The magnetic compass needle always points north. This feature of the magnetic needle was noticed back in the 13th century and they began to use a compass for orientation, primarily at sea. The device is extremely simple and its use seems no more difficult. However, if you draw a straight line on the map from the point of departure to the destination point, and without deviating a single degree follow the plotted course, using a magnetic compass as a course indicator, then you are unlikely to be lucky enough to end up exactly at the planned location, especially if the distance between the points is sufficient big.
To deviate your course ( compass course) from the course that you drew on the map (it is called true course), two phenomena influence:
- Distortion of compass readings - magnetic deviation
- Discrepancy between the magnetic pole and the true pole - magnetic declination
To calculate the compass course according to the true one or vice versa, you need to substitute the magnetic declination values for a given area, as well as the deviation values for your compass, into the appropriate fields of the calculator. The default values calculate the compass heading from Cadiz (Spain) to Cape St. Vincent (Portugal). To make the calculation, I first determined the true course using the calculator. Track angle and the distance between two points along the loxodrome (rumba line). , where I substituted the coordinates of the points from Google Maps. The magnetic declination value was obtained from sea map Western Mediterranean Sea.
You can find detailed explanations below.
Compass Magnetic True
Magnetic declination changes over time, here you should indicate the year for which the magnetic declination was determined
The amount by which magnetic declination changes each year
Update...
Update...
Update...
Date for which the calculation is carried out
Compass direction
Magnetic direction
True direction
Magnetic deviation
Those who read Jules Verne remember where the 15-year-old captain took the ship after Negoro placed an ax under the compass binnacle. On the ship, even without an ax in the binnacle, there are plenty of other objects that can influence the magnetic compass. To eliminate this effect, deviation tables are calculated for each ship's compass, showing the deviation of the compass readings for various compass courses. Over time, deviation may change due to the installation of new equipment or magnetization of old iron parts, so the tables are regularly updated. Using the value of the deviation table, you can bring the compass course to the course measured from the magnetic meridian, i.e. magnetic course. To do this, the deviation value for a given compass course is added to the compass course if the deviation is to the east (E) or subtracted if it is to the west (W).
Magnetic declination
Magnetic declination does not depend on the ship's equipment, but depends on its location and, like deviation, changes over time, but more predictably. The magnetic declination value is indicated on the map, with the obligatory indication of the year of measurement and the average annual change. To go to the true course, we first get the magnetic course, then add the value of the magnetic declination to the east (E) or subtract the one to the west (W), then the average annual change in the magnetic declination is taken into account in the same way (adding or subtracting multiplied by the number of years that have passed since moment of declination fixation).
How to remember how to correct or translate rumbas
The process of transition from compass courses to true ones is called correction of rhumbs, the reverse process from true to compass - translation of rhumbs.
In the English-language literature on navigation, there is a simple rule that makes it easy to remember how to move from one type of direction to another; for this you need to remember one simple word: CadET.
It deciphers like this: C(ompass) - to the compass direction ad(d) - add E(asterly error) - correction to the east T(rue) - we get the true direction. The reverse transformation is performed in a similar way, only instead of adding the eastern corrections, we subtract them.
Sources:
V. S. Mikhailov, V. G. Kudryavtsev, V. S. Davydov Navigation and pilotage.
Tim Bartlett An Introduction to Navigation. R.Y.A.
Magnetic compass correction
EdwART. Explanatory Naval Dictionary, 2010
See what “Magnetic compass correction” is in other dictionaries:
COMPASS CORRECTION- The angle between the true and compass directions, which is the algebraic sum of magnetic declination and deviation. It is expressed by the difference between the compass and true (taken from the map) directions to any lighthouse, navigation sign, etc... Marine encyclopedic reference book
A device for determining horizontal directions on the ground. Used to determine the direction in which a ship, aircraft, or ground vehicle is moving; the direction in which the pedestrian is walking; directions to some... ... Collier's Encyclopedia
A device for determining the sides of the horizon and measuring magnetic azimuths on the ground, for example. when moving along the route. Basic parts of the compass - a magnetic needle, freely rotating on the tip of a needle, a dial with degree divisions, and also (in some... ... Geographical encyclopedia
The Compass request is redirected here; see also other meanings. Brunton mountain compass, precision instrument ... Wikipedia
A device indicating direction on the earth's surface; it includes one or more gyroscopes. Used almost universally in navigation and control systems of large sea vessels; unlike a magnetic compass, its readings... ... Collier's Encyclopedia
The science that studies the shape, size and gravitational field of the Earth, and technical means and methods of field measurements. Geodesy originated in the countries of the Ancient East and in Egypt, where long before Christ. e. methods for measuring land were known... ... Geographical encyclopedia
Sometimes, when interviewing 3rd mates, I jokingly ask: “How does the morning begin for the 3rd mate and for the captain?”
