Tiger Strike Test Results

[Al Sayre]

Tiger Strike Test

Methodology:
The test consisted of a real world mission scenario and ground team tasking:

Scenario:
A Cessna C-172 aircraft departed Natchez MS (HEZ) in the early evening of 2/25/2011.  Destination: Hawkins Field (HKS), Jackson, MS.  The aircraft dropped below radar coverage from Houston Center at approximately 5000 MSL in the area of Clairborne County, MS.  At approximately 1730 local time, Pilot radioed Houston Center "I have a problem" no further radio transmissions were received.  There have been several pilot reports of a 121.775 MHz beacon, but all were at very high altitude over Central and Couth Mississippi, and the area of signal convergence does not help to narrow the search area. (A 121.775MHz training beacon with a new battery was placed as the target and activated at 1730 local time and left operating overnight to simulate normal signal degradation)

Tasking:
Depart Mission Base located at Hawkins Field in CAP van MS172, and proceed South-west along the Natchez Trace Highway (which roughly parallels the projected route and is within the 85% containment probability corridor) to HEZ, Natchez MS.  Listen to 121.775 MHz using aircraft VHF radio, and any other means of electronic detection available.  Aircraft may become available later in the day.  Contact Mission Base by radio and/or cell phone at the top and bottom of each hour with Ops Normal.  Report any positive signal to Mission Base upon hearing it.  Be aware cell phone coverage is very poor and spotty along the Natchez Trace. 

Actions:
Much as in a real mission, once we cleared the populated area just west of Clinton MS and got on the Natchez Trace where it intersects I-20, the GT stopped to listen and take a bearing with the TigerStrike unit.  Additional bearings were taken (with the TigerStrike unit) as the team proceeded South along the Natchez Trace.  The second bearing was taken from approximately 10 miles closer and successive bearings taken every approximately 5 miles (at a convenient pull off location), until a signal was heard via the aircraft VHF radio.  At that time additional bearings were taken using the TigerStrike, and a "Little L-Per" as well as via the body block method for comparison, and followed to the target.  TigerStrike Bearings were taken by the trained operator and by me in order to compare the accuracies of a trained and untrained user.

(I apologize for the table, it looks ok in the entry screen)

Bearing Taken Location                                        Miles Equipment/                                     Bearing Error(degrees)       Actual User              Latitude   Longitude            As Read   Actual*   Difference       Distance*                    TS-P         32° 20.067'N    90° 21.444'W     210   237.28   -27.28        31.27                    TS-P         32° 16.834'N    90° 28.040'W     264   236.27   27.73        23.92 TS-A         32° 16.834'N    90° 28.040'W     252   236.27   15.73        23.92                    TS-P        32° 14.270'N    90° 32.489'W     230   236.7   -6.7                18.61 TS-A        32° 14.270'N    90° 32.489'W     340   236.7   103.3        18.61                    TS-P        32° 11.501'N    90° 36.959'W     268   237.62   30.38        13.28 TS-A        32° 11.501'N    90° 36.959'W     259   237.62   21.38        13.28                    TS-P         32° 8.890'N    90° 43.435'W     264   229.95   34.05          6.37 TS-A         32° 8.890'N    90° 43.435'W     284   229.95   54.05          6.37 TS-A         32° 8.890'N    90° 43.435'W     289   229.95   59.05          6.37                    TS-P         32° 5.879'N    90° 46.959'W     239   246.64   -7.64          1.57 TS-A         32° 5.879'N    90° 46.959'W     277   246.64   30.36          1.57                    TS-P         32° 5.480'N    90° 47.370'W     255   261.36   -6.36          1.05 TS-A         32° 5.480'N    90° 47.370'W     254   261.36   -7.36          1.05                    A/C VHF    32° 5.404'N    90° 47.600'W   1st Heard                                0.81                    TS-P         32° 5.191'N    90° 47.927'W      333   290.02   42.98          0.52 LPER         32° 5.191'N    90° 47.927'W      342   290.02   51.98          0.52 Body Block 32° 5.191'N    90° 47.927'W      318   290.02   27.98          0.52                    TS-P         32° 5.325'N    90° 48.522'W        77   75.26   1.74                  0.09 LPER         32° 5.325'N    90° 48.522'W      120   75.26   44.74          0.09                    ACTUAL Location     32° 5.346'N    90° 48.428'W

         

*Actual Bearings and Distances were determined by plotting points on Google Earth and using the measuring tool from the bearing location to the actual target location.  TS-P indicates Pro User, TS-A indicates amateur user (me).

I can't attach the .kmz and .xls files for those who want to see or crunch their own numbers (file types not allowed), but it can be replicated from the table.  If you want to see mine, send me a pm with your email and I'll send it to you.

