User manual NORTHSTAR 941X

Northstar 941X Reference Manual SOFTWARE VERSION 2.05 30 SUDBURY ROAD ACTON, MASSACHUSETTS 01720 (508) 897-6600 Copyright 1994, 1995, 1996 Northstar Technologies P/N GM1100 Doc. Rev D WARRANTY Northstar Technologies, a Division of CMC Electronics, Inc., warrantees its products to be free from defects in material and workmanship for a period of two (2) years from the date of shipment to an authorized dealer. This warranty applies to the original purchaser or subsequent owner. This warranty covers repair and/or replacement, at our option, of any part or parts found to be defective, provided such defects in our opinion are due to faulty material or workmanship and are not caused by tampering, abuse, or normal wear. All warranties are F.O.B.: Northstar Technologies 30 Sudbury Road Acton, Massachusetts 01720 This warranty applies only to products in normal use. It does not apply to units or circuit boards defective due to improper installation, physical damage, tampering, lightning or other electrical discharge, receivers or mainframes subjected to fresh water or saltwater immersion*, units with altered serial numbers, or units repaired by unauthorized persons or in violation of Northstar service procedures. The foregoing are the only warranties expressed or implied. No other warranty exists. Northstar assumes no responsibility for any consequential losses or damages of any nature with respect to any products or services sold, rendered, or delivered. * Certain Northstar control heads are warranty protected against damage due to water leakage, provided the head has not been tampered with. IMPORTANT NOTICE Although Northstar products are designed to be very useful navigation tools, they are not substitutes for good seamanship. The prudent navigator should never rely on any single device as the sole source of navigation guidance. Exercise caution and good judgment whenever underway. ! CONTENTS ! 1 2 3 The Northstar 941X Introduction ................................................................. 2 Upon First Start-up ...................................................... 2 Using This Manual........................................................ 3 941X Features ............................................................... 4 941X Functions ............................................................. 5 Comparing GPS and Loran .......................................... 5 Mounting Basics ........................................................... 9 Special Functions.......................................................... 9 The Display Screen ..................................................... 10 Interfacing Capability.................................................. 11 Using the Controls POWER Key ................................................................ 14 CONTRAST Key.......................................................... 14 SAVE/MOB Key...........................................................15 Function Keys ............................................................. 16 Menu Keys....................................................................17 Cursor Keys ..................................................................17 Keypad .........................................................................17 Special Display Windows ........................................... 18 Basic Navigation Displaying Position, Heading & Speed ...................... 22 Position Plotter ........................................................... 22 Using GPS ................................................................... 25 Using DGPS ................................................................ 26 Using Loran ................................................................30 Using Phantom Loran ................................................ 32 4 5 6 Creating Waypoints and Routes Entering Data.............................................................. 36 Creating Waypoints .................................................... 37 Avoidance Areas ......................................................... 39 Waypoint Lists ............................................................ 41 Coordinate Options .................................................... 42 Updating Waypoint Coordinates ............................... 42 Editing Waypoints ...................................................... 43 Transferring Waypoints to a PC................................. 44 Creating Routes .......................................................... 44 Saving a Route ............................................................ 47 Changing a Route........................................................50 Naviga Waypoint & Route Navigation Quick-Start Waypoint................................................. 54 Navigating to Waypoints ............................................ 55 Navigating Along Routes ............................................ 59 Restarting the Course Line......................................... 61 The NAV LOG Function What NAVLOG Does .................................................. 64 Logging Your Trip....................................................... 65 Changing Your Trip .................................................... 65 Adding Waypoints to the Trip.................................... 66 7 8 9 Other Special Functions Alarms .........................................................................68 Screen Backlighting .....................................................71 TideTrackTM..................................................................71 Internal Differential Beacon Receiver ....................... 74 Customizing the 941X Time of Day................................................................. 78 Display Options .......................................................... 78 Navigation Options.....................................................82 Receiver Options......................................................... 87 Port Setup Options .....................................................90 Service Options ........................................................... 91 Geodetic Datum .......................................................... 94 Installation and Interfacing Mounting the 941X ................................................... 100 Wiring the 941X System ........................................... 102 Antenna Location ..................................................... 104 DGPS Antenna Coupler (ACU)................................. 108 Interfacing the 941X ..................................................112 Programming the Output Ports ................................ 115 Appendix (Specifications) ........................................ 129 Glossary..................................................................... 135 Glossary Index ......................................................................... 138 Figures FIGURE 1--MAX. POSITION VARIANCES WITH UNCORRECTED GPS.... 8 FIGURE 2--YOKE MOUNT DRILLING DIMENSIONS........................... 102 FIGURE 3--REAR CONNECTORS ...................................................... 103 FIGURE 4--941X GPS-ONLY ANTENNA (AN145 & AN150).......... 105 FIGURE 5--941X COMBO GPS/DGPS ANTENNA (AN190)............. 105 FIGURE 6--STRIPPING THE COAX CABLE JACKET............................ 107 FIGURE 7--FLARED CABLE BRAID .................................................. 108 FIGURE 8--COMPLETED BNC CONNECTOR .................................... 108 FIGURE 9--ACU ASSEMBLY ........................................................... 110 FIGURE 10--PL 259 (UHF) CONNECTOR........................................ 111 FIGURE 11--INTERFACE CONNECTOR (MATING SIDE)...................... 