A kind of inertial navigation based on gravity peak and the double calibration methods of gravity measurementTechnical field
The invention belongs to inertia/gravity autonomous navigation system technical field, it is related to inertial navigation error and gravity measurement missesDifference while calibration method, the double calibration methods of especially a kind of inertial navigation and gravity measurement based on " gravity peak ".
Background technique
Inertia/gravity autonomous navigation technology is an important development direction of contemporary autonomous navigation technology, it independent ofSatellite navigation system (GNSS), has many advantages, such as height independence, concealment, anti-interference and high-precision.Inertial navigationFor system since its own inherent characteristic has the shortcomings that navigation error dissipates at any time, long-time navigation accuracy is low, at present long boatWhen high-precision navigation based on the navigation of inertia/combinations of satellites, but GPS is vulnerable to interference, and in fields such as far-reaching seasIt closes application to be limited, lacks the effective passive means for obtaining high accuracy positioning information calibration inertial navigation system.Inertia/gravity is certainlyPrinciple navigation system by High Accuracy Inertial Navigation System, gravity measurement equipment, high-precision gravity Abnormal Map (abbreviation gravity map) and itsIts aiding sensors composition obtains high accuracy positioning information using gravity map information and gravity real-time measured information, corrects inertiaNavigation accumulated error realizes long endurance high-precision independent navigation, will be obviously improved the height of far-reaching extra large military activity and economic activityPrecision navigation information supportability.
Currently, inertia/gravity autonomous navigation technology is totally in theoretical research and research of technique stage, highly effective is obtainedGravity real-time measurement error drift inhibits skill when taking the technology and submerged applications of gravitational field location information calibration inertial navigation systemArt is the key technology that inertia/gravity autonomous navigation technology moves towards engineer application.Gravitational field location information calibration inertia is obtained to leadThe method of boat system realizes that process is complicated, and reliability and engineering realizability are poor, while real-time without effective subaqueous gravityDrift error calibration method is measured, therefore the invention proposes a kind of high reliablity, operation is simple and engineering practicability is good" gravity peak " characteristic area utilize gravity Feature information realization inertia/gravity autonomous navigation system inertial navigation and gravityThe method that measurement error is calibrated simultaneously.
Summary of the invention
Reasonable, easy to operate, reliable performance one kind is designed based on " gravity peak " the purpose of the present invention is to provide a kind ofInertial navigation and the double calibration methods of gravity measurement, improve long endurance inertial navigation and gravity measurement precision level.
The present invention solves its realistic problem and adopts the following technical solutions to achieve:
A kind of inertia/gravity autonomous navigation system inertial navigation and the double calibration methods of gravity measurement error, including following stepIt is rapid:
Step 1 chooses " gravity peak " characteristic area according to gravitational field Background information, and extracts gravity field distribution in regionKey feature information；
Step 2 designs ship trajectory and implements measurement during sailing, searches for and determines gravity anomaly peak point, completes inertial navigationLocation error and gravity measurement error are just calibrated；
Step 3, the essence calibration to inertial navigation and gravity measurement error and effect self-evaluating.
Moreover, the specific steps of the step 1 include:
(1) gravity peak region is chosen: in inertial navigation set resetting cycle within the scope of accessibility sea area, according to sea areaGravitational field characteristic distributions, choosing gravitational field, there are peak values, are similar to the region on mountain peak；
(2) location information and gravity anomaly information of gravity anomaly peak point O, longitude are read from the regional gravity mapBe denoted as Lo, latitude value is denoted as La, GRAVITY ANOMALIES is denoted as Gra；
(3) it according to gravity map information, searches for and determines optimal direction n and its vertical line direction m.
Moreover, the specific steps of the step 2 include:
(1) carrier " gravity peak " region selected by navigation entrance under inertial navigation information guidance, by navigating along default trackRow, and synchronous acquisition inertial navigation information and gravity anomaly metrical information, find identification region gravity anomaly peak point O；
(2) calculated gravity anomaly measurement error: GraErr1=Gra-Grao3.Gravity measurement is exported in real time in original outputGraErr1 is compensated, gravity measurement error is completed and just calibrates.
