A multi-standard navigation positioning method and system based on long baseline

Abstract

The present invention discloses a multi-beam navigation and positioning method and system based on a long baseline, wherein the method comprises the following steps: S1: sending a ranging query signal according to a preset period and starting timing, and continuously sampling through multiple channels at the same time; S2: performing demodulation operation on each sampled signal respectively, and closing the current channel and outputting the delay information of the current ID beacon according to the correlation coefficient between the demodulation operation result and the original code of the standard signal; S3: converting the delay information into the distance between the current ID beacon and the master beacon; S4: obtaining the coordinates of the target ID beacon and the distance between the target ID beacon and the master beacon, and solving the position information of the master beacon, wherein the target ID beacon is the four ID beacons with the smallest distance from the master beacon; S5: storing the delay information obtained after sending the ranging query signal each time. The method of the present invention can improve the continuity of positioning, and can reduce the influence of multipath effect and increased slant range.

Description

Technical Field

[0001] The present invention relates to the field of underwater positioning technology, and in particular to a multi-marker navigation positioning method and system based on a long baseline. Background Art

[0002] The ocean contains huge resources waiting for people to explore and develop. Submersibles are important tools for entering the deep sea for scientific research and exploration operations. The LBL long baseline navigation and positioning system has become one of the commonly used positioning methods in the ocean due to its high positioning accuracy. It is widely used in deep-sea AUV positioning and tracking, marine engineering construction, ROV positioning, and various seabed equipment precise positioning scenarios, ensuring safe seabed operations and construction efficiency.

[0003] However, the positioning accuracy of the traditional long baseline positioning system is affected by signal propagation, especially in long-distance positioning. Due to signal attenuation, individual ID beacons fail to respond, which means that the distance information is lost and the current position information cannot be calculated. This also makes the traditional long baseline positioning limited in range and cannot guarantee positioning continuity at long distances. On the other hand, due to the influence of environmental factors, there are technical problems such as multipath effect and increased slant range, which in turn affects the accuracy of positioning.

[0004] In view of this, this invention is proposed. Summary of the invention

[0005] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a multi-marker navigation positioning method and system based on a long baseline, which can improve the continuity of positioning and reduce the impact of multipath effects and increased slant range.

[0006] In order to achieve the above object, the present invention also adopts the following technical solution:

[0007] A multi-marker navigation and positioning method based on a long baseline comprises the following steps:

[0008] S1: Send ranging query signals according to the preset period and start timing, and continuously sample through multiple channels at the same time;

[0009] S2: Demodulate each sampled signal, and according to the correlation coefficient between the demodulation result and the original code of the standard signal, close the current channel and output the delay information of the current ID beacon;

[0010] S3: Convert the delay information into the distance between the current ID beacon and the master beacon;

[0011] S4: Obtain the coordinates of the target ID beacon and the distance between the target ID beacon and the master beacon, and solve the position information of the master beacon, wherein the target ID beacon is the four ID beacons with the smallest distance from the master beacon;

[0012] S5: storing the delay information obtained after each sending of the ranging inquiry signal.

[0013] Further, the S4 comprises the following steps:

[0014] S41: Determine whether the distances between the target ID beacon and the master beacon are both obtained, if so, execute S42, if not, execute S43;

[0015] S42: Calculate the coordinates of the master beacon according to the coordinates of the target ID beacon and the distance between the target ID beacon and the master beacon, and convert the coordinates of the master beacon into longitude and latitude;

[0016] S43: Determine whether there is one unanswered target ID beacon, if yes, execute S44, if no, execute S45;

[0017] S44: Compensate the distance between the target ID beacon and the master beacon lost in the current sampling period according to the data of the t-1 and t-2 sampling periods;

[0018] S45: Send a prompt message.

[0019] Further, the S44 comprises the following steps:

[0020] S441: Calculate the distance between the unanswered target ID beacon and the master beacon according to the following formula:

[0021] r i,t =r i,t-1 +λ×Δt×v i

[0022]

[0023] In the formula, r i,t is the distance between the target ID beacon that has not responded in the current sampling period and the master beacon, r i,t-1 and r i,t-2 They are the distances between the target ID beacon that has not responded to the current sampling period and the master beacon in the previous cycle and two cycles respectively, λ is +1 or -1, and △t is the cycle of sending the ranging inquiry signal.

