WB3JZV's Tracking and Recovery Report

Questions, send them to ME and I'll forward them to Paul

Discussion of EOSS#53 Tracking and Recovery Team Results

The Tracking and Recovery Team performed well during EOSS#53 with 9 member teams (tactical calls Alpha � India).

  • Congrats to the 2 tracking stations that scored one or more bearing bulls-eyes (zero degree errors): K0CO and WB0MTN.
  • N7MXO, Carl, and his partner, Mark joined the hunt for their first time. Due to antenna problems, they were not able to communicate their bearings. My partner, Lucas, no call sign, was taking bearings for his first time was hampered by available equipment.
  • The Average Separation in Miles between the GPS and tracking team fixes for EOSS#53 (5.8 miles) was greater than for EOSS#47 (3.3 miles). These results are due to an increase in Average Tracker [bearing] Error from 9 to 19 degrees for EOSS#47 and EOSS#53, respectively.
  • The Separation in Miles between the GPS and tracking team fixes was largest for the first Sample Time (23.3 miles). One reason for this is the tracker bearings crossed each other with acute angles. When bearings cross at such small angles over a great distance, even small bearing errors can cause large fix errors. See Worst Performance Chart to see the bearings and the resulting triangulated points. One way to avoid acute angles for this case would be to increase the tracker north-south separation distances. Increase the 22 N-S miles separation for the furthest trackers to 35 miles.
  • Large Average Tracking Team Errors may occur when the balloon is overhead. It is difficult to take an accurate RF bearing when the beacon is above 45 degrees elevation. Any tracker recognizing the balloon to be overhead should refrain from providing an RF bearing unless he can aim his DF antenna upwards and get a trusted bearing.
  • The final bearing before LOS is the team's most important. If GPS fixes become unavailable during descent, the Tracking Team's final fix will provide the best clue to locating the payload. For EOSS#53, the Tracking Team's final fix (63.4,21.8) was 6.8 miles from touchdown (68.3,15.9). Only 4 tracking stations of 9 provided bearings for the final sample time. I recommend a minimum of 75% of the T&R team provide bearings in the future. Of the 4 stations that provided this data for EOSS#53, 2 of the stations were off by 20 and 28 degrees.
  • It is practical for a 9-member Tracking and Recovery Team to comb an area of 100 square miles from the Tracking and Recovery Team�s final fix to locate a beacon. In such a situation, the field coordinator�s direction is vital. If the Separation in Miles for the final sample time is 10 miles or less, the team did well. For EOSS#53, the separation was 6.8 miles.
  • The best performance for the team happened at the 10:25 Sample Time with only 0.4 mile difference between the GPS and T&R team fixes. That�s terrific! See Best Performance Chart.

de Paul, WB3JZV

Excel Analysis

Absolute Bearing Errors in Degrees, by Tracker, by Sample Time, Based on GPS Fix

  Sample Number==> 1 2 3 4 5 6 7 8 Tracker
    Sample Time==> 9:40 9:55 10:10 10:25 10:35 10:45 10:52 10:57 Error
W0CBH Benjie Alpha   8     8 88 8 20 26
WB0MTN Roger Bravo 17 3 7 3 2 12 12 0 7
KB0YRZ Chris & Ben Charlie 23 10     7 1 18   12
N0PUF Dan Delta         46       46
K0CO Jack & Rich Echo 4 3 1 0 3 15     4
KA0ULN Russ Foxtrot 18     6         12
KI0DZ Mary-Francis Golf 4 1 1 10 13 4 1 4 5
N7MXO Carl & Mark Hotel                 -
No-call Lucas India   35 34 39 40 71   28 41
Average Tracking Team Error at Sample Time==> 13 10 11 12 17 32 10 13 19

Tabulated Results of Tracking Team vs GPS Fixes by Sample Time

  Tracking Team Fix==> (7.6,60.2) (42.5,40.7) (46.4,38.2) (46.8,27.6) (49.3,25.2) (55.3,22.1) (61.5,17.7) (63.4,21.8) Average 
  GPS Fix==> (22.2,42.1) (41,39) (44.7,35.3) (46.6,27.9) (50.5,24.8) (60.4,20.7) (64.7,17.3) (67.4,16.2) Separa.
  Separation in Miles==> 23.3 2.3 3.4 0.4 1.3 5.3 3.2 6.8 5.8
    revised C revised C           revised gps  
Best performance                    
Worst performance                    

Excel Charts