curry.eas.gatech.educurry.eas.gatech.edu/aerosonde/barrowplanning2001.doc · web viewthis is due to...

Commercial in Confidence

Aerosonde Operations off Barrow for April 2001Title: Planning document for year 2 of NSF contract (NSF 99-101) for Aerosonde

Operations in the Arctic Status: DraftPrepared By: Greg Tyrrell, Gavin Brett, Grant McFarlane, and Maurice GonellaDate: Oct 26 2000Distribution: Judy Curry, Jim Maslanik, Mathew Alan, Tom Demarino, Aerosonde InternalPurpose: To identify key issues and plan both R&D and Operational processes to achieve

objectives of NSF contract.

Aerosonde Robotic Aircraft Ltd41 Normanby Rd,

Notting Hill, VIC, 3168,Australia

www.aerosonde.com

ROBOTIC AIRCRAFTAEROSONDE

NSF Operations in the Arctic

TABLE OF CONTENTSExecutive Overview 31. Background 52. Engineering 63. Operations 74. Conclusions 13

of 12


EXECUTIVE OVERVIEWAerosonde Robotic Aircraft are a sub-contractor to the University of Colorado to undertake Aerosonde activities in the Arctic under NSF contract (NSF 99-101). The thrust of the program is to develop a facility at Barrow for Aerosonde deployment and reconnaissance in the Arctic, to increase routine observational capability of the atmosphere and the ice/ocean surface in the Beaufort/Chukchi sector of the Arctic Ocean. More specifically (from proposal “Applications of Aerosondes to Long-Term Measurements of the Atmosphere and Sea Ice Surface in the Beaufort/Chukchi Sector of the Arctic Ocean by J. Curry et al):

establish a facility for Aerosonde deployment and reconnaissance at Barrow

adapt the Aerosonde design to be more robust and efficient for arctic applications

integrate additional miniature instruments into the Aerosonde system (e.g. radiometers, laser altimeter, video camera, and chemistry measurements)

regularly deploy the Aerosondes to measure atmospheric state and surface characteristics

set up a data dissemination, distribution, and archiving system for the Aerosonde data

work with operational modelling and remote sensing centres to assimilate these data into their analysis

collaborate/cooperate with any field projects in the region and provide support to any local scientific issues put forward by the Barrow Arctic Science Consortium.

The primary targets for the observations are the following applications:1. Routine measurement of atmospheric state for assimilation into numerical weather prediction

(NWP) model analyses. This would substantially improve the analyses and forecasts in this region of the arctic. Note that NWP analyses are the main source of large-scale atmospheric information used for diagnostic studies, to force regional atmospheric models, and to provide surface forcing for ice/ocean models

2. Measurement of surface radiative fluxes and surface sea ice characteristics (e.g. surface temperature, lead and ridge characteristics, melt pond fraction, and possibly ice thickness distribution). These measurements would be used to evaluate sea ice models and remote sensing algorithms and could be incorporated into the RGPS analysis system and ice forecast models via data assimilation to improve estimates of sea ice characteristics.

A timeline summary for the project, as documented in the proposal, is given below:Year 1• work on icing strategy and begin the improvements to positioning and attitude• conduct aeroelastic simulations• begin integrating the radiometer and video camera onto the aerosonde• solidify logistics plans

Year 2• integrate the radiometer and video camera and conduct test flights• work on plans for a new airframe• work on thermal and engine improvements• implement online access to the data via the project web page• conduct 300 (minimum) flight hours from Barrow, emphasizing atmospheric state measurements

Year 3• begin integrating the laser altimeter• conduct 500 flight hours (minimum) from Barrow, including the first ice mapping missions,

ancillary science missions, and targeted observations for NWP applications of 12


Year 4• conduct test flights with the laser altimeter• conduct 1000 flight hours (minimum) from Barrow, including a complete summer survey of

surface characteristics and radiation fluxes

Year 5• arrange for final archive of data set at NSIDC• conduct 1500 flight hours (minimum) from Barrow, including 2 month “operational” demonstration

for NWP applications and wintertime ice mapping missions with the laser altimeter

of 12


This document is intended to serve for planning purposes for Aerosonde Robotic Aircraft and focuses largely on the activities in the first and second years while keeping long term goals in mind.1. BACKGROUND

Aerosonde operations in Barrow Alaska, August 2000, were undertaken by Aerosonde Robotic Aircraft and Colorado University under contract from NSF. All Aerosonde flights were conducted in accordance with requirements of scientists of the Colorado University and as required by R&D testing.