The young guys are confused and try to come up with something to answer my unexpected question.
I explain to them all that the captain’s morning begins with a cup of aromatic coffee, and for the 3rd mate, the morning begins with adjusting the compass. A joke of course, but with a grain of truth. This is what I want to talk about.
All navigators know that the compass correction must be determined every watch. How to do this?
In coastal navigation, when there are coastal landmarks, this is very simple and takes a few minutes. What to do if the ship is on the open ocean? There is nothing around, only the sky, the ocean, seagulls and the captain, who is watching with interest how the 3rd mate will solve the task. He probably considers you “GPS generation”. As they say, everything ingenious is simple.
There is a quick and easy way determining the compass correction based on the lower or upper edge of the Sun. To do this, you need very little - install a direction finder on board where the Sun sets, and at the moment when the last segment disappears behind the horizon. After this, you should take a bearing, note the time, latitude, longitude and enter the data into computer program Navimate or Skymate. If you don’t want to blush in front of the captain, or at some inspection, then show your class and calculate the correction manually.
For this we need a manual called Nautical Almanac.
So, we take a bearing on the Sun, record the current time and coordinates, record the course using the gyro and magnetic compass.
Example:
Date: 03/19/2013 LMT(UTC+2): 17:46:30 Lat: 35-12.3 N Long: 35-55.0 E
Gyro bearing: 270.6 Heading 005 Magnetic heading 000
We adjust the time to Greenwich (2nd time zone) GMT 15:46:30
Finding GHA (Greenwich Hour Angle)
Finding DEC (declension)
To find them, go to the main table of the Almanac and find the current date. We write out GHA and DEC for the current hour, and also write out correction d for the Sun (bottom right of the table). In our case it is equal to 1.0.
Then you need to correct the Greenwich hour angle and declination by adjustments to minutes and seconds.
This information can be found at the end of the book. The pages are headed by minutes and a GHA correction is provided for each second. There is also a correction for declination on the right side, which is selected according to d.
M’S” = 11-37.5 corr = 0-00.8
Now we adjust the Greenwich hour angle to the local time zone. To do this, we add (if E) or subtract (if W) our longitude:
GHA = 54-42.5 + Long 35-55.0
LHA = 90-37.5
Go to the Sight reduction table and select the values A, B, Z1:
A = 55.0 B = 0 Z1 = 0
For the second entry in the table we need F and A.
To get F you just add B and DEC (+/-).
Our DEC is positive if the sign of declination and latitude coincides (N and N/S and S).
If our declination and latitude are different, then DEC is negative.
B=0
DEC=0-20.6S
F = 359 39.4 (rounded to 360)
Now having F and A, we enter the same table for the second and last time, and write out the second component of the azimuth Z2:
Z2 = 90
Then we add Z1 and Z2 and get the semicircular azimuth Z:
Z = 0 + 90 = 90
We convert semicircular azimuth to circular using the rule:
For northern latitude, if LHA is greater than 180: Zn = Z, if LHA is less than 180: Zn = 360 Z
For Southern latitude, if LHA is greater than 180: Zn = 180 – Z, if LHA is less than 180: Zn = 180 + Z
In our case Zn = 360 – 90 = 270
The desired bearing has been found. We take away our compass bearing 270 – 270.6 = - 0.6W
In order not to get confused in the order of calculations, I present the algorithm:
- We make calculations, record bearing, position, time, and heading.
- We convert local time to Greenwich Mean Time.
- We select the value of LHA and Dec from the tables.
- We correct them by adjusting them for minutes and seconds.
- Select the values A, B, Z1 from the table.
- We calculate F and select Z2 from the table.
- We find the azimuth and convert it to circular.
- We find the compass correction (true bearing minus compass bearing).
- WE HANG A LARGE ASTRONOMICAL MEDAL ON OUR CHEST.
At first glance, everything looks cumbersome and unclear. But after a couple of practical calculations, everything will fall into place.
