An aided navigation positioning method of fusing image and terrain data

Abstract

The application discloses an auxiliary navigation positioning method of fusing images and terrains. In the process of aircraft flight, based on flight control system parameters, combined with a digital terrain elevation database, through combination of a Sandia inertial terrain auxiliary navigation system (SITAN) and actually measured ground images, navigation positioning correction of an inertial navigation system (INS) is realized based on an image matching algorithm, and high-precision navigation positioning is provided for the aircraft.

Description

Technical Field

[0001] This invention relates to avionics system technology and data analysis technology, and in particular to an assisted navigation and positioning method that integrates image and terrain data. Background Technology

[0002] Terrain-Aided Navigation (TAN) and Vision-Based Navigation (VBN) are both navigation techniques that utilize terrain or image information to correct accumulated errors in the Inertial Navigation System (INS) when the Global Positioning System (GPS) signal is weak or absent. These assisted navigation techniques offer high accuracy in areas with distinct terrain features and are highly useful for tactical flights such as close air support, low-altitude attack, penetration, and interception.

[0003] The commonly used TAN technology is Sandia Inertial Terrain Assisted Navigation System (SITAN). VBN technology is based on image matching algorithms and combines digital terrain elevation databases to correct the navigation and positioning of INS, providing high-precision navigation and positioning for aircraft. Summary of the Invention

[0004] The purpose of this invention is to disclose an auxiliary navigation and positioning method that integrates image and terrain data. During aircraft flight, based on flight control system parameters and combined with a digital terrain elevation database, the method combines the Sandia Inertial Terrain Assisted Navigation System (SITAN) and an image matching algorithm to correct the navigation and positioning of the Inertial Navigation System (INS), thereby providing high-precision navigation and positioning for the aircraft.

[0005] To achieve the above objectives, the present invention provides an assisted navigation and positioning method that fuses image and terrain data, comprising the following steps: Step A: The flight control system generates barometric altitude data h. p and radar altitude data h r ; Step B, the flight control system will generate the barometric altitude data h. p Send to the inertial navigation system (INS); Step C, combining the barometric altitude data h sent by the flight control system p The inertial navigation system (INS) generates inertial barometric altitude data h. INS ; Step D: The inertial navigation system (INS) sends position data P(L', λ') to the digital terrain elevation database; Step E: Based on the location data P(L', λ') from step D, extract the corresponding digital terrain elevation data h from the digital terrain elevation database. DEM ; Step F: The flight control system, inertial navigation system (INS), and digital terrain elevation database respectively transmit radar altitude data h. r Inertial pressure altitude data h INS and digital terrain elevation data h DEM For data processing systems; Step G: The data processing system processes the data from step F and calculates and generates the actual height data h. T and predicted height data h T ’ Send it to the SITAN algorithm; Step H, the SITAN algorithm uses the actual height data h t Calculate position correction data θ SITAN And send a digital terrain elevation database; Step I, based on the position data P(L', λ') from step D and the position correction data θ from step H. SITAN The digital terrain elevation database extracts θ centered at location P(L', λ') and twice the elevation. SITAN A square reference image P with side length P SITAN ; Step J: The airborne image sensor measures the area below the aircraft. The measured ground image I of size is sent to the image matching module; Step K: The image matching module matches the ground-measured image I and the reference image P. SITAN Perform image matching to obtain the center of the matched image, i.e., the precise flight position P(L, λ), in the reference image P. SITAN Find an image I' of the same size as the measured ground image I and match it with the measured ground image I. The matching formula is as follows:

[0006] In the formula, This is the size of the measured ground image. As the baseline image size, , ; Step L: Repeat steps A through K to continuously obtain the aircraft's precise location.

[0007] Furthermore, in step A, the flight control system generates barometric altitude data h based on the barometric altimeter and radar altimeter, respectively.p and radar altitude data h r ; Furthermore, in step B, the flight control system will generate the barometric altitude data h. p Send to the inertial navigation system (INS); Furthermore, in step C, the inertial navigation system (INS) combines the barometric altitude data h sent by the flight control system. p Generate inertial barometric altitude data h INS ; Furthermore, in step D, the inertial navigation system INS sends the current aircraft position data P(L', λ') to the digital terrain elevation database; Furthermore, in step E, the digital terrain elevation database extracts the corresponding digital terrain elevation data h based on the position data P(L', λ') sent by the inertial navigation system INS. DEM ; Furthermore, in step F, the flight control system, the inertial navigation system (INS), and the digital terrain elevation database respectively transmit the radar altitude data h. r Inertial pressure altitude data h INS and digital terrain elevation data h DEM Send to the data processing system; Furthermore, in step G, the data processing system processes the radar altitude data h r Inertial pressure altitude data h INS and digital terrain elevation data h DEM The data is processed and the actual height h is calculated. T and predicted height data h T ’ And send it to the SITAN algorithm; Furthermore, in step H, the SITAN algorithm uses the actual height data h t The elevation error is calculated and imported into the measurement equation. The position correction data θ is then calculated using Kalman filtering. SITAN And send a digital terrain elevation database; Furthermore, in step I, based on the position data P(L', λ') and the position correction data θ SITAN The digital terrain elevation database extracts θ centered at location P(L', λ') and twice the elevation. SITAN A square reference image P with side length P SITAN ; Furthermore, in step J, the airborne image sensor measures the area below the aircraft. The measured ground image I of size is sent to the image matching module; Furthermore, in step K, the image matching module matches the ground-measured image I and the reference image P. SITAN Perform image matching to obtain the center of the matched image, i.e., the precise flight position P(L, λ), in the reference image P. SITAN Find an image I' of the same size as the measured ground image I and match it with the measured ground image I. The matching formula is as follows:

[0008] In the formula, This is the size of the measured ground image. As the baseline image size, , ; Furthermore, in step L, steps A through K are repeated to continuously acquire the precise location of the aircraft in real time.

