INo, GPS, and Integrated INU-GPS

Transcription

1 INU, GPS, and Integrated INU-GPS Navigation INo, GPS, and Integrated INU-GPS Navigation 19.1 NAVIGATIONAL SYSTEM OVERVIEW Five independent navigational selections for the pilot's and copilot's steering functions are provided. The normal navigational selections are GPS, INUl, INUl/GPS, INU2, and INU2/GPS. If a pilot selects INU3 as the attitude and navigational source using the external auxiliary selector, then INU3 replaces INUI or INU2 as a selectable navigational source. The fundamental difference between the INU solutions and the INU/GPS solutions following loss of GPS information (INUI- - -) is that the INU outputs in the INU/- - - solution are corrected with the Kalman Filter estimated INU "real time" drift errors computed while GPS data was available, resulting in a more accurate navigational solution than the INU alone would provide. The navigational sources being used for the pilot's and copilot's steering are indicated on the Pilot and Copilot Lateral Steering Pages as shown in Figure 82. Toggles navigational for pilot steering: INU1/GPS INU2/GPS INU1 INU2 GPS source :INU1/GPS CMD GS: 18:: pilot str CID DTK 025 BRG/DIST TTG ETA 02/ :05:38 021" Pressing the STR key accesses the last-viewed Steering Page; laterally and/ or vertically scroll if necessary to access the Pilot or Copilot Lateral Steering Page BRT o XTK +[ R15.0nm DA:L1.2 Similar selections available for copilot steering on Copilot Steering page Figure 82 Pilot Lateral Steering and Steer Select Pages CPN: , Rev A 117

2 INU, GPS, and Integrated INU-GPS Navigation 19.2 POSITION, TRACK, AND AIR DATA DISPLAYS The steering selections determine the sources of the data for the Pilot and Copilot Position Pages shown in Figure 83. The air data shown on these pages comes from the central air data computers CADCl or CADC2. The baroset input sets the local barometric pressure for VNAV enroute, terminal, and approach guidance. The wind vector can be displayed as a current wind vector, crosswind component, or head/tail wind component. Navigation source selected on Pilot/Copilot Lateral Steer Pages Pressing the PSN key accesses the last-viewed Position Page; laterally scroll if necessary to access the Pilot or Copilot Position Page Track displays true or mag track, depending on external true/mag switch position Toggle to display WIND, HEADWIND or TAILWIND (depending on wind condition), or crosswind ("XWIND"); enter wind manually if CADC fails N4OO.432 W INU1/GPS pilot psn TRK 118 VAR W22.4 WIND GS SAT TAS :24T/ C 293 BAROSET[29.71]:i -[ ] Computed at present mag var position Toggle between inches and millibars with empty scratchpad; displays selected baroset on the "designated pilot's" barometric altimeter Figure 83 Pilot Position Page 118 CPN: , Rev A

3 INU, GPS, and Integrated INU-GPS Navigation Table 5 Display of Navigation Mode on Position Pages Selected Mode Displayed Mode Conditions for Display INU1/GPS INUl/GPS INU1 and GPS.are being used in the INU1/GPS integrated solution INU1/GPS INU1/GPS INU1/ /--- GPS is not being incorporated into the INUl/GPS integrated solution INU1 navigation data is invalid GPS NU2 MODEL U1 GPS INU1 NU2/GPS INU2/GPS INU2/GPS INU2/GPS ---/A/H GPS/-/H GPS/-/- GPS/A/H ---2/--- INU2/ INU1 MODEL. ---/-/- INU2 and GPS are being used in the INU2/GPS integrated solution GPS is not being incorporated solution INU2 navigation data is invalid into the INU2/GPS integrated INU1 navigation INU1 navigation INU2 navigation INU2 navigation data is valid data is invalid data is valid data is invalid GPS navigation data is smoothed with airspeed and heading GPS navigation data is being smoothed with GPS ground speed and heading data GPS is not being smoothed with airspeed and heading data GPS is invalid; FMS is dead reckoning with airspeed and heading data GPS is invalid The model aircraft function is providing the navigation solution. (This function is available only while on the ground.) CPN: , Rev A 119

