Transcript Locus H-field Loran-C Antenna Development

Status of GPS/Loran Prototype for FAA
Trials
by
James H. Doty and Patrick Y. Hwang, Ph.D., Rockwell Collins, Inc.,
Linn Roth, Ph.D., Locus, Inc., and Mitchell J. Narins, Federal Aviation
Administration,
Portions of this work are being performed under subcontract SK-00-18
between Locus, Inc. and Advanced Management Technology, Inc. (AMTI)
and under subcontract SK-02-02-001-00 between Rockwell Collins, Inc.
and AMTI under a Federal Aviation Administration (FAA) Broad Information
Technology Services (BITS) contract.
Outline
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Interest in Loran
GPS/Loran Integration Program
Program Status
Breadboard System design and test
results
• Brassboard System features
Resurgence In Loran Interest
• DOT’s Volpe Center study on GPS vulnerabilities spurred
interest in independent, backup systems for both
navigation and timing, i.e. critical infrastructure areas
• USCG interest in harbor entrance and approach
• FAA interest for NPA (Non-Precision Approach)
• Since 1997, Congress has provided $69M to further Loran
development, and estimate $21-25M in 2003
• Loran infrastructure upgrade well underway, and overall
system performance will improve when upgrade complete
GPS/Loran Integration Program
• The FAA is funding efforts to develop resources to evaluate
and demonstrate the use of Loran to enhance the integrity
and continuity of airborne navigation systems
• Rockwell Collins and Locus are under subcontracts to
Advanced Management Technology, Inc. (AMTI)
– Locus is leading the effort to develop a prototype
combined GPS & Loran H-field antenna and a standalone
Loran receiver
– Rockwell Collins is leading the Integration of a Locus
Loran receiver into a Collins Multimode Radio (MMR)
GPS/Loran Integration Program
Locus
Loran Receiver
Standard
SatMate 1020
Loran Receiver
H-Field Loran
Antenna
Loran Card
GPS/Loran Antenna Development
GPS/Loran
Antenna
GPS/Loran Integration Effort
GPS Antenna
Requirements
Standard
GNLU-930
MMR
Loran Card
ICD
Breadboard
GLIP
Rockwell Collins
Brassboard
GPS/Loran
GLIP Card
Breadboard
GPS/Loran
Program Responsibilities
Rockwell Collins :
• Develop interface definition for
embedded Loran card
• Perform integrity analysis and
develop integration algorithms
• Integrate Locus Loran receiver
into Multimode Receiver
(MMR)
• Support Locus antenna
integration
• Deliver prototype system and
support FAA tests
• Program efforts began May
2002
Locus :
• Develop Eurocard size
SatMate 1030
• Develop combined
GPS/Loran H-field antenna
• Support Rockwell MMR
integration
• Deliver prototype systems to
FAA and Rockwell and
support FAA tests
• Program efforts began
January 2002
Locus Program Status
Combined GPS/Loran
prototype antenna
functioning
Uses certified ADF
radome for flight tests
Eurocard SatMate 1030
prototype receiver
functioning
Locus Program Status
Eurocard SatMate 1030 in stand-alone enclosure
Front Panel
Rear Panel
Rockwell Collins Program Status
GLIP integration
processor card for
Brassboard System
assembled and tested
Breadboard GPS/Loran system
completed and van tested
Current Rockwell Collins MMR
MMR - GNLU-930
VHF
Loc /GBAS
ILS
loc/glide
UHF
L-band
C-band
Glideslope
GPS PVT
GLS PAN
Localizer/
Glideslope
deviations
MLS az/el
Other GPS users
(e.g. FMS, EGPWS)
• Current GNLU-930 MMR provides
Localizer/Glideslope deviation information for approach, and
PVT (position, velocity, time) information for area navigation
and other uses
Brassboard MMR Architecture
MMR - GNLU-930
VHF
Loc /GBAS
ILS
loc/glide
UHF
Glideslope
L-band
GPS PVT
LF
Loran
GLS PAN
Localizer/
Glideslope
deviations
Integration
Proc.
