Single-carrier high-precision two-way ranging method based on waveform domain orthogonality

Abstract

The single carrier high-precision two-way ranging method based on orthogonal waveform design belongs to the field of communication signal processing.The method of the present application is as follows: in the scene where the frequency spectrum and hardware implementation resources are strongly limited, a UAV node generates information according to a ranging frame structure.The frame structure comprises a pilot head, a frame synchronization head, a control field, ranging information, inertial navigation and dynamic information, and other redundant information. By using coherent pilots orthogonal to communication signals, combined with a two-way comparison algorithm and pilot phase discrimination, high-precision and low-processing-delay networking ranging is realized.The present application has the following advantages: (1) the orthogonal waveform is used to save spectrum resources without affecting the communication and ranging performance; (2) on the basis of simple pseudo-code ranging, the ranging result is corrected by using the phase discrimination method, which significantly improves the ranging accuracy and has low processing complexity and processing delay; (3) combined with the expandable two-way comparison strategy, networking ranging of large-scale UAV clusters is realized.

Description

Technical Field

[0001] This invention relates to a high-precision bidirectional ranging method based on waveform domain orthogonality using a single carrier, specifically a ranging method for an unmanned aerial vehicle (UAV) swarm ad hoc network system under conditions of severely limited hardware resources, and belongs to the field of communication signal processing. Background Technology

[0002] The collaborative operation of large-scale drone swarms is a current research hotspot, as their high adaptability and flexibility make them valuable in military, communications, and rescue fields. Especially in complex environments, drone swarms can improve mission efficiency and coverage through collaborative work.

[0003] Ad hoc network technology for unmanned aerial vehicles (UAVs) is fundamental to supporting swarm collaboration. Through a distributed network architecture, ad hoc networks do not rely on fixed infrastructure and can dynamically adjust the network topology according to mission requirements, greatly enhancing the flexibility and adaptability of UAV swarms. In such networks, efficient communication and accurate ranging between UAVs are prerequisites for collaborative operation. However, in large-scale swarm environments, traditional positioning methods are insufficient to meet practical needs.

[0004] Hardware resource constraints are a common problem in large-scale drone swarms. Limited by the size, weight, and power supply of drones, individual drones are typically equipped with low-power, lightweight hardware. This hardware limitation makes it difficult to efficiently complete high-precision ranging calculations. The high hardware performance requirements of delay-locked loops in traditional high-precision bidirectional ranging are difficult to implement in resource-constrained drone swarms. Meanwhile, the problem of limited spectrum resources is particularly prominent in large-scale drone swarms. Each drone in the swarm needs both communication and ranging, which significantly increases communication channel conflicts and the challenges of spectrum reuse. Traditional technologies typically treat communication and ranging as independent functional modules, using different signal and frequency resources. This approach not only increases spectrum usage but also adds complexity to the swarm system and the difficulty of communication coordination.

[0005] In the Chinese invention patent application CN108183878A, published on June 19, 2018, entitled "A Bit Timing Synchronization Implementation Method for Terahertz Communication," the transmitting end inserts a low-power single-tone pilot at the first zero point of the baseband signal spectrum. The receiving end performs phase detection on the single-tone pilot and compensates the local clock for frequency and phase based on the phase detection result, thereby completing the timing synchronization of the communication system. This invention utilizes this waveform orthogonal structure and high-precision phase detection synchronization approach, combined with the system's acquisition and communication functions, to obtain bidirectional comparison time, thereby completing ranging. Furthermore, the ranging method of this invention has significant scalability and can be applied to ranging in large-scale UAV swarm ad hoc networks, improving the communication and collaboration capabilities of UAV swarms, and possesses significant research value and application prospects. Summary of the Invention

[0006] To address the technical shortcomings of existing technologies: (i) traditional bidirectional comparison algorithms consume significant resources; (ii) there is a significant contradiction between accuracy, algorithm complexity, and processing latency; the purpose of this invention is to provide a single-carrier high-precision bidirectional ranging method based on orthogonal waveform design. In scenarios with severely limited spectrum and hardware implementation resources, this method utilizes coherent pilots orthogonal to the communication signal, combined with a bidirectional comparison strategy and pilot phase detection, to achieve high-precision and low-latency network ranging. This invention has the following advantages: (i) it saves spectrum resources without affecting communication and ranging performance by utilizing orthogonal waveform design; (ii) based on simple pseudocode ranging, it uses phase detection to correct the ranging results, significantly improving ranging accuracy while maintaining low processing complexity and latency; (iii) combined with an scalable bidirectional comparison strategy, it enables network ranging for large-scale UAV swarms.