By the way, by adjusting your compass as the sun sets, you will have a unique chance to see the green beam. The fact is that at sunset, at the moment when the Sun disappears behind the horizon, due to refraction and refraction of color, it is very rare, but you can observe a green ray for several seconds. This mysterious, enigmatic and very rare phenomenon is reflected in numerous legends of different peoples, and is overgrown with legends and predictions.
For example, according to one legend, the one who saw a green ray will receive a promotion, prosperity, and will be able to meet the one with whom he will meet his happiness.
And this is not a story, since the Captain, having seen and appreciated the efforts, as well as the competence of the young navigator, will, of course, recommend him for promotion.
So determining the compass correction based on sunset is a direct path to promotion and, as a result, to well-being and happiness.
I wish all young navigators calm seas, career advancement, and a return to their native shores. May the green ray bring you happiness in your life.
I bring to your attention a very interesting and useful post. Please note the author's name. I think we will hear him again!
Every navigator encounters the Compass Observation Book every day. Let's figure out WHAT it is and WHY is it needed?
Compass Observation Book– this is a log of corrections for magnetic and gyro compasses. A completely logical question arises: “How often should I fill out this journal? And anyway, what should I write there?”
For better information perception, you can download: Compass Observation Book Azimuth calculation
Let's figure it out in order. How often?– There are clear instructions on this question in the well-known manual – “Bridge Procedures Guide”, abbreviated as BPG (Soviet analogue – RShS – Recommendations for organizing navigator service on sea vessels). Also, similar instructions are probably present in MASTER’S STANDING ORDERS, and if you search carefully, you will find them in COMPANY SAFETY MANAGEMENT PROCEDURES in the Watch keeping section or something similar in meaning. As you can see, this is a serious matter and you will still have to calculate the correction :). To be clear, here are a couple of quotes:
BPG Section3. Duties of the officer of the watch. Paragraph3.2.5.2. Routine test and checks. Gyro and magnetic compass errors should be checked and recorded at least once a watch, where possible, and after any major course alternation.
BPG Section4. Operation and maintenance of bridge equipment. Paragraph4.6.3. Compass errors. Magnetic and Gyro compass errors should be checked and recorded each watch, where possible, using either azimuth or transit bearings. [Quotes from BPG 4th edition 2007].
Simply put, the navigator must calculate and enter the correction into the log at least once per watch, if possible. I pay special attention to the disclaimer “ " This is where the first mistakes begin. Very often I came across a similar entry instead of an amendment: “Sky overcast”. And the navigator’s argument, at first glance, is ironclad: “Well, then it’s clear that I tried to calculate, but I couldn’t, because... there were clouds." So, such an approach is doomed to failure, because... in this case, an entry in the log should be made every watch by each assistant (i.e. at least 6 times a day), which, to tell the truth, I have never seen. Most often, you will see by the dates that the amendment is either written down, or it is written down that “... there were clouds...” or even for a couple of days, and sometimes even weeks, there are no records. And if the Port State Control Officer or any other inspector wants to find fault with you, he will do it with ease. Because it is clearly visible that the correction is not calculated once per shift, but God willing, at least once a day. It would be more competent to make only calculated amendments to the journal. And if for some period there is no information, then you can easily hide behind that very clause “ ...if possible» = « …where possible…" And the proof that it was not possible is your records in the Bridge Log Book about the weather conditions, which are made every watch. With this approach, no one will ever tell you that you are not following the rules for filling out the Compass Observation Book. As a fellow auditor once told me during an internal ISM audit, “...this is not a weather log book.” So do not create evidence against yourself and write only what is necessary.
We’ve sorted out the question of how often to record, let’s now figure out what exactly needs to be written.
Inside the Compass Observation Book you will find the following table:
Columns 1, 2, 3. We record Greenwich time and date of observation, as well as the position of the vessel.
Column 4. Ship's Head. We record the course that the ship was following at the time of the observation. 4.1 Gyro– gyrocompass course, 4.2 Standard– magnetic course. 4.3 Steering- heading according to the compass according to which at the moment follow. For example, if you are driving an autopilot using a gyrocompass, then write down the gyrocompass heading, i.e. value 4.3 = 4.1. I admit, I once came across a colleague who desperately tried to prove to me that there is a third type of compass on the ship, which is called a steering compass. True, he was never able to find this unprecedented device and show it to me. Probably because it simply does not exist :). By entering data in column 4, you indicate which compass you are following at the moment: magnetic or gyro.