4 FMS-BOO Software User's Manual /NU, GPS, and Integrated /NU-GPS Navigation 19.3 NAVIGATIONAL SOURCE DATA DISPLAYS Each navigational source (whether selected for pilot/copilot steering or not) has its own Integrated Navigation (INAV) Page to display its current position and navigational status (see Figure 84), not dependent on whether that source is being used as either pilot's steering selection. Table 5 provides a summary of the possible navigation sources that are available and the current status of each source INUl/GPS and INU2/GPS Displays The INUl/GPS and INU2/GPS INAV Pages show the computed present position of those integrated navigation solutions, along with a "95% error" figure of merit for the probable system accuracy given the currentinu alignment and GPSsatellite navigational quality (see Figure 85). This page also shows the difference between its navigational position and that of the "designated pilot's" selected steering solution (if it is a different source). If, due to a grossly mis - aligned INU or other anomalous condition, the position shown is incorrect when compared with the known aircraft position (greater than loonm), the "INAV RESET" line select key may be used to zero the Kalman Filter error estimates and re-start its process. This action requires confirmation. "INAV RESET" will not degrade normal navigational accuracy, but it will eliminate the benefit of the INU error estimates if GPS data should become unavailable before they can be re-estimated (usually about half an hour after resetting). If GPS data becomes unavailable en route, the previously-computed INU corrections will continue to be applied to this navigational solution, so it will be more accurate than the uncorrected INU solution. However, to enable the crew to manually update the solution if necessary, the "UPDATE" line select key becomes available and may be used as described in Section Manually remove GPS inputs to an INU/GPS solution by toggling the "GPS" line select key to "OUT". To enable the inputs once again, toggle to "USE". Pressing the lnav key accesses the last-viewed INAV Page; laterally scroll if necessary to access the desired solution page Scrolls laterally among INAV Pages.. - lnul inav - IiIJr8 - GPS Secondary GPS.. inav = Figure 84 Navigation Source INAV Page Selection 120 CPN: , Rev A

5 FMS Software User's Manual INU, GPS, and Integrated INU-GPS Navigation INU1/GPS present position 95% probable position error Difference from "designated pilot's" source Resets Kalman Filter estimation of INU errors to zero N W lnu1/gps inav 95%ERR 0.07 DIFF lnu1/gps INAV -[ RESET Toggles between GPS USE or OUT in KALMAN filter Selects the INU1/GPS Update Page. This selection appears and is available only when GPS data is unavailable, see Section Figure 85 INU/GPS Integrated Navigation Page INUI,INU2 and INU3 Displays The INUI and INU2 and INU3 INAV Pages show the present position from the respective INUs, along with the alignment circular error probable (CEP) (see Figure 86). The current alignment mode is also displayed. The "DIFF" readout shows the difference between the INU position and the "designated pilot's" selected steering solution (if it is a different source). These pages also provide access to the individual INU control page functions of the Carousel IV INUs, as shown in Figure 86. Each INU's Control Page may only be accessed from the CDU which directly interfaces with that INU; i.e., INUI may only be controlled via CDUl, INU2 may only be controlled via CDU2, and INU3 may only be controlled via CDU3. Once a control page has been accessed for an INU, the procedures for initializing, controlling and displaying data for that INU is as described in the Carousel IV operational procedures. The "DTK-STS" selection is provided to access the INU status codes and enter modes and code data into the INU. Normal entries from the INU operator's guide are provided. To enable Triple Mix operations, enter "4" and press "INSERT". Caution: Triple Mix is a reversionary navigation state that should be used only when GPS data is unavailable. Use of a Triple Mix INU solution with the GPS integrated solutions can cause unpredictable behavior in the integrated solution. DO NOT use Triple Mix modes with the INU/GPS solutions. To disable Triple Mix operations, enter "5" and press "INSERT". The "POSITION" selection is provided for entering alignment present position. As a reminder to enter the present position, the annunciation line will display INUx PP (where x = 1, 2, or 3). After selecting the position function, the alignment position is entered, first a latitude, followed by "INSERT", then a longitude, followed by "INSERT". After the INU Mode Select Unit has transitioned to alignment, the current alignment state can be monitored by selecting "DTK-STS". The "TEST" and AUTO/MAN selections are provided to initiate INU tests and verify proper behavior of the Inertial system. When on the DTK-STS selection, TEST is used to review each of the INU status codes. The "WAY PT" selection is used to review the pure inertial data prior to disabling Triple Mix operation. To review pure inertial data, press "HOLD", then select the WAY PT toggle selection. Note: True waypoints are entered into the FMS flight plan, not on the INU waypoint list. The "HDG-DA" selection is used to review the current INU heading and drift angle. CPN: , Rev A 121

