Summary of Contents for GAMMA Remote Sensing AG GPRI-II
- Page 1 GAMMA Portable Radar Interferometer II (GPRI-II) User Manual 16-Nov-2011 GAMMA Remote Sensing AG Worbstrasse 225 CH-3073 Gümligen Switzerland www.gamma-rs.ch...
- Page 2 GAMMA Remote Sensing AG. The authors and GAMMA Remote Sensing AG have used their best efforts in preparing this manual. However, the author and GAMMA Remote Sensing AG make no warranties of any kind, expressed or implied, with regard to the informational content, documentation, or files contained in this manual, and shall not be liable for technical or editorial errors or omissions contained herein.
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Page 3: Table Of Contents
3.2.1 Operating the instrument through SSH..................13 3.2.2 Operating the instrument through HTTPS ................16 4. Detailed Instrument Description......................21 4.1 Instrument Components / Package List..................21 4.2 Instrument Hardware........................22 4.2.1 GPRI-II Electronics.......................23 Chirp Generator.........................23 4.2.2 Antenna..........................25 4.2.3 Mechanics..........................26 GPRI-II Antenna Tower......................26 Tripod, Positioner and Tribrach Leveler..................26 Azimuthal Scanner........................27... - Page 4 6.2.9 raspwr............................41 6.2.10 mk_tab..........................41 6.3 Postprocess data..........................42 6.3.1 SLC_stack.py ........................42 6.3.2 ts_plot_cpx.py........................42 6.3.3 ts_plot_diff.py........................43 6.4 Move the instrument........................43 6.4.1 get_pos.py..........................43 6.4.2 home_run.py..........................43 6.4.3 move_abs.py..........................44 6.4.4 move_rel.py...........................44 6.4.5 stop_scan.py...........................44 6.5 Maintenance..........................44 6.5.1 chupa_status.py........................44 6.5.2 chupa_test.py.........................44 6.5.3 ff_init.py..........................44 6.5.4 gps_poweron.py........................44 6.5.5 gps_poweroff.py........................44 6.5.6 ima_poweron.py........................45 6.5.7 ima_poweroff.py........................45 6.5.8 rfa_poweron.py........................45...
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Page 5: Read First
1. Read First First of all, thanks for buying this fascinating piece of hardware and software and we hope you can conduct many interesting and trouble free measurements. If you have feedback please do not hesitate to contact us (gamma@gamma-rs.ch or directly one of the staff). Feedback from our users is a strong element of our hardware and software evolution. -
Page 6: Manual Outline
cooling air to circulate effectively. 1.4 Manual Outline This manual shall help the user to setup and use the instrument but also provides background information on the instrument. Section 2 gives a quick access on the instrument. Section 3 provides setup instructions and the basic commands needed to operate the instrument. -
Page 7: Background
2. Background The GPRI-II is the second generation instrument of the Gamma Portable Radar Interferometer GPRI [1,2]. The GPRI-1 was developed as a proof of concept and later used on numerous scientific and commercial campaigns. The new second generation instrument GPRI-II has improved performance and is hardened for field measurements. -
Page 8: Quick Introduction
Leica tripod. However it can also be mounted on permanent pier or other structure. In any case there must be sufficient room for the instrument to rotate (about 2.5 meters). Figure 1: GPRI-II fully assembled. Instrument is aligned at 0 deg. azimuth position. -
Page 9: Motor With Leveler And Tower
be rotated to permit insertion of the rod. Once the rod is attached, rotate the arm back over the rod ends and it will lock into place. 2. The tripod legs are numbered 1,2, and 3 with label. Make sure that you note the location of each leg so that when you return to the site, the orientation of the tripod is identical. - Page 10 2. Make the antenna tower interface perfectly flat using the tribrach level adjustment screws. Note, the screw on side 1 is fixed and should never be change to not loose the absolute height reference. The large bubble level on the positioner should be used to determine if the tower mounting plate is level.