[0009] This method is combined with an inertial navigation system (INS) and implemented in navigation and positioning equipment to provide aircraft with a variety of functions such as navigation and positioning, threat avoidance, intelligent ground-level warning, and precision weapon delivery. The navigation and positioning results are used to correct the errors of the INS in order to meet the high-precision navigation and positioning needs of various aircraft. Attached Figure Description

[0010] The present invention will be further described below with reference to the accompanying drawings.

[0011] Figure 1 A typical process according to an embodiment of the present invention is illustrated. Detailed Implementation

[0012] The technical solution of the present invention will be described below through preferred examples, but the following examples do not limit the scope of protection of the present invention.

[0013] The assisted navigation and positioning method that fuses imagery and terrain data provided by this invention can be integrated into avionics devices on aircraft, such as navigation and positioning systems, flight control systems, and flight management systems. Furthermore, the high-precision fighter jet terrain-referenced navigation and positioning method provided by this invention can be applied not only to fighter jets but also to attack aircraft, combat drones, and other similar devices.

[0014] Appendix Figure 1 This is a typical single-cycle flowchart formed according to an embodiment of the present invention. Within each cycle, the method proceeds according to the appendix... Figure 1 Execute in the order shown.

[0015] Reference Figure 1 At block 101, the flight control system generates barometric altitude data h. p and radar altitude data h rAnd generate the air pressure altitude data h p Send the radar altitude data h to the inertial navigation system (INS). r Send it to the data processing system.

[0016] Reference Figure 1 At block 102, combined with the barometric altitude data h sent by the flight control system p The inertial navigation system (INS) generates inertial barometric altitude data h. INS And send inertial barometric altitude data h INS In addition to the data processing system, the inertial navigation system (INS) sends position data P(L', λ') to the digital terrain elevation database.

[0017] Reference Figure 1 At block 103, based on the location data P(L', λ'), the digital terrain elevation database extracts the corresponding digital terrain elevation data h. DEM This data is then sent to the data processing system and combined with the position correction data θ sent by the SITAN algorithm. SITAN The digital terrain elevation database extracts θ centered at location P(L', λ') and twice the elevation. SITAN A square reference image P with side length P SITAN And send it to the image matching module.

[0018] Reference Figure 1 At block 104, the data processing system processes the data and calculates the actual height data h. T and predicted height data h T ’ It is then sent to the SITAN algorithm.

[0019] Reference Figure 1 At block 105, the SITAN algorithm uses the actual height data h t Calculate the position correction data θ SITAN And calculate the position correction data θ SITAN Send to the digital terrain elevation database.

[0020] Reference Figure 1 At square 106, the airborne image sensor detected the area below the aircraft. A ground-measured image of size I is generated and sent to the image matching module.

[0021] Reference Figure 1 At block 107, the image matching module matches the measured ground image I and the reference image P. SITAN Perform image matching to obtain the center of the matched image, i.e., the precise flight position P(L, λ), in the reference image P. SITANFind an image I' of the same size as the measured ground image I and match it with the measured ground image I. The matching formula is as follows:

[0022] In the formula, This is the size of the measured ground image. As the baseline image size, .

[0023] It is worth noting that the above description is based on specific embodiments of the invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for assisted navigation and positioning that integrates image and terrain data, characterized in that, It includes the following steps: The flight control system determines the current pressure altitude data h of the aircraft. p and radar altitude data h r ; The inertial navigation system (INS) uses barometric altitude data (h) from the flight control system. p Determine the corresponding inertial pressure altitude data h INS ; The current position data P(L',λ') of the aircraft is determined by the inertial navigation system INS; The digital terrain elevation data h is extracted from the position data P(L',λ') from the inertial navigation system INS by the digital terrain elevation database. DEM ; The data processing system uses radar altitude data h from the flight control system. r Inertial barometric altitude data h from the inertial navigation system INS INS Digital terrain elevation data h from the Digital Terrain Elevation Database DEM Determine the corresponding actual height data h T and predicted height data h T ’ ; The SITAN algorithm module uses the actual height data h from the data processing system. T Determine the corresponding position correction data θ SITAN ; The digital terrain elevation database is based on position data P(L',λ') from the inertial navigation system INS and position correction data θ from the SITAN algorithm module. SITAN Extract θ centered at position P(L',λ') at twice the value of θ SITAN A rectangular reference image P with side length P SITAN ; Ground-based image I below the aircraft, obtained from an airborne image sensor; The image matching module combines the measured ground image I from the airborne image sensor with the reference image P from the digital terrain elevation database. SITAN A matching process is performed, where the center of the matched image is the precise flight position P(L,λ).

2. The assisted navigation and positioning method according to claim 1, characterized in that, During the matching process, in the reference image P SITAN Find an image I' that is the same size as the ground-measured image I and match it with the ground-measured image I. The matching formula is as follows: ； In the formula, M×N is the size of the measured ground image, m×n is the size of the reference image, 1≤i≤m−M+1, 1≤j≤n−N+1; where i, j, m, n, M, and N are all positive integers.

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