113 FIGURE 12--200 PPNM OUTPUT BLOCK DIAGRAM........................ 115 FIGURE 13--941X DIMENSIONS ...................................................... 132 Tables TABLE 1--DATUM LIST..................................................................... 97 TABLE 2--INTERFACE CONNECTOR PINS ........................................ 114 TABLE 3--PORT SETUP OPTIONS..................................................... 116 TABLE 4--NMEA 0183 SENTENCE IDENTIFIERS............................. 120 TABLE 5--CONNECTION TO NORTHSTAR 800 PORT A..................... 123 TABLE 6--CONNECTION TO NORTHSTAR 800 PORT B..................... 123 TABLE 7--NORTHSTAR 800 SERIES OUTPUT PORT SETUP............... 123 TABLE 8--YEOMAN ELECTRONIC PLOTTER SETUP WITH 941X ....... 124 TABLE 9--CONNECTING TO EXTERNAL NS BEACON RECEIVER...... 125 1 Introducing the Northstar 941X Introduction Upon First Start-up Using This Manual Features Functions Comparing GPS and Loran Mounting Special Functions The Display Screen Interfacing Capability 2 2 3 4 5 5 9 9 10 11 T his section introduces you to the Northstar 941X navigator, outlining its various operational functions, installation configurations, and specifications. Use this section to get a quick overview of what the 941X is all about, and how you can use it to your best advantage. Rev. D 1 -- Introduction Page 1 Introduction T HE NORTHSTAR 941X combines 12-channel GPS navigation with Differential GPS capability, a high-definition display, loran compati- bility, built-in tide data up to the year 2010, and many other navigation features. For the ultimate in GPS accuracy, the 941X may be purchased as the 941XD, featuring an internal DGPS (Differential GPS) receiver. This advanced system gives you even greater accuracy by accepting Differential GPS signal "corrections" from shore-based transmitters (called "beacons"), and using them to display position fixes as accurate as 2-5 meters. You can also connect your 941X to any external source of DGPS corrections meeting the SC-104 standard (such as the Northstar 8800 DGPS Sensor). Upon First Start-up When you turn your 941X on for the very first time, you may be greeted with a flashing exclamation point symbol in the lower right portion of the GPS POSITION screen, and the word ACQUIRE or SKY SEARCH in the status box at the top. The flashing exclamation point simply means that an alarm message is present and waiting for your acknowledgment. To see the message, press the STAR key once. The ALARMS AND BACKLIGHT screen will be displayed. Page 2 1 -- Introduction Rev. D The alarm message NO GPS POSITION FIX, along with its time and date, are shown in the RECENT ALARMS box. The word NEW in the upper right corner of the box indicates that this is a previously unacknowledged message. This sequence is a normal part of powering-up the 941X for the first time, as it notifies you that it is in the process of acquiring satellite information necessary for navigation. It normally takes only two to five minutes to acquire this data, after which the 941X is ready to navigate. (This alarm condition usually occurs in units shipped to customers located more than several hundred miles from the Northstar factory, and only the first time the 941X is turned on after being installed.) Press the CLEAR ALARM menu key to the right of the display screen to acknowledge and clear the message. Press the POSITION key below the left of the screen to return to the main GPS POSITION screen. The 941X is now ready to navigate. (For more on alarms, see page 68. If you wish to proceed directly to navigating with the 941X, skip to page 22.) Using This Manual Your 941X was designed to be an easy-to-use, full-function GPS navigator, understandable in the information it displays and dependable in its performance. This Reference Manual is intended to complement that ease of use by illustrating and describing the 941X's various functions in a format helpful to quick learning and safe operation. The sections in this manual are grouped by related functions, beginning with an overview of basic control panel layout and function commands, and gradually progressing to more advanced waypoint and route navigation operations. Sample screen images are used throughout to help illustrate what the 941X display screen looks like for the function being described. The "helpful hand" (pictured at left) is a convenient shortcut that leads you directly to step-by-step instructions. You can also use it as a quickreference for locating less-frequently-used operations. " Rev. D 1 -- Introduction Page 3 Features Upon using the 941X, you'll see that you can actually learn to operate the system's various features without constant referral to this manual. After you've read through it once, you won't have to refer to it very often again. Since the 941X anticipates your most frequent requests for navigation information, accessing most functions requires only one or two button pushes. By minimizing the attention needed to navigate, you can now devote more time to other aspects of your trip. GPS features · accurate, worldwide position data in any weather, 24 hours a day · optional internal DGPS (Differential GPS) Beacon Receiver for accuracy as good as 2-5 meters · fast signal acquisition · fast-reacting, accurate speed and course navigation features · lat/lon display · built-in plotter shows: 1) your position relative to nearby waypoints; 2) your recent track line; 3) your intended course line; and 4) avoidance areas, all against a latitude/longitude grid. · tide prediction software integrated with navigation display (at any NOAA tide station; for today or any other date.) waypoints and routes · stores up to 1,000 waypoints and 500 routes · displays waypoints: 1) in alphabetical order 2) in order of distance from your present position 3) saved with the SAVE button 4) stored as avoidance points · plots position of: 1) nearby waypoints 2) routes 3) avoidance areas Page 4 1 -- Introduction Rev. D Functions Five keys on the 941X instantly select the most commonly used functions, as described below: POSITION displays position coordinates as 1) GPS lat/lon coordinates 2) loran TDs, if you have a loran receiver interfaced to the unit 3) or calculated "Phantom Loran" TDs if you don't. Speed- and Course-Over-Ground, and Time and Date are also displayed. An alternate position screen plots your position graphically, along with any nearby waypoints and your track history. STEER shows how to steer precisely along a course line to your current waypoint. It also displays your Cross Track Error, Estimated time to waypoint, Estimated Time of Arrival, Course Over Ground, Speed Over Ground, Speed of Advance, etc. ( ) (The STAR key) displays alarm conditions and tide information, and accesses setup functions for customizing the operation and displays of your 941X, including screen brightness. WAYPTS/ROUTES lets you enter or access waypoints and routes for navigation. NAV LOG displays the progress of your current navigation plan (today's trip) and lets you modify it. In addition to these function keys, the SAVE/MOB key instantly saves your position as a waypoint, and provides a Man Overboard function for returning to the saved point. Five MENU KEYS on the right edge of the display are used to select between specific choices displayed on the screen. Comparing GPS and Loran The nation's GPS system has received much publicity, often described as providing the ultimate in navigation accuracy for all applications. Its major advantage over all other commercially-available navigation systems, including loran, is its all-weather, worldwide availability and absolute accuracy. (Absolute accuracy refers to the ability of a navigation device to determine your actual