(3) inertial navigation longitude error: LoErr1=Lo-Lo3, latitude error LaErr1=La-La3 is calculated.Inertia is ledThe output of boat longitude compensates LoErr1 in original output, and the output of inertial navigation latitude compensates LaErr1 in original output, completes inertiaNavigation position output error is just calibrated.
Moreover, the specific steps of the step 3 include:
(1) the inertia/gravity autonomous navigation system just calibrated for completing inertial navigation with gravity measurement error repeats to walkRapid 2 full content completes the essence calibration of inertial navigation and gravity measurement error；
(2) the gravity anomaly measurement error value obtained twice in step 2 and step 3 and inertial navigation longitude and latitude are calculated separatelyThe difference of error amount is realized while being calibrated as the reference frame of evaluation inertial navigation and gravity measurement error calibration accuracy simultaneouslyThe self-evaluating of effect.
Moreover, the specific steps of (3) step of the step 1 include:
1. enabling the angle θ successively change from 0 ° to 180 ° (not including 180 °) with a fixed step size, the corresponding line segment in each angle θE, the midpoint line segment E is O point, along the angular direction θ；
2. line segment E corresponding for each angle θ is enabled d successively be changed with a fixed step size from 0 to ± N and obtains the flat of line segment ELine section group { Ei } obtains gravity anomaly on the line segment from gravity map interpolation for each line segment Ei, records weight on line segment EiDistance zi of the power anomaly peak corresponding position apart from line segment midpoint Oi can be, but not limited to all using parallel segment group { Ei }The sum of absolute value of zi of line segment is that ∑ ︱ zi ︳ deviates in line segment as the gravity anomaly peak value of the parallel segment group { Ei } of line segment EThe quantizating index of point degree；
3. choosing gravity anomaly peak value in the parallel segment group { Ei } of corresponding line segment E for all angles θ and deviateing line segment midpointThe smallest direction determines that the corresponding angle θ when ∑ ︱ zi ︳ value minimum, the angle the θ direction corresponding line segment E are optimal direction n, sideIt is rotated by 90 ° to obtain its vertical direction vector m counterclockwise to vector n.
Moreover, the specific steps of (1) step of the step 2 include:
1. determining track N1:N1 along the direction vector n, the inertial navigation latitude and longitude coordinates value of midpoint O1 is respectively Lo, La；Wherein, N1 length is 4 times or more of inertial navigation system position precision；
2. carrier navigates by water under inertial navigation information guidance along track N1, synchronous to enroll the track each point inertial navigation positionValue and gravity anomaly measured value read the inertial navigation latitude and longitude coordinates value on track N1 at gravity anomaly measurement peak point O2,It is denoted as Lo2, La2；As limited by gravity measurement resolution ratio, gravity anomaly measures peak value corresponding not a point but one section,Then taking this section of intermediate point is O2 point；
3. determining track N2:N2 along the direction vector m, midpoint is O2 point；Length determines the same N1 of principle；
4. carrier navigates by water under inertial navigation information guidance along track N2, synchronous to enroll the track each point inertial navigation positionValue and gravity anomaly measured value, read inertial navigation latitude and longitude coordinates value at the upper gravity anomaly measurement peak point O3 of track N2 withGravity anomaly measured value, is denoted as Lo3, La3 and Grao3；O3 point is considered as regional gravity anomaly peak point O, then point O3 is really passed throughLatitude value takes Lo, La, and GRAVITY ANOMALIES takes Gra.
