GPS progress report

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GPS progress report

• Agnieszka Jacholkowska
• LPTA, IN2P3/CNRS
• AMSTIM, 28/07/2005

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GPS system goals
GPS system will deliver UTC time for AMS02
triggers with few ?sec precision
? time stamp for each event Useful
for ? ? astrophysics transient source
studies (GRBs, Pulsars, ..) ? monitoring of
Cosmic Events (Super Novae, flairs, ..) ?
monitoring of technical incidents on ISS ?
providing UTC time for AST ? providing common
reference time for AMS02 sub-detectors
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GPS integration
Meeting at ETH, Zurich, June 2, 2005 Discussion
about Power supply control, RS422
specifications, Test bench for GPS on ground
October 2005 at CERN Loan of GPS module and
expert support for testing
ETHZ G. Viertel, V. Commichau
conception and realization of the GPSE card MIT
M. Capell, A. Lebedev system
engineering and integration in AMS02 DAQ and
Trigger System LPTA A. Jacholkowska, C.
Zurbach negotiations with CNES and
Alcatel, interface with CNES and Alcatel,
code development for GPS acquisition and
monitoring ALCATEL-SPACE and CNES technical
support, GPS specifications, test bench
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GPS integration - antenna
R. Becker, 2004
GPS
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GPS integration - antenna

• Antenna
• conclusions of discussions with CNES and Alcatel
• 1 passive antenna should be chosen
  (more reliable than GPS module)
• 2 antennas
• - need to be placed
  back-to-back
• - if not, spurious
  interference effects and a lot of computing
• - would need more equipment
  higher cost
• ? constraint GPS-antenna distance lt 2
  m
• ? Implementation to be discussed in
  Safety Meeting (Trent Martin)

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GPS integration test technical scheme
C. Zurbach
Components
GPS
PPS
Antenna or simulator
GPSE
RS422
Power supply 6.3 V 5.2 V
USCM
Can Bus
GPS monitoring TC TM
Test bench GPS gets antenna signals and TC
(telecomands) from monitoring system by
GPSE GPS provides Pulse Per Second and TM
(teledata) GPSE provides time reference to the
trigger system USCM gets UTC time and TM from
GPS-GPSE, and transmits TC GPS monitoring
emulates DAQ system, sending TC and getting TM
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GPS integration
Given to John Heilig
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GPSE V.Commichau IPP/ETHZ
GPSE GPS interface board A. Lebedev, V.
Commichau
The GPSE module will link the GPS and the AST to
the two USCM modules part of the M-crate. Via a
16 bit status register various modes may be set
and status information is available on read
operations. The contents of a second register
defines the USCMs serial output ports linked to
GPS and AST serial input ports. Independent of
the output port settings the USCMs serial inputs
may be linked via a third register to any
possible combination to the GPS and AST serial
outputs.
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GPSE V.Commichau IPP/ETHZ
A write only register may be used to release a
software PulsePerSecond, open/close the EPOCHGATE
or COMGATE and reset the GPS module under
software control. GPS PPS and serial I/O are
implemented as RS422 I/O. In case of AST the PPS
input should be a LVDS port, the two serial I/O
port will be handled via TTL signals. Only one
port will be used at a time, software selected
via the GPSE status register. The PPS is fed to
the JTBX (trigger) as LVDS signal, active low,
duration gt70ns - lt200ns.
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GPSE V.Commichau IPP/ETHZ
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GPS summary
? GPSE EM card ready for end of August, 2005
document delivered by V. Commichau and A.
Lebedev ? Loan of GPS QM module for 10 days
accepted by CNES with expert support of CNES
engineer at CERN in October 2005 (MoU with
CNES-Toulouse signed) ? Antenna implementation
under discussion with NASA ? Production of GPS
FM started at ALCATEL-SPACE which became
Alcatel Alenia Space company