U.S. patent application number 10/645763 was filed with the patent office on 2005-06-09 for method and apparatus to align auxiliary aircraft equipment attitude and heading.
Invention is credited to Cawley, John Edward, Huynh, Dan Nhan, Roth, Gary Michael.
Application Number | 20050125120 10/645763 |
Document ID | / |
Family ID | 34633083 |
Filed Date | 2005-06-09 |
United States Patent
Application |
20050125120 |
Kind Code |
A1 |
Huynh, Dan Nhan ; et
al. |
June 9, 2005 |
METHOD AND APPARATUS TO ALIGN AUXILIARY AIRCRAFT EQUIPMENT ATTITUDE
AND HEADING
Abstract
Precision alignment of auxiliary equipment on an aircraft is
accomplished by a locating tool for the aircraft inertial reference
unit (IRU) attached to the auxiliary equipment mount. Aircraft
attitude and heading are obtained using the IRU. The IRU is removed
from its avionics tray in the aircraft and installed on the
locating tool. The locating tool is connected for remote operation
of the IRU and the IRU is operated to obtain attitude and heading.
This attitude and heading is then compared to the IRU reading for
the attitude and heading of the aircraft.
Inventors: |
Huynh, Dan Nhan; (Irvine,
CA) ; Roth, Gary Michael; (Lakewood, CA) ;
Cawley, John Edward; (San Pedro, CA) |
Correspondence
Address: |
FELIX L. FISCHER, ATTORNEY AT LAW
1607 MISSION DRIVE
SUITE 204
SOLVANG
CA
93463
US
|
Family ID: |
34633083 |
Appl. No.: |
10/645763 |
Filed: |
August 18, 2003 |
Current U.S.
Class: |
701/36 |
Current CPC
Class: |
H05K 7/1412
20130101 |
Class at
Publication: |
701/036 |
International
Class: |
G06F 007/00 |
Claims
1. An aircraft auxiliary equipment precision alignment system
comprising: an auxiliary equipment mount attached to the aircraft;
an inertial reference unit (IRU) having means for removable
attachment to an in-service avionics tray onboard the aircraft; a
locating assembly having means for precision engagement with the
auxiliary equipment mount, the locating assembly further having a
mating means adapted to receive the IRU; and, a means for remote
operation of the IRU.
2. An aircraft auxiliary equipment precision alignment system as
defined in claim 1 wherein the means for remote operation comprises
an extension cable assembly for operatively connecting the locating
assembly to the avionics tray for remote operation of the IRU.
3. An aircraft auxiliary equipment precision alignment system as
defined in claim 1 wherein the means for remote operation comprises
a powerpack and remote display for the IRU connected to the
locating assembly.
4. An aircraft auxiliary equipment precision alignment system as
defined in claim 1 wherein the means for precision engagement
comprises a common interface assembly having means for indexing to
the auxiliary equipment mount and wherein the mating means
comprises a model specific interface assembly having a connector
block for electrical connection to the IRU and quick disconnect
means for mechanical attachment of the IRU, the common interface
assembly and model specific interface assembly having means for
indexing and alignment.
5. An aircraft auxiliary equipment precision alignment system as
defined in claim 4 wherein the auxiliary equipment mount comprises
a plurality of brackets and the common interface assembly has a
plurality of legs, equal in number to the plurality of brackets,
each leg having first precision indexing holes for alignment with
auxiliary equipment mounting holes in each respective bracket, the
common interface assembly further having a surface plate attached
to the legs and wherein the model specific interface assembly
further comprises a second surface plate and the means for indexing
and alignment comprises a second plurality of mating blocks
extending from the surface plate opposite the legs and a third
plurality of mating blocks, equal in number to and in spaced
relation for engagement with the second plurality of mating blocks,
extending from the second surface plate, the second surface plate
further incorporating means to support the connector block opposite
from the mating blocks.
6. An aircraft auxiliary equipment precision alignment system as
defined in claim 5 wherein the means for indexing and alignment
further comprises second precision indexing holes in each of second
and third plurality of mating blocks and locating pins received in
the second precision indexing holes.
7. An aircraft auxiliary equipment precision alignment system
comprising: an auxiliary equipment mount having a plurality of
brackets attached to the aircraft; an inertial reference unit (IRU)
having an electrical connector and mechanical quick disconnect for
removable attachment to an in-service avionics tray onboard the
aircraft; a locating assembly having a common interface assembly
including a plurality of legs, equal in number to the plurality of
brackets, each leg having precision indexing holes for alignment
with auxiliary equipment mounting holes in each respective bracket,
the common interface assembly further having a surface plate
attached to the legs, a model specific interface assembly having a
second surface plate and quick disconnect means for mechanical
attachment of the IRU mounted to the second surface plate, a second
plurality of mating blocks extending from the surface plate
opposite the legs and a third plurality of mating blocks, equal in
number to and in spaced relation for engagement with the second
plurality of mating blocks, extending from the second surface
plate; and, a connector block for electrical connection to the IRU
and a means for remote operation of the IRU.
