Implementation Plan for NETCOM by dopdm303

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									                           XTAR Demonstration Results
                                      For the
                          AS-4429 and AS-3036A Antennas

Dennis Evanchik
Project Leader, LHGXA
Project Manager, Multichannel Satellite Terminals
PM-MST
Office 732-532-3742, DSN 992-3742
Cell 908-309-1650
dennis.evanchik@us.army.mil

Executive Summary: A series of demonstrations were conducted in Mannheim, Germany
during the week of 11 April 2005, using assets from the 7th SIG Bde. An AN/TSC-85C TACSAT
Van, using both a standard and modified feed assembly on the LHGXA (AS-4429), accessed
the new LORAL XTAR X-Band Satellite. Using the standard modem presently installed in the
TACSAT van, a data link of 8 Mbps was immediately established. After the installation of a new
modem, stable data rates in excess of 100 Mbps were achieved, using less than 10% of satellite
transponder power and 20 watts of terminal power when operating within the satellite spot
beam. When transmitting with the smaller AS-3036 antenna (standard and modified), stable
data rates in excess of 75 Mbps were established using less than 21% of satellite transponder
power and 370 watts of terminal power.

Purpose: A series of demonstrations were conducted to demonstrate the interoperability of a
modified LHGXA feed assembly (Lightweight High Gain X-Band Antenna AS4429) with the new
XTAR satellite, in both conventional uplink Right Hand Circular Polarization (RHCP) and reverse
polarization Left Hand Circular Polarization (LHCP). A standard AN/TSC-85C was used to
support this demonstration. Due to the location of the visible footprint of the XTAR satellite, the
demonstration was held in Mannheim, Germany, using assets and support from the 7th SIG Bde
during the week of 11 April 2005.

Background:

LHGXA - The AS-4429/TSC was originally developed as an alternate antenna for the AN/TSC-
85B Communications Systems. It was meant to replace the QRSA, 20ft antenna, with a lighter
and more mobile alternative without compromising the functionality of the antenna. Currently,
130 antennas are fielded to TACSAT units in the Army, Marine Corps, JCSE and Air Force
inventories. PM-MST, in anticipation of the requirement for frequency reuse and the benefits of
a high power satellite, and in harmony with Harris Corp, Melbourne, Fla , modified the standard
LHGXA X-Band feed to support this initiative.

XTAR – The XTAR satellite is a X-Band only satellite launched on 12 Feb 2005. It is privately
owned by LORAL LLC, Inc. It is intended to supply leased X-Band satellite services to the US
Government, US Allies and NATO countries only. It consists of 6 RHCP and 6 LHCP high power
100-watt transponders. Due to the high demand for these services, 4 of the 6 RHCP
transponders are already leased. None of the LHCP transponders are leased. The satellite is
permanently located at 29 degrees East (over Africa). This position allows global beam
coverage over a 5,000 mile radius, and steerable Spot beam coverage of 1,000 miles radius,
including the entire South West Asia (SWA) Area of Responsibility (AOR).
Harris Corp: Harris Corp, Melbourne, Fla, using Independent Research and Development
(IR&D) funding, modified a standard LHGXA RHCP feed. A rotary coupling was installed to
allow 90 degrees of feed rotation. This rotation changed the standard RHCP configuration to a
LHCP configuration. This modification allows operation over the XTAR satellite in both RHCP
and LHCP configurations.

L3 Corp, Salt Lake City, Utah: L3 Corp, Salt Lake City, Utah, using Independent Research and
Development (IR&D) funding, modified a standard AS-3036A RHCP feed. The feed was
modified to allow 90 degrees of feed rotation. This modification allows operation over the XTAR
satellite in both RHCP and LHCP configurations but is not yet fielded as a part of any antenna
upgrade program. Additionally, L3 also supplied a new modem from Advantech (model AMT-
73L-this is the same version to be installed in the PHOENIX Block 2 upgrade effort). This
modem was used later in the demonstration to demonstrate enhanced data rates in excess of
the current L3 modem (L3 model 3501) presently installed in the AN/TSC-85C TACSAT van.

