Calculate communication azimuth and great-circle distance

 Degree(s)   Minute(s)   Second(s) 
 Degree(s)   Minute(s)   Second(s) 
 Degree(s)   Minute(s)   Second(s) 
 Degree(s)   Minute(s)   Second(s) 
Calculation results:
The circle distance is {{gcdkm}}(km)
The azimuth angle from the sending point to the receiving point is {{btrdd}}Degree(s) {{btrdm}}Minute(s) {{btrds}}Second(s)
The azimuth angle from the receiving point to the sending point is {{brtdd}}Degree(s) {{brtdm}}Minute(s) {{brtds}}Second(s)
Algorithm source: Amateur Radio Communications 童效勇BA1AA 陈方BA4RC Appendix 18
Language translation: Bigsk (Git Repo)