latitude and longitude coordinates on the surface of the earth, as compared to position information determined Rev. D 1 -- Introduction Page 5 from a chart or other reference. Repeatable accuracy refers to the ability to return to a position whose coordinates you have previously recorded with the same equipment.) Developed by the United States Department of Defense (DOD) the GPS system of 21 active satellites (with 3 additional spares) literally encircles the earth with navigation information. GPS is offered in two forms: for military users and for civil users. selective availability With GPS available to virtually anyone around the world, the DOD wanted to avoid the possibility that its precision could be used by hostile forces as a source of accurate targeting data against U.S. interests. To guard against such actions, they introduced intentional errors into the GPS signals that only U.S. forces could bypass. Called Selective AvailAvail ability (or SA), it involves a complex formula of data encryption that can be turned on or off without the end-user ever knowing for sure whether it is in effect or not. DOD's stated position is that SA will remain in effect indefinitely. GPS and DGPS Selective Availability effectively reduces GPS's absolute and repeatable accuracy from 30 meters (roughly 100 feet) 95% of the time, to 100 meters (330 feet) 95% of the time. This means that, with SA, you can expect to be within 300 feet of your intended position 95% of the time, and beyond that area approximately 5% of the time. At first, this was accepted by most end-users as an inevitable part of GPS, a tradeoff against its global availability. But it didn't meet the Coast Guard's requirement of 820 meter accuracy for navigating harbors. It was then that a system of differential corrections was developed by the Coast Guard that enabled them to effectively circumvent SA's built-in errors. These differential corrections are generated by fixed "reference stations" and broadcast by marine radiobeacons over a relatively limited area-- usually a maximum broadcast radius of 250 miles--to Differentialcapable GPS (DGPS) receivers. The precise geographic location of the reference station is used to calculate corrections based on the GPS data received from the satellites, and the corrections are then broadcast to DGPS receivers. The receivers then convert this data into extremely precise position, heading and speed information. (Referred to as Page 6 1 -- Introduction Rev. D "beacons," the transmitters are being situated at various locations along the U.S. coastline and Great Lakes, most of which are former marine radiobeacon sites.) With DGPS, navigators are guaranteed position accuracy on the order of 2-5 meters 50% of the time, and to 10 meters 95% of the time (usually, much better). Lat/lon positions displayed to thousandths of minutes (roughly 6 feet) are common with DGPS. When using a radar or electronic plotter, DGPS corrections improve the steadiness of your displayed plot line dramatically. In addition to accurate positioning information, DGPS provides critical "integrity monitoring" of the received GPS signals, enabling the user to be notified in seconds (as opposed to hours, with uncorrected GPS) that an anomaly has been detected in a transmitted satellite signal. The integrity monitor instructs the DGPS receiver not to use data from the satellite in question. loran Loran, on the other hand, can still outperform non-differential GPS-- when SA is in effect--in repeatable accuracy. Though susceptible to weather and characterized by a relatively limited range (when compared to GPS), it's a dependable system familiar to thousands of boat owners. Since the 1970's, LORAN users have relied upon that system's ability to repeatedly get them back to a previously-saved location with extreme accuracy. Fishermen especially appreciated this capability because each subsequent visit to a lobster trap or buoy was virtually "on the mark," saving them valuable time and money. Loran's repeatable accuracy was superior to anything else commercially-available at the time. In very good coverage areas, loran can typically get you to within 50 feet (or roughly 14 meters) of your previously-visited target. On the other hand, at its very best, uncorrected GPS with SA enabled will get you to within 300 feet (100 meters) of your intended destination. Obviously, uncorrected GPS--with variations of up to 300 feet in displayed position--wouldn't be much help in getting you through a narrow channel. Since most loran chains were configured for optimum coastline navigation, it's easy to see why loran's repeatable accuracy has served harbormasters and fishermen well for the last 25 years. Rev. D 1 -- Introduction Page 7 Loran, however, isn't as proficient as GPS in absolute accuracy, or visiting a spot for the first time. Since it transmits at a relatively low frequency (100 kiloHertz--similar to that on your AM radio), your ability to get an accurate position "fix" is directly related to: 1) your distance from the loran transmitters, and 2) the weather between you and the transmitters. It's in these two areas that GPS consistently excels when it comes to absolute accuracy. Even with SA, GPS provides an absolute accuracy of around 300 feet nearly everywhere in the world, under virtually any conditions. With a "constellation" of satellites orbiting the earth and transmitting their position data on an extremely high frequency (1.575 GigaHertz, or 1.5 billion cycles per second), GPS is impervious to weather and your location on the surface of the earth. You can receive position fixes at any time, anywhere, in any weather. This far surpasses the absolute accuracy that is achievable from a good loran receiver in a strong signal coverage area, in favorable weather conditions: usually 600 feet. If you are accustomed to using your Northstar loran's repeatable accuracy to return to within a boat length of a lobster trap or a buoy, time after time, you will not necessarily see this same performance with uncorrected GPS--you could be as much as 600 feet from your expected position. This will be especially apparent when using the 941X's plotter screen (without DGPS), where you may see your boat's plotted position appear to wander around within an area up to 600 feet in diameter (see Figure 1 below). Position circle of 300-foot radius, showing possible 600-foot error between fixes. ACTUAL 40°00.000 N 72°00.000 W 300' 300' You could be anywhere within the circle, 95% of the time. Figure 1--Max. Position Variances with Uncorrected GPS Page 8 1 -- Introduction Rev. D getting more If you need a higher level of accuracy than what basic GPS provides, accuracy there are two choices available to you: 1. Use Differential GPS by installing a Northstar internal differential beacon receiver (or use an externally-located Northstar differential beacon receiver), or other source of differential corrections for your 941X. DGPS should provide better than 10-meter accuracy (repeatable and absolute) 95% of the time. See "Using GPS" on page 25 for more information. 