GAMMA Remote Sensing AG GPRI-II User manual

GAMMA Portable Radar Interferometer II (GPRI-II)
User Manual
16-Nov-2011
GAMMA Remote Sensing AG
Worbstrasse 225
CH-3073 Güm igen
Switzer and
www.gamma-rs.ch

Copyright 2011, GAMMA Remote Sensing AG. A rights reserved. This document contains
proprietary information that is protected by copyright. No part of this document may be reproduced,
transmitted, transcribed, stored in a retrieva system, or trans ated into any anguage in any form by any
means without the written express of GAMMA Remote Sensing AG.
The authors and GAMMA Remote Sensing AG have used their best efforts in preparing this manua .
However, the author and GAMMA Remote Sensing AG make no warranties of any kind, expressed or
imp ied, with regard to the informationa content, documentation, or fi es contained in this manua , and
sha not be iab e for technica or editoria errors or omissions contained herein. In no event sha the
author or pub isher be responsib e or iab e for any incidenta or consequentia damages resu ting from
the furnishing, performance, or use of this materia .
TRADEMARKS Products mentioned herein may be trademarks/or registered trademarks of their
respective owners.

Table of Contents
1. Read First...............................................................................................................................................5
1.1 EMC Notice.....................................................................................................................................5
1.2 Safety Guide ines............................................................................................................................5
1.3 Operating Safety..............................................................................................................................5
1.4 Manua Out ine................................................................................................................................6
2. Background............................................................................................................................................7
3. Quick Introduction.................................................................................................................................8
3.1 Instrument Setup..............................................................................................................................8
3.1.1 Leica heavy-duty tripod...........................................................................................................8
3.1.2 Motor with eve er and tower..................................................................................................9
3.1.3 RF Unit..................................................................................................................................11
3.1.4 Antenna..................................................................................................................................12
3.1.5 Instrument Contro er and Power Unit..................................................................................12
3.2 Operating the Instrument...............................................................................................................13
3.2.1 Operating the instrument through SSH..................................................................................13
3.2.2 Operating the instrument through HTTPS ............................................................................16
4. Detai ed Instrument Description..........................................................................................................21
4.1 Instrument Components / Package List.........................................................................................21
4.2 Instrument Hardware.....................................................................................................................22
4.2.1 GPRI-II E ectronics...............................................................................................................23
Chirp Generator.........................................................................................................................23
4.2.2 Antenna..................................................................................................................................25
4.2.3 Mechanics..............................................................................................................................26
GPRI-II Antenna Tower.............................................................................................................26
Tripod, Positioner and Tribrach Leve er....................................................................................26
Azimutha Scanner.....................................................................................................................27
Radio Frequency Assemb y (RFA)............................................................................................28
Contro er and Power Unit.........................................................................................................29
4.3 Instrument Software......................................................................................................................30
5. User Interface.......................................................................................................................................31
5.1 Loca Access..................................................................................................................................31
5.2 Graphica User Interface...............................................................................................................31
5.3 Termina Access.............................................................................................................................31
6. Software Reference..............................................................................................................................32
6.1 Acquire data...................................................................................................................................32
6.1.1 gpri2_capture_utc.py ............................................................................................................32
6.1.2 gpri2_capture.py ...................................................................................................................33
6.2 Qua ity contro fie d ana ysis of data............................................................................................34
6.2.1 gpri2_p ot.py .........................................................................................................................34
6.2.2 gpri2_raw_p ot.py..................................................................................................................35
6.2.3 gpri2_proc.py.........................................................................................................................36
6.2.4 gpri2_proc_a .p ...................................................................................................................38
6.2.5 mu ti_ ook..............................................................................................................................39
6.2.6 create_offset...........................................................................................................................39
6.2.7 SLC_intf................................................................................................................................40
6.2.8 rasmph_pwr...........................................................................................................................40