[0007] The objective of this invention is achieved through the following technical solution.

[0008] The high-precision bidirectional ranging method based on waveform domain orthogonality disclosed in this invention includes the following steps:

[0009] Step 1: The UAV node generates information according to the ranging frame structure. The frame structure includes a pilot header, frame synchronization header, control fields, ranging information, inertial navigation and dynamic information, and other redundant information.

[0010] ◆Pilot Head: The core purpose of the pilot head is to detect the presence or absence of a signal and to preliminarily determine the optimal sampling point for the received signal, thereby achieving coarse distance estimation with an estimation resolution on the order of sampling clocks. A pseudo-random sequence with good autocorrelation properties is used to design the pilot head.

[0011] ◆Frame synchronization header: The frame synchronization header is used to realize the synchronization of communication symbol frames; after the receiver completes the acquisition of the pilot header, it immediately enters the frame synchronization detection; this sequence is also used as carrier synchronization to eliminate the carrier error caused by the up and down conversion of the system, thereby realizing the demodulation and decoding of subsequent information.

[0012] ◆Control Fields: Control fields include the sending node information, sending timestamp information, and sending node status information of the current ranging frame. These are key information for achieving bidirectional comparison ranging and network formation.

[0013] ◆Distance information: Distance information carries the basic information used for distance measurement and the specific distance measurement results, including node number, auxiliary distance measurement information, and specific distance measurement value.

[0014] ◆Inertial Navigation and Dynamic Information: This section includes the current inertial navigation information of the device, which is used to assist nodes in converting measurement nodes into specific coordinates; the inertial navigation and dynamic information includes accelerometer parameters, gyroscope parameters, magnetic compass parameters, and barometer parameters.

[0015] ◆Other redundant information: used for CRC check, encoding / decoding redundancy, and other reserved information.

[0016] Step 2: UAV node A modulates the information obtained in Step 1 using QPSK modulation to obtain a QPSK modulated signal. An orthogonal ranging single-tone signal is added to the QPSK modulated signal to obtain the transmitted signal s(t). The transmitted signal s(t) consists of two parts: a communication modulation signal s with a symbol period of T. QPSK (t) and pilot signal s with frequency 1 / T pilot The pilot signal's zero phase is aligned with the start point of the communication modulation signal (t), thus achieving coherence. The modulation process of signal s(t) employs quadrature modulation and quadrature up-conversion, as shown below:

[0017]

[0018] Where g(t-kT) is the value of a rectangular non-return-to-zero pulse with amplitude of 1 and duration of T during the duration of the kth symbol; a k b k Let I(t) be the first and second bits of the k-th symbol in the QPSK modulated signal; t be the time; I(t) be the in-phase component and Q(t) be the quadrature component.

[0019] By using orthogonal upconversion to shift s(t) to radio frequency, the radio frequency transmitted signal s c (t) is represented as:

[0020] s c (t)=I(t)cos(2πf ct)-Q(t)sin(2πf c t)

[0021] Among them, f c This refers to the radio frequency (RF) frequency. The RF transmission signal s is then transmitted using a DAC and an antenna. c (t) is used for transmission, and at the same time, the local timer starts to count the bidirectional comparison delay.