The advantages of the present invention:
1, the present invention is based on using " gravity peak " distribution character of gravitational field, the high-resolution characteristic of gravity real-time measurementThe accurate gravity Feature information grasped in advance, proposes a kind of inertial navigation applied to inertia/gravity autonomous navigation systemThe method that location error and gravity real-time measurement error are calibrated simultaneously can correct inertial navigation position diverging error and gravity simultaneouslyReal-time measurement drift error solves INS errors accumulated divergence and the drift of gravity sensor measurement error at any timeThe problem of, the long endurance independent navigation precision of inertia/gravity autonomous navigation system and gravity real-time accuracy are improved, is met deepThe demand that the long endurance of off-lying sea operation or job platform is independently navigated in high precision with the measurement of accurate gravity field information.
2, the present invention applies gravity Feature information and non-area whole gravity field information, core demand are at gravity peak valueHigh-precision gravity exception information and location information, it is few to overall information demand, therefore building high-precision gravity will be substantially reducedThe task amount of figure is conducive to Project Realization.
3, the present invention utilize gravimetric high resolution identification gravity anomaly peak position, realize inertial navigation error withIt is calibrated while gravity measurement error, precision is high, calculation amount is few, easy to operate, it is easy to accomplish, while passing through step 2, step 3Iterative search gravity anomaly peak position realize calibration accuracy self-evaluating, it is ensured that reliable performance.
Detailed description of the invention
Fig. 1 is " gravity peak " distribution characteristics schematic three dimensional views of the invention；
Fig. 2 is Regional Gravity Field isopleth shown in Fig. 1 of the invention and line segment E, Ei schematic diagram；
Fig. 3 is step-length of the invention when being 15 °, and each angle θ corresponds to the schematic diagram of line segment E；
Fig. 4 is that each angle θ of the invention corresponds to each line segment Ei gravity anomaly peak value in the parallel segment group of line segment E and deviates whereinThe relational graph of point distance and d (at a distance from Ei to E)；
Fig. 5 is track N1, N2 schematic diagram of the invention；
Gravity anomaly experiment curv when Fig. 6 is the navigation of the invention along track N1.
Specific embodiment
The embodiment of the present invention is described in further detail below in conjunction with attached drawing:
It is adopted simultaneously based on domestic and international high-precision inertial navigation technology current situation using low drifting high-precision inertance elementThe inertial navigation system of systematic error modulation measure is taken, resetting cycle is up to 10 a couple of days, it is assumed that inertial navigation system resetting cycleInterior positioning accuracy is N nautical miles, illustrates the inertia/gravity autonomous navigation system inertial navigation and gravity that invention proposes as exampleThe double calibration methods of measurement error.
The double calibration methods of inertial navigation and gravity measurement of the one kind based on " gravity peak ", comprising the following steps:
Step 1 chooses " gravity peak " characteristic area according to gravitational field Background information, and extracts gravity field distribution in regionKey feature information.
The specific steps of the step 1 include:
(1) " gravity peak " region is chosen: in inertial navigation set resetting cycle within the scope of accessibility sea area, according to seaDomain gravitational field characteristic distributions, choose it is as shown in Figure 1 there are peak values, be similar to the region on mountain peak；The regional characteristics is to exist and onlyThere are a gravity anomaly peak point O, when extending from peak point O to all directions around, with the increase of distance O point distance, weightThe decline of power exceptional value.
(2) location information and gravity anomaly information of gravity anomaly peak point O, longitude are read from the regional gravity mapBe denoted as Lo, latitude value is denoted as La, GRAVITY ANOMALIES is denoted as Gra.
