DATA ACQUISITION
transferred during the flight via IRIG106
Chapter 7 Packet Telemetry Downlink in
order to make optimum use of the
available telemetry bandwidth.
Figure 4 above shows different
possibilities of data processing during the
flight. An example shows an on-board FFT
analysis of analog data where the resulting
harmonics are transmitted to the ground
station via telemetry.
INTERFACE & STORAGE INNOVATION
The memory canister features a range of
innovations. The content of a MPC
canister is very diverse and flexible. It can
contain up to 40TB of NVMe or SATA
based storage and can support high end
video acquisition such as 4K or 8K video
capture. There are also canisters available
which support traditional interfaces, such
as: Ethernet, HD/SD video, PCM, MILSTD
1553, ARINC429, IEEE1394, Fibre
Channel, strain gage, generic analog,
HDLC, low latency voice and discrete. The
canister connectors can also vary.
Canisters with D-Sub are available, but the
flexible recorder concept also allows using
canisters equipped with MIL-DTL 38999
102 SHOWCASE 2020 \\ AEROSPACETESTINGINTERNATIONAL.COM
connectors. Depending on where the
recorder is located in the aircraft, it can be
difficult to get to the removable storage
media. For this reason the new generation
recorder supports two mainframe options.
Figures 1 and 2 show the two possibilities
of horizontal and vertical canister
removal. There are different variants of
storage media canister types. Data can be
stored on these storage media in various
formats like IRIG106 Chapter 10, IENA,
DAR and iNET. High write/read speed and
high capacity storage is a bottleneck in the
development of recorders in most cases.
Write performance to the storage
medium is a challenge at write speeds
greater than 10Gb/s. Previous technologies
were based on serial AT attachment
(SATA) technology, which used the
advanced host controller interface (AHCI)
protocol for data transfer. While in earlier
times the mechanics of hard drives limited
the speed of the storage, the SATA port
and the AHCI protocol are the limitations
of today’s Solid State Disks (SSDs).
Today’s SATA ports provide transfer
rates of around 600 MB/s maximum for
SSDs, which is not sufficient for the
support of many applications. And this is
where nonvolatile memory express
(NVMe) protocol comes in. The new data
transmission protocol will replace the
outdated AHCI protocol and provide even
more speed for SSDs. NVME offers 65536
so-called I/O queues with 65536
commands instead of just one queue with
32 commands at AHCI. This leads to a
lower utilization of the connected CPU
and thus to a higher data transfer speed.
Both SATA and NVMe based storage
media are taken into account in the
concept. The memory capacity must be
designed for a flight test duration of at
least two hours. At an assumed bitrate
of 16Gb/s as an example, this results
in 14.4TB as the minimum storage
capacity requirement.
POWER AND SECURITY
Thermal energy and power management
is another major design consideration.
Extensive intelligent power management
features are designed into the MDR-GT.
The smaller the mainframe and the higher
the operational speed, the more critical
thermal management becomes, especially
in rugged dynamic environments. More
power implies more heat generation.
Zodiac Data Systems incorporated an
advanced intelligent thermal management
functionality to sense the workload
required and scale the electronics to
dynamically operate at a minimum
capacity to support the variable workload.
Cyber security must also be addressed
early in the design stage in order to
support demanding cyber requirements.
The MDR-GT uses a Trusted Platform
Module (TPM) which supports hardwarebased
security functions. The TPM chip is
a secure crypto-processor that provides
the abilities to generate, store, and limit
the use of cryptographic keys. This is a
very important capability to verify
authenticity of the media module, which
can contain the firmware, and is
instrumental in preventing foreign
unauthorized devices to be detected and
be rejected for operations.
Reliable operation in a wide range of
environmental conditions is another
critical design element incorporated into
the MDR- GT. The GT’s flexible design
offers the optimal mechanical
configuration for the specific type of
operational environment. One MDR-GT
configuration is nearly identical to our
MDR family of instrumentation recorders.
The users can easily exchange the modules
on a daily basis in order to support
dynamic data acquisition requirements.
Zodiac Data Systems also designed in
the ability to offer a closed mainframe
case with only 38999 connectors. This
configuration is for harsh environments
such as rain and salt spray. \\
Marc Faber is head of development and Johnny
Pappas is executive vice president and chief technical
officer at Zodiac Data Systems
3 // Architecture of an
internal recorder
4 // Diagram showing
different data processing
possibilities during a flight
“The guarantee of reliable operation in a wide range of
environmental conditions is a critical design element”
4
3
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