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Page 11: Rf Unit
Figure 8: Bottom of Antenna Tower mounted on the motor. Visible is the level, the 4 hexagon socket screws and the knob enforcing the defined tower orientation. 3.1.3 RF Unit 1. Mount the RF Unit on monting brackets at the back of the Antenna Tower. Use the 2 screws on the back to secure the RF unit 2. -
Page 12: Antenna
3.1.4 Antenna 1. Take each antenna out of the tube by loosening the 2 thumb screws. NOTE it is important that you push them out with the antenna cable plug in front to avoid damaging the antenna cable. 2. Mount the antennas one by one on the corresponding antenna holders. Make sure you use a fix order for the antennas (TX, RX1, RX2) to avoid phase effects due to slightly different antenna characteristics. -
Page 13: Operating The Instrument
6. Switch Instrument Controller on. There are no user serviceable parts in the RF Assembly or the Instrument Controller Box. The Instrument Controller Box must not be opened with the power cable attached! Figure 11: Instrument Controller and Power Unit in Pelican case. Connectors uper line from left to right: WLAN (not connected), Ethernet, RF Unit, Power. - Page 14 1. Login to instrument: ssh -X -l gpri2 192.168.1.7x 2. Check available disk space for data. The data are stored in their own disk partition called /data: df /data 3. Move to the data directory cd data 4. Initiate home run of the positioner (check first visually that the instrument can move freely and the cables have enough room!): home_run.py The instrument is now looking at 0 degrees instrument azimuth angle.
- Page 15 12. Then display the processed data: eog mli/20110714/20110714_084014*l.ras gpri2_plot.py gpri_2ms_ro.prf raw/20110714/20110714_084014.raw Check signal levels in gpri2_plot to make sure there is no saturation and that there is sufficient signal and adjust attenuation setting in the prf file. Redo step 11./12. until gain is ok 13.
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Page 16: Operating The Instrument Through Https
int/20110714_084014l_20110714_084014u.snr int/20110714_084014l_20110714_084014u.off int/20110714_084014l_20110714_084014u.coffs - - 1 0 SLC_interp slc/20110714/20110714_084014u.slc $slc1.par \ slc/20110714/20110714_084014u.slc.par \ int/20110714_084014l_20110714_084014u.off \ rslc/20110714/20110714_084014u.slc.rslc \ rslc/20110714/20110714_084014u.slc.rslc.par \ now that the interferogram is created using the master slc and the rslc as in Step 14 above. 16. Backup data. e.g. with secure copy or rsync to a network attached disk. Use ionice to avoid disk timeouts while acquiring data: ionice -c2 n7 scp -r Rosenlaui 192.168.1.1:backupdirectory/ ionice -c2 n7 rsync -av Rosenlaui 192.168.1.1:backupdirectory/... - Page 17 form is setup setp-by-step when the corresponding data is provided (Figure 16) First you have to either select an existing Project Directory or create a new one. The • directory is/will be allocated in the data directory. Then you have to select an existing measurement profile or create a new one. •...
- Page 18 Figure 12: Instrument Web Access Login. Figure 14: Initial Measurement Control Tab. Figure 13: Motor Status Accordion Panel.
- Page 19 Figure 16: Measurement Settings. The button starts the measurement as a single task, the links allow to transfer the settings to the Repeat task Scheduler.
- Page 20 Figure 17: Recurrent Task Menu (Cron Interface). Figure 18: Compute Interferogram Tab. Figure 19: Main Menu.
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Page 21: Detailed Instrument Description
4. Detailed Instrument Description Figure 20: GPRI-II fully assembled. Instrument is aligned at 0 deg. azimuth position. 4.1 Instrument Components / Package List The instrument consists of the following components: – 3 Fan-Beam Antennas – 1 RF Assembly (Aluminum case) –... -
Page 22: Instrument Hardware
– Drill and screws, washers, anchors to fix the tripod to the ground (6mm screws should be fine) – socket screw key (socket screw key) 5mm 4.2 Instrument Hardware The GPRI-II instrument benefits from the experience of the GPRI-1 in the mechanical and electronic design. The GPRI-II has the following enhancements with respect to the GPRI-1: 1. -
Page 23: Gpri-Ii Electronics
4.2.1 GPRI-II Electronics Figure 21: GPRI-II System Level Design The high-level block design of the GPRI-II is shown in Figure 21. The main elements in the electronics are the Chirp Generator Assembly (CHUPA), IF Amplifier/Mixer Assembly (IMA), Ku-Band Microwave Assembly (KuMA), and the Computer and Power Assembly (CPA). We retain the dual receive channel design of the GPRI-1 to support recording interferograms with a spatial baseline defined by the antenna separation on the tower. - Page 24 Firefly-II). The DDS 1 GHz clock signal is generated using a Phase-Locked Loop (PLL) oscillator that uses the 100 MHz system clock as reference. All GPRI-II timing and reference signals are derived from the 100 MHz reference oscillator such that the radar is fully synchronous.