[0022] Step 3: Define m as the ranging initiating node and n as the ranging relaying node. The receiving end of the ranging relaying node receives the radio frequency transmission signal s from Step 2. c (t) performs down-conversion and uses a traditional matched filter method to capture the pilot header in the QPSK signal. Each ranging and forwarding node n needs to calculate the forwarding processing delay τ based on the capture time. mn This refers to the time from capturing the ranging initiation signal from node m to the transmission from node n. The forwarding processing delay τ is also included. mn It needs to be transmitted as control field information. The ranging forwarding node n needs to transmit the signal according to steps one and two, which includes n-1 forwarding processing delays.

[0023] Step 4: The UAV ranging initiating node captures the transmitted signal from the ranging relay node. Upon signal capture, the timing for the corresponding ranging pair is stopped, and the total transmission delay for the corresponding ranging pair is obtained.

[0024] Step 5: The UAV ranging initiating node processes the received signal and completes coarse time synchronization.

[0025] Because the orthogonal pilot signals and the communication signals are orthogonal, the node receiver performs matched filtering and carrier synchronization on the received signals to losslessly demodulate the forwarding processing delay information τ contained in the communication signals. mn The coarse transmission delay estimate is obtained using the following formula:

[0026]

[0027] Due to total transmission delay and forwarding processing delay τ mn All use local processing clock f s Start timing, at this time The resolution is 1 / f s .

[0028] Step 6: The UAV ranging initiation node estimates the residual time delay τ using coherent pilot signals. r And combined with coarse transmission delay estimation results High-precision distance measurement can be performed using the following formula:

[0029]

[0030] Where c is the speed of electromagnetic wave propagation in air. For residual delay τ r The estimation results, This provides a high-precision distance estimation result;

[0031] The estimation method involves the receiver multiplying the acquired signal by the local coherent carrier frequency generated based on the acquisition time, and then performing phase detection to obtain the estimated signal. The specific estimation method is as follows:

[0032] Due to the coarse transmission delay estimation results With low time resolution, the signal r(t) captured by the receiver will have a residual transmission time τ. r And there will be a phase deviation θ, which is expressed as:

[0033] r(t) = s c (t+τ r )e jθ

[0034] The phase deviation θ is eliminated by carrier synchronization in step five.

[0035] Based on the initial phase of the coherent pilot generated at the capture time and s c (0) Aligned, and a single-tone signal with a frequency of 1 / T is represented as: For s c (t+τ r Performing orthogonal downconversion and multiplying it by the local coherent pilot signal yields:

[0036]

[0037] Among them, s Ih (t) and s Qh (t) are the higher-order components generated by orthogonally downconverting I(t) and Q(t) and multiplying them with the local coherent pilot, respectively. Since f c Typically, the frequency of the coherent pilot is an integer multiple of 1 / T, s Ih (t) and s Qh The higher-order frequency components contained in (t) are all coherent pilot frequencies of 1 / T, which are also integer multiples of the communication symbol rate. Accumulating the frequency conversion result over N symbol periods to eliminate high-frequency components yields:

[0038]

[0039] Phase detection of the accumulated results yields the residual propagation time τ. r The precise estimation results are as follows:

[0040]

[0041] Here, angle(·) represents phase detection of the variable, and the result takes values ​​in the range of [-π, π).

[0042] Beneficial effects:

[0043] 1. The single-carrier high-precision bidirectional ranging method based on orthogonal waveform design disclosed in this invention utilizes coherent pilots orthogonal to the signal, without using additional spectrum resources. It does not require accumulation and phase detection during ranging, and has lower implementation complexity compared to traditional code ring bidirectional ranging methods.

[0044] 2. The single-carrier high-precision bidirectional ranging method based on orthogonal waveform design disclosed in this invention utilizes the phase detection compensation pseudocode time estimation method, which can improve ranging resolution and ranging accuracy without increasing processing delay and processing complexity.