8. An aircraft auxiliary equipment precision alignment system as
defined in claim 7 wherein the means for remote operation comprises
an extension cable assembly having a cable extending from the
connector block and, mounted to the cable distal from the connector
block, a simulator box having a connector substantially identical
to the IRU for electrically mating to the in-service avionics tray
and quick disconnect substantially identical to the IRU for
mechanically mating to the in-service avionics tray for operatively
connecting the locating assembly to the avionics tray for remote
operation of the IRU.
9. An aircraft auxiliary equipment precision alignment system as
defined in claim 7 wherein the means for remote operation comprises
a powerpack and remote display for the IRU operably connected to
the connector block of the model specific interface assembly.
10. An aircraft auxiliary equipment precision alignment system as
defined in claim 1 further comprising a second IRU mounted in the
aircraft for simultaneous operation during remote operation of the
first IRU.
11. A method for precision alignment of auxiliary equipment on an
aircraft comprising the steps of: attaching to the aircraft a
mounting means intended for mounting the auxiliary equipment to the
aircraft; mounting a locating tool to the mounting means; obtaining
aircraft attitude and heading using an inertial reference unit
(IRU); removing the IRU from an IRU avionics tray in the aircraft;
installing the IRU on the locating tool; and, operating the IRU to
obtain attitude and heading.
12. A method for precision alignment of auxiliary equipment on an
aircraft as defined in claim 11 wherein the step of mounting a
locating tool comprises the steps of: mounting a common interface
assembly to the mounting means; and mounting a model specific
interface assembly to the common interface assembly; and wherein
the step of installing the IRU comprises installing the IRU on the
model specific interface assembly.
13. A method for precision alignment of auxiliary equipment on an
aircraft as defined in claim 11 wherein the step of operating the
IRU further comprises the initial step of connecting the locating
tool to the avionics tray for remote operation of the IRU.
14. A method for precision alignment of auxiliary equipment on an
aircraft as defined in claim 11 wherein the step of operating the
IRU further comprises the initial step of connecting a powerpack
and remote display for the IRU to the locating assembly.
15. A method for precision alignment of auxiliary equipment on an
aircraft as defined in claim 14 wherein the remote display
comprises a portable computer.
16. A method for prescision alignment of auxiliary equipment on an
aircraft as defined in claim 11 further comprising the steps of:
comparing the aircraft attitude and heading using a second IRU
mounted in the aircraft during the step of obtaining the aircraft
heading with the first IRU; and substantially simultaneously
reading the aircraft attitude and heading with the second IRU while
performing the step of operating the first IRU to obtain attitude
and heading while mounted on the locating tool.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates generally to the field of precision
mounting of aircraft auxiliary equipment and, more particularly, to
a system employing an aircraft inertial reference unit (IRU) with a
remote IRU interface on precision locating tooling for alignment of
the auxiliary equipment using the mounting brackets.
[0003] 2. Description of the Related Art
[0004] Auxiliary equipment such as antennas and receiving equipment
for various avionics and other subsystems is regularly attached to
aircraft during assembly or as a retrofit. Many such systems
require precise calibration with respect to overall aircraft
heading and attitude for proper operation in the aircraft.
Traditional methods of measuring the attitude and heading require
expensive external tooling and typically require positioning of the
aircraft with respect to an absolute reference. Such external
tooling incorporates pitch and roll sensors, laser reflection
systems or position receivers such as GPS devices which are
expensive and require repetitive periodic tool certification and
calibration. Further, the tools must often be aircraft model
specific requiring extensive duplication and inventorying of tools.
The components of these tools are often prone to damage due to
their complexity.
[0005] It is therefore desirable to reduce the cost and complexity
of interface tooling required for auxiliary equipment heading and
attitude alignment. It is further desirable to make use of existing
aircraft systems to accomplish alignment relative to those systems
without the requirement for aircraft repositioning.
SUMMARY OF THE INVENTION
[0006] Precision alignment of auxiliary equipment on an aircraft is
accomplished in the present invention by first attaching to the
aircraft a mounting bracket or other means intended for mounting
the auxiliary equipment to the aircraft. A locating tool is mounted
to the bracket and aircraft attitude and heading are obtained using
an inertial reference unit (IRU). The IRU is removed from its
avionics tray in the aircraft and installed on the locating tool.