6 /NU, GPS, and Integrated INU-GPS Navigation The "HOLD" selection is used to hold the present position and review the data for updating the INU. Caution: The FMS-800 allows manual updates of the INU per the INU operator's manual procedures. Manually updating an INU with this procedure can cause adverse effects to the Kalman filter models of the FMS-800 and temporarily degrade the Kalman filtered navigation solution. The TESTIHOLD and TEST buttons can be used together to review INU Fault History. See the INU operator's guide for further instructions. The Remote and Hold selections are used to enable gimbal testing of the INU in accordance with INU TOs. Present INU1 position N42O.432 W lnul inav Difference from "designated source pilot's" DIFF lnu1/gps ----nm Selects the INU1 Update Page, see section :DTK-STS lnul control - INSRT/ADV HOLD=ON N W - TEST AUTO: Indicates status of INU and enables mode when selected. BRT o -TEST/HOLD REMOTE=OFF Figure 86 INU Integrated Navigation and Control Pages 122 CPN: , Rev A

7 FMS-BOO Software User's Manual INU, GPS, and Integrated INU-GPS Navigation GPS Display The GPS INAV Page shows the present position output from the GPS receiver, along with a "95% error" figure of merit for the probable system accuracy, given the current GPS satellite navigational quality (satellite tracking state and geometry) as shown in Figure 87. If "GPS/A/H" is indicated on the title line, the FMS-800 is using airspeed and heading sensor inputs to smooth the GPS data. This is required to have a valid bank (roll) command output to the flight director and autopilot. The "MODE" indicates the current GPS receiver tracking/aiding mode: "INIT", "TEST", "NAVIINU", or "NAVIPVI\'. If in the "NAVIINU" mode, the GPS satellite tracking performance is enhanced over the "NAV/PV/\' mode in the presence of jamming and while maneuvering. The "STATE" indicates the lowest tracking state 01 the four primary satellite tracking channels: "STATE 1" is acquisition, "STATE 3" is code track only (in jamming) and "STATE 5" is code and carrier lock (no jamming). The number of satellites being tracked for primary navigational purposes is also indicated; the normal "fully determined" number is 4. Less than 4 may result in GPS data invalidity. Access the GPS Satellite Data Page to view information on the satellites currently being tracked by the GPS receiver, including satellite vehicle number, signal quality, and state. Present GPS position 95% probable position error Current GPS tracking/aiding mode GPS receiver state BRT o N42' W093"3 GPS/A/H inav 95%ERR 0.2 run MODE NAV /INU DIFF lnu1/gps O.02run STATE 5 -[ 4 SATfr Selects GPS RAIM Page Difference from "designated pilot's" source Number of GPS satellites tracked Figure 87 GPS Integrated Navigation Page CPN: , Rev A 123