Column 5. Bearing. 5.1 True– true bearing to the object. To calculate it, you will need the well-known Brown’s Nautical Almanac and Norie’s Nautical Tables. Alternatively, you can also calculate the correction using “Rapid Sight Reduction Tables for Navigation”, however, the accuracy then comes down to whole degrees. You can also see how your colleagues calculate the amendment to the programs (there are many of them, the most popular, perhaps, is sky mate). If you are too lazy to count from tables, then take the time to at least make sure that the program you are using is licensed for your ship or ship owner. Then, in case of verification, you will be able to refer to the calculations using this program, but if your “Sky mate” is Licensed to: -=skyhacker1986=- or something like that, then it’s better not to even stutter about what you calculate according to the program, and maybe you lucky. In general, be prepared for the fact that you will have to re-calculate your previous adjustment in front of the inspector; this happens, although very rarely. In his lessons, Evgeniy (the author of the project, if anyone doesn’t understand) explained in more than detail and very clearly how exactly to calculate the amendment. I admit that during my academic years this knowledge was very difficult for me - I chewed up more than one cobblestone of the granite of science until I figured out what was what. So don’t be lazy and watch the corresponding video lesson.
Columns 5.2 and 5.3. Gyro bearing and magnetic bearing to the selected object. At first glance, everything is very simple, and it is not clear where you can go wrong. But before entering data into the column 5.3 Standard bearing make sure that it is practical to take a bearing on a landmark using a magnetic compass. I have often come across systems that allow you to display magnetic compass readings on the heading indicator, then everything is clear, switch to the magnetic compass and take the magnetic bearing. And if this is not possible, and you are in fact unable to take a magnetic bearing to the object, then it is better not to write anything in this column - put a dash.
TO Column 6. Object. Write down the name of the celestial body by which you calculate the correction. To add a personal touch to your entries, you can also include an object symbol next to it. These symbols can be found in Brown’s Nautical Almanac on page 5. It is also worth noting that the correction can be calculated not only by the luminaries, but also by the alignments, for example, or while standing in the port - along the berth line.
Column 7. Error. Now we come to the main part of the magazine, namely the amendments themselves. Gyro error= True bearing – Gyro bearing. Calculation Standard error: if you took a magnetic bearing to a landmark, then the calculation is similar to the previous one: Standard error = True bearing – Standard bearing. If you put a dash in column 5.3, then the correction is calculated by comparing the true course and the magnetic one. We obtain the true course by adding to the gyro course the correction of the gyro compass with its sign: . We obtain magnetic compass corrections by subtracting magnetic from the true heading: . In column 7.3 we write down the correction of the compass that the ship is currently following (similar to column 4.3).
Column 8. Variation. Translated into Russian - magnetic declination, take it from the map. There are also cases when variation taken from the GPS indicator readings. Here we are talking about the level of trust in information sources. You can refer to map data with a clear conscience - maps in most cases are published by UKHO (United Kingdom Hydrographic Office), but there is less trust in magnetic declination data taken from GPS, because their source is not so well known, if known at all.
Column 9.1 Standard Deviation. The translation is obvious - magnetic compass deviation. The deviation table immediately comes to mind, but don’t rush to rejoice. As practice shows, the data between the real deviation and that indicated in the table are very different. There are a lot of reasons for this, starting from the influence of the magnetic field of the load on the compass and ending with the banal human factor when compiling a deviation table. I personally saw tables several times on ships where all values = zero, i.e. There was no deviation at all, which is a priori impossible. But there were plenty of bulky seals and beautiful sweeping paintings on the table, only monograms and the coat of arms of the Queen of England were missing :). What to do, you ask? So the answer is obvious, we will calculate the deviation ourselves. We recall the navigation course, where we were told that the magnetic compass correction consists of magnetic declination and deviation. Thus, we get that Deviation = Standard Error – Variation. If the calculations on the ship were carried out correctly, then after some time, you can create your own deviation table, the trust in which is directly proportional to the trust in the calculations of your colleagues. I sincerely wish that life does not put you in conditions in which the value of the deviation of the magnetic compass will have a significant impact on the safety of navigation. But all the same, all calculations and entries should be made as competently as possible, otherwise why are you reading this article :)?
