The sun is shining, it’s early morning and I’m on my deck, Colombian coffee in hand, reading a fantastic book “China Clipper: The Age of the Great Flying Boats” by Robert Gandt (Ref.1). It is the amazing story of the American airline Pan Am crossing the Pacific in 1935. In order to fly safely with… Continue reading Celestial Navigation Basics – Aim Off
Category: Navigation
Navigation: Celestial, Sextant, Equipment
RTL-SDR for Marine HF Weather Fax
Introduction Up to date weather information is critical for sailors and can make the difference between a safe or a hazardous passage. Marine HF Weather Fax has been working reliably for many years and is an independent source of valuable information. NOAA’s Marine Weather Fax page (Ref.1) has all the information you need to use… Continue reading RTL-SDR for Marine HF Weather Fax
Celestial Navigation Basics – Fix
In this post we will look at how to generate a fix from observations of two Celestial Bodies. In previous posts we looked at Hc (Ref.9), Ho (Ref.8), Ha (Ref.7) and Hs (Ref.6). Now we are in a position to use Ho & Hc from two measurements to get our fix. The Marcq St. Hilaire… Continue reading Celestial Navigation Basics – Fix
RTL-SDR for AIS
Introduction AIS Automatic Identification System for Ships is a traffic system that uses VHF transponders on vessels to periodically send out location information. It was developed by Swedish inventor Hakan Lans and is similar in concept to the ADS-B transponder system used on aircraft for position reporting. AIS uses two VHF marine channels 87B (161.975 MHz)… Continue reading RTL-SDR for AIS
Celestial Navigation Basics – Hc Calculated Altitude
In this post we will look at how to determine Hc the calculated altitude and compare this to Ho the observed altitude. The difference between Ho and Hc is the intercept and is used in the Marc Saint Hilaire method for solving position. In previous posts we found Hs (Ref.3), Ha (Ref.4) and Ho (Ref.5).… Continue reading Celestial Navigation Basics – Hc Calculated Altitude