8 INU, GPS, and Integrated INU-GPS Navigation 19.4 INU AND INTEGRATED NAVIGATIONAL POSITION UPDATES To update the INUs or the INU-GPS navigational solutions when GP$ data is unavailable, select the "UPDATE" line select key on the respective INAV Page (see Figure 88) to access the Update Page. Then select the type of update desired using the left line select key second from the top as shown. Tne three types of updates are as follows: 1. MANUAL. Updates present position (on line 1) to displayed checkpoint ("PT") position on line TACAN. Updates present position to the manually entered bearing/slant range position. 3. INUI/GPS, INU2/GPS, INUI, INU2, or GPS (whichever is currently selected as the "designated pilot's" steering solution). Updates present position to the displayed navigation solution position. The Update Page can be accessed from: INU1 INAV Page INU2 INAV Page INU3 INAV Page INU1/--- Page (GPS data unavailable) INU2/- - - Page (GPS data unavailable) Present INU1 position Freezes displayed position and difference for update verification prior to acceptance Selects type of position update: 1. MANUAL (overfly) 2. TACAN 3. "Designated pilot's" steering solution BRT o N4OO.432 W tinult update :MANUAL FREEZE* UPDATE DIFF O.82nm PT[N41029 W0125J ACCEPT -[ REJECT The INU1 Update Page with "MANUAL:' selected as the update type is shown here as an example; other examples are shown in Figures 89 through 91. Figure 88 Performing Navigational Position Updates 124 CPN: , Rev A

9 /NU, GPS, and Integrated INU-GPS Navigation MANUAL Overfly Updates To perform a manual overfly update, (1) toggle the left line select key second from the top to "MANUAe' on the Update Page. The "PT" coordinates automatically default to the current active waypoint in the flight plan. (2) If another checkpoint is desired, enter the coordinates, identifier, or identifierlbearingldistance checkpoint as the "PT", as shown in Figure 89. To return to the active waypoint default, enter a "-" at the "PT" line select key. (3) Freeze the display to review the displayed update difference ("DIFF") for reasonableness by pressing the "FREEZE" line select key. (4) Press the "ACCEPT" line select key to accept the updated position difference correction or the "REJECT" line select key to reject it. rn Select "MANUAt.:' for overfly updates []J Insert the checkpoint position (defaults to active waypoint) [ZJ Enter desired checkpoint in the scratch pad BRT o N4OO.432 W t INUl t update :MANUAL FREEZ UPDATE DIFF 30.5nm PT[N W093 30] -[N42 Freeze the position and update difference N W tinult update :MANUAL FREEZE UPDATE DIFF 0.82nm PT [N42 00 W093 34] ACCEPT -[ REJECT ffij Check the difference display for reasonableness lid...or reject the update Figure 89 Manual Overfly Position Update CPN: , Rev A 125

10 /NU, GPS, and Integrated /NU-GPS Navigation TACAN Updates TACAN updates provide the ability to update position using radial bearing and slant range data from TACAN or VORJDME equipment. Given the radial bearing and slant range from the TACAN or VOR/DME and the location of the Navaid station from the ICAO identifier data base, the FMS can compute the present position of the aircraft. This computed position can be used to update the selected navigational solution displayed on the Update Page. To perform a TACAN update, the TACAN radio to be used should first be tuned using an ICAO station identifier correct. and the station should be verified to be On the Update Page (Figure 90), (1) Toggle the left line select key second from the top to "TACAN". (2) Enter the TACAN bearing/slant range FROM the indicated station as read from the HSI or TACAN bearing indicator. (3) "FREEZE" the position and update difference ("DIFF") displays, and verify reasonableness. (4) "ACCEPT" or "REJECT" the difference for update of the selected navigational solution. -[ ORL/325/49.2 Bearing/slant tlnu1/---t N4OO.432 BRG/RNG update lzj [ORL/325/49.2] FREEZE W (JJ DATE DIFF O.82nm range FROM the TACAN station Figure 90 Update Page with TACAN as the Update Source Updates to "Designated Pilot" Solution Position To update the navigational solution to that of the current "designated pilot's" steering solution (see Figure 91), (1) toggle the left line select key second from the top to show the current solution; (2) "FREEZE" the position and update difference ("DIFF") displays; (3) verify the reasonableness of the difference displayed; (4) "ACCEPT" correction. or "REJECT" the difference Note that if GPS data is not available and the pilot desires to update all remaining valid navigational solutions (INU1, INU2, INU3, INUlI---, and INU2/- - -) to the same position, the optimum procedure is to first update the selected "designated pilot" steering solution using a MANUAL, or TACAN update, then update the others individually to that solution. Then, all will be exactly the same immediately thereafter. 126 CPN: , Rev A