The specific goals were to:

Serve as a proof-of-concept for future Aerosonde operations in Barrow. Newer variants of the Aerosonde will have longer range and icing robustness capabilities that will permit atmospheric data collection over larger areas of the Arctic Ocean and North Slope of Alaska. These data can be used to help better initialize atmospheric models, radiation flux models and possibly wildlife studies over a currently data sparse region.

Photograph the sea ice. See Fig 1 Below. Photo of sea ice at 150m.

Sample the lower troposphere north of Barrow and send the data to the ECMWF.

Evaluate surface mapping potential.

The mission objectives were achieved during 20 flights totaling 40 hours over a 9-day period. All missions were completed without major incident. On each flying day, the Aerosonde operated between the surface and 4000m ASL within one of two available operations areas, either nearby over Point Barrow or outside 12nm from the coast.

of 12


2. ENGINEERING

The proposed engineering development activities for 2001 to occur at Barrow will build upon the experience gained in previous seasons. Previously identified problems with carburation (both due to icing and inadequate fuel vaporisation) will be addressed by the introduction of a new Engine Management Unit (EMU) controlling direct fuel injection. This new system will be trialed in April after testing in Australia. Investigative work to date on the wing icing problem has provided more information on how the ice forms and has suggested a few solutions on how to handle the problem. None the less no ‘cure-all’ solution has been found at this time and more tests will be carried out in April. Work last season on the pitot tube heater and ice sensor has resulted in revised heaters and sensors that will be tested this season.

2.1 Engine - Grant McFarlane

H-type EFI Engine Improvements

For Barrow 2001 we are intending to conduct Aerosonde missions with aircraft fitted with the newly developed H-type engines. The H-type engines consist of several modifications and these are namely the Electronic Fuel Injection hardware, together with an aluminium cylinder Liner (with a Nicasil surface plating) and a new piston & ring package. The fuel injection hardware is expected to deliver improved fuelling control with more consistency, for the cold conditions in the Arctic. The new cylinder and piston ring package also aids reliability due to a reduction in oil consumption and cylinder head deposits. Previous flights in the Arctic highlighted this problem and the new engine configuration is set to address it.

Depending on resources, we are also intending to ship with us (& possibly fly) Aerosondes fitted with G-type engines. These engines have proven to be reliable in recent field exercises in Guam, but differ by not having the EFI hardware fitted. They have been a well benchmarked and proven engine configuration for missions to date. Other benefits exist as well in having the two engine types available for operations.

Further proposed engine testing will include

1. EFI cold temperature Fuel mapping development

During the time in Barrow the programmable Engine Fuelling maps will be developed further to optimise engine performance and reliability. The Acceleration enrichment tables will be developed & refined to give accurate transient fuelling under dynamic changes in throttle operation. As well as this, the cold start tables may also be edited for rapid and hassle free starting in the cold climate.

2. G-type and H-type In-flight Cylinder Head temperature tests

Flight testing at Barrow in April 2000 will provide us with more information and data on engine cooling performance in the Arctic with the new engine. The new engine configuration has an increased fin area compared to the old f-type and allows reliable engine operation at higher Cylinder Head temperatures. The effect however is that operating temperatures may be lower than optimum, so this needs to established as a baseline.

3. Further Propeller Icing tests

We are also intending to conduct more testing to investigate the possibility of prop icing on the Aerosonde. A few simple tests were performed in the previous visit to Barrow, but due to the

of 12


relative warm conditions, some doubt still exists on the possibility of this occurring. Further testing and experience is therefore recommended.

4. Endurance EFI hardware testing

It is envisaged that a Cold endurance test will be performed on the new components making up the fuel injection hardware. The fuel pressure accumulator, pump and ECU will be endurance tested to see if any problems arise.