2. Interface your loran receiver to your 941X (provided the loran has the appropriate NMEA 0183 format output capability). You will then keep the "repeatable accuracy" of your loran, and add all of the navigation features of the 941X, including the excellent worldwide "absolute accuracy" of GPS. Refer to Table 2 on page 114 for connector pin wiring guide. Mounting The 941X is designed to be yoke- or flush-mounted on your boat. The unit is waterproof and can be exposed directly to the weather. The GPS antenna should be mounted fairly low on the vessel to minimize the effects of pitch and roll, and where it has a clear view of the entire sky. The Beacon Receiver antenna (if installed) should be mounted fairly high, like a loran antenna. Refer to "Mounting the 941X," on page 100, for details. Special Functions loran TDs The following functions are unique to the 941X; you may want to read about them in detail before using them. The 941X automatically converts GPS coordinates to loran TDs for those who have lists of fishing spots and other waypoints recorded as TDs. This feature is called Phantom LoranTM. You can display your position as TDs or enter waypoints as TDs. The accuracy to be expected from this conversion is generally better than 500 to 1500 feet. You can also interface your existing loran receiver to the 941X and then display and navigate with Rev. D 1 -- Introduction Page 9 real-time loran TDs. These features greatly ease the transition from using loran to using GPS. See page 30 for further details on using loran TDs. plotter functions The 941X's plotter provides a picture of your position, and of what is around you. Nearby waypoints, avoidance areas, and a lat/lon grid may be displayed along with an image of your boat. When you are using the plotter, the five menu keys below the display screen allow you to perform the following functions: 1) restart the desired track line to run directly from your position to the waypoint, "zeroing" the cross-track error display 2) change the options available for the plotter 3) center the image of the boat on the screen 4) zoom in to show more detail 5) zoom out to show more area See page 22 for more information on using the plotter. TideTrackTM TideTrack displays a 24-hour tide graph for any of over 3,000 NOAA tide stations covering the entire U.S. coast, including Alaska and Hawaii, as well as much of the western Canadian coastline. Tides may be shown for today or any other day you choose. See page 71 for more information on using TideTrack. The Display Screen The Liquid Crystal Display (LCD) and all controls are lighted for nighttime use. The display is easily readable under all conditions, from full sunlight to total darkness. Anti-reflection treatment of the display and its window eliminates over 90% of the reflection and glare. Important data can be displayed using large numbers which can be seen from a distance. To adjust the brightness, press the STAR key ( ) and use the BRIGHT and DIM menu keys to set the desired illumination. Contrast is controlled by the ARROW key to the left of the screen. cleaning the screen Use caution when cleaning the plastic window in front of the display screen. Although it is resistant to scratches, it can be damaged if you wipe dirt off with a dry cloth. Always use a damp cloth when wiping the window. Use a small amount of window cleaner or alcohol to dissolve Page 10 1 -- Introduction Rev. D any oil or grease on the screen. Whenever possible, avoid touching the window with your fingers, as natural oils from your hand will temporarily degrade the characteristics of the window and cause your fingerprints to appear as bright reflections. These will disappear when the screen is cleaned as described above. CLEANING HINT Pre-packaged moist towellettes (especially those containing a small amount of alcohol) are excellent for cleaning the display window. You might wish to keep a supply on hand to wipe off fingerprints and other smudges. Interfacing Capability The 941X contains two independent output ports for driving NMEAcompatible devices, two input ports for accepting data from other NMEA devices, and an auxiliary port reserved for future use. It also features an RS-232 port for input or output of SC-104 DGPS corrections, and waypoint/route or software program loading from a PC. The 941X can be interfaced to a wide variety of devices, including autopilots, plotters, radars, etc. Refer to "Interfacing the 941X," beginning on page 112, for more information. Rev. D 1 -- Introduction Page 11 Page 12 1 -- Introduction Rev. D 2 Using the Controls POWER Key CONTRAST Key SAVE/MOB Key Function Keys Menu Keys Cursor Keys Keypad Special Display Windows 14 14 15 16 17 17 17 18 HIS SECTION describes each of the Northstar 941X's controls. Use this section for learning what each control does and for an overview of using its various functions. T Rev. D 2 -- Using the Controls Page 13 T POWER Key HE MAJOR FUNCTIONS of each of the 941X's controls are described in this section. Press the POWER switch briefly to turn on the 941X. The unit displays a special startup screen that includes an owner-identification message which you may customize to aid in theft-prevention. Next, the 941X displays the results of the internal self-tests that are automatically run each time the unit is turned on. Finally, navigation data is displayed. If any of the six major components of the 941X fails the self-test, the notification SYSTEM TEST: FAILED will remain on the screen until you acknowledge it with the press of any function key (located below the display screen). Return the 941X to the factory for service. To turn the 941X off, press the POWER switch and hold it in for at least one full second until the unit turns off. CONTRAST Key Liquid Crystal Display (LCD) screens require a contrast adjustment to compensate for different viewing angles, temperature conditions, etc. The 941X's contrast control allows you to adjust its display screen to give the best picture for your current conditions. Pressing the upper contrast arrow darkens the screen, and pressing the lower arrow lightens it. Adjust the screen for the best contrast as seen from your normal operating location. Page 14 2 -- Using the Controls Rev. D SAVE/MOB Key The SAVE/MOB key is used to save your current position as a waypoint. It does this in either of two ways, depending on whether you press the key briefly, or press and hold it. saving a waypoint Press the SAVE/MOB button briefly to simply store your position. This new waypoint will automatically be given a name, such as ­S002­, where the letter S indicates a saved waypoint, and the 3-digit number increases by one every time you save a waypoint. The waypoint's 3-digit number will "wrap around," or revert, to ­S001­ when the 941X has reached the limit you set using the MAX SAVED WPT # function under DISPLAY OPTIONS (see page 80). Man Overboard feature Press and hold the SAVE/MOB button for three seconds to enter "Man Overboard" (MOB) mode. The 941X saves your position and displays it in the plotter screen as an "X." The plotter screen is locked on the display, showing your position and the MOB location. The MOB location immediately becomes your current waypoint, with new bearing and distance information displayed on the right-hand side of the screen. INVOKING MOB WHILE USING AN AUTOPILOT Some autopilots will attempt to steer your boat according to any bearing changes output by the 941X, regardless of the severity of the change. Others automatically disengage when a severe or abrupt turn is required. Please refer to your autopilot manual for information regarding this procedure. Rev. D 2 -- Using the Controls Page 15 To leave MOB mode and return to normal navigation, press SAVE/MOB for at least three seconds. Function Keys The five function keys located below the display screen control what the 941X is doing. Any function key may be pressed at any time to display the information you need to see. POSITION key The POSITION key displays your position coordinates, or displays a plotter screen to show your position graphically, relative to nearby waypoints and your track history. Course-Over-Ground and Speed-OverGround are displayed at the bottom of the screens. "Where am I? Position coordinates may be shown as any of the following: 1) Lat/lon from GPS 2) Lat/lon from an external loran receiver 