Airborne Science ProgramAirborne Science Program

ISPRS / Canadian Geomatics ConferenceJune 14 – 18, 2010

Jeff MyersCarl SorensonUniv. of California, Santa CruzNASA Ames Research Center

Developing Airborne Sensor and Data Network Interface Standards

WG-I TOR 2

Goal:

“Develop airborne sensor interface format standards, in coordination with other working groups, to promote maximum sensor portability between aircraft, and increasing science yield from the sensors”

Basic Factors for Instrument Portability

1. Mechanical Accommodation (mounts, windows, ports, antennas, inlets, etc.)

- Airworthiness certification - Safety (active systems, gas bottles, etc.)

2. Electrical power (28V DC, 110V/440Hz AC) - Connectors & polarity - Hard-wired controls

3. Data communications: - From aircraft to sensor - From sensor to aircraft (& beyond)

Instrument Portability: Data Communication Requirements

• Data from aircraft to sensor:

- Command and control - Aircraft state data (navigation, met data, etc.) (RS-232,-422, ARINC-429,-1553, Synchro, etc) - GPS antenna feeds (L1/L2, OmniStar, etc.

• Data from sensor to aircraft (& beyond)

- System health and status, engineering data - Science data (high and low rate content) • Most requirements can be satisfied via a single Ethernet

connection (may include AIRINC-664 for low-latency state data)

Common data formats are essential

Common Data Formats: The IWGADTS* IWG1 Standard Packet

It is designed to provide a common aircraft housekeeping data format to replace all the various legacy formats on the different science aircraft.

The Interagency Working Group Standard Format Number 1 (IWG1) is a simple ASCII CSV format which is transmitted as a UDP packet at 1 Hz.

Currently in use on the NASA and NSF/NCAR platforms.

Example Packet:“IWG1,yyyymmddThhmmss,value,value,value,,value\r\n”

http://www.eol.ucar.edu/raf/Software/iwgadts/IWG1_Def.html

*Intergovernmental Working Group for Airborne Data and Telemetry Standards

Enabling Standards: Instrument Communication Formats

• From Aircraft: - IWG1 Standard housekeeping data broadcast (ASCII CSV) --- - International Standard Port 7071

Ex: “IWG1, Timestamp, std aircraft state parameters, + as needed”http://www.eol.ucar.edu/raf/Software/iwgadts/IWG1_Def.html

• From Instrument: - Instrument status and low-rate data CSV packets (1 Hz broadcast

by instrument)

Ex: “Instrument identifier, time stamp, status code, up to 16 parms”

- Arbitrary data packet (Bidirectional, port-to-port)

Example Implementation: RQ4-A Global Hawk Payload Support Infrastructure

Payload communication on the NASA Global Hawk aircraft is implemented using an airborne 100-T Ethernet network with a port for each instrument

Network services include:• Housekeeping data broadcast• Bi-directional sat-com connections• Payload status monitoring• Shared mass data storage • GIS database server• Time synchronization• Uses IWGADTS standards

Global Hawk UAS Payload Communications & Control System

Payload Instruments

Network HostLink Module (Database &

Telemetry I/O)

GHOC Link Server

Experimenter Workstations

Web-Based Users

Master Payload Control System

& PDU

Pilot’s MPCS GUI

Instrument Power & Control

Eth

ern

et

Global Hawk Ground

Operations Center

AIRCRAFT

GROUND

PI Hardware

Aircraft HW

Iridium (4 ch) Iridium (2 ch)Ku-Band Sat-Com

Flight Deck

Interface Panels (8)

Visualization Tools

The Real-Time Airborne Science DataNetwork Architecture

Airborne Science Web Portal

Provides:Science Data Bases, CDE, OGC Web Services, KML Generators,

Data Visualization Tools

DFRC GHOC

Web-Based Mission Participants

DC-8, P-3, ER-2, WB-57B200, Small UAS Global Hawk, Ikhana

Portable Ground Stations

Satellite Products

Model Inputs

Sensor Webs

INMARSAT-BGAN & Iridium Sat-Com Ku-Band & Iridium

Sat-Com

Instrument Power & Control Interfaces

AC Circuit #2AC Circuit #1

DC Circuit #2DC Circuit #1

Safety Interlock Circuit

IRIG-B (coax insert)

GPS (coax insert)

• The New NASA Standard Experimenter Interface Panel (Intended for Global Hawk, ER-2, WB-57, and others)

• Available Signals:• Two (2) sets of 3ф, 400Hz AC (Phases A,B,C + Neutral; 10 Amps/phase)• Two (2) sets of 28VDC power + return (15 Amps ea.)• Safety Interlock circuit – both contacts of a normally open relay• GPS (L1/L2 Omnistar)• IRIG-B

Experimenter Interface Panel (EIP)

Connector: D38999/20WG-16SN (16x AWG #16)

Instrument Ethernet Data Interfaces

Ethernet Connectors – Two Types• Amphenol D38999/III Quadrax

• ARINC-664 recommendation• Very high reliability, more expensive • One insert for 100Mbit, two for Gig-E

• Amphenol PCD RJ Field – RJ45 in 38999 Shell• Less reliability, cheaper

• Recommendation: • Quadrax for permanent installation on the plane (Server, EIP, feed-throughs, etc.)• Instruments have option of Quadrax or RJ45 Field; use adapters as needed

Quadrax RJ45 Field

Airborne Ethernet Switch

Network Host

(REVEAL/NASDAT)

Summary

The aircraft network is a standard Ethernet TCP/IP LAN with 10/100T ports.

Instruments are required to include an Ethernet interface and to provide a simple Comma Separated Value (CSV) status packet

Connections to the switches are made with standard RJ45 or ruggedized RJ45 connectors

Instruments are required to implement Universal Time Codesynchronization via Network Time Protocol (NTP), IRIG-B,or GPS signal.

Routing of any direct connections to the ground via the wide band satcom link, when available, is done using Network Address Translation (NAT) using the aircraft router

Towards an Integrated Sensor Web for Environmental Observation

Courtesy MBARI