[0024] Further, the S2 comprises the following steps:

[0025] S21: Demodulate the sampled signal;

[0026] S22: According to the correlation coefficient between the demodulation operation result and the original code of the standard signal, the current channel is closed and the delay information of the current ID beacon is output.

[0027] Further, the S21 comprises the following steps:

[0028] S211: amplify and filter the sampled signal;

[0029] S212: The digital signals after AD conversion enter the fast Fourier transform IP core inside the FPGA in groups of 2048 digital signals, and 2048 frequency domain signals x(m) are obtained through the calculation;

[0030] S213: Find the position of 11k and the position of 14k within the ID signal bandwidth by the following formula:

[0031]

[0032] In the formula, N is the number of Fourier transform points 2048, m1 is the 11k signal position within the bandwidth, m2 is the 14k signal position within the bandwidth, fc1 is 11k, fc2 is 14k, and fs is the signal sampling rate 50k;

[0033] S214: Extract data from x(m1) to x(m2) within the ID signal bandwidth and perform demodulation operation using the following formula:

[0034]

[0035] In the formula, x(m) is the actual collected signal, and y(m) is the original code of the standard ID signal.

[0036] Further, the S22 comprises the following steps:

[0037] S221: Determine whether the correlation coefficient between the demodulated signal and the original code of the standard ID signal is greater than 0.4, if so, execute S222, if not, return to S21;

[0038] S222: Stop timing of the channel, and calculate the total time taken by the channel to correspond to the ID signal, which is the delay information of the ID signal corresponding to the ID beacon.

[0039] In order to achieve the above object, the present invention also adopts the following technical solution:

[0040] A multi-standard navigation and positioning system based on a long baseline, comprising:

[0041] A master beacon, a response beacon and a PS end, wherein the master beacon is arranged on a submersible, and there are several response beacons arranged on the bottom of the water, and the PS end is communicatively connected with the master beacon; wherein the master beacon executes S1-S3 of any one of the methods provided by the present invention, and the PS end executes S4-S5 of any one of the methods provided by the present invention.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] 1. Store the delay information obtained after each distance inquiry signal is sent. When individual ID beacons do not respond, that is, when the distance information is lost, the lost distance information is compensated according to the stored data, thereby improving the continuity of positioning.

[0044] 2. Start timing after sending the ranging inquiry signal, and continue sampling through multiple channels at the same time. After each channel receives the corresponding ID signal, it turns off the reception, thereby preventing multi-path interference.

[0045] 3. By deploying multiple transponder beacons to reduce the slant range, the four transponder beacons closest to the main control beacon are used to participate in positioning and solving, thereby reducing the impact of increased slant range and expanding the service area of ​​long baseline positioning. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 This is a block diagram of a multi-standard navigation and positioning system based on a long baseline;

[0047] Figure 2 This is a flow chart of the multi-marker navigation and positioning method based on long baseline;

[0048] Figure 3 This is the schematic diagram of multi-marker navigation and positioning based on long baseline. DETAILED DESCRIPTION

[0049] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0050] Embodiment 1:

[0051] A multi-standard navigation and positioning method based on a long baseline. The system of this embodiment can be based on Figure 1 The navigation system shown is used for positioning a submersible. The navigation system includes a master beacon, a response beacon and a PS end. The master beacon is arranged on the submersible. There are several response beacons (ID beacons) arranged on the bottom of the water. The PS end is communicatively connected with the master beacon.

[0052] like Figure 2 As shown, the multi-marker navigation and positioning method based on long baseline includes the following steps:

[0053] S1: Send the ranging query signal according to the preset period and start the timing, and continue sampling through multiple channels at the same time.

[0054] In this embodiment, S1 and subsequent S2 and S3 are executed by the master beacon. In S1, the master beacon starts timing each time it sends a ranging inquiry signal to obtain delay information.