[0045] 3. The single-carrier high-precision bidirectional ranging method based on orthogonal waveform design disclosed in this invention utilizes an scalable bidirectional comparison strategy. Each node generates radio frequency signals sequentially, and each transmitted data contains forwarding processing delay information of multiple nodes, which can quickly complete multi-node network ranging. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the single-carrier high-precision bidirectional ranging method based on orthogonal waveform design of the present invention;

[0047] Figure 2 This is a schematic diagram of the frequency domain of the orthogonal waveform in this invention;

[0048] Figure 3 This is the two-way comparison strategy for drone clusters in this invention;

[0049] Figure 4 This is a curve showing how the ranging accuracy of this invention changes with the signal-to-noise ratio. Detailed Implementation

[0050] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. The technical problems solved by the present invention and its beneficial effects are also described. It should be noted that the described embodiments are only intended to facilitate understanding of the present invention and do not constitute any limitation thereof.

[0051] To make the above-mentioned objectives, features and advantages of the present invention easier to understand, they will be further described in detail below with reference to the accompanying drawings and specific embodiments. This embodiment is a single-carrier high-precision bidirectional ranging method based on orthogonal waveform design for an unmanned aerial vehicle (UAV) ad hoc network system. The parameters in this embodiment are shown in Table 1:

[0052] Table 1 Parameters of the Example

[0053]

[0054] like Figure 1 As shown in the figure, the specific implementation steps of the single-carrier high-precision bidirectional ranging method based on orthogonal waveform design disclosed in this embodiment are as follows:

[0055] Step 1: The UAV node generates information according to the ranging frame structure. A ranging communication frame is 0.3ms long, and for a symbol rate of 15M, it contains a total of 4500 symbols, including the following main parts:

[0056] ◆Pilot Head: The pilot head uses 8 pseudo-random sequences of 64 symbols each, occupying a total of 512 symbols, to ensure the correctness of signal detection and time estimation. Matched filtering and TONG decision detection methods are used together for detection.

[0057] ◆Frame Synchronization Header: The frame synchronization header is implemented using 32 pseudo-random symbols. In carrier synchronization, this pseudo-random sequence is correlated with the receiver to obtain the phase deviation.

[0058] ◆Control Fields: The control fields mainly include the sending node information, sending timestamp information, and sending node status information of the current ranging frame, totaling 512 symbols.

[0059] ◆Distance Measurement Information: The distance measurement information carries the basic information used for distance measurement and the specific distance measurement result. Each node is assigned 50 symbols, including node number (6), valid information bits (2), auxiliary distance measurement information (16), specific distance measurement value (16), and other reserved bits (10). For 50 nodes, there are a total of 2500 symbols.

[0060] ◆Inertial Navigation and Dynamic Information: This information typically includes parameters from the accelerometer, gyroscope, magnetic compass, and barometer. To ensure this information covers all situations, the inertial navigation and dynamic information includes a total of 512 symbols.

[0061] ◆Other redundant information: 432 symbols remain, used for CRC check, encoding / decoding redundancy and other reserved information.

[0062] Step 2: UAV node A modulates the information obtained in Step 1 using QPSK modulation to obtain a QPSK modulated signal. An orthogonal ranging single-tone signal is added to the QPSK modulated signal to obtain the transmitted signal s(t). The transmitted signal s(t) consists of two parts: a communication modulation signal s with a symbol rate of 15Msps. QPSK (t) and a pilot signal s with a frequency of 15MHz pilotThe pilot signal's zero phase is aligned with the start point of the communication modulation signal (t), thus achieving coherence. The modulation process of signal s(t) employs quadrature modulation and quadrature up-conversion, as shown below:

[0063]

[0064] Where g(t-kT) is the value of a rectangular non-return-to-zero pulse with amplitude of 1 and duration of T during the duration of the kth symbol; a k b k Let I(t) be the first and second bits of the k-th symbol in the QPSK modulated signal; t be the time; I(t) be the in-phase component and Q(t) be the quadrature component. A schematic diagram of the power spectral density of this signal is attached. Figure 2 As shown.

