Multi-node data fusion sliding carrier phase smoothing pseudo-range measurement method

Abstract

The invention discloses a multi-node data fusion sliding carrier phase smoothing pseudo-range measurement method, and belongs to the technical field of navigation system pseudo-range measurement. The method comprises the following steps that: a node A simultaneously performs microwave bidirectional comparison data transmission with each peripheral node in a space division multiplexing manner, and obtains a bidirectional comparison carrier phase smoothing pseudo-range measurement value of each link in a window sliding manner; and the node A completes data fusion of each pseudo-range measurement value by interpolating a weighted filter coefficient to obtain a carrier phase smoothing pseudo-range measurement result after multi-node data fusion. According to the invention, the idea of fusion of communication transmission and navigation ranging is combined, based on a conduction integration system design and a capability of realizing conduction integration by multiplexing a frame structure leader sequence, a multi-node data fusion sliding carrier phase smoothing pseudo-code ranging method is adopted, and multi-node sliding carrier phase smoothing pseudo-range measurement values are fused. Advantages of respective algorithms can be exerted, algorithm insufficiency is avoided, and ranging and time synchronization precision is improved.

Description

Technical Field

[0001] The invention relates to the technical field of pseudo-range measurement of navigation systems, and in particular to a sliding carrier phase smoothing pseudo-range measurement method of multi-node data fusion. Background Art

[0002] The existing satellite timing technology is relatively mature and has low requirements for hardware and algorithm complexity. However, this technology is no longer applicable under satellite denial conditions and when there is interference from complex electromagnetic environments. Therefore, it is necessary to conduct technical research on pseudo-range measurement and time synchronization that does not rely on satellite navigation. The dual one-way pseudo-range measurement (DOWR) system eliminates most of the common errors between the two ranging terminals due to the symmetry of its path, thereby achieving higher measurement accuracy than one-way ranging. This technology was first applied in the field of deep space exploration to complete ranging and time synchronization between deep space satellites. At present, the research on two-way one-way pseudo-range measurement technology has gradually shifted from early intersatellite link timing to drone group timing, among which pseudo-code ranging technology has been widely used.

[0003] However, the accuracy of the two-way one-way pseudo-code ranging algorithm is affected by factors such as system thermal noise, crystal oscillator phase noise, and chip rate limitation, and its ranging and time synchronization accuracy needs to be improved. In addition, in the communication and networking of drone clusters, high-precision time synchronization technology is required to unify the clocks of each node. Therefore, it is of great significance to study technologies such as high-precision ranging and time synchronization, and coordinated processing of communication and navigation signals. Summary of the invention

[0004] The purpose of the present invention is to solve the above problems and propose a sliding carrier phase smoothed pseudorange measurement method with multi-node data fusion. The present invention is based on a two-way one-way pseudorange measurement system with conduction fusion, uses a sliding windowing method to filter and smooth the carrier phase smoothed pseudorange measurement value, and fuses the microwave two-way comparison ranging values ​​of multiple nodes, and obtains the fused pseudorange measurement result by interpolating the weighted filter coefficient.

[0005] The technical solution adopted by the present invention is as follows:

[0006] A sliding carrier phase smoothing pseudorange measurement method for multi-node data fusion is applied to any node A of a multi-node wireless microwave communication system, comprising the following steps:

[0007] Step 1: Node A transmits microwave two-way comparison data with surrounding nodes simultaneously in a space division multiplexing manner, and obtains the two-way comparison carrier phase smoothed pseudo-range measurement value of each link by window sliding;

[0008] Step 2: Node A completes the data fusion of each pseudorange measurement value by interpolating the weighted filter coefficient to obtain the fused multi-node carrier phase smoothed pseudorange measurement result.