[0055] In this embodiment, after the master beacon sends a ranging inquiry signal according to a preset period, each ID beacon will immediately send its own ID signal after receiving the ranging inquiry signal; in addition, the master beacon continuously samples through multiple channels (such as ADC) at the same time to obtain the ID signal sent by each ID beacon, that is, the sampling signal.

[0056] S2: Demodulate each sampled signal respectively, and according to the correlation coefficient between the demodulation result and the original code of the standard signal, close the current channel and output the delay information of the current ID beacon.

[0057] In this embodiment, S2 is a process for processing signals collected by a single signal channel. After S2 is executed, the current channel is closed and the delay information of the ID beacon corresponding to the signal collected by the channel is output. It should be understood that S2 is executed for the signals collected by each channel.

[0058] In this embodiment, the current ID beacon is the ID beacon corresponding to the current channel.

[0059] S3: Convert the delay information into the distance between the current ID beacon and the master beacon.

[0060] In this embodiment, the distance between the current ID beacon and the master beacon can be calculated by the following formula:

[0061]

[0062] In the formula, L i is the distance between the current ID beacon and the master beacon, τ i is the delay information of the current ID beacon, and c is the average sound speed in the current sea area.

[0063] S4: Obtain the coordinates of the target ID beacon and the distance between the target ID beacon and the master beacon, and solve the position information of the master beacon, wherein the target ID beacons are the four ID beacons with the smallest distance from the master beacon.

[0064] S5: storing the delay information obtained after each sending of the ranging inquiry signal.

[0065] The multi-beam navigation and positioning method based on a long baseline in this embodiment stores the delay information obtained after each distance measurement inquiry signal is sent. When an individual ID beacon does not respond, that is, the distance information is lost, the lost distance information is compensated according to the stored data, thereby improving the continuity of positioning.

[0066] The multi-marker navigation and positioning method based on a long baseline in this embodiment starts timing after sending a ranging inquiry signal, and continuously samples through multiple channels at the same time. After each channel receives the corresponding ID signal, it turns off reception, thereby preventing multipath interference.

[0067] The multi-beacon navigation and positioning method based on a long baseline in this embodiment reduces the slant range by deploying multiple reply beacons, and the four reply beacons closest to the main control beacon participate in the positioning solution, thereby reducing the impact of the increase in slant range and increasing the service area of ​​the long baseline positioning.

[0068] In summary, the long baseline-based multi-marker navigation and positioning method of this embodiment reduces the impact of multipath effects and increased slant range in traditional long baseline positioning, thereby improving its positioning accuracy, enabling it to complete positioning in a larger ocean area.

[0069] In an optional embodiment, the S4 comprises the following steps:

[0070] S41: Determine whether the distances between the target ID beacon and the master beacon are both obtained, if so, execute S42, if not, execute S43.

[0071] S42: Calculate the coordinates of the master beacon according to the coordinates of the target ID beacon and the distance between the target ID beacon and the master beacon, and convert the coordinates of the master beacon into longitude and latitude.

[0072] S43: Determine whether there is one unanswered target ID beacon. If so, execute S44; otherwise, execute S45.

[0073] S44: Compensate the distance between the target ID beacon and the master beacon lost in the current sampling period according to the data of the t-1 and t-2 sampling periods.

[0074] S45: Send a prompt message.

[0075] In this optional embodiment, when all target ID beacons respond, the coordinates of the master beacon are directly solved. When one target beacon does not respond, the distance between the target ID beacon that did not respond in the current sampling period and the master beacon is compensated based on the data of the two sampling periods before the current sampling period (the data here refers to the distance between the target ID beacon and the master beacon), thereby improving the continuity of positioning.

[0076] In this alternative embodiment, reference is made to Figure 3 In the ID beacon layout stage, after the ID beacon is arranged, its three adjacent ID beacons can be determined; in the navigation and positioning stage, the master beacon must be located in the upward projection space range of the quadrilateral defined by the four ID beacons. At this time, the distance between the master beacon and the four ID beacons is the smallest, and the four ID beacons are the target ID beacons of the current cycle; in addition, in the navigation and positioning stage, when the master beacon receives the four distances to the ID beacons, it can be known whether the four ID beacons are adjacent. If they are adjacent, it means that the four ID beacons are the target ID beacons. Otherwise, execute S43-S45.