The locating tool is connected to the avionics tray for remote
operation of the IRU and the IRU is operated to obtain attitude and
heading. This attitude and heading is then compared to the IRU
reading for the attitude and heading of the aircraft.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] These and other features and advantages of the present
invention will be better understood by reference to the following
detailed description when considered in connection with the
accompanying drawings wherein:
[0008] FIG. 1 is a cutaway pictorial view of the forward fuselage
of an aircraft showing elements of the invention in use;
[0009] FIG. 2 is a front partial section view of the top of the
fuselage showing details of an embodiment of the mounting of
elements of the present invention;
[0010] FIG. 3 is a front isometric exploded view of the elements of
one embodiment of the invention;
[0011] FIG. 4 is a rear isometric exploded view of the elements
shown in FIG. 3; and,
[0012] FIG. 5 is an isometric view of an alternative embodiment of
the invention employing a remote power pack and instrument readout
for the IRU mounted on the precision locating tool assembly.
DETAILED DESCRIPTION OF THE INVENTION
[0013] Most current commercial aircraft rely on an inertial
reference system or unit for precise determination of aircraft
attitude and heading. The inertial reference unit (IRU) is
typically a line replaceable unit (LRU) that is designed for easy
installation and removal. Use of the IRU as an aircraft specific
tool for alignment of auxiliary equipment to be mounted to the
aircraft eliminates the need for additional dedicated and complex
tooling for that task.
[0014] For alignment of an auxiliary equipment element such as an
antenna, a simple, compact mechanical interface assembly is
provided which mates with the attachment brackets for the auxiliary
equipment. The interface assembly acts as a precision locating tool
for the mounting bracket and a remote platform for mounting of the
IRU. An extension cable assembly is provided to connect the IRU to
its avionics tray in the aircraft when mounted in the interface
assembly. The IRU, in its normal mounting in the aircraft avionics
tray, is used to obtain heading and attitude for the aircraft. The
IRU is then disconnected from its avionics tray and mounted on the
interface assembly that has been attached to the auxiliary
equipment mounting brackets. The extension cable is attached to the
interface assembly and avionics tray to power the IRU and allow the
aircraft cockpit displays to read the attitude and heading of the
IRU as mounted on the interface assembly. A comparison of the IRU
readings from its aircraft mount and interface assembly mount then
provide precise alignment information for the auxiliary
equipment.
[0015] Referring to the drawings, FIG. 1 shows the forward fuselage
10 of an aircraft on which auxiliary equipment is to be mounted. As
an exemplary embodiment, the fuselage incorporates a radome adapter
plate 12 for a next generation antenna (NGA). NGA mounting angles
14, to which the NGA will be mounted, are attached to the adapter
plate or the top skin of the fuselage within the adapter plate
footprint. As best seen in FIG. 2, a precision locating tool
assembly 16 incorporates a common interface assembly 18 and an
aircraft model-specific interface assembly 20. The common interface
assembly has legs 22 which are attached to the mounting angles
through precision indexing holes 24 adapted for alignment with
mounting holes 26 in the mounting angles. Precision pins or
mounting bolts 28 secure the common interface assembly to the
mounting angles. A rigid surface plate 30 is attached to the legs
as a reference surface for engagement with the model specific
interface assembly.
[0016] As shown in the exploded views of the precision locating
tool assembly looking aft in FIG. 3 and looking forward in FIG. 4,
the common interface assembly is adapted for indexing to the
attachment brackets for the type of auxiliary equipment to be
mounted on the aircraft. For the embodiment shown, the attachment
brackets constitute the mounting angles for the NGA including two
forward angles 14a, two aft angles 14b and starboard and port
angles 14c and 14d. In alternative embodiments for other types of
auxiliary equipment, various bracket arrangements or mounting holes
in the fuselage structure are employed. A common interface assembly
indexed to such mounting arrangements is employed for each
particular auxiliary equipment configuration.
[0017] The aircraft model-specific interface assembly is adapted to
receive the IRU for the particular aircraft on which the auxiliary
equipment is being mounted. Guide pin assemblies 38 and quick
disconnect fasteners 40 are mounted on the second surface plate of
the model-specific interface assembly in conjunction with the
connector to precisely receive and secure the IRU in a comparable
manner to the IRU's mounting tray in the avionics bay or instrument
panel of the aircraft. The IRU 42 is shown in phantom mounted to
the model-specific interface assembly in FIG. 4. A connector block
32 such as an ARINC 600 connector common to IRU mounting trays in
aircraft is connected to the IRU mounted on the model-specific
interface assembly. The connector is supported on the model
specific interface assembly by channel bracket 36. A backing bar 37
restrains the connector block in the channel bracket.
[0018] Connection cabling 44 extends from the connector block to an
IRU simulator 46 having a mating connector 48 identical to the IRU
and a box or frame 50 having interface holes 52 and quick
disconnect attachments 54 simulating the IRU for mounting in the
IRU mounting tray 55 in the aircraft, as shown in FIG. 1. The cable
assembly including the connector block, cable and simulator with
mating connector, when connected to the precision locating tool
assembly and the aircraft IRU mounting tray, allows power to be
provided to the IRU and data from the IRU to be read out on the
aircraft displays.