Other GPS users
(e.g. FMS, EGPWS)
• Locus SatMate 1030 Loran card will be
embedded into Rockwell Collins MMR
• An independent GPS/Loran Integration Processor (GLIP) card
will be added to minimize development risk
New GPS Loran Integration Processor (GLIP)
Functions
GNSS
I/O
GPS-Only
Loran
I/O
Loran-Only
Federated
GPS-Loran
Output
I/O
ARINC
I/O
Integrated
GPS-Loran
• To facilitate flight test evaluation of alternative Loran utilization techniques,
multiple solutions of position and integrity limits are generated and output
– “GPS-only” passes through GNSS solution
– “Loran-only” recomputes position solution from Loran measurements
– “Federated” GPS-Loran processes Loran and GPS measurements but
maintains independence between sensors for improved integrity
– “Integrated” GPS-Loran calibrates Loran errors using GPS and produces
a more accurate position solution
Breadboard GPS/Loran System
GPS
Antenna
J3
Data
J5
+28VDC
J1
Loran
Antenna
Cable
CB2
CB1
GNSS
ARINC
ARINC
Power Strip
Power
Supply
Serial
Port #4
GLIP
Processor
Box Loran
GNLU-930
Antenna
Serial Port A
RS-232
Loran PC
Control
Nav Outputs
GPS
GPS Loran Loran
WOW
• Takes data from unmodified
115VAC
60 Hz
GNLU-930 MMR and SatMate
1020 Loran Receiver
• Recreates Loran Position
solution from Loran timing
measurements
• Produces an integrated GPSaided Loran Solution
Locus
Satmate
RS232 I/O
GPS-Only
Solution
ARINC 429
Combined
Data
RS-232
J2
Data J4
• Solutions available on
both ARINC 429 and
RS232 output formats
GNSS
ARINC I/O
Integrated
GPS-Loran
ARINC I/O
Integrated
Solution
ARINC 429
Loran
RS232 I/O
Loran-Only
ARINC I/O
Loran-Only
Solution
ARINC 429
GLIP Functions
Breadboard Pallet I/O
Antenna Connections
Loran H-field
Antenna
GPS
Antenna
Output Data
Input power
110V AC 60 Hz
28V DC
GPS/Loran
Breadboard
ARINC 1 GPS only
ARINC 2 Loran only
ARINC 3 GPS/Loran
RS232 Combined data
for collection
• The Breadboard GPS/Loran (GPS-aided Loran) solution is a Loran solution
corrected with ASFs calibrated using GPS PVT data
• RS232 output includes ASF correction data, all three position solutions, and
raw Loran Data messages
Breadboard Loran-Only Position Solution
0
0
No Weighting
Amp Weighting
Power Weighting
Locus Reciever
-20
-20
-40
-40
-60
-60
-80
-80
With only three stations
weighting does not
change position
solution
-100
-120
-140
-120
-140
-160
-180
-180
-280
-260
-240
-220
-200
-180
-160
-140
With more stations the weighting
algorithm has a significant impact
on estimated position
-100
-160
-200
-300
No Weighting
Amp Weighting
Power Weighting
Locus Receiver
No
Weighting
-120
-100
-200
-300
Revised weighting
algorithm overlays Locus
solution
-280
-260
-240
-220
-200
-180
Original
Collins
Weighting
-160
-140
-120
• Extensive work was required to reproduce the Locus position
solution from the delta-time measurements
– Locus provided implementation details of the Locus weighting
algorithm
– Position solution differences consistently well under 10 meters
-100
Breadboard Van Testing
• The Breadboard GPS/Loran system was tested
in the Collins Mobile Navigation Lab Van
• The antenna mount was raised to reduce interference from other van
systems
Breadboard Van Test Results
Breadboard Position Outputs
42.036
GPS-aided
Loran-only
GPS-only
Locus
100x100m
42.035
42.034
GPS-Aided
Loran
Latitude
42.033
42.032
GPS
42.031
42.03
GLIP Loran-only
42.029
100m
42.028
42.027
-91.662
Locus Loran
Solution
-91.66
-91.658
-91.656
-91.654
Longitude
100m
-91.652
-91.65
-91.648
-91.646
The GPSaided Loran
solution is
corrected for
position bias
errors, but has
noise
characteristics
matching the
Loran-only
solution
Highway Breadboard Van Testing
GPS-only
Van Test Results
Van Test Results
Loran-only
42.3
GPS-aided
GPS-only
Locus
Loran-only
Turn
42.25
42.2
Latitude in degrees
Locus
1 km X 1 km
Latitude in degrees
1 km X 1 km
42.22
GPS-aided
1 km
42.21
1 km
42.15
Passed under
power lines
42.1
42.2
-91.86
End
-91.85
-91.84
-91.83
-91.82
-91.81
Longitude in degrees
42.05
Start
42
-91.95
-91.9
-91.85
-91.8
-91.75
Longitude in degrees
-91.7
-91.65
GPS-aided Loran solution tracked GPS
position well except for a brief anomaly
when the van passed under highvoltage power lines
Typical Van Test Results
Van test solution errors relative to GPS in meters
Average
North Pos.
Offset
Average
East Pos.
Offset
North
Position
Noise
East
Position
Noise
Locus receiver solution
(no ASF corrections)
-164.3
-195.6
20.9
26.6
GLIP Loran-only solution
(no ASF corrections)
-164.0
-196.4
20.9
26.8
-2.0
-1.4
18.8
24.3
GPS-Aided solution
GPS-derived ASF corrections
dramatically reduce position error
in GPS-aided solution
ASF corrections do not
significantly reduce noise
GPS-aiding Loran corrects slowly-varying ASF errors of Loran
but a more tightly integrated solution is required to reduce noise
Brassboard System Features
• The brassboard system will integrate the
Breadboard system functionality into the
standard GNLU-930 MMR form factor
• Brassboard will include Locus SatMate
1030 prototype card and Collins GLIP card
• The integrated solution will be more tightly
coupled to GPS to improve noise when
GPS is available
• A new Federated GPS/Loran solution will be added for
improved integrity monitoring
• All outputs will ARINC 429 and RS-232 monitor port will be
eliminated
Brassboard MMR System
• Locus Loran card will be installed in place of the MLS
slice on door of a modified GNLU-930
MMR – Added Cards
GLIP
Loran
• The new Collins GPS Loran Integration Processor (GLIP) card
will be installed in the center card cluster in place of the FMS
slice
• A ribbon cable from the GLIP to the Loran card will provide
power and data communications
MMR Card Modifications
Rear
Interconnect
Card
ILS Card
System
Processor
Power
Supply
• The ILS and other MMR cards will remain unmodified (except
for minor additions to the rear interconnect card)
Summary
• The FAA is supporting efforts to evaluate Loran for suitability of
use in NPA and other airborne navigation applications
• Rockwell Collins and Locus are participating in coordinated
programs to develop demonstration prototype GPS/Loran
antenna and GPS/Loran MMR
– Will be utilized by FAA to evaluate and demonstrate the use of
Loran to enhance integrity and continuity
• The Breadboard GPS/Loran system has been completed and
van tested
• The Breadboard system is working well and performance
characteristics are about as expected
• Components for both the Brassboard System and GPS/Loran
Antenna have been assembled and are being tested