Editor’s Note: As Iran blocks the Straits of Hormuz, (with the exception of oil for the People’s Republic of China), this is a good time to look at the GPS satellite galaxies and the ‘one-way’ drones that Iran sends out to cause mayhem and death.
Mankind has found a series of instruments and systems to more accurately define position on Earth as well as way-points to show voyage timing and passage markers. The goals are to make passages safe from groundings and collisions, to separate vessels to increase safety, to define routes for minimal fuel consumption, and to avoid severe weather.
Inertial Navigation Systems (INS)
These nav systems have been around since the 1950s. Initially they were installed in intercontinental ballistic missiles (ICBMs) and bombers, such as the B-52. The 1950s version of INS weighed in at several hundred pounds. Since 2017, an INS has the required sensors contained on a single chip smaller than a US penny. When atomic submarines came along, INS was key to their navigation since subs stay submerged for months at a time. But subs must rise to periscope depth so the GPS receiver on the sub can get updates for the INS system to be more accurate. The INS uses three gyroscopes set at 90-degree angles to each other.
Iranian Drones– The Iranian drone guidance system is GPS and inertial, plus it can fly pre-planned routes! The accuracy of an INS derived flight path is relatively poor compared to GPS; however an INS can have the ability to use GPS intermittently for re-calibration. If you watch much network news, you will likely see video of delta-winged Shahed 136 drones. They cost $20,000 to $50,000 each, depending on options. They weigh about 450 lbs and carry 65 to 120 lbs of explosive for about 1,200 miles. The gas-powered piston engine and pusher propeller lets this poor man’s cruise missile fly along at 112 mph. On the other hand, US cruise missiles fly at probably 600 mph, can be launched from planes, ships, or submarines, and cost several million dollars each.
There is a wide-spread view that only one GPS system exists. Would you believe there are actually six positioning systems as of now, but only four are global. Here they are:
GPS– The US military system, which allows civilians to also use it. The US GPS is called a constellation, and consists of 32 satellites. Prior to the year 2000, there was a controversy over Selective Availability (SA) between the military and worldwide civilian users. When President Clinton banned the use of SA in 2000, position accuracy improved significantly. Now your fishing guide could take you to his favorite fishing hole using GPS, and end up within a few feet of the exact spot!
The military could give up SA since military radios have access to a second channel to improve accuracy. Even if the enemy were to access our military radios, there is a special code that is changed frequently to ensure security.
Other GPS additions allow accuracy improvements such as Differential GPS (DGPS) and Wide Area Augmentation System (WAAS). Both of these systems help move commercial and General Aviation aircraft in instrument-weather conditions with automated takeoff and landings in specially equipped aircraft. .
GLONASS– This is the Russian satellite positioning system. It has a 24-satellite constellation (the minimum necessary for global coverage) and works better than the US GPS in harsh weather, the higher latitudes, and cities with high-rise buildings.
GALILEO– This is Europe’s GPS system. Its basic accuracy is three feet horizontally. This system has 30 satellites and augmentation systems similar to those of the US GPS system.
Bei Dou– This is the Communist Chinese’s system with 35 satellites with the added capability to pass short text messages over this system.
Regional Only Systems
QZSS– Japan operates this system within about 1,000 miles of Japan.
NavIC– Is the India system with 7 satellites and works within 1,500 miles of the country.
Predecessor Technology
The Astrolabe is a very ancient instrument that had built-in star and moon charts. This device gave latitudes, but not longitudes. It took until more modern times for an accurate clock to be developed for finding longitude. Astrolabes and sextants required good weather so the sun and stars were visible to be functional.
During WWII, the US developed a navigation system known as Long RAnge Navigation, (LORAN) that used several chains of transmitters around the world — accurately timed to emit radio pulses at specific times after the master transmitter sent out the beginning pulse. Charts were printed with hyperbolic lines on them so pulse timing would produce intersections of the lines to show position. Ocean liners, fishermen, sailors, and pilots flying long distance routes now had a way to navigate with precision of a few tens of miles.
What the US and Israel need is a Russian-styled Electro Magnetic Pulse (EMP) generator that can be flown near Iran to fry the “brains” of their drones. Who knows? That may be in the works!
Gordon is a frequent contributor to The County Compass