[0019] The surface plate of the common interface assembly and the
second surface plate in the model-specific interface assembly each
support mating blocks 56 with indexing holes 58 to receive
precision locating pins or balls 60 to precisely index and align
the two interface assemblies. In certain embodiments, one or more
of the locating pins is replaced with clamps or threaded fasteners
for securing the surface plates. With the common interface assembly
attached to the NGA mounting angles, the model-specific interface
assembly mounted to the common interface assembly and the IRU
mounted in the model-specific interface assembly, the IRU is
rigidly positioned to precisely measure the attitude (pitch and
roll) and heading of the NGA mounting angles and hence a mounted
NGA. Comparison with the measured aircraft attitude and heading
using the same IRU mounted in its mounting tray or a second IRU
mounted in the aircraft with prior cross calibration, allows
precise differential definition of the NGA attitude and heading for
calibration/correction of the NGA. The dual IRU process allows
simultaneous aircraft/antenna readings in case the aircraft is
moved during alignment and is faster than the single IRU
method.
[0020] To accommodate cooling requirements of the IRU, the model
specific interface assembly includes one or more fans 61 mounted in
cooling apertures 59 in the surface plate 34. For exemplary
purposes, fan blades are shown in the apertures in the embodiment
shown in the drawings. In alternative embodiments, box fans or
other appropriate fan device are mounted under the surface plate in
communication with the apertures 59.
[0021] The sequence of operation for the method of the invention on
the exemplary NGA mounting can be characterized as follows.
[0022] 1. The NGA mounting angles are installed on the aircraft per
design requirements.
[0023] 2. The common interface assembly is installed on the NGA
mounting angles and the model-specific interface assembly is
mounted to the common interface assembly.
[0024] 3. The aircraft is stabilized to prevent movement and
avionics power is provided.
[0025] 4. The IRU is powered and the cockpit display is read to
record attitude and heading of the installed IRU.
[0026] 5. The IRU is powered down by removing power from the
aircraft or using the IRU circuit breaker, removed from the
mounting tray and installed on the precision locating tool assembly
using the guide pins and quick disconnects. The connector block of
the cable assembly is then mated to the IRU and restrained in place
in the support channel with the backing bar.
[0027] 6. The cable of the cable assembly is routed to the IRU
mounting tray and the IRU simulator installed in the IRU mounting
tray.
[0028] 7. Power is restored to the IRU by powering the aircraft or
resetting the IRU circuit breaker and use the cockpit display to
record the attitude and heading on the IRU as installed on the
precision locating tool assembly, thereby establishing the relative
differential between the aircraft attitude and heading and the NGA
mounting angles (and mounted NGA) attitude and heading.
[0029] 8. The IRU is powered down, the cable assembly disconnected,
the IRU removed from the precision locating tool assembly and the
IRU reinstalled in the aircraft IRU mounting tray. For calibration
verification, the IRU is powered up again and comparative aircraft
attitude and heading readings are made.
[0030] In certain aircraft applications, the distance or difficulty
in routing the cable assembly from the auxiliary equipment mounting
location to the IRU mounting tray precludes the use of a cable
assembly as defined in the prior embodiment. In an alternative
embodiment, a powerpack and remote display assembly 62 is provided
as shown in FIG. 5. The powerpack 64 provides conditioned power
from a start cart or other ground power unit (not shown) or other
power source such as a battery to the IRU through the connector
block. The remote display 66 simulates the aircraft IRU cockpit
display or otherwise displays the attitude and heading information
generated by the IRU when mounted in the precision locating tool
assembly. In certain embodiments, a portable computer is configured
to act as the remote display. With appropriate software, the
portable computer is employed to record the IRU data with
manipulation to provide direct input into the auxiliary equipment
system for correction/calibration.
[0031] In this embodiment the powerpack and remote display assembly
is positioned near the precision locating tool assembly at the
auxiliary equipment mounting location and steps 7 and 8 of the
operational procedure are modified as follows.
[0032] 7. Power is provided to the IRU through the power pack and
the remote display is used to record the attitude and heading on
the IRU as installed on the precision locating tool assembly,
thereby establishing the relative differential between the aircraft
attitude and heading and the NGA mounting angles (and mounted NGA)
attitude and heading.
[0033] 8. The powerpack is powered down removing power from the
IRU, the IRU removed from the precision locating tool assembly and
the IRU reinstalled in the aircraft IRU mounting tray. For
calibration verification, the IRU is powered up again and
comparative aircraft attitude and heading readings are made.
[0034] Having now described the invention in detail as required by
the patent statutes, those skilled in the art will recognize
modifications and substitutions to the specific embodiments
disclosed herein. Such modifications are within the scope and
intent of the present invention as defined in the following
claims.
* * * * *