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Page 25: Antenna
ADCs in the CPA enclosure. 4.2.2 Antenna The GPRI-II antenna is an end-fed slotted-waveguide antenna. The azimuth antenna sidelobes remain constant over the entire operational bandwidth from 17.1 to 17.3 GHz at an acceptable level (-15 dB). -
Page 26: Mechanics
There is a thin plastic sheet over the flare opening to seal the antenna against moisture. The GPRI-II antennas and support is designed to fit in a 125 mm PVC shipping tube. The antennas are supported on a carbon-fiber truss structure as shown in Figure 23. The carbon tubes are symmetrically positioned about the waveguide so there is access from -45 degrees to +45 degrees in elevation. -
Page 27: Azimuthal Scanner
Azimuthal Scanner Te GPRI-II uses the Newmark RMS-5S azimuthal scanner. This scanner uses a stepper motor with a 72:1 gear reduction. This positioner has a repeatability of 5 arc-sec, and a resolution of 0.36 arc-... -
Page 28: Radio Frequency Assembly (Rfa)
controller and stepper driver support smooth ramp-up and ramp-down of the rotational velocity to permit stable rotation without vibration. Nominal rotational scan velocity is in the range of 5 to 10 deg./sec. Radio Frequency Assembly (RFA) The radar RF electronics are mounted in an aluminum enclosure made of single aluminum slab 56mm thick with a 6 mm central plate dividing the enclosure into two 22 mm deep cavities. -
Page 29: Controller And Power Unit
Figure 26: RF Electronics Assembly Interior showing KuMA-TX and KuMA-RX modules along with the SIMA. The microwave up- and down converters and IMA are located on one side and the GPS receiver, CHUPA and DISTRI on the opposite side of the enclosure. Controller and Power Unit The control and power unit (Figure 27) contains the power supplies that convert 100-240 VAC or 18-32 V DC to the voltages required by the radar. -
Page 30: Instrument Software
Additional instrument specific software is provided through the GAMMA gpri2 Debian software repository (deb http://apt.gamma-rs.ch/lucid_gpri2 stable/). It covers the GPRI-II instrument software, and the GPRI-II data post-processing software. Not included is the standard GAMMA software packages for InSAR data analysis. -
Page 31: User Interface
5. User Interface The GPRI-II instrument can be accessed through TCP/IP over the Ethernet connection provided at the Instrument Controller, or by opening the Pelican case and connecting a computer display and keyboard/mouse. The latter allows access in case the IP address of the instrument is unknown or any other communication problem occurs. -
Page 32: Software Reference
6. Software Reference In this section the command line tools are described grouped by functionality. Furthermore at the end of the section the parameter and data file formats are given. Section 6.5 shows the list of auxiliary tools that are not needed for every day use but can be helpful in case of instrument problems. 6.1 Acquire data The basic program to acquire data is gpri2_capture.py. -
Page 33: Gpri2_Capture.py
and -m options. If the user desires, the raw data can then be deleted (-x option) in order to save disk space. The SLC images are typically about 10% the size of the raw data due to data decimation performed by the processor. The raw data files include the UTC time in the file name in the format YYYYMMDD_HHMMSS.raw For each RAW data file there is also a RAW_PAR file with the same root name and the extension “raw_par”. -
Page 34: Quality Control Field Analysis Of Data
s, outputshorts output interleaved shorts instead of complex floats M, lockmasterclocktoSMA lock usrp2 100 Mhz master clock to external 10 Mhz reference clock on SMA input P, synctofirst1PPS reset the usrp2 samplecounter on the first PPS received on the PPS SMA input j RX_START_TIMESTAMP, rxstarttimestamp=RX_START_TIMESTAMP set start_at time of first RX packet in usrp2 100 Mhz clockpulses (long) [default=1 start immediately] k RX_START_TIME_SECONDS, rxstarttimeseconds=RX_START_TIME_SECONDS set start_at time of first RX packet in seconds (float) [default=1.0 start immediately] C EXTERNAL_PROGRAM, externalprogram=EXTERNAL_PROGRAM give a programname to start this as external program just before streaming starts (string) [default=None do not start an external program] v, verbose verbose output p GPRI_PROFILE, gpriprofile=GPRI_PROFILE GPRIII acquisition profile [default=None] 6.2 Quality control field analysis of data Here we group the programs that are needed to check data quality. That includes range profile analysis, (gpri2_plot.py) conversion of raw data to SLC (gpri2_proc.py and gpri2_proc_all.py) and MLI (multi_look) and visualisation (raspwr), and computation of an interferogram of two co-registered images (create_offset, SLC_intf) and visualisation rasmph_pwr. -
Page 35: Gpri2_Raw_Plot.py
6.2.2 gpri2_raw_plot.py Usage: gpri2_raw_plot.py v1.6 30-Sep-2011: [options] raw_par raw_data Takes a GPRI raw data set and raw data acquisition parameters and displays the two channels and the slant range echo. The start position in the file can be set by specifying -o or --offset and defaults to 0 (the start of the file). A specified number of points can be set to zero using the -z option Options: -h, --help... -
Page 36: Gpri2_Proc.py
6.2.3 gpri2_proc.py Takes a GPRI2 echo data and process to SLCs for channel-1 and channel-2. In the case that the data are acquired with alternating transmit polarization (C- Band only) then the user can specify the transmit polarization. The two SLCs are then obtained with from the data where the specified transmit polarization was used. - Page 37 The decimation factor -d DEC is an azimuth averaging parameter and specifies the number of echoes averaged to improve the Signal to Noise Ratio (SNR). The aim is to set the DEC factor such that the azimuth spacing is 0.1 degrees. Hence given a 2ms chirp and rotation rate of 10 deg/sec, the decimation factor should be set to 5.
