The Radio Meteor Project: It's All About Time
It's All About Time
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One of the biggest hurtles with long-term operation of these systems is keeping the computer's time synchronized with UTC. Computers are notoriously bad at
maintaining an accurate time stamp and the need to provide frequent manual clock updates was a perpetual challenge to collecting quality data. An Internet
solution is not feasible as the NJAA observatory does not have an internet connection.
The primary focus was to provide for an automatic update to the clocks on the computers using the Metrec, All-sky camera software. 
Metrec software interface sample. Click on image for full size view
The Metrec program (click here for a sample view of the Metrec interface) conveniently time stamps all of its
saved images with the computer time. However, the default setting merely uses the internal computer time. If it is wrong, the reliability of the data is
reduced. The program does contain a method for computer time updating. However, it requires a special radio time receiver similar to the atomic clock
signal used in many digital watches. The German author of the software, Sirko Molau, designed the software time update feature to work only with a specific
model of receiver tuned to the German national time standard signal, DCF-77. This is a good option for his Central Europe location, but is unworkable for
US-based sites. The software environment also presents another impediment to time updating; Metrec runs exclusively in DOS protected mode environment
ruling out the use of a simple TSR time update method. Furthermore, the software expects to see the time signal on the computer serial port in the DCF-77
format. US government time signal WWVB, broadcast from Ft. Collins, Colorado is similar to the DCF-77 signal but Internet searches revealed that no such
"off-the-shelf" receiver is available that would provide the correct serial output. Global Positioning Satellite (GPS) time was also considered but there
was still the same problem of interfacing to the serial port of the computer running Metrec.
To avoid the rather onerous task of building a receiver for the WWBV signal from discrete parts and then modifying its output to the correct format, research team member Steve Pappas, QED137 Corp, devised another solution. He proposed writing a small Visual Basic applet program that would read its host computer's system time, which got its corrected time from a GPS receiver. |
 DFC77 Sim applet Next, Steve turned his attention to the available GPS-to-computer interface software. With few ideally suited alternatives available, Steve created a software utility, GPS Comm. 
It takes the serial output of a NMEA GPS receiver and updates a host time-server computer running Windows XP. His Visual Basic interface displays the data obtained from the raw GPS signal as well as accomplishes its original task of providing for the time correction of the host computer system clock.
The GPS receiver, selected for both robustness and reliability, was a Garmin GPS 17 marine duty receiver (left). It was permanently installed at the Observatory in November 2008.
This time update project also provides the ability to synchronize the time for other XP computers and cross-match data collected from different platforms as well as the planetarium software used at NJAA. In other words, accurate time data allows for the easy correlation of video observations with radio data. |
Overview |
Radio Meteor Detection |
Initial Test |
HROFFT Enhancement |
2008 Geminids |
The Next Step
The NJAA operates on leased premises administered by The State of New Jersey, Department of Environmental Protection, Division of Parks and Forestry