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_p ot_cpx.py........................................................................................................................42
6.3.3 ts_p ot_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_re .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
6.5.9 rfa_poweroff.py.....................................................................................................................45
6.5.10 rx_poweron.py.....................................................................................................................45
6.5.11 rx_poweroff.py....................................................................................................................45
6.5.12 tscc_status.py.......................................................................................................................45
6.5.13 tx_poweron.py.....................................................................................................................45
6.5.14 tx_poweroff.py.....................................................................................................................45
6.5.15 usrp_poweron.py.................................................................................................................45
6.5.16 usrp_poweroff.py.................................................................................................................45
6.6 Fi e Formats...................................................................................................................................45
6.6.1 Measurement Profi es............................................................................................................46
6.6.2 Raw data................................................................................................................................47
6.6.3 SLC (Sing e-Look Comp ex) Data........................................................................................48
7. Instrument Specifications.....................................................................................................................51
8. References............................................................................................................................................52
9. Appendix A..........................................................................................................................................53
10. Demo Data Processing.......................................................................................................................54
10.1 Continuous Measurements..........................................................................................................54
10.2 Repeat Measurements..................................................................................................................54

1. Read First
First of a , thanks for buying this fascinating piece of hardware and software and we hope you can
conduct many interesting and troub e free measurements. If you have feedback p ease do not hesitate to
contact us ([email protected] or direct y one of the staff). Feedback from our users is a strong
e ement of our hardware and software evo ution.
1.1 EMC Notice
This device comp ies with Part 15 of the FCC Ru es and with RSS-210 of Industry Canada.
Operation is subject to the fo owing two conditions:
1. this device may not cause harmfu interference, and
2. this device must accept any interference received, inc uding interference that may cause
undesired operation.
Changes or modifications made to this equipment not express y approved by (GAMMA Remote
Sensing AG) may void the FCC authorization to operate this equipment.
This equipment comp ies with FCC radiation exposure imits set forth for an uncontro ed environment.
This equipment shou d be insta ed and operated with minimum distance of 500 cm between the
radiator (antenna in view direction) and your body. For proper radar imaging, no obstac e must be
between the antennas and the target area during image acquisition at a (shadow effects).
This transmitter must not be co- ocated or operating in conjunction with any other antenna or
transmitter.
1.2 Safety Guidelines
Fo ow these guide ines to ensure genera safety:
•Keep the working area c ear during insta ation and instrument operation.
•Wear safety g asses if you are working under any conditions that might be hazardous to your
eyes.
•Do not perform any action that creates a potentia hazard to peop e or makes the equipment
unsafe.
•Disconnect a power by turning off the power and unp ugging the power cord before insta ing
or removing a chassis or working near power supp ies
•Do not work a one if potentia y hazardous conditions exist.
•Never assume that power is disconnected from a circuit; a ways check the circuit.
•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!
1.3 Operating Safety
•E ectrica equipment generates heat. Ambient air temperature may not be adequate to coo
equipment to acceptab e operating temperatures without additiona measures.
•Ensure that the RF assemb y and Instrument Contro er cover is secure. The design a ows

coo ing air to circu ate effective y.
1.4 Manual Outline
This manua sha he p the user to setup and use the instrument but a so 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. Section 4 gives more
detai ed information on the instrument. Section 5 gives insight in the communication interfaces.
Section 6 summarizes the instrument specifications and Section 7 a ist of references and iterature.
Fina y in the Appendix A in Section 8 a temp ate for a measurement protoco is provided. Whi e
everything can be contro ed digita y, neverthe ess we recommend to keep a handwritten ogbook.

2. Background
The GPRI-II is the second generation instrument of the Gamma Portab e Radar Interferometer GPRI
[1,2]. The GPRI-1 was deve oped as a proof of concept and ater used on numerous scientific and
commercia campaigns. The new second generation instrument GPRI-II has improved performance and
is hardened for fie d measurements.
The GPRI deve opment at Gamma was initiated based on the perceived benefits of in-situ measurement
of deformation using differentia radar interferometry. Our extensive experience with sate ite
differentia interferometry has demonstrated successfu app ication of this technique for measuring
deformation due ands ides, pumping of oi and water, mining, g aciers, and tectonic motion.
However, when the deformation between repeat observations exceeds wave ength/4 the usefu ness and
interpretation of the data rapid y become difficu t. A ground-based instrument can be rapid y dep oyed
and obtain data with both high spatia and tempora reso utions that are particu ar y we suited to
measuring rapid deformation.
Un ike orbita SAR systems, in-situ measurement permit f exibi ity in the se ection of the observation
geometry. The geometry can be se ected to give maximum sensitivity to deformation a ong the ine of
sight. Observations from mu tip e aspect ang es can be combined to reso ve the deformation into
components a ong different ook vectors.
Path de ay variation due to tropospheric water vapor is the most significant cause of error in
deformation using differentia interferometry. A stationary instrument has the abi ity to acquire mu tip e
observations for mitigation of path de ay variations. Note that ground measurements have a shorter
path ength through the atmosphere than orbita observations a so eading to reduced error from this
source.
Mu tip e observations acquired over short time interva s have the advantage that decorre ation is
minimized by the shorter time interva s. Successive measurements can be processed to track non- inear
deformation within the scene.