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Page 38: Gpri2_Proc_All.pl
6.2.4 gpri2_proc_all.pl Script to process a series of SLC images using gpri2_proc.py: *** ./gpri2_proc_all.pl *** GPRI2 groundbased radar image processing for raw data *** *** Copyright 2011, Gamma Remote Sensing, v1.7 28Jul2011 clw *** usage: ./gpri2_proc_all.pl <RAW_list> <SLC_dir> <min_range> <max_range> <dec> <SLC_tab> <log> RAW_list (input) list of raw data files (2 columns): 1. GPRI2 raw data file (*.raw) 2. GPRI2 raw data parameter file (*.raw_par) SLC_dir directory to store output SLC images and SLC parameter files max_range maximum slant range (enter for default) dec azimuth decimation factor (1 > 64) SLC_tab output file containing list of SLC and SLC_par files log processing log file a (option) alongtrack interferometry processing: turn off azimuth interpolation t TX_ant (option) transmit antenna (H or V) when using HV alternating TX mode (default: V) z NSAMP (option) number samples to weight at the start of the echo (default: 300) k beta (option) set Kaiser window beta parameter (default: 3.84) r rmin (option) set starting slant range (default: 50) h head (option) set heading at the center of the scan (default: 0) This script is used to process an entire stack of raw data to produce SLC images. The script generates the arguments to call the processing program gpri2_proc.py. -
Page 39: Multi_Look
The decimation factor is an azimuth averaging parameter and specifies the number of echoes averaged to improve the Signal to Noise Ratio (SNR). The aim is to set the dec factor such that the azimuth spacing is 0.1 degrees. Hence given a 2ms chirp and rotation rate of 10 deg/sec, the decimation factor should be set to 5. -
Page 40: Slc_Intf
input parameters: SLC1_par (input) SLC-1/MLI-1 ISP image parameter filename (reference) SLC2_par (input) SLC-2/MLI-2 ISP image parameter filename OFF_par (output) ISP offset/interferogram parameter file offset_algorithm offset estimation algorithm: 1: intensity cross-correlation (default) 2: fringe visibility rlks number of interferogram range looks (default: 1) azlks number of interferogram azimuth looks (default: 1) 6.2.7 SLC_intf... -
Page 41: Raspwr
*** Copyright 2005, Gamma Remote Sensing, v2.5 10-Oct-2005 clw *** usage: rasmph_pwr <cpx> <pwr> <width> [start_cpx] [start_pwr] [nlines] [pixavr] [pixavaz] [scale] [exp] [LR] [rasf] [cc] [start_cc] [cc_min] input parameters: (input) complex image (fcomplex, e.g. interferogram) (input) intensity image width samples per row of cpx and pwr start_cpx starting line of cpx (default=1) start_pwr... -
Page 42: Postprocess Data
*** Copyright 2011, Gamma Remote Sensing, v1.2 29-Apr-2011 clw *** *** Generate SLC_tab, MLI_tab, or RAW_list for processing usage: ./mk_tab <dir> <ext-1> <ext-2> <tab> (input) directory including paths that contain the data files ext-1 (input) pattern to select data files (examples: slc, raw...) ext-2 (input) pattern to select parameter files that match the data (enter - for none, examples: slc.par, raw_par, raw.par) -
Page 43: Ts_Plot_Diff.py
Usage: ts_plot_cpx.py [SLC_tab] [image] [-r rpix azpix] SLC_tab (input) two column list of SLC filenames and SLC parameter filenames (including paths) 1. SLC filename (includes path) 2. SLC parameter filename (includes path) image display image of deformation used to select point for time series plot (PNG or JPEG format) Options: -h, --help... -
Page 44: Move_Abs.py
is a significant chance that the RFA power cable will be wrapped around the tower. 6.4.3 move_abs.py Move the antenna the a absolute motor angle. *** Move antenna positioner to an absolute angle *** Usage: move_abs.py <angle> [rate] [--nosemaphore] angle relative angle (deg.) rate rotational velocity (deg/s 0.5 -->... -
