Remote Station Engineering - McMurdo Station Test Facility

For winter 2013, two identical NetR9 receivers were installed, with telemetery to the McMurdo network via two individual point-to-point radios. The purpose of this test is to further confirm that new NetR9 firmware and configuration settings have solved a persistent power-up problem, where remote NetR9 receivers that power down during wintertime do not turn back on in the summer, even when the returning sun has recharged the battery bank. It also evaluates if an external LVD is needed to ensure proper receiver power-up behavior (less desirable), or if the receiver can control its own power and run directly from the battery bank (more desirable).

The receivers were configured identically except for one is powered directly from the external battery while the other is powered through an external LVD circuit. The receivers also have slightly different shutdown voltage settings. Both receivers are powered from one 100 amp-hour battery, with wintertime power from the same wind turbine as used during winter 2012. The combination of the wind turbine and small battery bank means that both receivers should experience many power cycles during the winter. As of June 2013, both receivers are still operating normally, providing an excellent indicator that the prior power-up problems have been elminated, and an external LVD is not necessary.

In 2011 UNAVCO collaborated with the University of Wisconsin AWS Project to develop a version of their Antarctic Automatic Weather Station system that can be integrated with the UNAVCO Polar GPS station design. A prototype was fielded at McMurdo during winter 2012, with both the GPS and weather instruments sharing the same power and communications systems. The system operated successfully during the winter season and weather data was delivered to AMRC.

Testing also included a Trimble NetR9, a Leading Edge LEv50 vertical axis wind turbine, and a continuation of the previous season's testing with a Xeos XI-100 Iridium RUDICS modem.

The McMurdo test system was rebuilt in January 2011 with hardware that reflects the current UNAVCO Polar remote station design, including new frame, enclosure, and ancillary hardware. For winter 2011, several advanced technologies are being tested at this site.

The first field test of the advanced XI-100 Iridium modem is underway. This modem was developed by Xeos Technologies for UNAVCO, and is based on an earlier successful design developed for IRIS/PASSCAL. The XI-100 features Iridium RUDICS connectivity, a faster and more robust service than the dial-up technology currently employed by UNAVCO. Iridium SBD messaging is also used for remote control and retrieval of smaller data packets. This modem features targeted heating to improve modem cold performance, TCP/IP and serial communications to remote devices, and switched relay output.

A Rutland 910-3 wind turbine has been installed for winter 2011. It is being evaluated as a candidate medium-power turbine for high wind polar sites, to enable deployment of lightweight autonomous polar instrument stations in the ~20W range. It has been used with success previously by others including the Autonomous Real-Time Remote Observatory (ARRO) project and the New Zealand Darwin Glacier project. Thanks to Nick Key from University of Canterbury for loan of the mechanical mount platform for this turbine.

Finally, the lithium battery bank is again being used as an automatic backup power supply if the wind turbine fails to power the system through winter.

The winter 2010 confiuguration is similar to that used in 2009. Significant capacity remains within the lithium battery bank, so the same batteries are again being used to provide backup wintertime power when the lead-acid battery bank becomes depleted. This will replicate the successful test from winter 2009 of automatically switching between battery banks. This station is also UNAVCO's first polar field deployment of the new NAL Research A3LA-X modem, which replaces the discontinued A3LA-SA modem. Finally, it is the first polar field deployment of the newest firmware for the Trimble NetRS receiver. This firmware enables a new auto-reboot feature which will restore communications in the occasional scenario where the receiver's serial port becomes seized.

The UNAVCO test station was modified with a new Iridium antenna, new GPS receiver and Iridium modem configurations, with new GPS receiver firmware and data format. The system also had solar-powered battery heating. Finally, the previous year's test with lithium battery backup power was repeated. During this winter, when this system's lead-acid battery bank was depleted the GPS receiver automaticlly switched to lithium batteries and the Iridium modem turned off. When the sun returned several months later, the GPS receiver switched back to lead-acid batteries and the Iridium modem turned on, allowing full retrieval of all wintertime data.

During winter 2009, five other systems were also operated nearby. A combination GPS/seismic station using a shared structural frame, power supply, and data modem continued a test started during winter 2008. Four other stations, constructed from POLENET hardware that was not deployed during summer 2008-09, were also operated to provide a long duration burn-in, as well as to evaluate effects of wind power and communications settings. Vaisala WXT-520 weather stations were also deployed on 5 of the 6 stations at this location, all with successful wintertime operation.

Station reconfigured with Iridium comms, rechargeable gel cell batteries, and non-rechargeable lithium-ion battery packs in order to test ability of GPS system to automatically switch between, and operate from, independent power supply systems during austral winter. Lithium-ion batteries have extremely high power density and good cold performance, are well-proven by IRIS/PASSCAL for powering seismic systems, and have the potential to reduce GPS system weight for logistically constrained projects.

During this test a severe bug involving dual power inputs to the GPS receiver was identified. With help from the McMurdo Research Associate, the system was modified and repaired in austral spring 2008 and testing was successfully resumed.

NetRS system installed with Intuicom comms and Campbell datalogger to record engineering data on system performance during winter shutdown and spring startup. System voltages, temperatures, and current draws were recorded for an entire year. Wind turbine power output was also measured in side-by-side test with a Forgen 500 and an Ampair Dolphin (now discontinued). A Vaisala WXT-510 weather station, integrated with the Trimble NetRS GPS receiver, was also tested.

Side-by-side test using two identical R7 systems with FreeWave comms to evaluate thermal performance of foam-insulated plastic enclosure versus vacuum-panel enclosure. Data was retrieved through a master radio at the Crary Laboratory, and the lifetimes of each system extending into winter 2006 were compared.