3. Quick Introduction
3.1 Instrument Setup
The instrument setup needs to be stab e (consider a so wind!) and reproducib e (if repeat measurements
from a given position are foreseen). The standard setup of the GPRI-2 is on the supp ied heavy duty
Leica tripod. However it can a so 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.
3.1.1 Leica heav -dut tripod
Insta ation of the tripod is the first step in setting up the GPRI2. The tripod egs shou d be initia y
fu y retracted. Take the tripod out of the canvas transport bag and take out the 3 stain ess stee rods.
1. Insta the stain ess stee support rods to the tripod to maintain the egs at a fixed 30 degree
ang e. These rods fit into the attachments at the bottom of each eg. The end of the rod is shaped
to fit into the s ots on the attachment points. A sma ocking arm on each attachment point must

be rotated to permit insertion of the rod. Once the rod is attached, rotate the arm back over the
rod ends and it wi ock into p ace.
2. The tripod egs are numbered 1,2, and 3 with abe . Make sure that you note the ocation of each
eg so that when you return to the site, the orientation of the tripod is identica . One eg of the
tripod shou d remain fu y retracted and this shou d not change. In s oping terrain, this eg
shou d be the eg with the highest e evation. The zero degree ook direction of the radar is in the
direction of eg 1.
3. Using the bubb e eve on top of the tripod, extend the other 2 feet of the tripod unti the tripod
top surface is horizonta . Remember to keep one eg of the tripod fu y retracted and on y
extend the other 2 egs.
4. Screw the feet through the ho e in the tip to the ground using anchor screws (6mm anchors).
5. Measure and note the extension of the egs for future repositioning.
Figure 2: Fi ature of rods to have tripod
legs at fi distance.
Figure 3: Tripod foot with
special tip that allows
screwing to the ground.
Figure 4: Tripod leg e tent
documentation.
Figure 5: Interface Plate of the Leica
Tripod with level and 5/8" screw.
3.1.2 Motor with leveler and tower
1. Mount the rotary positioner and eve ing assemb y on the tripod using the b ack 5/8” screw
interface of the tripod. The positioner has abe s with the numbers 1 and 3. Position this edge of
the positioner + eve er between tripod egs 1 and 3. Rotate the positioner and eve er assemb y
such that the edge of the positioner p ate is para e with the tripod stain ess-stee rod between
egs 1 and 3.

2. Make the antenna tower interface perfect y f at using the tribrach eve adjustment screws.
Note, the screw on side 1 is fixed and shou d never be change to not oose the abso ute height
reference. The arge bubb e eve on the positioner shou d be used to determine if the tower
mounting p ate is eve . Be sure to ook down from direct y above the eve to make sure the
bubb e is centered.
3. Power on the aser p ummet using the battery pack. If this is the first measurement, mark the
position of the aser on the ground for future repositioning. This point is precise y on the
rotation axis of the tower. If you are returning to the site, adjust the positioner and eve er so
that the aser beam hits the previous y marked rotation center
4. Remove the 4 socket screws on the tower mounting p ate, and mount the tower on the p ate.
There is an a ignment pin on the p ate that makes sure that there is on y one way to position the
tower. Screw the tower to the mounting p ate. When you remove the tower, be sure to screw the
4 screws back on to the p ate for future use and storage.
5. Define the antenna e evation ang e and set a six antenna ho ders according y. The antenna
i uminates about 60 degrees in e evation, Set the e evation ang e so that the beam center aims
at the area of interest. If there are areas that are significant y farther away, adjust the beam to be
centered on these areas.
Figure 6: Side view of the Tripod - leveler -
positioner - Antenna Tower setup. The leveler is
adjust by rotating the red knobs. The black
screw is to fi the knob setting. At the bottom of
the motor, the connector for the laser battery is
indicated.
Figure 7: Top view of the positioner. The 4 socket
screws need to be removed before mounting the
antenna tower.