I sm doing an experiment with our OPUS X90 GPS units. On the morning of 2 September 2014, we started 3 OPUS X90 GPS units running on 3 secure points, all set on fixed height tripods. One of these points is a 1st Order BM. We went out and checked that one today, and it is still collecting data. I am going to pick them up on the 15th. I want to see if they will run for 2 weeks on a battery. We have them hooked up to Deep Cycle Marine Batteries. So far they have meet all of my expecations including the price.
Thanks for the update. You forgot to mention that your PALS will have access to the data for THEIR experiments. I'm trying to "light up" our two X-90s for OPUS Project session(s).
DDSM:beer:
We are in the process of building a pillar at David D. terry Lock & Dam, and I plan to run an OPUS X90 there most of the time. We may have to start new files weekly to avoid going over 50,000 observations in file. This long session will put that to the test. And yes I can make the data avaliable. I am going to break the files for the weekend into 48 hour files and submit them to OPUS DB.
Space Weather
Collecting all this long term data should help to determine if the Space Weather has a big effect on our accuracy.
Space Weather
Not exactly new. See: http://www.decodesystems.com/gps.html
NUDET a long-standing capability.
Taken from the link:
The two NDC packages will include x-ray and optical sensors, Bhangmeters, EMP (electromagnetic pulse) sensors, and a data processing capability that will allow the detection of nuclear weapons detonations "anywhere in the world at any time and get its location down to less than a [100 meters]." Data will be reported on a real-time basis - either directly to ground stations located at Diego Garcia; Kwajalein Atoll; Ascension Island; Kaena Point, Hawaii; Andersen Air Base, Guam; Adak, Alaska - or first to airborne terminals or other GPS satellites for subsequent downlink transmissions. All principal U.S. command posts, including E-4B and EC-135 aircraft, will receive NDS sensor data directly.
Of course, this data is undoubtedly classified hence the development by the civilian sector of an open approach.
More on NUDET
Also of possible interest
The Global Positioning Satellite Nuclear Event Detector
On occasion, you may see one or more short bursts of rfi, lasting from 30 to 180 seconds, centered at 1381 MHz and extending over 1-2 MHz. These bursts arise from the NUclear DETonation detection (NUDET) system aboard the Global Positioning System (GPS) satellites. This system was established in the late 1970's as the US was planning to sign the Comprehensive Test Ban Treaty giving up the right to conduct tests of nuclear weapons. The NUDET system was designed to allow the US to verify that other nations are in compliance with the treaty. See this link.
The image to the right shows an example of a GPS/NUDET burst (along with the FAA radar at 1350 and the mysterious new 1375 MHz birdie whose identity is not yet known.) Notice that GPS/NUDET is polarized and not identical in all beams. If you are curious, Phil has a set of IDL routines which predict the passage of satellites over AO.
Click here to enlarge. You might want to compare that with this normal display without GPS
If you notice up to a few, short (<300 sec) GPS/NUDET bursts, make a note(s) in the log file.
The use of the 1381 MHz frequency for GPS/NUDET was carefully negotiated back in the 1980's to minimize impact on radio astronomy while still insuring national security (No kidding: this discussion including folks whose offices were in the White House...!). As a result, there are limits to the burst duration and total accumulated time per day, month etc that the NUDET system can transmit for system tests under "normal" circumstances. Once in a while, the Air Force notifies the observatory of planned systems tests which may exceed the normal limits; we post received NUDET test notifications. If you are observing when there is not a posted alert and the duration of the GPS/NUDET seems excessive, file an rfi report by emailing "rfi-grp_AT_naic.edu". Include in the message the AST time, frequency, description of the RFI, and please cc Martha (haynes_astro.cornell).
Fortunately, GPS/NUDET bursts results from system tests and do not mean that an above-ground nuclear event has taken place so you don't need to dive under a desk. (That is a joke to us old folks.)
Site link is http://www.naic.edu/~a2010/rfi_common.htm
Enjoy,
DMM
OPUS X90 and LONG Sessions
We finally got a chance to retrieve our OPUS X90 receeivers that we left running on secure marks. The Deep Cycle Marine Batteries lasted 13.75 days. We are looking into electrical outlets near these points. If they are there, we will put a trickle charger on each battery and should be good for a long time.
The size of the files chokes the software. I contacted Mark Silver about it, and he asked me to send him the *.hcn file. I got the file off the receiver and sent it to him, then started messing with the HCN to RINEX converter that is an option in the software. About the time I had stumbled through the process, I got another e-mail from Mark, with detailed step by step instructions of how he fixed the issue. He also posted these instructions to his web site http://alltopo.com/out/SCorely/X90-OPUS-DealingWithGIANTFiles.pdf
I used his instructions to help build my workflow to use the data. I had 14 days of observations on a monument that I have observed many times before with several different receivers. The positions that the OPUS X90 got from OPUS were within milimeters on the previous observations.
I think that Mark Should receive the Inovator of the Year Award for his development of the OPUS X90 GPS receiver due to it's low cost and ease of use!
😀 :beer: :beer::beer: :beer::beer: :beer::beer: :beer:
OPUS X90 and LONG Sessions
With secure sites if no outlets are available, look at using solar panels. There are several on the market that are approx. 18" square with built-in regulators that are made for maintaining/trickle charging boat and rv batteries.
