frequency RTK receivers, and to provide real-time performance in a lightweight handheld system.
The technology combines ranging and carrier phase data from both the GPS and Space Based Augmentation System (SBAS), for superior satellite coverage and signal reliability.
These SBAS measurements, which are GPS-like, improve satellite geometry and allow centimetre-level accuracies to be achieved in a shorter time, compared with GPS-only algorithms.
Although other systems use the SBAS correction message to achieve sub-metre positioning, ProMark3 RTK is the only GNSS receiver using SBAS ranging and carrier phase data in the RTK computation.
The technology is designed to provide rapid initialisation. Initialisation times will vary depending on SBAS availability and sky conditions. For example, the addition of one SBAS satellite improves the time to ambiguity resolution by 50 per cent; two satellites improved this time by 75 per cent. In open sky environments, when two SBAS satellites are in common view, centimetre-level accuracy is usually reached in less than three minutes.
Magellan has developed this technology with the aim of enabling more surveyors to access RTK technology by lowering the price barrier. With ProMark3 RTK, surveyors who were reluctant to invest in an RTK solution because of its high-cost, can now access real-time centimetre surveying at less than half the price of dual-frequency GPS. ProMark3 RTK costs less than US$14,000 ($17,000) for a pair, and less than US$7000 for a rover only.
For surveyors who need GPS capability, ProMark3 RTK offers a complete range of survey modes including real-time solutions, real-time solutions plus raw data, post processing and mapping. ProMark3 RTK is ideally suited for short baseline surveys such as construction site, stake out and cadastral, and excels in an open sky environment.
Base and Rover ProMark3 RTK is available as a base and a rover combination linked by a plug-and-play, licence free radio. The radios are easily integrated with the receiver. Because they are directly powered from the GPS receiver, they do not require additional separate batteries.
The radios are configurable via a simple menu and are perfectly adapted to professional use (IP65 environmental specification). The radio is licence free because it operates on a standard 900 MHz band, transmitting at 500 mWatt, which does not require a licence in most countries.
The standard radio models included in both elements of a rover-base system are CE, FCC and IC compliant. If another type of user supplied radio is desired, it can be used, since the receiver has a serial port for RTK data transfer.
When operating in an area where RTK network corrections are available, the ProMark3 RTK can be used as a rover only. Bluetooth connections can be established between the unit and a cellular phone.
ProMark3 RTK is compatible with NTRIP and direct IP and can be connected to any GPS network broadcasting corrections (RTCM 2.3, RTCM 3.0).
In a rover configuration, the real-time performance of the receiver is directly related to the quality of the network (distance to the station, interval between stations, VRS quality, etc).
As with the original ProMark3 receiver, post processing features are included in ProMark3 RTK. For superior integrity of the surveys, the raw data simultaneously recorded during RTK jobs can also be post processed via Magellan’s GNSS Solutions office software. Post processing ensures that users retain full control on the quality of the data collected.
The unit enables users to take any supported GIS files into the field. Surveyors can navigate to field infrastructure, reconnoitre, map or update the GIS data and easily transfer the file back to the office GIS.
In mapping mode, where the user is moving quickly and accuracy is less important, it delivers decimetre accurate positioning. Since mapping users usually find decimetre accuracy acceptable, it is not important to resolve signal ambiguities.
However, if centimetre accuracy is desired, the user must wait sufficient time when logging, and set up the RTK mode before doing the mapping.
The FAST Survey Option offers features that meet the needs of users such as compatibility to a wide range of survey instruments, extensive data formats and local co-ordinate systems.
FAST Survey includes topographic features typically associated with dual frequency. This makes it possible for both professional surveyors and novice RTK users to run complete survey jobs, including stake out. They can also combine projects carried out in association with total stations, and much more.
Information is transmitted to the office computer via either an SD card or a USB cable. The transfer of raw GPS and SBAS data for post processing is in proprietary (B, E and S) formats. In addition vector files are transferred in O-file format for least squares adjustment.
GNSS Solutions Office software is a comprehensive package which contains all the tools required to successfully process the raw GPS and SBAS pseudo range and carrier phase data.
Focusing on simplicity, the software is used for data transfer and management. GNSS Solutions includes advanced error detection and quality analysis tools to ensure accurate and reliable results. Loop closures, automatic repeat, observation analysis and least-squares adjustments are integral components of the software.
It guides the user through mission preparation, planning, processing, quality control, reporting and exporting. Survey data is presented in graphical and tabular form, making post processing very simple. Jobs can be viewed in different forms through simple drag and drop operations.
It also includes a new raster maps support capability. This lets surveyors combine background projects with land survey projects. They can also prepare missions in the office for stake out. Raster file formats that are supported are BMP (Windows Bitmap), JPG (JPEG Images), JPG2000, and TIF (not compressed).
MobileMapper Office is a mobile mapping system, combining full GIS data collection and navigation software. Backed by office software for easy data display, users can import GIS data into job files to be updated in the field.
The software links the receiver to the GIS base and provides convenient features such as: quick and easy editing and exporting of data, including support for .SHP, .MIF, .DXF and .CSV files; uploading or creation of vector background maps for use in the field; and post processing.
The software also includes a Feature Library Editor that creates lists of features and attributes for describing GIS assets in the field. It can even generate the feature libraries automatically by reading imported .SHP and .MIF files. ProMark3 RTK is a turnkey solution for the operator who wants to create or maintain GIS maps or feature in the field. With ProMark3 RTK, surveyors can offer a mapping service without investing in additional GIS equipment.
All three software applications use the same GPS engine, and are designed with the same look and feel for a single user experience.
Current users can upgrade their systems with the new RTK version. All its features, firmware and radios can be made available on all previous versions of ProMark3.
The RTK firmware upgrade is available for upload. It can be activated with a licence activation code, which allows access to all the new RTK features, both on the receiver itself and for GNSS solutions office software.
Eric Moisset [email protected] is product marketing manager for Magellan Professional. Visit www.pro.magellanGPS.com for more information.