(3) it according to gravity map information, searches for and determines optimal direction n and its vertical line direction m:
The isopleth of gravitational field shown in Fig. 1 such as Fig. 2, middle conductor E, midpoint is gravity anomaly peak point O, with east orientation angleIt is denoted as θ.It was O point and the straight line F perpendicular to line segment E；Line segment E is translated to the two sides line segment E along straight line F and is obtained line segment Ei, line segmentThe midpoint Ei is the intersection point of the line segment Yu straight line F, is denoted as Oi, and the distance of line segment Ei to line segment E are denoted as d and (specify any to EiSide translation distance is positive, then is negative to the other side).With segment positions information, the available line segment of interpolation is corresponding in gravity mapGravity anomaly；When line segment Ei is overlapped with E, gravity anomaly peak value be will appear at the O of line segment midpoint thereon；As line segment Ei is separateLine segment E, i.e., as ︱ d ︱ increases, the upper gravity anomaly peak value of Ei may be gradually deviated from line segment midpoint Oi；Based on above-mentioned setting and divideAnalysis, the specific steps of step 1 (3) step include:
1. enabling the angle θ successively change from 0 ° to 180 ° (not including 180 °) with a fixed step size, the corresponding line segment in each angle θE, the midpoint line segment E is O point, along the angular direction θ；
In the present embodiment, shown in Fig. 1 for region, line segment length takes 20 nautical miles, the angle θ step-length take 15 ° from 0 ° to180 ° (not including 180 °) successively change, and obtained each line segment E is as shown in Figure 3.
2. line segment E corresponding for each angle θ enables d successively change with a fixed step size (such as ± 0.1 nautical mile) from 0 to ± NThe parallel segment group { Ei } for obtaining line segment E obtains gravity anomaly on the line segment from gravity map interpolation for each line segment Ei,Distance zi of the gravity anomaly peak position apart from line segment midpoint Oi on line segment Ei is recorded, can be, but not limited to parallel using line segment EThe sum of absolute value of zi of line segment group { Ei } all line segments is parallel segment group { Ei } gravity anomaly peak of the ∑ ︱ zi ︱ as line segment EIt is worth the quantizating index that line segment midpoint degree is deviateed in position；
Every line segment gravity anomaly peak value deviates its line segment in the corresponding parallel segment group { Ei } of all line segment E shown in Fig. 3Midpoint distance and the relationship of the line segment to E distance d are shown in Fig. 4.
3. choosing gravity anomaly peak value in the parallel segment group { Ei } of corresponding line segment E for all angles θ and deviateing line segment midpointThe smallest direction determines the corresponding angle θ when ∑ ︱ zi ︱ value minimum, the direction which corresponds to line segment E is optimal direction n, sideIt is rotated by 90 ° to obtain its vertical direction vector m counterclockwise to vector n.
Gravity anomaly peak point on parallel segment group { Ei } is corresponded to when the angle θ is 90 ° in Fig. 4 deviates line segment midpoint minimum, it shouldDirection is n, and direction vector n is rotated by 90 ° to obtain direction vector m counterclockwise.
Step 2 designs ship trajectory and implements measurement during sailing, searches for and determines gravity anomaly peak point, completes inertial navigationLocation error and gravity measurement error are just calibrated.
The specific steps of the step 2 include:
(1) carrier inertial navigation information guidance under navigation enter selected by " gravity peak " region, by along default track N1,N2 navigation, as shown in figure 5, simultaneously synchronous acquisition inertial navigation information and gravity anomaly metrical information, it is different to find identification region gravityNormal peak point O.
The specific steps of (1) step of the step 2 include:
1. determining track N1:N1 along the direction vector n, the inertial navigation latitude and longitude coordinates value of midpoint O1 is respectively Lo, La,N1 length is generally 4 times or more of inertial navigation system position precision (N is in the sea), to guarantee that there are peak values for gravity anomaly on N1.
2. carrier navigates by water under inertial navigation information guidance along track N1, synchronous to enroll the track each point inertial navigation positionValue and gravity anomaly measured value, the upper gravity anomaly measured value of track N1 is as shown in fig. 6, abscissa is each point on track N1 in Fig. 6To the distance of track midpoint O1, ordinate is gravity abnormal measures.It reads on track N1 at gravity anomaly measurement peak point O2Inertial navigation latitude and longitude coordinates value, be denoted as Lo2, La2.As limited by gravity measurement resolution ratio, gravity anomaly measures peak value pairNot a point but one section answered, then taking this section of intermediate point is O2 point.