2.2 Icing Strategy - Brad Phillips

2.2.1 Icing sensorsThe original icing sensor is constructed using a piezoelectric ceramic element. The element is placed in the feedback loop of a linear oscillator where the resonant frequency controls the frequency of oscillation. The piezoelectric element is mounted on the wing and as ice forms on it, the resonant frequency varies.

Studies with this sensor last season indicated that it would provide a reasonable analogue of conditions on the wing. It was noted that the output of the sensor would ‘jump’ occasionally at certain points of ice thickness. This is due to the mechanical moment of the piezo sensor changing which in turn causes a change in the mode of oscillation. The sensor electronics have been revised to better control the oscillator with the intention of giving the sensor a monotonic output.

2.2.2 New icing sensors

Investigation of the OD Systems ice sensor last season showed that it is not really suitable for our application so at this point in time it has been removed as an option. Work on other sensors including flexible piezoelectric materials and capacitive sensors is still in the developmental stage. It is unlikely that these will be ready for field trials in April.

2.2.3 Anti-icing wing coatings

A number of different anti-icing wing coatings were trialed last season again with no stand out solution. It was felt however that finishes such as Hyper Polish were of some value and these will be used again this season.

2.3 Pitot Heaters – Brad Phillips

2.3.1 Heated Pitot tube Design prototypes MKII

Three prototype pitot tube heaters were tested last season with all providing reasonable results. The experience gained has been used to produce a new set of prototypes that will be tested during the April flights. A new heater controller has been implemented and this will be trialed with the newer pitot tubes.

2.4 Pyrometer – Brad Phillips

To provide a method of sea surface temperature profiling it is intended to trial a new infrared pyrometer. For reasons of weight and size a Heitronics KT11 unit with a K6 lense (FOV 1:35) has been selected. For the trials the unit will be connected to a separate data logger. Data will be time stamped for correlation with GPS data, post flight.

of 12


2.5 Camera - Brad Phillips

The digital camera used last season in Barrow (an Olympus 3030c) has undergone further refinement during the off season. The camera is now controlled via a serial link from the avionics and as such is capable of greater control from the ground. It is now possible to take individual photographs or a sequence of photos spaced at a fixed interval (eg. 10 exposures, 30 seconds apart). The total number of exposures taken is now displayed on the Groundbase software. The camera itself has been modified to remove the internal infrared filters. As a result the spectral sensitivity of the camera can be shifted by the addition of suitable external filters. As before an optional wide angle lens can be fitted to provide a 1km wide image from approximately 700m altitude.

of 12


3. OPERATIONS

The Operations plan for the second year will probably consist of two separate missions. A 120 hour, 2-3 week exercise in April to coincide with generally cold dry weather and an experiment being conducted by the Army. The tentative dates are set as April 10th-26th 2001. Another mission is scheduled for sometime between July and September and is expected to last 4 weeks or so.

The tasks earmarked for the April mission are as follows.

1. Fly a single column model experiment 50kms from base over the ocean. Altitudes flown will be around the 500mb region and lower to limit airframe-icing risk. It is intended that Aerosondes will be kept monitoring this region for 4 continuous days (depending on FAA restrictions and the number of operators that will be used).

2. Conduct low altitude flights (down to 100m) to image the sea ice and possibly do some altimetry and determine some boundary layer fluxes. It is hoped that this will enable the documentation of fluxes from open leads and the footprint of the convective plume. Note that flying oven an open lead at low altitude is particularly risky as the rising air is generally very humid due to the relatively warm open water below.

