Previous systems[ edit ] Taking a " fix " in any navigation system requires the determination of two measurements.
The US Army Air Corps was interested in the concept for aircraft navigation, and after some discussion they returned a requirement for a system offering accuracy of about 1 mile 1. The Microwave Committee, by this time organized into what would become the Radiation Laboratorytook up development as Project 3.
During the initial meetings a member of the UK liaison team, Taffy Bowenmentioned that he was aware the British were also working on a similar concept, but had no information on its performance.
Extensive signal-strength measurements were made by mounting a conventional radio receiver in a station wagon and driving around the eastern states. In spite of several efforts to design around the problem, instability in the display prevented accurate timing measurements.
They met with the Gee team inand immediately adopted this solution. They also found that Project Loran and shoran and Gee called for almost identical systems, with similar performance, range and accuracy.
But Gee had already completed basic development and was entering into initial production, making Project 3 superfluous. Additional stations followed, covering the European side, and then a massive expansion in the Pacific.
The former requires sharp Loran and shoran of signal, and their accuracy is generally limited to how rapidly the pulses can be turned on and off, which is, in turn, a function of the carrier frequency.
There is an ambiguity in the signal, the same measurements can be valid at two locations relative to the broadcasters, but in normal operation these are hundreds of kilometers apart so one possibility can be eliminated.
The second system requires constant signals "continuous wave" and is easy to use even at low frequencies. However, its signal is ambiguous over the distance of a wavelength, meaning there are hundreds of locations that will return the same signal, referred to as cells in Decca. This demands some other navigation method to be used in conjunction to pick which cell the receiver is within.
Among the many methods were a directional broadcast systems known as POPIand a variety of systems combining pulse-timing for low-accuracy navigation and then using phase-comparison for fine adjustment. Decca themselves had set aside one frequency, "9f", for testing this concept, but did not have the chance to do so until much later.
Similar concepts were also used in the experimental Navarho system in the US. This meant that pulse-matching could be used to get a rough fix, and then the operator could gain additional timing accuracy by lining up the individual waves within the pulse, like Decca. This could either be used to greatly increase the accuracy of LORAN, or alternately, offer similar accuracy using much lower carrier frequencies, and thus greatly extend range.
This would require the transmitter stations to be synchronized both in time and phase, but much of this problem had been solved by Decca engineers. Testing was carried out throughout the year, including several long-distance flights as far as Brazil. The experimental system was then sent to Canada where it was used during Operation Muskox in the Arctic.
The system ran until September The system became operational in and ran for two years until February Unfortunately the stations proved poorly sited, as the radio transmission over the permafrost was much shorter than expected and synchronization of the signals between the stations using groundwaves proved impossible.
The tests also showed that the system was extremely difficult to use in practice; it was easy for the operator to select the wrong sections of the waveforms on their display, leading to significant real-world inaccuracy.
As the US Army Air Force was moving towards smaller crews, only three in the Boeing B Stratojet for instance, a high degree of automation was desired. In spite of great efforts, Whyn could never be made to work, and was abandoned.
The associated equipment would look for a rising amplitude that indicated the start of the signal pulse, and then use sampling gates to extract the carrier phase.
Using two receivers solved the problem of mis-aligning the pulses, because the phases would only align properly between the two copies of the signal when the same pulses were being compared.
It appeared that a system using a single frequency would work just as well, given the right electronics. CYCLAN appeared to suggest that accuracy at even lower frequencies was not a problem, and the only real concern was the expense of the equipment involved.
These goals would normally be contradictory, but the CYCLAN system gave all involved the confidence that these could be met.
The resulting system was known as Cytac. This consisted of a circuit to extract the envelope of the pulse, another to extract the derivative of the envelope, and finally another that subtracted the derivative from the envelope. The result of this final operation would become negative during a very specific and stable part of the rising edge of the pulse, and this zero-crossing was used to trigger a very short-time sampling gate.
By simply measuring the time between the zero-crossings of the master and slave, pulse-timing was extracted.Synonyms, crossword answers and other related words for RADIO NAVIGATION SYSTEM [loran].
We hope that the following list of synonyms for the word loran will help you to finish your crossword today.
SHORAN is an acronym for SHOrt RAnge Navigation, a type of electronic navigation and bombing system using a precision radar beacon. It was developed during World War II and the first stations were being set up in Europe when the war ended.
CHRONOMETER 'CHRONOMETER' is a 11 letter word starting with C and ending with R Crossword clues for 'CHRONOMETER'. Loran, abbreviation of long-range navigation, was developed, as were short-range navigational systems, called shoran.
Combinations of radar and communications for the landing of aircraft in zero visibility were perfected. One such system was the GCA, or ground-controlled approach system. Combinations of radio.
Loran: Loran, land-based system of radio navigation, first developed at the Massachusetts Institute of Technology during World War II for military ships and aircraft located within miles (about km) of the American coast. In the s a more accurate (within mile [ km]), longer-range system.
Sharon married Loren L. Lone of Augusta on March 21, and they had three wonderful children together, Michael, Jenny and Benjamin.
Although they divorced in , Loren and Sharon remained life long faithful friends until her passing.