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Triangulation Report
by Paul Ternlund, WB3JZV
EOSS#64 Tracking and Recovery Team Results using the WB3JZV Triangulation Program � 30 March 2003
- The Tracking and Recovery (T&R) Team comprised 6 DF teams
- Chris, KB0YRZ
- Larry, N0NDM/Benjie, W0CBH
- Dan, N0PUF
- Mike, KC0CNT
- Mark, KC0JHQ
- Jim, K0JLZ.
- There were four 2m beacon (payload) fixes computed between 8:00 and 8:49AM, and two 70 cm (balloon) fixes computed after separation, during decent.
- The fourth (last) 2m computation tabulated was a re-run using refined (last known) bearings before Loss of Signal (LOS) from the original 3 stations, plus KC0CNT and K0JLZ were in range and provided their data.
- The best performance (lowest bearing error) was 3 degrees by KC0CNT.
- The lowest Average Tracker Error was 10 degrees by K0JLZ.
- The average tracker bearing error was 20 degrees.
- Separations in miles between GPS and the T&R group fixes ranged from a worst case of 34 miles (1st sample) to 3.8 miles.
- The final or LOS fix error �most important one�was 3.8 miles for the payload beacon and 4.3 miles for the balloon beacon. These are very good team results.
- The distance between the 2 LOS triangulation fixes and the 2 pickup point GPS fixes were 3.8 and 4.2 miles. This relates to a 14.4 and 18.5 square mile uncertainty, respectively. The latter is well within the program�s goal of a 100 square mile T&R team search area.
FYI, the WB3JZV Triangulation Program is designed to provide a good fix when most (more than half) of the LOBs are �good� for the given sample time. The goal of the program is to obtain a final fix to within 100 square miles of the beacon�s touchdown point (i.e., within a 10 mile by 10 mile area). Mobile tracking units can easily patrol this size area while listening for a beacon.
The following is true�
- Single-digit bearing errors are better than double-digit
- When a station has multiple double-digit bearing errors, it is likely the station is having equipment and /or technique problems.
- Every station will encounter LOB errors some time for many reasons especially multi-path.
- The greater the T&R team participation (i.e., the more lines of bearing (LOBs) submitted) for a sample time, the better the chance of a good fix resulting from the program. Of course equipment capability and technique play a vital role too.
- The T&R team group error is commonly largest during the initial sample times when the beacon is farthest away and the T&R group has a small perpendicular dispersion. This is because the lines of bearing cross at more acute angles and small bearing errors can result in large fix displacements.
- Once in the field, prior to a launch, a DF team may request an LOB test to my station to practice/validate a DF process.
VHF Beacon DF Analysis
UHF Beacon DF Analysis
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