3) loran TDs from an external loran receiver 4) Phantom Loran TDs which the 941X calculates from its GPS coordinates STEER key The STEER key shows how to steer to a waypoint you have designated. A picture of your position relative to the course line is displayed, along with all the numeric information you need to steer directly to your waypoint. Two versions of the steer display are available. Press STEER once to see "How do I get to my waypoint?" the version you were last using. Press it again to see the other version. STAR key The STAR key ( ) has several functions. The first press displays any alarms and messages the 941X has waiting for you. The second press displays information about tides for your choice of over 3000 NOAA tide stations. The third press displays the time of day, and the time of today's sunrise and sunset. The fourth press displays a menu of setup and customization functions used whenever you wish to change the way the 941X works for you. WAYPTS and ROUTES key "Where do I want to go?" The WAYPTS/ROUTES key allows you to enter waypoints and routes, access a library of waypoints and routes that you have entered previously, or specify where you want to navigate to. See Sections 4 and 5 for waypoint and route information. Page 16 2 -- Using the Controls Rev. D NAV LOG key The NAV LOG key displays the waypoints you have passed, and allows you to change those ahead of you. See "What NAV LOG Does," on page 64, for more information. "How am I doing?" Menu Keys The five round MENU keys on the right side of the display screen are used for different purposes depending on what function is currently being used or displayed. The function of each key is labeled on the screen, and pressing the key performs the displayed function. Cursor Keys A large cursor pad in the upper right corner of the 941X allows you to move the flashing cursor on the display screen to the data you want to display or change. For example, when entering data (such as a waypoint's name or coordinates) press the down arrow to move the cursor downwards to a particular field of data and press the right arrow key to move the cursor to a particular character in that field. Keypad entering numbers The 12-button alphanumeric keypad is used for entering numbers, letters or special characters for waypoint coordinates, names, etc. When the 941X is expecting you to enter numbers only, such as for waypoint coordinates, the keypad keys enter one digit, 0-9, with each keypress. The flashing cursor moves automatically to the next digit position. For entries such as latitude and longitude--where the digits must be entered into specific character positions--the cursor starts on the left side of the field and characters are entered left to right into their correct positions. For other numeric entries such as distances--where a number of variable length may be entered--the digits are entered calculator-style from the Rev. D 2 -- Using the Controls Page 17 right side of the field. If you make a mistake, you can press CLEAR to clear the entire number and re-enter it, or you can press the left-arrow cursor key to reenter particular digits, one at a time. entering letters When the 941X is expecting letters to be entered, such as waypoint names and descriptions, the operation is slightly different. Each key is labeled with three letters (or other special characters) and a digit. For example, the upper left key is labeled with the letters A, B, C and the digit 1. Pressing the key one time displays the letter A. Press the key again to display the second letter, B. Pressing a third and fourth time displays the letter C and the digit 1, respectively. A fifth press brings you back to the letter A again. " CLEAR and ENTER keys To enter a character, first find the key containing the character, and press that key one to four times to display the desired character. Finally, move the cursor to the next character position by pressing the right arrow symbol on the cursor key. The keypad also contains CLEAR and ENTER keys for erasing or entering data that has been typed on the keypad. Pressing the ENTER key is always the last step when entering or changing data, or acknowledging an action. The CLEAR key removes any data you typed before you press ENTER, and sets the field to all blanks or restores it to its value before you changed it. Special Display Windows Occasionally, the 941X needs to inform you of something or ask permission to do something. When this happens, a special information or question window appears on the display. The window contains an exclamation point ("!"), an "INFO" label, or a large question mark ("?"), ! and a message for you to read. alarm messages Alarm messages contain information you should read right away. Alarms are communicated by the flashing exclamation symbol in the bottomright portion of the display. Press the STAR key once to show the alarm condition on the ALARMS & BACKLIGHT screen. Press the CLEAR ALARM menu key to acknowledge and clear the message. Page 18 2 -- Using the Controls Rev. D information Information windows are displayed while you are entering data or using windows control functions. They give you extra details pertaining to what is about to happen, or let you acknowledge a command. Information windows always appear with the word "INFO" in a small box. question windows Question windows appear when the 941X needs to know more about what you want to do. A question mark will always appear in this type of window. You must respond to any question window by pressing ENTER to answer "YES," or CLEAR to answer "NO." All other keys, including the function keys, are inactive when a question window is displayed. Rev. D 2 -- Using the Controls Page 19 Page 20 2 -- Using the Controls Rev. D 3 Basic Navigation Displaying Position, Heading & Speed Position Plotter Using GPS Using Loran Using Phantom Loran 22 22 25 30 32 T HIS SECTION describes the most basic--yet important--navigation function available in the Northstar 941X: determining your position. Position coordinates may be determined from the GPS satellite system, or you may display loran coordinates if you have connected a loran receiver. For those who no longer have a loran receiver, but wish to view their position in loran TDs, the 941X can convert GPS coordinates into Phantom Loran coordinates. Rev. D 3 -- Basic Navigation Page 21 Displaying Position, Heading & Speed T O DISPLAY the coordinates of your current position, simply press the button marked POSITION. A screen is displayed showing your position coordinates at the top, and your Course-Over-Ground (COG) and Speed-Over-Ground (SOG) at the bottom. (If you see the PLOT screen displayed instead of your position coordinates, just press the POSITION button again). GPS position coordinates are displayed as latitude and longitude. You may choose to display loran coordinates instead, as described below. (Loran coordinates may be obtained from a loran receiver connected to the 941X, or may be calculated by the 941X from the GPS position coordinates.) Position Plotter The position plotter screen is a "north-up" display, and provides an overall view of the surrounding area and all nearby waypoints. Press the POSITION key to show your position plotted relative to your current route (if any), your track history, and any nearby waypoints and avoidance points. A maximum of 30 local waypoints can be displayed on the plotter screen at one time. Page 22 3 -- Basic Navigation Rev. D The image of your boat displayed on the screen points in the direction of your Course-Over-Ground. Remember, this direction may be different from your heading. The boat image shows your actual direction of travel over the bottom, not the direction your boat is headed. If