3. Try to co-ordinate further with ECMWF to see if we can do any targeted observations for them within the radio range.

4. Conduct some icing missions as in August 2000. In April, the supercooled layers are typically fairly thin.

5. Conduct some flight testing to validate the engine, antenna, payloads and icing sensors for the colder conditions.

6. Hopefully conduct preliminary trials with the Heitronix thermometer.

3.1 AirspaceC. B. Emmanuel

In 1999 and 2000, the FAA were quite conservative in providing limited airspace in the vicinity of Barrow. The juristriction of the FAA in terms of airspace extended to 12nm north of the Alaskan coastline, after this point, the airspace becomes non-restrictive. Over the runway and within 12nm of the coast, Aerosonde operations were restricted to a narrow corridor and altitudes not above 700 ft. In 2000 we also had a 2 mile square box to 5000ft over Point Barrow to conduct icing testing. In addition, special provisions in the FAA waiver stated that for follow up exercises in the region, the Aerosonde shall be equipped with operational position and anti-collision lights (which were fitted in 2000) and an operating altitude encoding transponder which has yet to be addressed.

Issues this time around include:a) Unrestricted region within glide slope distance of the runway for flight testing as per

August 2000.b) Alternative notification means to transponder for Oceanic flights such as the AMPI

system currently being used at East Sale RAAF base in Australia.c) Facilitation of sound operating procedures to allow flexibility and safety for the duration

of the program.

of 12


3.2 ALRS

The Aerosondes are flown out of the old runway at the UIC/NARL site (see Fig.2). The surface is made of steel segments joined together and, although hard on the Aerosonde for landings, is a suitable surface. It will need to be cleared of snow for the April exercise. We have had permission to use this runway in the past and we will endeavor to use it again if possible. BASC has purchased a new building(see below), which was used as the August 2000 ALRS with success. Current plans are to add another door to facilitate Aerosonde access.

Figure 3.2A: Aerosonde Launch Recovery Site (ALRS) comprising old steel runway, new control hut, antennae mast, launch vehicle and generator (obscured from view).

Note that this site is not secure and has been broken into in the past.

Size is 4m X 8m (12’X24”). It will also have the following power 110V 16Amp min supplied by diesel generator heating 1.5KW and insulation, a window facing the runway (lockable door on this side also), large desk or table, 4 chairs, perforation to outside for cables,

We will then fit out with Aerosonde equipment including: 2 stage boxes (1 spare). Stage UHF and GPS antennae and cabling. Antenna mast. 2 Pilots consoles (1 spare). 2 laptop computers. Launch site tool kit Meteorological sensor ground check kit Air band radios and antennas Hand held radios and antennas Cell phone Gas heater

In 2000 we used the BASC Ford crew-cab truck as a launch vehicle.

3.3 Local Command

of 12


During the 1999 ARM program, Aerosonde control was handed off from the ALRS to a more hospitable control centre (ARM Duplex). This type of set up again would be practical for this year’s NSF operations but a larger site will ultimately be required for the latter years. The ARM Duplex was equipped with antenna farms located on high poles (fig. 3.3A) and Aerosonde ground station equipment contained in a comfortable area. The duplex has 5 bedrooms suitable for accommodation. The ARM duplex also has access to a T1 communications line, which is required to send real time data to ECMWF. We would do well to try and gain access to this facility again if possible.

Figure 3.3A: Antenna farm at ARM Duplex.

The command room will need power, heat, telephone and amenities. To this we need to add Aerosonde ground station equipment that comprises of:

Remote stage boxes (2, 1 spare) 1 Multiplexing PC 2 Ground station PCs Archiving/web PC Phone line Data line UHF Antenna farm and cabling GPS antennas Air band radios and antennas Hand held radios and antennas

Use of the BASC warehouse would be again advantageous as it is a suitable facility to prepare aircraft and ground equipment and our equipment is currently stored there.

of 12


3.4 Personnel3.41 Scientific teamJudy Curry as PI.Jim MaslanikMatt AllanAmanda Lynch and Ron Brunner

3.42 Operations team Aerosonde Robotic Aircraft Maurice Gonella leader Others TBA

FAA liaisonC. B. Emmanuel

Local contact. Dave Ramey BASC

Local launch and recovery crew.Plan to have Aerosonde personnel run operations with training initially so that eventually local crew can run facility. Barrow is a planned Aerosonde Launch/Recovery Site ALRS.

3.43 Engineering team.Gavin Brett leader AeRATom Demarino Brad Phillips

of 12

curry.eas.gatech.educurry.eas.gatech.edu/aerosonde/barrowplanning2001.doc · web viewthis is due to...

Documents