Blackstone, VA (37.10 N, -77.95 E)
| The SuperDARN radar at Blackstone saw first light in February 2008. It uses the new Twin-Terminated-Folded-Dipole antenna design. The Blackstone site has had two phases of operation defined by hardware: (i) until 11-JUL-2011 it ran on electronics provided by Leicester University and was capable of stereo operations(see Notes for additional details), (ii) since 01-OCT-2011 it has been running on electronics provided by Virginia Tech. |
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Notes
- Software update for new VT hardware (since 17-Jan-2012):
- The ROS.1.25 was reinstalled on Jan. 17, 2012 with a newly developed site library that presented cleaner code than the modified site library that was developed for the Univ. of Leicester hardware.
- One of the bigger changes from the newly developed software will be the availability to run the tauscan control program and its THEMIS variation.
- Description of VT hardware operations (01-Oct-2011 to 17-Jan-2012):
- The physical boresight and the scanning boresight are now one and the same at -40 degrees relative to geogrpahic North.
- The radar operates with a beam separation of 3.24 degrees, and has had the velocity sign of the recorded data flipped as a result of a new receiver front end design.
- As of 17 Nov 2011, the new time differential for the new electronics has not been measured and thus the tdiff value is listed as a zero. It is hoped that in the coming month or so, the electrical path lengths through the new electronics can be measured.
- Lastly, with the smaller beam separation, the radar has increased the number of beams it uses to 24. However, due to time constraints with certain control programs, few beams may be used at certain times.
- NOTE:RAWACF data during this time was found to be using an incorrect value for the prm.lagfr and prm.frang. These parameters were found to be 4 ranges gates too close do to an error in the sample delay figure as noted below. The original data was placed within a sub-directory of the rawacf/bks directory labeled 'uncorr'. The RAWACF data was corrected on March 2, 2012 and the FITACF and FITEX data was reprocessed from this corrected data. The corrected RAWACF data should go out with the usual data distribution in early-to-mid March 2012.
- For the installation of the new software at Blackstone, the following items have had to be modified:
- Various settings related to setting the ROS to use the non-TS receiver card drivers, involved changing a variable called prm.gort.
- The site library needed to be updated to exclude the stereoscan portions of the code.
- The site library's SiteIntegrate function needed to be updated to include additional variable calls.
- The site library's SiteSetBeam needed to be fully commented out and replaced instead with SiteSetPhase which is called within the SiteIntegrate function and not from the control program.
- The gc214if.1.24 driver needed to be updated to include better filters hardcoded in by Ray Greenwald. This modification involves removing a calls from the main.c file to the setCFIR and setPFIR functions located in the filter.c file. Instead the main.c file uses hardcoded Bessel function coefficients that Ray obtained from an unknown website.
- The gc214if.1.24 driver was also noticed to have a sampling delay that was 4 range gates too far. Thus, a line of code that added 1 additional delay was changed to subtract 3 as noted by: smpdlyAB=(int)ceil(smpdlyF)-3;
- There is also a modification to the gc214if.1.24 driver somewhere that as Ray noted 'calls bad data good and good data bad'. It appears as though it may be an interaction of the receiver driver and the acf and fitacf software per Ray's e-mail on 10Nov2011.
- There is also an issue with the data processing stream that is not writing values correctly to the ACFs when the tauscan mode is run.
- Also, a changed needed to be applied to the integrategc214.c library source code to correct for a miscalculation of the integration time. The IntegrateSetTock function in this c file has a few additional lines of code to account for when the intus is not equal 0.
- Description of Leicester hardware operations (until 11-JUL-2011):
- The physical boresite of the radar, i.e. the direction normal to the antenna array, is -40 degree relative to geographic North. However the scanning boresite, i.e. the direction of the middle beam, is cranked by 7.72 degree to -32 degree, in order to close the gap between the fields-of-view of the Wallops and the Blackstone radar.
- Due to oversteering the beam width of Blackstone is 3.86 degree, i.e. about 0.6 degree larger than that of other radars.
- All these changes are reflected in the hardware file.
- Time delays between I/F path and main path (positive if main path is shorter)
Channel Ground Coax Delay [μs] Electronics Delay Total Delay [μs] Mean [ns] StDev across frequencies [ns] A -0.618406 -29.93 5.62 -0.648330 B 12.71 7.08 -0.605700 - From the start of operations until 7/11/2011, the radar operated using the ROS 1.21-beta software and a pulse scheme of either stereoscan or THEMIS tauscan. The radar also used the GC214TS digital receiver card.
- When operations resume in the fall of 2011, the radar will operate using the ROS 1.25 software. Also the radar will use the GC214 digital receiver card using the gc214if.1.24 driver.