[0009] Furthermore, the specific method of step 1 is:

[0010] Step 101, node A uses different beam space division multiplexing to communicate with surrounding nodes at the same time. Node A and surrounding nodes use a communication and guidance fusion system for data transmission, and pseudo code ranging and time synchronization are achieved by multiplexing the communication frame structure leading sequence; wherein the pseudo code ranging result is:

[0011] r n = l(f n +N) (1-1)

[0012] Among them, r n is the pseudo-range measurement value of the node at the current moment, λ is the carrier wavelength, and f n is the carrier phase, N is the integer ambiguity of the carrier phase measurement;

[0013] Step 102: Set the window length of the smoothing window to m, compare the sequence number n of the current pseudo code ranging result with the window length m, and when n≤m, perform real-time carrier phase smoothing processing according to the following formula:

[0014]

[0015] When n>m, the real-time carrier phase smoothing process is performed according to the following formula:

[0016]

[0017] in, is the pseudo-range measurement value after carrier phase smoothing, f k is the carrier phase measurement value of the kth observation in the continuous observation.

[0018] Furthermore, the specific method of step 2 is:

[0019] Set the weight α according to the distance between node A and surrounding nodes k , weight α k r is inversely proportional to the distance, and the sum of all weights is 1. The carrier phase smoothed pseudorange measurement value after weighted fusion is calculated:

[0020]

[0021] Among them, k is the serial number of the surrounding node, is the two-way comparison carrier phase smoothed pseudorange measurement value before weighted fusion, It is the multi-node carrier phase smoothed pseudo-range measurement result after weighted fusion.

[0022] The beneficial effects of the present invention are:

[0023] 1. In the prior art, the pseudo-range measurement method based on two-way one-way can offset most of the errors on the transmission path through two-way comparison because of the symmetry of its signal propagation path, but the pseudo-code ranging method will introduce measurement noise, and the limitation between the code rate and bandwidth cannot provide higher precision measurement results. The present invention considers that carrier phase ranging obtains higher ranging accuracy through high-frequency carrier, but there is a problem of integer ambiguity. The method of using carrier phase smoothing pseudo-range measurement can solve this problem to a certain extent. Before the equipment works stably, the ranging value may fluctuate, and sudden interference will also affect the result. The present invention introduces sliding windowing to filter the data. As the window slides, special values ​​can be filtered out, thereby achieving the effect of using effective values ​​for pseudo-range smoothing.

[0024] 2. In a multi-node distributed wireless ranging system, each node communicates in a network. The present invention uses the method of fusing the ranging values ​​between the current node and multiple surrounding nodes to improve the ranging and time synchronization accuracy. The interpolation weighted filter coefficient is designed according to the distance between the nodes, and the pseudo-range smoothing value on each link is weightedly calculated. Then, the smoothed results of the two-way comparison between the same node and multiple surrounding nodes are weightedly fused, thereby further improving the ranging and time synchronization accuracy.

[0025] 3. The method of the present invention is real-time. The measured values ​​in the window or even the current and previous measured values ​​are needed to obtain the smoothed result of the current pseudo-range measurement. The calculated data can be updated in real time while the window slides, which has the accuracy and real-time performance of ranging smoothing. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The invention is a flow chart of a sliding carrier phase smoothing pseudo-range measurement method with multi-node data fusion.

[0027] Figure 2 It is a schematic diagram of communication node distribution.

[0028] Figure 3 This is the design diagram of the communication ranging frame structure. DETAILED DESCRIPTION

[0029] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in combination with specific implementation examples and with reference to the accompanying drawings.

[0030] A sliding carrier phase smoothing pseudo-range measurement method based on multi-node data fusion, such as Figure 1 As shown, the specific steps are as follows:

[0031] A sliding carrier phase smoothing pseudorange measurement method for multi-node data fusion, characterized in that it is applied to any node A of a multi-node wireless microwave communication system, and comprises the following steps:

[0032] Step 1: Node A transmits microwave two-way comparison data with surrounding nodes simultaneously in a space division multiplexing manner, and obtains the two-way comparison carrier phase smoothed pseudo-range measurement value of each link by window sliding; the specific method is:

[0033] Step 101, node A uses different beams of space division multiplexing to communicate with surrounding nodes at the same time. The same pair of communication nodes use different frequencies for transmission and reception to avoid mutual interference. The communication beam directions between the same node and the other nodes are different. Space division multiplexing is used to avoid signal interference and conflict between different node pairs. The communication stations are distributed as follows: Figure 2 shown. Figure 2 In the figure, A is the current node and is regarded as the central node, so the other nodes B, C, and D are peripheral nodes. The distance between nodes A and B is 2 km, the distance between nodes A and C is 3 km, and the distance between nodes A and D is 6 km. The dotted lines in the figure delineate the beam range. Nodes B, C, and D are respectively located within the three beams emitted by node A to avoid mutual interference.

[0034] Node A and surrounding nodes use a communication-conductor fusion system for data transmission. The data transmission mode between each pair of nodes uses a communication-conductor fusion system, that is, during communication, pseudo-code ranging and time synchronization functions are realized by multiplexing the preamble sequence of the communication frame structure. The communication ranging frame structure design is as follows: Figure 3 As shown, the pilot segment consists of a short preamble and a long preamble, and the data segment consists of an alternating pilot and data. SP is a short preamble sequence, and the long preamble sequence is composed of LP and its time domain conjugate sequence LP*, which is essentially a pseudo-random code. The communication and ranging functions are realized by multiplexing the long preamble sequence in the time-frequency dual domain, that is, the frequency domain value of the long preamble sequence is used for communication channel estimation and equalization, and the time domain value of the long preamble sequence is multiplexed for pseudo-range measurement. The basic two-way comparison pseudo-range measurement process is used to obtain the pseudo-code ranging result shown below:

[0035] r n = l(f n +N) (1-1)

[0036] Among them, r n is the pseudo-range measurement value of the node at the current moment, λ is the carrier wavelength, and f n is the carrier phase, and N is the integer ambiguity of the carrier phase measurement, which can be regarded as a constant value.

[0037] Since the pseudorange measurement accuracy is low, the carrier phase is used to smooth the pseudorange measurement value to improve the accuracy, while also avoiding the integer ambiguity problem in carrier phase ranging.

[0038] Step 102: Set the window length of the smoothing window to m, compare the sequence number n of the current pseudo code ranging result with the window length m, and when n≤m, perform real-time carrier phase smoothing processing according to the following formula:

[0039]

[0040] When n>m, the real-time carrier phase smoothing process is performed according to the following formula:

[0041]

[0042] in, is the pseudo-range measurement value after carrier phase smoothing, f k is the carrier phase measurement value of the kth observation in the continuous observation.

[0043] There will be certain measurement errors when using all the previous data for smoothing, because early unstable errors, such as the unstable state of the receiving end during the steady state, still exist, and the smoothed pseudo-range value calculated using all the data may not be accurate. To this end, this method uses a sliding window design to filter the previous two-way comparison ranging results, so that the smoothed data is updated in real time, and the data with a long time interval with the current ranging value is continuously filtered out to improve the accuracy of the ranging results.

[0044] Step 2: In a multi-node communication environment, the current node is regarded as the central station, and other surrounding nodes are peripheral stations. The central station and the peripheral stations use space division multiplexing and use different beams for transmission and ranging. Through the above-mentioned sliding filtering of data, the central station obtains a two-way comparison carrier phase smoothed pseudo-range value with multiple nodes. Within the communication range, nearby stations have lower path loss and higher signal quality, and have higher communication and ranging effects. In order to balance the ranging results of distant and nearby peripheral stations and obtain higher-precision ranging results, the interpolation coefficient α is A , α B …α k Multiply them with the ranging results between the corresponding stations respectively, weight the ranging results according to the distance between the peripheral stations and the central station, and obtain the weighted fusion carrier phase smoothed pseudorange measurement value:

[0045]

[0046] Among them, k is the serial number of the surrounding node, is the two-way comparison carrier phase smoothed pseudorange measurement value before weighted fusion, is the multi-node carrier phase smoothed pseudo-range measurement result after weighted fusion, α k r is the weight set according to the distance between node A and its surrounding nodes, and the weight α k Inversely proportional to the distance, the sum of all weights is 1.