[0077] In this optional embodiment, Figure 3 In the figure, positions 1 and 2 refer to the positions of the master beacon at sampling times t-1 and t-2 respectively, and position 3 refers to the position of the master beacon at the current sampling time.

[0078] In this optional embodiment, when the lost data is too much to be compensated, a prompt message is issued, and other means are used for compensatory navigation, such as inertial navigation.

[0079] In an optional embodiment, the S44 includes the following steps:

[0080] S441: Calculate the distance between the unanswered target ID beacon and the master beacon according to the following formula:

[0081] r i,t =r i,t-1 +λ×Δt×v i

[0082]

[0083] In the formula, r i，t is the distance between the target ID beacon that has not responded in the current sampling period and the master beacon, r i，t-1 and r i，t-2 They are the distances between the target ID beacon that has not responded to the current sampling period and the master beacon in the previous cycle and two cycles respectively, λ is +1 or -1, and △t is the cycle of sending the ranging inquiry signal.

[0084] In this optional embodiment, the value of λ is determined by the following process:

[0085] S442: Calculate △r1, △r2, △r3 and △r4 according to the following formula:

[0086] △r1=r 1,t-1 -r 1，t-2

[0087] △r2=r 2,t-1 -r 2,t-2

[0088] △r3=r 3,t-1 -r 3,t-2

[0089] △r4=r 4,t-1 -r 4,t-2

[0090] In the formula, r1, r2, r3 and r4 are the distances between the target ID beacon and the master beacon at the upper left corner, lower left corner, lower right corner and upper right corner of the master beacon respectively.

[0091] S443: Determine the moving direction of the master beacon in the current sampling period according to the following table:

[0092]

[0093] When the moving direction of the current sampling period is the same as the historical moving direction, λ is +1; when the moving direction of the current sampling period is different from the historical moving direction, λ is -1; when the moving direction of the current sampling period cannot be determined, two r are calculated. i，t Value, according to the two r i，t In S42 , the coordinates of the master beacon are solved by Gauss-Newton iteration, and the solution that can converge or converge faster is taken as the coordinates of the master beacon.

[0094] In an optional embodiment, the S2 comprises the following steps:

[0095] S21: Demodulate the sampled signal;

[0096] S22: According to the correlation coefficient between the demodulation operation result and the original code of the standard signal, the current channel is closed and the delay information of the current ID beacon is output.

[0097] In an optional embodiment, the S21 includes the following steps:

[0098] S211: Amplify and filter the sampled signal.

[0099] S212: The digital signals after AD conversion enter the fast Fourier transform IP core inside the FPGA in groups of 2048 digital signals, and 2048 frequency domain signals x(m) are obtained through the calculation.

[0100] S213: Find the position of 11k and the position of 14k within the ID signal bandwidth by the following formula:

[0101]

[0102] In the formula, N is the number of Fourier transform points 2048, m1 is the 11k signal position within the bandwidth, m2 is the 14k signal position within the bandwidth, fc1 is 11k, fc2 is 14k, and fs is the signal sampling rate 50k.

[0103] S214: Extract data from x(m1) to x(m2) within the ID signal bandwidth and perform demodulation operation using the following formula:

[0104]

[0105] In the formula, x(m) is the actual collected signal, and y(m) is the original code of the standard ID signal.

[0106] In an optional embodiment, the S22 includes the following steps:

[0107] S221: Determine whether the correlation coefficient between the demodulated signal and the original code of the standard ID signal is greater than 0.4, if so, execute S222, if not, return to S21;

[0108] S222: Stop timing of the channel, and calculate the total time taken by the channel to correspond to the ID signal, which is the delay information of the ID signal corresponding to the ID beacon.

[0109] In this optional embodiment, the delay information refers to the duration between the time point when the navigation system sends the ranging inquiry signal and the time point when S222 stops timing.