11 /NU, GPS, and Integrated INU-GPS Navigation,., PDATE INU1/---t DIFF O.82nm -[ ] N4OO.432 PSN :INU1/GPS N41029 update FREEZ W W "Designated pilot's" solution present position Figure 91 Update Page with "Designated Pilot" as the Update Source CPN: , Rev A 127

12 /NU, GPS, and Integrated INU-GPS Navigation 19.5 ACTIVE GPS AND AIDING CONFIGURATION The crew may control which of the two available GPS receivers is used for active navigation calculations and Kalman filter INU corrections, through the navigation configuration (NAV CONFIG) page, access as shown in Figure 92. t [ index 1 GPS NAV CONFIG I-l 1 1 t"'-i SA/AS LOCK/ZERO DATA ""-1 LOADER TIMERS POWER TEST "4-1 ' --1 START ] 1-' ' 1--" 1-'" I- l BP.T o [2.0]XTK ALERT SPD[15] n3.v <::onfig [120] WPT ALERT PILOT designated ACTIVE: GPSl BANK[25]O :INU1 [ GPSAID ADC2: ] Figure 92 Navigation Configuration Page Access and Usage Normally, GPSI should be selected as the Active GPS. Whichever one is selected, the other one will be automatically used as a monitor of the active GPS. If the difference in positions between the two GPS solutions exceeds the integrity limit for the current phase of flight, a "COMPARE GPS" annunciation will be given. If GPSI fails, GPS2 may be selected as the active one. Also on the NAV CONFIG page, the crew may select the INU to be used for velocity aiding of the GPS receivers, and the air data source to be used for altitude aiding. Normally these should be set to INUI and ADCl respectively. 128 CPN: , Rev A USAF C-S Version

13 FMS-BOO Software User's Manual INU, GPS, and Integrated INU-GPS Navigation --' GPS SATELLITE DATAAND RECEIVER state -of- health and orbital geometry, the FMS -800 AUTONOMOUS INTEGRITY is capable of determining when the GPS navigation MONITORING (RAIM) solution is degraded or suspect due to satellite failures. If the GPS receiver is unable to provide a The FMS-800 provides the crew access to pages displaying the individual channel/satellite tracking RAIM solution due to satellite tracking problems or status for each GPS receiver and the RAIM problems with the satellite constellation geometry, a NO RAIM annunciation and external RAIM alert will control/predictive RAIM for the active GPS receiver. These pages are accessed by selecting the related line be provided to inform the crew of the absence of key on the GPS INAV page as shown in Figure 93. RAIM protection. During a NO RAIM period, the GPS navigation solution may be acceptable but the To request the availability of approach RAIM at a integrity of that solution will be indeterminate. destination airport, first enter the identifier of the During normal GPS navigation with an active RAIM airport in the top line of the RAIMIPREDICfION solution, if the GPS receiver determines that there is page. Then enter the expected time of arrival (ETA) an inconsistency in the GPS navigation solution, a in UTe. After performing the prediction calculation, RAIM WARN annunciation and external RAIM alert the FMS-800 will display the availability of approach will be provided to inform the crew of a degraded GPS RAIM on the page information line. This availability navigation solution. When a RAIM WARN is applies to a period from 15 minutes prior to the entered ETA until 15 minutes after the ETA. provided, the crew should immediately select a non-gps based navigation solution on the Lateral The FMS-800 provides an active RAIM solution at Steer page (see Figure 82) until the integrity of the present position. By tracking GPS satellite GPS navigation solution is restored..- SATS PS/A/H MODE NAV/lNU inav -[ 5- RAIM - N4P SATS 4 ] W l - -I , ,---II-I satellite [CID data RAIM/prediction ] APPR RAIM [ 1"'-1I- I C/N [1212]ETA 1P AVAILl\BLE 2C2P 1P UTC 1P STATE 5D 3D BRT ---I f -I D RAIM:ON ls 3I ] ] 1'4-1 RTN "'-1 I-I + CPN: , Rev A Figure 93 GPS Satellite Data and RAIM Pages 129

14 FMS-BOO Software User's Manual INU, GPS, and Integrated INU-GPS Navigation This page intentionally left blank. 130 CPN: , Rev A USAF C-S Version