Page 45: Ima_Poweron.py
6.5.6 ima_poweron.py Turn on power to IMA located in the RFA 6.5.7 ima_poweroff.py Turn off power to IMA located in the RFA 6.5.8 rfa_poweron.py Turn on RFA power supplied by the DISTRII to the chirp generator (CHUPA), IF amplifiers (IMA), and microwave electronics (except for the transmitter) 6.5.9 rfa_poweroff.py Turn off RFA power supplied by the DISTRII to the chirp generator (CHUPA), IF amplifiers (IMA),... -
Page 46: Measurement Profiles
6.6.1 Measurement Profiles The measurement profile dataset, contains the instrument and observation geometry parameters used for a given observation. The format is self describing, an example is shown below: RF_center_freq: 1.720000e+10 IMA_atten_dB: CHP_freq_min: 100.0e6 CHP_freq_max: 300.0e6 CHP_num_samp: 12500 STP_antenna_start: STP_antenna_end: 180.0 STP_gear_ratio: STP_rotation_speed:... -
Page 47: Raw Data
The transmitter power can be turned on or off using the TX_power option. The data acquisition program itself turns the transmitter on only during data acquisition. TX_mode is only used when there are multiple transmit output channels. On the C-Band system, the transmitter has 3 mode values: H transmit, V transmit, and HV alternating. -
Page 48: Slc (Single-Look Complex) Data
TSC_temperature: 28.400 The time is specified in UTC time the +00:00 is the offset in Hours and Minutes relate to UTC. Geographic coordinates are in latitude and longitude in the WGS84 horizontal data in decimal degrees. The geographic_coordinates string format is: latitude decimal degrees WGS84 horizontal datum longitude... - Page 49 range_samples: 2667 azimuth_lines: range_looks: azimuth_looks: image_format: FCOMPLEX image_geometry: SLANT_RANGE range_scale_factor: azimuth_scale_factor: center_latitude: 0.00000000 degrees center_longitude: 0.00000000 degrees heading: 0.000000 degrees range_pixel_spacing: 0.749912 azimuth_pixel_spacing: 0.000000 near_range_slc: 0.000000 center_range_slc: 1000.000000 far_range_slc: 2000.000000 first_slant_range_polynomial: 0.0 0.0 0.0 0.0 0.0 0.0 center_slant_range_polynomial: 0.0 0.0 0.0 0.0 0.0 0.0 last_slant_range_polynomial: 0.0 0.0 0.0 0.0 0.0 0.0 incidence_angle:...
- Page 50 parameter. The reference position is the location of the GPS antenna on the top of the antenna tower. The GPRI_tx_coord, GPRI_rx1_coord, and GPRI_rx2_coord are the positions of the antenna phase centers in the local tower coordinate system. The origin of the tower coordinates is the intersection of the rotation axis and the central plane of the tower, 40 cm from the bottom mounting plate.
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Page 51: Instrument Specifications
7. Instrument Specifications The GPRI-II instrument specifications are as follows: Frequency Range 17.1 to 17.3 GHz Antenna Pattern 0.5 deg 3 dB azimuth beamwidth 35 deg. 3 dB beamwidth Elevation Peak sidelobes: -15 dB sidelobes (1-way) Radar type FM-CW, chirps between 0.25 and 8 milliseconds Radar operational range 10 m →10 km... -
Page 52: References
8. References Werner C., T. Strozzi, A. Wiesmann, and U. Wegmüller, "GAMMA’s Portable Radar Interferometer”, Procs. IAG – FIG Symposium Lisbon, Portugal, 12 – 15 May 2008. Wiesmann A., C. Werner, T. Strozzi, and U. Wegmüller, "Measuring deformation and topography with a portable Radar interferometer”, Procs. -
Page 53: Appendix A
9. Appendix A Measurement Protocol Campaign Name Customer Site Name and Coordinates Date Weather (Temp, Wind) Antenna elevation Tripod legs etc. GPS Position Power Source Chirps TX_mode (C-Band) RX IMA Attenuation Start Azimuth Stop Azimuth Start/End Time Time Intervals Dataset Names Pictures Remarks... -
Page 54: Demo Data Processing
Demo Data Processing 10.1 Continuous Measurements 10.2 Repeat Measurements...