your boat is not moving, the Course-Over-Ground cannot be determined by the 941X, and the direction of the boat on the screen has no meaning. Avoidance areas (waypoints for which a warning radius has been specified) are shown as a circle surrounding the waypoint. Your present Speed-Over-Ground (SOG) and Course-Over-Ground (COG) are displayed at the bottom of the screen, along with the chart scale. The chart scale is the distance from the top edge to the bottom edge of the plot. NOTE: The plotter screen can be used to steer by when the objective is simply to get to the waypoint without needing to remain precisely on the designated course line. zooming Press the ZOOM IN menu key to zoom in for a closer look at the area in the center of the screen. Press the ZOOM OUT menu key to zoom out to see more area. Each press of the IN or OUT key approximately halves or doubles the chart scale, respectively. The maximum zoom-in screen displays an area that is approximately ¼mile from the top edge to the bottom, while maximum zoom-out shows you an area that is up to 128 miles, top to bottom. centering the plot course restart Press the CENTER menu key at any time to move the plotted area so that your boat is at the center of the screen. If you wander off your intended course line, and you want to navigate directly to the waypoint rather than returning to the original course line, press the RESTART menu key, then ENTER. A new course line will be computed and displayed, running from your present position to the next waypoint. Rev. D 3 -- Basic Navigation Page 23 plotter options To set up the parameters for the display of data on the plotter screen, press the OPTIONS menu key. The following screen is displayed: The plotter control menu allows you to change the following items: · The plotter scale at and above which waypoint names will not be displayed on the plotter screen · Whether local waypoints are displayed on the screen · How often your position is recorded on the screen · Whether your track history is displayed on the screen · Whether a lat/lon grid is displayed on the screen To change any one of these, use the up and down cursor keys to move the arrow to the item you want to change, and press the EDIT menu key. This will cause a large cursor to flash on the field, indicating you should use the up and down cursor keys to select the option you want. Press ENTER when done, or CLEAR to restore the field to its original value. The 941X can store up to 900 points in its track, so the maximum length of the track depends on how often points are stored. You may choose to store track points every second, with a maximum length of 15 minutes, or every two minutes for a maximum length of 30 hours, or a number of settings in between. " Page 24 3 -- Basic Navigation Rev. D You may also choose to freeze the track, so that no more points will be stored and the track will remain unchanged. Pressing the CLEAR TRACK menu key clears the track history displayed on the screen. Press the RETURN menu key to go back to the plotter screen. Using GPS Your 941X contains an internal GPS receiver which is used as the primary source of position data. GPS data is displayed directly on the GPS POSITION screen. lat/lon The GPS position screen displays your latitude and longitude in large coordinates digits near the top of the screen. If GPS data is not available, dashes are displayed in place of the numbers. You can display lat/lon as either degrees, minutes and seconds, or as degrees, minutes and thousandths of minutes. See "Display Options," on page 78, to select one or the other. time of day The time of day and today's day and date (obtained from the GPS satellites) are displayed at the bottom of the screen. speed and course Near the bottom of the screen, your Speed-Over-Ground and CourseOver-Ground are displayed in large digits. Rev. D 3 -- Basic Navigation Page 25 NOTE The 941X's speed and course readings are the result of instantaneous measurements derived from satellite signals. GPS speed is updated every second. However, you may average these readings by changing the "GPS speed averaging" value (see page 87). datum In the center of the screen, the name of the datum currently in use is displayed. The datum describes the reference of the chart you are currently using (the reference datum used is indicated on each chart). Applying the datum corrects for any position differences between your chart and the GPS coordinate system. See "Geodetic Datum," on page 94, for more information on selecting the datum for your area. NOTE When using differential GPS (DGPS) as your navigation source, your position, as displayed by the 941X, may actually exceed the accuracy of some charts. status summary At the top center of the position screen is a brief status summary of the GPS receiver. The following table shows the various status messages the 941X may display, along with their meanings. Message ACQUIRE SKY SEARCH TRACKING 2D NAV 3D NAV POOR FIX COMM FAIL Meaning trying to acquire satellites searching for satellites with no previous information satellites have been acquired; almost ready to navigate navigating with 3 satellites in 2-D mode navigating with 4 or more satellites in 3-D mode tracking satellites with poor geometry/accuracy communication link to GPS sensor has failed--unit needs repair Using DGPS In the upper right corner of the GPS POSITION screen is an indicator that shows whether Differential GPS (DGPS) corrections are in use. If your installation includes an optional Northstar internal differential GPS receiver, or other external source of differential corrections, navigational accuracy will be significantly improved when this indicator is present. Page 26 3 -- Basic Navigation Rev. D For further information on operating in DGPS mode, refer to "Internal Differential Beacon Receiver," on page 74. With DGPS active, you will often see position measurements accurate to about 2-5 meters, speed measurements accurate to about 0.1 knot, and Course-Over-Ground measurements accurate to about 0.5 degree. DGPS corrections remove the errors caused by Selective Availability (SA) and the atmosphere, and provide an accuracy exceeding that obtained by military users of the GPS system. If the DGPS indicator is displayed, you have this higher level of accuracy. For the POSITION and STEERING screens, the DGPS indicator is a large letter "D." For the plotter screen, the DGPS indicator is the symbol DGPS. satellite status To display more information about signals received from the GPS satellites, press the SATS menu key on the GPS position screen. A screen is displayed showing the received Signal-to-Noise Ratio for each satellite, and a map indicating where the satellites are currently located in the sky (the 12-channel GPS SATS screen is shown on the next page). Satellites are identified by their PRN number, a two-digit number assigned by the U.S. government. The center of the satellite map represents the center of the sky, and the outer (or last) ring is the horizon. The view is looking down from above, with East to your right and West to your left. Rev. D 3 -- Basic Navigation Page 27 NOTE On five-channel 941Xs, the last bar at the bottom of the screen will sometimes "jump" around once per second as the 941X receiver sequences among other satellites. The following GPS data is also displayed: ACCURACY: ACCURACY The estimated accuracy of the GPS system to be expected at the current time. Your position readings should be more accurate than this estimate 95% of the time. HDOP: HDOP This is a technical measure of the "quality" of your fix. HDOP (Horizontal Dilution of Precision) can range from an ideal value of 1, up to 10 or more. Any value less than 2 indicates excellent performance. HDOP is calculated from the satellites' current positions, and is not based on actual received signals. You will usually see an HDOP value displayed immediately after the unit is turned on, and before it is ready to navigate. Press the RETURN menu key to return to the previous screen. DGPS status To display more information about DGPS corrections that are being received, press the DGPS menu key on the GPS position screen. A screen is displayed showing the DGPS beacon transmitter currently in use. The upper part of the screen shows the beacon's name and position, the frequency of the transmitter, and the baud rate of the transmitted data. Page 28 3 -- Basic Navigation Rev. D The lower part of the screen shows three bar graphs: 1. SNR The Signal to Noise Ratio (SNR) is a good overall measure of overall signal quality, and should be as high as possible. Values of 15 and higher are preferred, while anything below 10 could indicate poor reception. 