POSITIONING SYSTEMS: Trimble Introduces Marine GPS Receiver with Two-Centimeter Vertical Accuracy
PJ, a well-known hydrographic surveyor in New Zealand and Australia, working on a Van Oord dredge with a Trimble SPS750 and SPS550H (Heading) receiver pair. The new SPS651 receiver was developed for this application where centimeter – level vertical accuracy is required for tide and draft determination, and decimeter-level is suitable for horizontal. The dredge was working on an offshore outfall sewage pipeline in New Zealand.
It is designed to operate on projects where an RTK (real time kinematic) base station or RTK correction messages are available. The receiver can be installed in a marine vessel or construction site vehicle (such as a supervisor’s truck), where cost effective centimeter-level vertical positions for cut and fill computations or real time tide corrections are required along with decimeter-level position.
The SPS651 receiver can be combined with HYDROpro™ software for marine positioning or Trimble SCS900 Site Controller software for land-based rover applications. It can operate in all Location GPS modes, including Satellite Based Augmentation Systems (SBAS), DGPS, OmniSTAR (VBS, XP and HP services), and the higher-accuracy Location RTK mode.
Location RTK mode delivers a horizontal positioning accuracy of 10 centimeters and vertical accuracy of two centimeters. Location RTK operations can be accomplished using CMR+™ correction outputs from any available Trimble RTK base or CORS station, or Trimble VRS™ (virtual reference station) network through radio, cell phone or an Internet connection.
For DGPS and Location RTK operations, the receiver can be used with an external radio modem or be equipped with a 450 MHz (UHF) or 900 MHz internal radio.
The receiver and antenna can be mounted in a variety of ways - on a vessel, pole, backpack, site vehicle or light machinery. The receiver can be mounted in an accessible location where it is easy to configure and is secure from theft and protected from the weather, and the antenna can be mounted where there is a clear line of sight to the sky, reducing the potential for multipath.
The SPS 651 can be combined with the new SPS551H heading add-on receiver for marine applications requiring both position and heading of the vessel, such as dredging, placement of pilings, and harbor construction.
The receiver is equipped as standard with the ability to track the GPS L1/LS and L2C signals, and can be upgraded to track the GLONASS satellite constellation signals. Tracking GLONASS signals allows the receiver to provide positioning solutions in harsh GPS conditions, such as where obstructions create sky visibility, or during times of limited GPS-only availability.
This new receiver was announced in July at Trimble’s annual Boot Camp, a field-based, hands-on training event for the construction industry held this year in Dayton, Ohio.
At the same time, the company announced the SPS551, SPS551H, SPS751 and SPS851 GPS receivers and the SPS781 and SPS881 Smart GPS Antennas.
The SPS551 and SPS551H Modular Receivers are location receivers that provide decimeter-level positioning for land and marine construction applications. The SPS551H is an add-on heading receiver described above.
The SPS751 and SPS851 Modular GPS Receivers are for mobile, semi-permanent and permanent base station setups on construction sites as well as for vehicle, vessel or pole-mounted rover applications. By integrating the radio and GPS receiver in a single housing, components of a contractor’s GPS fleet can be protected from the elements and theft by securing them inside a site trailer, vehicle or carrying case, while only the antennas are left outside. Antennas can be mounted high and away from obstructions to allow a clearer, less noisy GPS signal, as well as maximizing radio coverage.
The SPS751 and SPS851 receivers offer a range of GPS positioning techniques delivering accuracies from centimeters to sub-meter. The new receivers include Autobase, a feature that allows the user set up the receiver as a base station with a single button push.
The SPS781 and SPS881 Smart GPS antennas are designed for fast setup and take down. The GPS receiver, radio, and antenna are integrated in one housing, making this GPS positioning product useful for all sites, including small- to medium-size construction sites as a base station, as well as for all site rover applications where mobility is critical.
All of the new receivers use Trimble’s RTK Engine for fast initialization and low downtime. The receivers also track and use the L2C GPS signals as a standard configuration, and some models can be upgraded to include GLONASS and L5 signals to facilitate performance on jobsites with obstructed visibility. The new line of construction GPS receivers comply with European Union requirements for the Reduction of Hazardous Substances (ROHS) initiative.
The new GPS-based Trimble Site Positioning Systems are available through the Trimble worldwide distributor network.