Column 9.2. If the ship is following a magnetic compass, then the value is equal to the previous one. If you follow a gyrocompass, then we are talking about speed and latitude deviations, which are usually taken into account and adjusted automatically by the gyrocompass. Personally, I put a dash in this column, because... whatever the value is, it is part of the already calculated Gyro Error.
Column 10. Heel. We are talking about the roll of the ship; if you are swaying, write “+ -” a couple of degrees.
Column 11. Remarks. Indicate which pelorus you took the bearing from (Port Repeater / Starboard Repeater). Surprisingly, you can make a mistake here, for example, the ship is heading strictly north, you take the bearing of the star on the right abeam, then it would be correct to indicate that you took the bearing from the pelorus on the right wing, and not on the left :). This will seem obvious to many, but believe me, there have been cases of such recordings. You can see for yourself by looking through the magazine and studying the records of predecessors and you will understand how neglected everything is :). In truth, this is what prompted me to write this article. Also, don't make stupid mistakes like taking the direction of the Sun at noon on a ship with covered wings, because... this is clearly impossible and calls into question all the entries in the journal, as well as the competence of those who made them. And what could be worse for a navigator than a well-founded accusation of incompetence. So before you sign any journal entry, make sure it is correct.
Well, since we’re talking about signatures, it’s time to put your beautiful autograph in the column 12.Observer and close the log until the next watch, provided “ ...if possible» = « …where possible…».
P.S. I am attaching a file to the article – Azimuth Calculation. In it you will find table forms for calculating the gyrocompass correction. The tables are created based on the calculation algorithm given in Brown's Nautical Almanac on pages 12 and 13. Also, for convenience, lines have been added to continue calculating the correction according to Norie's Nautical Tables (ABC tables). Print out the forms and enter separate folder and file the completed forms. You can also practice your eloquence skills and convince your fellow navigators to use your innovation.
With respect, to all those who read the article to the end :) Gusev Valery
Post added by Evgeny Bogachenko after comments.
The fact is that Valery cannot promptly answer the question right now, so for now I’ll write, and he’ll add it when he’s in touch again. As I understand the question, I want to decide how necessary it is to calculate the compass correction and keep a Compass Correction Log.
First, ability to make corrections STCW required. These requirements apply to officers responsible for maintaining a navigational watch on ships with a gross tonnage of 500 tons or more. Those. theoretically, during any check they may be required to calculate the compass correction.
But that's not the question. That's why second. Amendments should be correctly applied (taken into account) to courses and bearings. And then the question arises: how to take them into account if not count them? And if you don’t keep a journal, how can you prove that the amendments were recorded?
But captains and first mates You shouldn't relax either. Since the requirements for them are no less stringent. Not a reproach, as I understand that everyone has a lot of work. However, I don’t think that every captain and first mate will be able to immediately calculate the compass correction.
Well at last. When taking over a watch, among all the points that must be taken into account, there is a mention of corrections for gyro- and magnetic compasses. Again, you can be able to calculate the correction, you can verbally convey its value. But some inspector will resist and then prove to him, without a compass correction log, that everything was done.
I understand that you can take a folder and collect sheets of calculations there. At the same time, without filling out the journal. There is nothing to add here. Since I have not encountered a specific international requirement for the presence of a compass correction log on the bridge. But there are Company Standards, and this requirement can often be found there. And trying to prove to someone that this is how it is and that there is no need for anything else is a waste of nerves and time. On a ship, so many records are made with reserve, so many unnecessary procedures and reports to cover one place, that the Compass Correction Log pales in comparison with them.
Text excerpts from STCW 2011. Additionally, I am posting for download the pages where I got these texts from.
The design of a magnetic compass is based on the property magnetic needle be installed in the direction of the magnetic field lines. The NS line of the compass card is set in the direction of the horizontal component of the Earth’s magnetic field – magnetic meridian Nm.
Magnetic declination(d) called the angle between the plane of the true meridian (Ni) and the direction of the horizontal component of the Earth's magnetic field (magnetic meridian Nm) (Fig. 1.17). Positive declination is given the name E, negative declination – W.
The magnitude of magnetic declination is different at different points on the Earth and changes from year to year. This annual change (increase or decrease) is indicated on nautical charts.
In order to select declination from a map, you must:
1 - we give the declination to the year of voyage, which is produced according to the formula:
dpl = dc + n∆d
Where: dk– declination taken from the map;
n– the difference between the year of navigation and the year to which the declination is given (selected from the map);
Rice. 1.17 Magnetic declination ∆d– annual change in declination (from the map).
