(32S II) Position, Distance & Bearing Calculations

05182019, 11:37 AM
Post: #1




(32S II) Position, Distance & Bearing Calculations
An extract from Position, Distance & Bearing Calculations, Whitham D. Reeve (©2014 W. Reeve)
Two frequent calculations required in radio propagation work are distance and bearing between two radio terminals. Distance and bearing may be taken from topographical maps for quick analyses but great circle calculations are needed for more accurate work and are described here … If more than a few sites are being evaluated, it can be more productive to use a programmable calculator or spreadsheet program to find distance and bearings. The program listing in the appendix was written for this purpose on the HewlettPackard HP32S II calculator, but it can be adapted for other scientific calculators that use Reverse Polish Notation (RPN) with minor changes (if any). The program can accept the coordinates in either dd+mm+ss (for example, 66 52' 31.5") or dd.dddd (for example, 66.5407) by setting the input mode, and it automatically resolves any ambiguity. Excellent documentation w equations, tables, figures, examples etc., … BEST! SlideRule 

01272023, 06:24 PM
Post: #2




RE: (32S II) Position, Distance & Bearing Calculations
It's never too late to say thank you!
Indeed excellent documentation. I'm always amazed by the excellents professionals and their eager to help! Thanks again and Cheers JL 

02042023, 03:43 PM
(This post was last modified: 02042023 04:08 PM by Gil.)
Post: #3




RE: (32S II) Position, Distance & Bearing Calculations
I just checked, with the given reference,
some of the control results in that paper. Note that the results are not at all accurate when reviewed with Vincenty's formulae (error <= 1 mm). : Point A in deg.mmssss { 66.53507 162.35557 } Point B in deg.mmssss { 66.50033 161.02032 } Correct results: Bearing forward 1 D.mmss¦ 264.513132284 Backward :2 D.mmss¦ 90: 83.2511696433 effective distance on geoid/Earth surface [km]: 68.981609066, or 42.8631846678_mi' ≠indicated 42.7 miles Besides, Euclidean distance through the Earth (initial altitude 0¦end altitude 0): 68.9812747629 km. See also, further down, the Post "Geodesic distance & Earth Euclidean distance calculator, bearing calc", Ver06b.hp for HP50G calculator. Regards, Gil 

02062023, 12:40 PM
Post: #4




RE: (32S II) Position, Distance & Bearing Calculations
This program is a verbatim translation of those for the HP42S or HP15C from (15C) Haversine Navigation:
Code: D01 LBL D Example Kotzebue: 66°53′50.7″N 162°35′55.7″W Noorvik: 66°50′03.3″N 161°02′03.2″W 66.53507 →HR 162.35557 →HR 66.50033 →HR 161.02032 →HR XEQ D 37.07535 x<>y 95.14735 The Xregister contains the distance in (old) nautical miles, while the Yregister contains the bearing. For a final result in kilometers, substitute 60 with 111.19. For a final result in statute miles, substitute 60 with 69.09. Thus you will get either 68.70681 km or 42.69227 statute miles. Caveats
Advantages
Compared to Gil's program it assumes the Earth is a sphere. Thus the results are probably not that accurate. 

02062023, 01:24 PM
(This post was last modified: 02062023 04:17 PM by Gil.)
Post: #5




RE: (32S II) Position, Distance & Bearing Calculations
Regarding previous message.
It is written: "For a final result in kilometers, substitute 60 with 111.19." Correct should be: "with 111.12“. And "For a final result in statute miles, substitute 60 with 69.09." Correct should be: "with 69.05 or 69.047". Regards, Gil 

02062023, 05:54 PM
Post: #6




RE: (32S II) Position, Distance & Bearing Calculations
(02062023 01:24 PM)Gil Wrote: Correct should be: (…) I was just using the values from the original document: Quote:The above expressions assume the arguments in all trigonometric functions and results are in degrees. If the The idea was to get the same results. How did you come up with your numbers? 

02062023, 09:18 PM
(This post was last modified: 02072023 01:21 PM by Gil.)
Post: #7




RE: (32S II) Position, Distance & Bearing Calculations
A1)
Radius Equator WGS84 (Ra) : 6378137 m Radius Pole WGS84 (Rb) : 6356752.3142451794975639665996336551567981713110854973388485716512832085220868351009394057094507133 A2) Acccoring to International Union of Geodesy and Geophysics, Earth radius (2Ra+Rb) / 3 : (about) 6371008.77141505983252 m Mean Earth circumference = 2×pi× Mmean Earth radius = (about) 40030228.7044 m for 360 degrees (circle) =40030228.7044/360 m for 1 degree (longitude) =40030228.7044/360/60 for 1/60 of degree (or 1' longitude) =40030228.7044/360/60 = about 1853.25132891 m for 1' (longitude) B) Depending on where you are located, this value (of about 1853...) of "your" nautical mile might vary (for 1' longitudel —> by convention, nautical mile defined later as = exactly 1852.000000 m. C) 1 nautical mile —> exactly 1.852 km 60 nautical mile —> 1.852 × 60 = exactly 111.12 km D) 1 mile —> exactly 1760 yards 1 yard —> exactly .9144 m Therefore, 1 mile —> 1760 × 0.9144 = exactly 1609.344 m, or 1.609344 km E) 1 nautical mile —> exactly to 1852/1609.344 mile = about 1. 1507794480235425117314881094408653463771574007794480235425117314881094408653463771574007794480235 mile F) 60 nautical miles —> 60 × 1. 1507794480235425117314881094408653463771574007794480235425117314881094408653463771574007794480235 = about 69. 0467668814125507038892865664519207826294440467668814125507038892865664519207826294440467668814100 miles = about 69.05 or 69.047 miles Regards, Gil 

« Next Oldest  Next Newest »

User(s) browsing this thread: 1 Guest(s)