[0047] In this embodiment, for example Figure 2 The node distribution is shown in Figure 2, and the interpolation weighted filter coefficients are set to

[0048] By using the method of the present invention, regardless of the relationship between the window length and the data length, the smooth real-time calculation of the pseudorange value can be realized. When the data length is less than or equal to the window length, according to formula (1-2), only the current pseudorange value, carrier phase and the previous smoothed pseudorange value and carrier phase are needed to calculate the current smoothed pseudorange value; when the data length is greater than or equal to the window length, according to formula (1-3), the pseudorange value corresponding to the beginning and end of the window, carrier phase and the previous smoothed pseudorange value and carrier phase can be used to calculate the current smoothed pseudorange value.

[0049] Regardless of the relationship between the sliding window length and the data length, the sliding carrier phase smoothing pseudorange measurement accuracy can be obtained by formula (1-5):

[0050]

[0051] Among them, the pseudorange smoothing error is ε, and the pseudorange measurement error is ε r , the carrier phase measurement error is ε f , random error of carrier phase measurement ε f is much smaller than the pseudo code ranging error ε r , can be ignored.

[0052] In summary, the present invention combines the idea of ​​integrating communication transmission and navigation ranging, is based on the design of an integrated communication and navigation system, reuses the frame structure leading sequence to realize the integrated communication and navigation capabilities, and adopts a sliding carrier phase smoothed pseudo-code ranging method with multi-node data fusion. The sliding carrier phase smoothed pseudo-range measurement values ​​of multiple nodes are fused and processed, which can give full play to the advantages of each algorithm, avoid the shortcomings of the algorithm, and improve the ranging and time synchronization accuracy.

[0053] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A sliding carrier phase smoothing pseudorange measurement method with multi-node data fusion, characterized in that: The method is applied to any node A of a multi-node wireless microwave communication system and includes the following steps: Step 1: Node A transmits microwave two-way comparison data with surrounding nodes simultaneously in a space division multiplexing manner, and obtains the two-way comparison carrier phase smoothed pseudo-range measurement value of each link by window sliding; Step 2: Node A completes the data fusion of each pseudorange measurement value by interpolating the weighted filter coefficient to obtain the fused multi-node carrier phase smoothed pseudorange measurement result.

2. According to the multi-node data fusion sliding carrier phase smoothing pseudo-range measurement method of claim 1, it is characterized in that: The specific method of step 1 is: Step 101, node A uses different beam space division multiplexing to communicate with surrounding nodes at the same time. Node A and surrounding nodes use a communication and guidance fusion system for data transmission, and pseudo code ranging and time synchronization are achieved by multiplexing the communication frame structure leading sequence; wherein the pseudo code ranging result is: r n =l(f n +N) (1-1) Among them, r n is the pseudo-range measurement value of the node at the current moment, λ is the carrier wavelength, and f n is the carrier phase, N is the integer ambiguity of the carrier phase measurement; Step 102: Set the window length of the smoothing window to m, compare the sequence number n of the current pseudo code ranging result with the window length m, and when n≤m, perform real-time carrier phase smoothing processing according to the following formula: When n>m, the real-time carrier phase smoothing process is performed according to the following formula: in, is the pseudo-range measurement value after carrier phase smoothing, f k is the carrier phase measurement value of the kth observation in the continuous observation.

3. The sliding carrier phase smoothing pseudorange measurement method of multi-node data fusion according to claim 1 is characterized in that: The specific method of step 2 is: Set the weight α according to the distance between node A and surrounding nodes k , weight α k r is inversely proportional to the distance, and the sum of all weights is 1. The carrier phase smoothed pseudorange measurement value after weighted fusion is calculated: Among them, k is the serial number of the surrounding node, is the two-way comparison carrier phase smoothed pseudorange measurement value before weighted fusion, It is the multi-node carrier phase smoothed pseudo-range measurement result after weighted fusion.

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