Example. On the map, the magnetic declination is shown for 2003 dк = 7.3 0 W. The annual increase in W ∆d = 0.1 0. Determine the declination for the year of navigation dpl in 2010.
Solution.
1 – find the difference n : _ Sailing year = 2010
Year on the map = 2003
2 – determine the change in declination n∆d: Х n = 7
∆d = 0.1 0
n∆d = 0.7 0 k W
3 – we give the declination to the year of voyage dpl: + dк = 7.3 0 W
n∆d = 0.7 0 kW
Answer: d 10 = 8.0 0 W or d 10 = - 8.0 0
In addition to the Earth’s magnetic field, the magnetic compass is affected by the ship’s magnetic field, which arises as a result of the magnetization of the ship’s iron structures by the Earth’s magnetic field.
The NS axis of the magnetic compass is set in the direction of the horizontal component with the direction of the magnetic meridian.
Deviation(δ) – angle between plane Nк and Nм. The magnitude of the deviation depends on the magnetic course of the MK vessel. To ensure that it is not too large, the deviation is compensated using magnets placed in the compass binnacle. The residual deviation is determined and tabulated. The argument used to compile the deviation table is usually the compass course of the spacecraft. However, taking into account that with a small deviation, the difference between QC and MK is small, you can enter the table with MK.
General magnetic compass correction(∆μ)– angle between the true meridian N and
and compass meridian Nк – represent the sum of d and δ:
∆μ = δ + d
The calculation is made in the following form:
If the CC is known with it, enter the “Deviation Table” and select the deviation δ from it.
When the QC coincides with the table value, then the deviation value is taken from the table; in cases where the QC value does not coincide with the table value, it is necessary to select the deviation by interpolating between the QCs.
The declination given for the year of the map dk is removed from the map, the declination given for the year of navigation dpl is given and the general correction ∆mk is calculated.
When using a magnetic compass, we encounter two corrections to its reading. Since the directions to the true geographic and magnetic poles do not coincide due to the specific location of the magnetic lines of force of the Earth’s magnetic field, it is necessary to introduce a correction for declination (d). This correction, due to the different magnetic state of the rock underlying the body of water, is different in different areas of the area. Sometimes it changes significantly in a small space and is not constant. These places are marked on the navigation map as magnetic anomalies. In the polar regions, close to the location of the magnetic pole, this declination reaches significant values. In the area of the magnetic pole, the use of a magnetic compass becomes impossible due to the smallness of the horizontal component of the earth's magnetism, which holds the compass needle in the magnetic meridian.
In general, within the permissible deviations of the magnetic needle from the direction of the true meridian, it is entered into the calculation correction for declination (Fig. 1.18) This correction may have a positive (+) or negative (-) sign. If the magnetic meridian is to the east (E) of the true one, then the declination sign is (+); if it is to the west (W), then the sign is (-). The transition from magnetic directions to true ones is carried out as follows:
IR = MK + d IP = MP + d
These formulas are algebraic, and the corresponding sign is placed before the declension d.
A compass installed on a ship is subject to the forces of not only the Earth's magnetic field, but also the magnetic field of the ship. In this case, the compass needle is positioned according to the resultant of these forces. The direction in this case is called compass.
In order to bring the compass readings to the direction of the magnetic pole, you need to introduce a correction for deviation (d) (Fig.1.19)
Deviation is the angle between the directions of the magnetic and conventional compass poles. This correction is characterized by a value in degrees and signs (+) plus or (-) minus.
Fig.1.18 Magnetic and true Fig.1.19 Compass directions
directions
1. When the northern part of the compass meridian is deviated from the magnetic meridian to the east (E), then the deviation is assigned a sign (+). If the compass meridian is located to the west (W) of the magnetic meridian, then the deviation is assigned a sign (-).
2. The relationship between magnetic and compass directions will be written as:
MK = KK + d MP = KP + d
IR = KK + d + d IP = KP + d + d
D MK = d + d(1.31)
IR = KK + D MK IP = KP + D MK (1.32)
KK = IR - D MK (1.33)
D MK = IR – KK (1.34)
In navigation, three types of direction correction problems are solved:
4. Inverse problem - true directions are converted to compass directions.
Auxiliary - using the known IC, CC, d (d), the compass correction, deviation or declination are determined.