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Show Hardware Table
| Blackstone (code: BKS, ID: 33) | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Geog. Position: (+37.100°, -77.950°, 125.0m) | ||||||||||||||
Configuration valid from | Configuration valid until | Scanning Boresite [°] | Beam Separation [°] | Velocity Sign | Attenuation Step* [dB] | Time Difference [μs] | Phase Sign | Interferometer Array Position [m] | Receiver Rise Time* [μs] | Stages of Attenuation* | No. of Gates | No. of Beams | ||
18/Feb/2008 16:51:00.0 |
-32.0 |
3.86 |
-1 |
0 |
-0.324 |
+1 |
+0.0 |
-58.9 |
-2.7 |
0.0 |
0 |
110 |
16 |
|
18/Feb/2008 16:51:00.0 |
03/May/2008 09:15:42.0 |
+1 |
||||||||||||
03/May/2008 09:15:42.0 |
05/Aug/2009 13:27:33.0 |
-1 |
||||||||||||
05/Aug/2009 13:27:33.0 |
24/Sep/2009 00:01:57.0 |
+1 |
||||||||||||
24/Sep/2009 00:01:57.0 |
27/Oct/2009 00:00:59.0 |
-1 |
||||||||||||
27/Oct/2009 00:00:59.0 |
12/Sep/2011 00:00:00.0 |
+1 |
||||||||||||
12/Sep/2011 00:00:00.0 |
17/Jan/2012 15:00:00.0 |
-40.0 |
3.24 |
-1 |
24 |
|||||||||
17/Jan/2012 15:00:00.0 |
28/Jan/2012 14:31:00.0 |
+1 |
||||||||||||
28/Jan/2012 14:31:00.0 |
31/Jan/2012 17:10:55.0 |
-1 |
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31/Jan/2012 17:10:55.0 |
10/Apr/2013 20:00:00.0 |
+1 |
||||||||||||
10/Apr/2013 20:00:00.0 |
09/Jul/2013 20:00:00.0 |
-0.378 |
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09/Jul/2013 20:00:00.0 |
08/Apr/2014 20:54:00.0 |
-0.338 |
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08/Apr/2014 20:54:00.0 |
03/Nov/2016 21:12:00.0 |
-0.333 |
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03/Nov/2016 21:12:00.0 |
Current |
-40.0 |
3.24 |
+1 |
0 |
-0.336 |
+1 |
+0.0 |
-58.9 |
-2.7 |
0.0 |
0 |
110 |
24 |
* Only valid for analog receivers, 0 for digital receivers
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Last Updated: Mon Jul 8 07:25:01 2019 |
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Show a detailed decription of the parameters in the hardware files
| Position in Line | Parameter Name | Description |
|---|---|---|
| 1 | Station ID | The unique numeric ID of the radar. Assigned by Rob Barnes. |
| 2 | Year | This and the next parameter describe the date up until which the radar configuration described in that line was valid. |
| 3 | Seconds in Year | This and the previous parameter describe the date up until which the radar configuration described in that line was valid. |
| 4 | Geog. Latitude | The geographic latitude of the radar location, given in decimal degrees to 3 decimal places. Southern hemisphere values are negative. |
| 5 | Geog. Longitude | The geographic longitude of the radar location, in degree given in decimal degrees to 3 decimal places. West longitude values are negative. |
| 6 | Altitude | The altitude above sealevel of the radar location, in meter. |
| 7 | Scanning Boresite | The direction of the center of the field-of-view of the radar, in degree, relative to geographic North, positive clockwise. Traditionally, this direction was the same as the direction of the main antenna array normal. |
| 8 | Beam Separation | The angular separation of two adjacent beams, in degree. Normally 3.24 degrees. |
| 9 | Velocity Sign | The sign of the velocity direction, either +1 or -1, usually +1.(At the radar level, backscattered signals with frequencies above the transmitted frequency are assigned positive Doppler velocities while backscattered signals with frequencies below the transmitted frequency are assigned negative Doppler velocity. This convention can be reversed by changes in receiver design or in the data samping rate. This parameter is set to +1 or -1 to maintain the convention.) |
| 10 | Attenuation Step* | The step size of the receiver attenuation in dB. |
| 11 | Time Difference | The relative time delay of signal paths from the interferometer array to the receiver and the main array to the receiver, in microseconds. tdiff = signal_travel_time_from_interferometer_to_receiver - signal_travel_time_from_main_to_receiver If tdiff is positive, the signal travel time from the interferometer array to the receiver is longer than the travel time from the main array to the receiver. |
| 12 | Phase Sign | The sign of the phase shift between interferometer and main array, either +1 or -1, usually +1. (Cabling errors can lead to a 180 degree shift of the interferometry phase measurement. +1 indicates that the sign is correct, -1 indicates that it must be flipped.) |
| 13 | Interferometer Array Position X | The offset distance between the mid points of the interferometer and main array, in the direction along the main array, positive towards higher antenna numbers, in meter. |
| 14 | Interferometer Array Position Y | The offset distance between the mid points of the interferometer and main array, in the direction perpendicular to the main array, positive values indicate that the interferometer array is in front of the main array, in meter. |
| 15 | Interferometer Array Position Z | The offset distance between the mid points of the interferometer and main array, in the vertical direction, positive up, in meter. |
| 16 | Receiver Rise Time* | The rise time of the analog receiver, in microseconds. (Time delays of less than ~10 microseconds can be ignored. If narrow-band filters are used in analog receivers or front-ends, the time delays should be specified.) |
| 17 | Stages of Attenuation* | The maximum number of steps of analog attenuation in the receiver. (This is used for gain control of an analog receiver or front-end.) |
| 18 | No. of Gates | The maximum number of range gates from which the radar can receive data. Usually 75. (This is used for allocation of array storage.) |
| 19 | No. of Beams | The maximum number of beams the radar can form. Usually 16. Together with the scanning boresite, this parameter defined the direction of each beam relative to geographic North. (It is important to specify the true maximum. This will assure that a given beam number always points in the same direction. A subset of these beams, e.g. 8-23, can be used for standard 16 beam operation.) |
* Only valid for analog receivers, 0 for digital receivers |
Last Updated: Fri Mar 24 07:25:02 2023 |
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