Topography:  The land in the search area is made up of small rolling hills and gullies with a general elevation of between 0 and 400 ft MSL.  It is primarily farmland and large tracts of timber as can readily be seen on Google Earth.  The actual target was located in a gully approximately 10 feet below the highest nearby elevations.  A solid 100 feet of earth was almost always laterally between the target beacon and the TigerStrike unit until the team actually headed into the woods following the signal rather than taking bearings.

Accuracy Calculations:
As the variations were both positive and negative, by using the square root of the sum of the squares of the differences divided by the number of samples the following accuracies were determined.

Both users: +/- 9.753○     Pro user:  +/- 8.307○    Amateur user:  +/-19.567○

It should be noted that there was a second practice beacon placed at 32° 20.067'N, 90° 21.444'W.  This may have influenced the accuracy of the first 3 or 4 bearings.  It should also be noted that before the actual test, the representative Paul and I walked out onto the green of the golf course next to our Wing HQ so he could give me a quick demo on how the Tiger Strike unit is used.  Standing on the green in downtown Jackson, he was able to draw a bearing to the second target which was located approximately 18.5 miles away.  In the interest of the test, I couldn't tell him that the 2nd beacon was there or active until we were well into the testing, and I was sure that the unit was tracking the correct target.

Observations:

The unit is still in development. 

There are some issues with the mapping function that need to be worked out.  The Map location and GPS locations on the unit disagree by a mile or two depending on the location. 

As demonstrated, the unit is a bit heavy, and I could see a smaller person or a cadet having trouble holding it in the correct position for any length of time.  This is probably not an issue as it is unlikely that anyone would be handing an expensive unit like this to a cadet. 

Per the representative Paul, there is a software update due in the next week or so that will allow the user to store a bearing location and bearing and then move a fairly short distance and take another bearing.  The software will then calculate the GPS location of the signal coincidence which in theory will be the target location. 

The current antennas are straight wire approx 3/32" in diameter, and could probably be damaged fairly easily by careless handling.  The representative told me that a set of flexible antennas is in the works.

The touch screen buttons and readouts on the "hunt" screen are a bit small and could probably be enlarged without much loss of screen functionality.  The screen takes a bit of getting used to, much like transition from steam gauges to G1000, but once you use it a few times it's fairly easy to figure out. 

The representative told me that in the future you wouldn't need to use the hunt screen, and that all functions could be done on the map page.  Right now the hunt screen gives you a bearing, and your gps location.  Any ELT hunter worth his salt can work with that, and it beats the heck out of trying to take a compass reading over your partners back with an L-Per.

The biggest negative for me is a lack of audio.  You can't actually hear the beacon, so you are relying on the filters to ensure that the only signal you are tracking is the 121.5 (or 121.775 etc.) and not some random noise.  However, I don't consider lack of an audio warble at greater than 10 miles a detraction.

The other big negative at this time is price, at $5000, it is almost 7x as expensive as the current model of L-Per. I honestly don't know what the Becker ground unit costs, but I have heard estimates of as much as $10K.

We hear a lot about how 121.5MHz is becoming obsolete, but most of the ELT's we are hunting are still 121.5MHz, but now instead of a 15 mile radius from satellite hits, we get a 300 mile radius from a airliner PIREP.  In fact MS wing already has 3 finds this year, all of them 121.5MHz, and 2 of them were on the same mission in the same area of signal coincidence due to the altitudes of the PIREPS...

Summary:
I'm actually quite favorably impressed.  The unit was able to detect the signal at better than 30 miles and give a good general bearing at that range.  The +/- 8-10 degree overall error is reasonable based on the fact that our current ground equipment really can't do any better and does it at a much shorter range.  The TigerStrike unit is still somewhat operator dependent, much as our current equipment.  I'm sure as the software and other stated improvements are made, the inherent accuracy will improve, and with operator training and familiarity, this could be the equipment of choice for hunting ELT's.  Given the choice today between an L-Per and the TigerStrike unit I used, I'd take the TigerStrike into the field.  I believe that this technology could also be adapted for aircraft use, and has the potential to be a better tool than the Becker DF units we now use.

JMHO...

[starshippe]

. . if i let my imagination wander much, i get into trouble.
. . how about a 10 minute demo on you tube?

thanks & 73,
bill

[ECHO35]

First I want to thank Maj Sayre and the men and women of the CAP wing out of Jackson MS. It was a great learning experience I really got a better idea of how the Tigerstrike reacts to different situations. We are still working on flushing out some of the bugs in the software and tests like this really help us focus on the functionality and how it applies to the user on the ground.