Results Overview

   1. The primary intent of this test was to verify the Cross Polarization Isolation performance
      of the LHGXA LHCP feed. Measurements taken from both on the ground and via remote
      monitoring indicated that the Harris LHCP feed performed as required. (Cross Pol
      isolation <2.0db)

   2. The secondary intent of this test was to verify the Cross Polarization Isolation
      performance of the AS-3036 LHCP feed. Measurements taken from both on the ground
      and via remote monitoring indicated that the L3 LHCP feed performed as required.
      (Cross Pol isolation <2.0db)

   3. As time permitted, a new MODEM (model AMT-73L) from Advantech was installed to
      measure maximum data throughput at the system level. For this effort, the ETSSP
      (Enhanced Tactical Satellite Signal Processor) was not used, since its performance is
      limited to 8 Mbps.

          a. When transmitting via the LHGXA, in either RHCP or LHCP, stable data rates in
             excess of 100 Mbps were achieved, using less than 9% of satellite transponder
             power and 20 watts of terminal power when operating within the satellite spot
             beam. (16 QAM-Quadrature Amplitude Modulation, 7/8 rate, with Reed-Soloman
             coding)

          b. When transmitting via the LHGXA, in either RHCP or LHCP, stable data rates in
             excess of 20 Mbps were achieved, using less than 35% of satellite transponder
             power and 250 watts of terminal power when operating within the satellite global
             beam. (OQPSK-Offset Quadrature Phase Shift Keying), ¾ rate)

          c. When transmitting with the smaller AS-3036 antenna, in either RHCP or LHCP,
             stable data rates in excess of 75 Mbps were established using less than 21% of
             satellite transponder power and 370 watts of terminal power when operating
             within the satellite spot beam. (16 QAM, 3/4 rate, no Reed-Soloman coding)

          d. When transmitting with the smaller AS-3036 antenna, in either RHCP or LHCP,
             stable data rates in excess of 20 Mbps were established using less than 34% of
             satellite transponder power and 370 watts of terminal power when operating
             within the satellite global beam. (OQPSK, ¾ rate)
   4. Additional testing was halted due to the limited bandwidth of the AN/TSC-85C
      Upconverter (40 MHz). Using 16 QAM, the bandwidth for a 105 Mbps data rate was 39
      MHz. At this point, the Upconverter became unstable. Conversations with the Advantech
      system engineer indicated that an additional 10% of data can be achieved when using
      the optional Turbo Code modulation scheme. This option was not installed on this
      modem.

Advantages:

   1. Minimal antenna hardware upgrade required to access XTAR LHCP Transponders
      (Modified antenna feed).

   2. Minimal hardware upgrade required for the AN/TSC-85C TACSAT Van (Modem,
      different multiplexer).

   3. Cost per bit significantly lower than commercial leases on Ku band.

   4. As demonstrated, can achieve data rates in X-Band in excess of present
      Ku-Band capability.

   5. No longer power limited.

   6. Can get significantly increased data rates even with smaller AS-30306A (>20Mbps in
      Spot Beam).

Recommendations:

   1. Initiate formal studies to further investigate the advantages and capabilities of the
      LHGXA and AS-3036 antennas when operating with the LORAL XTAR satellite in LHCP
      configuration, using both legacy GMF equipment and newer satellite transmission
      systems presently entering the DOD inventory.

   2. Initiate conversations with LORAL LLC to capitalize on the unused LHCP transponders
      on the XTAR satellite. Other than the LHGXA, there are no present customers with
      LHCP feed systems in production right now.

   3. LORAL to provide concurrence that both the LHGXA and AS-3036 RHCP/LHCP
      antenna feeds are suitable for operation over the XTAR satellite.

   4. Initiate formal study to determine benefits of using the LORAL XTAR satellite in military
      operational scenarios.

Note- actual over the air and ground test results are available, but omitted for clarity from this
report.


Dennis Evanchik
Project Leader, LHGXA
Project Manager, MultiChannel Satellite Terminals
PM-MST
Office 732-532-3742, DSN 992-3742
Cell 908-309-1650
dennis.evanchik@us.army.mil

								
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