2. SIGNAL The actual strength of the received signal--should be as high as possible. Varies with distance from beacon transmitter. 3. NOISE Noise level measures the "static" caused by lightning and other atmospheric effects, and should be low for best results. See "DGPS antenna mounting" on page 112, for further details. NOISE LEVEL VALUE 200 or less 1,000 ­ 3,000 5,000 ­ 10,000 MEANING excellent typical at night thunderstorm At the bottom of the screen a summary of DGPS operation is displayed. You may see one of the following messages: Rev. D 3 -- Basic Navigation Page 29 MESSAGE OLD CORRECTIONS NOT INSTALLED UNHEALTHY BEACON UNHEALTHY SATS ACQUIRING SATS DGPS IN USE/ OK MEANING No DGPS corrections have been received within the DGPS DATA TIMEOUT limit set in RECEIVER OPTIONS (default is 1 minute), and the navigator has returned to nondifferential operation. See "GPS data timeout" on page 89 for details. A beacon receiver is not installed. The beacon transmitter reports it has problems. Data received from satellites cannot be relied upon. 1) The GPS receiver cannot operate in DGPS mode until it has received ephemeris data from the satellites; or 2) the receiver does not have a GPS fix yet. DGPS corrections are being received and used. DGPS signal quality information for the 941X is available from the optional internal beacon receiver, or from an optional external Northstar beacon receiver. Other brands of beacon receivers may supply DGPS corrections but omit the additional signal information shown on the 941X's screen. Press the RETURN menu key to return to the previous screen. Using Loran If you have a loran receiver connected to your 941X, you can navigate using loran coordinates as well as GPS. Just select loran as the source of navigation data, as described below, and you're on your way. selecting loran To display loran TD coordinates from a loran receiver interfaced to the 941X, first select loran as the navigation source, as described below. " 1. Press the STAR key until the USER CUSTOMIZATION screen is displayed. 2. Press the NAVIGATION OPTIONS menu key. The NAVIGATION SOURCE line will be designated by the cursor arrow. 3. Press the EDIT menu key. The cursor will begin flashing. Page 30 3 -- Basic Navigation Rev. D 4. Press the up and down cursor arrow keys to display EXTERNAL LRN as the position source. If you change your mind, press CLEAR to restore the original setting; otherwise, press ENTER, then the RETURN menu key. loran TDs The loran display screen looks like this: Press the L/L TDS menu key several times to select either the particular pair of TDs you wish to use, or the loran-derived latitude/longitude. NOTE In order to display loran position coordinates on the 941X from an externally-connected loran receiver, the loran must support the standard NMEA 0183 "RMA" output data sentence structure. Without this output capability, the 941X will not receive position data from the loran. For best results, connect a Northstar 800 series loran to the 941X, using the 800's "PRINTER 3" output format. See "connecting to a Northstar 800 series loran" on page 123. loran GRI The four-digit loran Group Repetition Interval (GRI) is changed using the SET GRI menu key on the LORAN POSITION screen. You must set this to correctly match the GRI being used by your loran receiver for the 941X to accurately convert the loran's TDs to latitude/longitude position fixes. loran warnings Loran warning indicators obtained from any Northstar 800 series loran receiver are displayed to the right of each TD. These are: Rev. D 3 -- Basic Navigation Page 31 INDICATOR SNR BLNK CYC LOCK MEANING Signal-to-Noise Ratio is low--use caution Coast Guard is transmitting a blink signal indicating a probable transmitter problem the receiver has detected a possible cycle slip the receiver has locked onto the loran track point. This is not a warning indicator but an indication of normal performance. Note: These indicators are available only from Northstar 800 lorans. The "L/L" indicator to the left of a TD designates it as one of the two TDs that the loran receiver has chosen to use to calculate latitude and longitude. The "F/L" indicator to the left of a TD indicates that it has been forced by the user to be used to calculate lat/lon. loran info To check the quality of signals being received by your loran, press the LORAN INFO menu key from the LORAN POSITION screen. The Signal-to-Noise Ratio for each loran transmitting station is displayed graphically. Press RETURN to go back to the loran position screen. checking GPS status To temporarily display GPS coordinates and signal status, press the CHECK GPS menu key. The unit continues to navigate using loran, and will display loran data the next time you return to the position screen. returning to GPS navigation To return to GPS signals for navigation, repeat the steps shown above for selecting loran, except specify GPS instead of loran. Using Phantom Loran The 941X's Phantom Loran feature is designed for those users who have compiled lists of fishing spots or other locations as loran TDs, and are now using the 941X as a GPS-only navigator. The 941X will mathematically convert GPS lat/lon coordinates to loran TDs, enabling you to display your position as TDs. Phantom Loran operation The 941X may be used to simulate full operation of a loran receiver. Position coordinates may be displayed as TDs, and all navigation functions may be used as if the unit were actually receiving loran signals. Remem Page 32 3 -- Basic Navigation Rev. D ber, however, that these calculated TDs will not match exactly the positions of previously recorded TD coordinates obtained directly from actual loran signals. In most areas, errors should not exceed 0.2 microsecond. However, larger errors are possible in areas for which the 941X does not contain accurate, factory-programmed ASF correction points. selecting Phantom Loran To display Phantom Loran TDs as position coordinates, first select Phantom Loran as the position source, as described below. 1. Press the STAR key until the USER CUSTOMIZATION screen is displayed. 2. Press the NAVIGATION OPTIONS menu key. THE NAVIGATION SOURCE line will be designated. 3. Press the EDIT menu key. 4. Press the up or down arrow keys to display PHANTOM LRN as the position source. 