One observation I took away from the SAREX is that the Tigerstrike is so sensitive that the techniques used in the past with other equipment need to be adjusted. In the scenario there were 2 beacons one was to the west roughly 20 miles from the CAP building located at Hawkins Field. The other was to the south south west (est.) about 35-40 miles away. With conventional equipment this is not something you would consider, but with the Tigerstrike and its sensitivity it needs to be considered. In hindsight I would of shielded myself from the competing signal by using terrain or offsetting further to the east. After mapping the data out on google earth and speaking to some of my colleagues it was obvious that the competing signal was causing the LOB reading to drift to the north.

All and all it was a good exercise and all of the suggestions made by the CAP members will be looked at closely. We are working on the mapping and should have solution very soon. As for the audio we are actively working on this and we should see a proto type with this capability soon. I will work on a youtube demo and post it as soon as I get it done.

If there are any questions or anyone who has an upcoming SAREX and would like to see the Tigerstrike let me know and I will see if we can set something up.

Paul   pgreaves23@gmail.com

[4x4junky]

Congrats Paul on your successful demonstration!

My son and I have been considering joining CAP and SAR is a passion of mine.  I am looking forward to hear more of your demonstrations.  Good to know these things before I build or buy gear I don't have.


Thanks

[ECHO35]

The mapping function has been updated and is now functioning properly. There is still some tweaking to do which will be customer driven

[lordmonar]

First I want to thank Maj Sayre and the men and women of the CAP wing out of Jackson MS. It was a great learning experience I really got a better idea of how the Tigerstrike reacts to different situations. We are still working on flushing out some of the bugs in the software and tests like this really help us focus on the functionality and how it applies to the user on the ground.

One observation I took away from the SAREX is that the Tigerstrike is so sensitive that the techniques used in the past with other equipment need to be adjusted. In the scenario there were 2 beacons one was to the west roughly 20 miles from the CAP building located at Hawkins Field. The other was to the south south west (est.) about 35-40 miles away. With conventional equipment this is not something you would consider, but with the Tigerstrike and its sensitivity it needs to be considered. In hindsight I would of shielded myself from the competing signal by using terrain or offsetting further to the east. After mapping the data out on google earth and speaking to some of my colleagues it was obvious that the competing signal was causing the LOB reading to drift to the north.

All and all it was a good exercise and all of the suggestions made by the CAP members will be looked at closely. We are working on the mapping and should have solution very soon. As for the audio we are actively working on this and we should see a proto type with this capability soon. I will work on a youtube demo and post it as soon as I get it done.

If there are any questions or anyone who has an upcoming SAREX and would like to see the Tigerstrike let me know and I will see if we can set something up.

Paul   pgreaves23@gmail.com

On that note.....we have to consider the possibility of mutiple ELTs acitvated at one time.  Consider CAWG or some East Coast wings where they have a lot of small air ports all over the place......it is not un common to be out looking for two or even three ELTs at the same time....especially during the days of satellite tracking.

[ECHO35]

Agreed it was a lesson learned and we are currently working on the audio which we think will help with the multiple target scenario. Also there is a multiple target mode that was originally developed for tactical use that would greatly enhance the user feedback when hunting multiple targets. We are putting the finishing touches on that program and I will post when it is ready.

[Eclipse]

On that note.....we have to consider the possibility of mutiple ELTs acitvated at one time.  Consider CAWG or some East Coast wings where they have a lot of small air ports all over the place......it is not un common to be out looking for two or even three ELTs at the same time....especially during the days of satellite tracking.

During major windstorms or worse, like they just has in LAWG, it isn't uncommon for 1/2 the planes on 1/2 the airports to have ELT's going off.
The "easy" ones are upside down, the rest are more of a challenge.

Multiple beacons are generally a scenario in most SAREX's, especially ones run by CAP-USAF as evals.

[Major Lord]

Related to the problem of multiple ELT differentiation, is the problem of other electronic signals on or near the target frequency. Receivers typically trade selectivity for sensitivity. This means that extremely sensitive receivers tend to be sensitive to signals outside their 'tuned" frequency. I know that some of you old timers out there have spent time looking for that darned 121.xxx carrier that actually is coming from a gray market CD player while the ELT down the block is breathing its last breath.

Major Lord

[ECHO35]

Its not really a problem the receiver does not have a problem with signals outside of 121.5. The software has the ability to distinguish multiple targets the challenge is to tweak the user interface to make it easier to visually make that distinction. Once we add audio which should happen soon it will make it that much easier to focus in on targets at close range.

I will be conducting a test today from multiple distances out 25 miles. I will post the results later today
If there are any tests or scenarios anyone would like to see let me know.