[0110] Embodiment 2:

[0111] A multi-beacon navigation and positioning system based on a long baseline includes: a master beacon, a reply beacon and a PS end, wherein the master beacon is arranged on a submersible, and there are a plurality of reply beacons arranged on the bottom of the water, and the PS end is communicatively connected with the master beacon; wherein the master beacon executes S1-S3 of the method of embodiment 1, and the PS end executes S4-S5 of the method of embodiment 1.

[0112] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A multi-standard navigation and positioning method based on a long baseline, characterized in that: The steps include: S1: Send ranging query signals according to the preset period and start timing, and continuously sample through multiple channels at the same time; S2: Demodulate each sampled signal, and according to the correlation coefficient between the demodulation result and the original code of the standard signal, close the current channel and output the delay information of the current ID beacon; S3: Convert the delay information into the distance between the current ID beacon and the master beacon; S4: Obtain the coordinates of the target ID beacon and the distance between the target ID beacon and the master beacon, and solve the position information of the master beacon, wherein the target ID beacon is the four ID beacons with the smallest distance from the master beacon; S5: storing the delay information obtained after each sending of the ranging inquiry signal; The S4 comprises the following steps: S41: Determine whether the distances between the target ID beacon and the master beacon are both obtained, if so, execute S42, if not, execute S43; S42: Calculate the coordinates of the master beacon according to the coordinates of the target ID beacon and the distance between the target ID beacon and the master beacon, and convert the coordinates of the master beacon into longitude and latitude; S43: Determine whether there is one unanswered target ID beacon, if yes, execute S44, if no, execute S45; S44: Compensate the distance between the target ID beacon and the master beacon lost in the current sampling period according to the data of the t-1 and t-2 sampling periods; S45: Sending a prompt message; The S44 comprises the following steps: S441: Calculate the distance between the unanswered target ID beacon and the master beacon according to the following formula: r i,t =r i,t-1 +λ×Δt×v i In the formula, r i,t is the distance between the target ID beacon that has not responded in the current sampling period and the master beacon, r i,t-1 and r i,t-2 They are the distances between the target ID beacon that has not responded to the current sampling period and the master beacon in the previous cycle and two cycles respectively, λ is +1 or -1, and △t is the cycle of sending the ranging inquiry signal.

2. The multi-marker navigation and positioning method based on a long baseline according to claim 1, characterized in that: The S2 comprises the following steps: S21: Demodulate the sampled signal; S22: According to the correlation coefficient between the demodulation operation result and the original code of the standard signal, the current channel is closed and the delay information of the current ID beacon is output.

3. The multi-marker navigation and positioning method based on a long baseline according to claim 2 is characterized in that: The S21 comprises the following steps: S211: amplify and filter the sampled signal; S212: The digital signals after AD conversion enter the fast Fourier transform IP core inside the FPGA in groups of 2048 digital signals, and 2048 frequency domain signals x(m) are obtained through the calculation; S213: Find the position of 11k and the position of 14k within the ID signal bandwidth by the following formula: In the formula, N is the number of Fourier transform points 2048, m1 is the 11k signal position within the bandwidth, m2 is the 14k signal position within the bandwidth, fc1 is 11k, fc2 is 14k, and fs is the signal sampling rate 50k; S214: Extract data from x(m1) to x(m2) within the ID signal bandwidth and perform demodulation operation using the following formula: In the formula, x(m) is the actual collected signal, and y(m) is the original code of the standard ID signal.

4. The multi-marker navigation and positioning method based on a long baseline according to claim 2 is characterized in that: The S22 comprises the following steps: S221: Determine whether the correlation coefficient between the demodulated signal and the original code of the standard ID signal is greater than 0.4, if so, execute S222, if not, return to S21; S222: Stop timing of the channel, and calculate the total time taken by the channel to correspond to the ID signal, which is the delay information of the ID signal corresponding to the ID beacon.

5. A multi-standard navigation and positioning system based on a long baseline, comprising: A master beacon, a response beacon and a PS end. The master beacon is set on the submersible, and there are several response beacons set on the bottom of the water. The PS end is connected to the master beacon for communication; The master beacon executes S1-S3 of the method described in any one of claims 1-4, and the PS end executes S4-S5 of the method described in any one of claims 1-4.

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