3. determining track N2:N2 along the direction vector m, midpoint is O2 point, and length determines the same N1 of principle.
4. carrier navigates by water under inertial navigation information guidance along track N2, synchronous to enroll the track each point inertial navigation positionValue and gravity anomaly measured value, read inertial navigation latitude and longitude coordinates value at the upper gravity anomaly measurement peak point O3 of track N2 withGravity anomaly measured value, is denoted as Lo3, La3 and Grao3.O3 point is considered as regional gravity anomaly peak point O, then point O3 is really passed throughLatitude value takes Lo, La, and GRAVITY ANOMALIES takes Gra.
(2) calculated gravity anomaly measurement error: GraErr1=Gra-Grao3.Gravity measurement is exported in real time in original outputGraErr1 is compensated, gravity measurement error is completed and just calibrates.
(3) inertial navigation longitude error: LoErr1=Lo-Lo3, latitude error LaErr1=La-La3 is calculated.Inertia is ledThe output of boat longitude compensates LoErr1 in original output, and the output of inertial navigation latitude compensates LaErr1 in original output, completes inertiaNavigation position output error is just calibrated.
Essence calibration and the effect self-evaluating of step 3, inertial navigation and gravity measurement error.
The specific steps of the step 3 include:
(1) the inertia/gravity autonomous navigation system just calibrated for completing inertial navigation with gravity measurement error repeats to walkRapid 2 full content completes the essence calibration of inertial navigation and gravity measurement error；
(2) the gravity anomaly measurement error value obtained twice in step 2 and step 3 and inertial navigation longitude and latitude are calculated separatelyThe difference of error amount realizes calibration effect as the reference frame of evaluation inertial navigation and gravity measurement error calibration accuracy simultaneouslySelf-evaluating.
The working principle of the invention is:
Inertial navigation system is since itself working principle determines its error accumulated divergence feature at any time, since gravity is surveyedQuantity sensor physical characteristic, high an order of magnitude of gravity real-time measurement its precision of resolution ratio or so, gravity measurement exist at any timeBetween drift error (drift error can be eliminated by post-processing, but real-time measurement cannot eliminate this error).The present invention mentionsA kind of inertia/gravity autonomous navigation system inertial navigation error and gravity measurement error based on " gravity peak " distribution characteristics outDouble calibration methods select gravitational field to have the sea area (referred to as " gravity peak ") of " mountain peak " feature according to gravitational field distribution situation.
Carrier enters the region under inertial navigation information guidance, and navigates by water according to the track of design, real-time using gravityThe high-resolution of measurement identifies the peak value of gravity anomaly experiment curv on ship trajectory, orthogonal at preset one group by completingThe measurement during sailing of track, search for simultaneously determine regional gravity anomaly peak point, obtain peak point at inertial navigation location information andGravity anomaly metrical information；From obtaining from the regional gravity anomaly peak point true location information and again in high-precision gravity figurePower exception information.Inertial navigation position and true location information, which compare, at gravity anomaly peak value obtains inertial navigation position mistakeDifference, to correct inertial navigation position output information；Gravity anomaly measured value and true gravity at gravity anomaly peak value is differentNormal information comparison obtains gravimetric error, measures real-time output information to correct gravity anomaly；To realize inertia/weightIt is calibrated while power autonomous navigation system inertial navigation position diverging error and gravity real-time measurement drift error.Promotion inertia/The long endurance high-precision independent navigation performance of gravity autonomous navigation system, meets the autonomous height of far-reaching Hainan Airlines row operation or job platformPrecision navigation needs.
It is emphasized that embodiment of the present invention be it is illustrative, without being restrictive, therefore the present invention includesIt is not limited to embodiment described in specific embodiment, it is all to be obtained according to the technique and scheme of the present invention by those skilled in the artOther embodiments, also belong to the scope of protection of the invention.