5. Press ENTER, then the RETURN menu key. 6. To view your position in Phantom Loran coordinates, press POSITION. " Phantom Loran TDs The Phantom Loran display screen looks like this: Rev. D 3 -- Basic Navigation Page 33 choosing L/L or TDs Phantom Loran GRI Press the L/L TDS menu key several times to select the particular pair of TDs you wish to use or to display GPS latitude/longitude. Press the SET GRI menu key to change the GRI to be used in calculating the displayed TDs. Press the up and down cursor keys to display the available GRIs one at a time. When the GRI is correct, press ENTER. checking GPS status checking DGPS status Press the SAT INFO menu key to check on the received GPS satellite status, as described on page 27. Press the DGPS INFO menu button to display the current status of the beacon receiver, including SNR, SIGNAL and NOISE values (as previously described on page 29). Press RETURN when you wish to go back to the PHANTOM LORAN position screen. displayed in the upper right corner of DGPS The large letter corrections the display indicates differential GPS corrections are being received and used to improve the accuracy of the received data. returning to GPS To return to GPS signals for navigation, repeat the steps shown above for navigation selecting loran, except specify GPS instead of Phantom Loran. See "Navigating to Waypoints," beginning on page 55, to learn how to navigate to loran, Phantom loran, or GPS coordinates. Page 34 3 -- Basic Navigation Rev. D 4 Creating Waypoints and Routes Entering Data Creating Waypoints Avoidance Areas Waypoint Lists Coordinate Options Updating Waypoint Coordinates Editing Waypoints Transferring Waypoints to a PC Creating Routes Saving a Route Changing a Route 36 37 39 41 42 42 43 44 44 47 50 In this section, we'll learn how to create waypoints, use them to form routes, and change them as necessary. Rev. D 4 -- Creating Waypoints and Routes Page 35 Entering Data Before we move on to the sections describing how to enter waypoints and routes into the 941X's memory, let's take a break and review the methods for entering data into the unit. Some screens, such as coordinate entry screens, allow entry of numbers only. Others, such as waypoint names, allow entry of letters, digits and punctuation characters. A typical entry screen will have several items of data displayed. First, choose the item you wish to change by pressing the up or down cursor arrow key to move the flashing cursor to that item. The flashing cursor indicates which character position will be written into. Use the left and right cursor arrows to move the flashing cursor to the next character you want to enter. Use the up and down arrows to move to the next line you want to enter. When the entire screen is correct, press the ENTER key. The 941X will accept the full screen of data and store it in memory. " entering numbers To enter numbers, simply press the digits of the keypad. The flashing cursor automatically moves to the next character. You can use the arrow keys to "back up" and correct any mistakes you might have made. entering letters Many items, such as waypoint names, accept letters as well as numbers. Each key of the keypad is labeled with up to four characters. Find the key with the desired character, and press that key one or more times to display the character. When the character has been selected, use the right arrow cursor key to move the cursor to the next character position. Press ENTER when all the characters are correct. Here are some of the things you can do with waypoints using your 941X: 1. Navigate to a point in one step (a "quick start" waypoint) 2. Enter waypoints into the 941X's memory for later use 3. Navigate to these waypoints Page 36 4 -- Creating Waypoints and Routes Rev. D 4. String these waypoints together to form routes 5. Follow these routes 6. Edit or erase waypoints or routes 7. Plot waypoints or routes 8. Transfer waypoints and routes from the 941X to a personal computer, and back again. Creating Waypoints To enter waypoints, press the WAYPTS/ROUTES key. Press the WAYPT LIST menu key and then the ADD menu key. A screen similar to the following is displayed: To store a waypoint permanently in the 941X's memory, first assign it a name. The name can be from 1 to 6 characters long, and it must differ by at least one character from any other waypoint name in the unit's memory. Enter the desired waypoint name. If you wish, you may also enter up to 16 characters of descriptive information for the waypoint on the line below the name (the description is optional). If the name you chose is already in use in the unit's memory, a message is displayed, indicating you cannot use that name. You can either erase the old waypoint, if it is no longer needed, or choose a different name for the new waypoint. The name of the new waypoint need only be different from the existing waypoint by one character in order to be accepted as a valid name. Rev. D 4 -- Creating Waypoints and Routes Page 37 waypoint coordinates Waypoint coordinates can be entered as lat/lon coordinates, loran TDs, or as distance and bearing from your present location or from any waypoint in the 941X's memory. To change the coordinate type from what is currently displayed, press the COORD TYPE menu key until you see the option you want. Enter the waypoint coordinates as previously described on page 36. If you make a mistake, press CLR to erase any characters from the line and start over; otherwise, press ENTER when the screen is correct. If you are entering coordinates as distance and bearing, the 941X normally asks for these coordinates relative to your current position, known as "­HERE­." " To select an entirely different location from which distance and bearing are to be measured, such as an existing waypoint, press the FROM menu key. A waypoint list is displayed. You can press the NEXT LIST or COORD OPTION menu keys to help select the waypoint. Use the up and down cursor arrow keys to point to the desired waypoint. Press the ENTER key to designate this waypoint and return to the previous screen. If you wish instead to use your present position as the reference point, press the FROM `HERE' menu key on the `FROM' POSITION screen. Page 38 4 -- Creating Waypoints and Routes Rev. D avoidance area If this new waypoint is to be used as the center of an avoidance area, enter the warning radius at the bottom of the screen in the WARN RADIUS box. If no radius is entered, the point will be treated as a regular waypoint, and not as an avoidance area. Avoidance Areas You may designate new or existing waypoints as avoidance areas. Avoidance areas are depicted on the PLOT screen as waypoints with circles around them. In addition, an alarm will be given both as an audio beep and a flashing exclamation point on the screen, if you should enter and avoidance area. The 941X will display each avoidance area as a circle the size of the warning radius you entered. For new waypoints, enter a distance in the WARN RADIUS box at the bottom of the NEW WAYPT screen. For existing waypoints, use the EDIT WAYPOINT function to access the waypoint coordinate screen, then enter the warning radius. Be sure to include a little extra distance around the hazard so that you will have time to respond by turning or stopping after you hear the alarm. Rev. D 4 -- Creating Waypoints and Routes Page 39 As a precaution, once you have designated a waypoint as an avoidance area, the 941X does not allow you to navigate to it. avoidance area alarm Once you have designated a waypoint as an avoidance area, the 941X will alert you upon penetration of that area. To set the audible avoidance area alert feature: 1. Press the STAR key once to display the ALARMS & BACKLIGHT screen. 2. Be sure that the cursor arrow is in front of the ALARM AUDIO option. 3. Press the EDIT ALARM menu key. 4. Use the up/down cursor keys to toggle the setting ON or OFF. 5. Press ENTER to make your selection, or CLEAR to leave it unchanged. (NOTE: If you do not want to be notified of any other navigational alarms, set the ANCHOR DRAG, CROSS TRACK, ARRIVE RADIUS, and DGPS alarms to OFF. The audible alert will now only beep when you enter an avoidance area.)