[0065] By using orthogonal upconversion to shift s(t) to radio frequency, the radio frequency transmitted signal s c (t) is represented as:

[0066] s c (t)=I(t)cos(2πf c t)-Q(t)sin(2πf c t)

[0067] Among them, f c The frequency is radio frequency; then the DAC and antenna are used to transmit the radio frequency signal s. c (t) is transmitted, and at the same time, the local timer starts to count the bidirectional comparison delay;

[0068] Step 3: The ranging and relaying node receiver processes the radio frequency transmission signal s from Step 2. c (t) Perform down-conversion and use the traditional matched filter method to capture the pilot header in the QPSK signal; each ranging and forwarding node n needs to calculate the forwarding processing delay τ based on the capture time. mn That is, the time from capturing the ranging initiation signal from node m to the transmission from node n; the forwarding processing delay τ. mn It needs to be transmitted as control field information. The ranging and forwarding node n needs to transmit the signal according to steps one and two, which includes n-1 forwarding processing delays.

[0069] like Figure 3 As shown, the estimation of 1225 ranging pairs is completed using 50 launch processes. The specific implementation method is as follows:

[0070] ①The other nodes simultaneously receive the signal sent by node A;

[0071] ② Node B generates an RF transmission signal according to steps one and two. The control field in the transmission signal needs to include the forwarding processing delay τ.AB Node A acts as the ranging initiating node and receives the transmitted signal from node B, while the other nodes act as ranging forwarding nodes and receive the transmitted signal from node B.

[0072] ③ Node C generates an RF transmission signal according to steps one and two. The control field in the transmitted signal needs to include the forwarding processing delay τ. AC and τ BC Nodes A and B act as ranging initiating nodes and receive the transmitted signals from node C, while the remaining nodes act as ranging forwarding nodes and receive the transmitted signals from node C.

[0073] ④ Subsequent nodes repeat the above process until all 50 nodes have completed the launch.

[0074] Step 4: The UAV ranging initiating node captures the transmission signal of the ranging relay node.

[0075] Taking the distance measurement pair AB as an example, we assume that the distance between AB is 117m and the processing delay of node B is 1000 local clock cycles.

[0076] Because the precise time is

[0077] T AB =2r / c+τ AB

[0078] =2×117 / c+1000 / f s

[0079] =1093.6 / f s

[0080] After the signal is captured, stop the timing of the corresponding ranging pair and obtain the total transmission delay.

[0081] Step 5: The UAV ranging initiating node processes the received signal and completes coarse time synchronization.

[0082] Because the orthogonal pilot signals and the communication signals are orthogonal, the node receiver performs matched filtering and carrier synchronization on the received signals to losslessly demodulate the forwarding processing delay information τ contained in the communication signals. AB =1000; The coarse transmission delay estimate is obtained according to the following formula:

[0083]

[0084] Due to total transmission delay and forwarding processing delay τ mn All use local processing clock f s Start timing, at this time The resolution is 1 / f s ;

[0085] Due to total transmission delay and forwarding processing delay τ mn All of them use a local processing clock f s Timing is initiated at a resolution of 1 / f. s Residual transmission delay τ r 0.4 / f s .

[0086] Step 6: The UAV ranging initiation node estimates the residual time delay τ using coherent pilot signals. r And combined with coarse transmission delay estimation results Perform high-precision distance measurement using the following formula:

[0087]

[0088] Where c is the speed of electromagnetic wave propagation in air. For residual delay τ r The estimation results, This provides a high-precision distance estimation result;

[0089] The estimation method involves the receiver multiplying the acquired signal by the local coherent carrier frequency generated based on the acquisition time, and then performing phase detection; the specific estimation method is as follows:

[0090] Due to the coarse transmission delay estimation results With low time resolution, the signal r(t) captured by the receiver will have a residual transmission time τ. r And there will be a phase deviation θ, which is expressed as:

[0091] r(t) = s c (t+τ r )e jθ

[0092] According to step five, carrier synchronization can eliminate phase deviation θ;

[0093] Based on the initial phase of the coherent pilot generated at the capture time and s c A single-tone signal with (0) alignment and a frequency of 1 / T can be represented as: For s c (t+τ r By performing orthogonal downconversion and multiplying it by the local coherent pilot, we can obtain:

[0094]

[0095] Among them, s Ih (t) and s Qh(t) are the higher-order components generated by orthogonally downconverting I(t) and Q(t) and multiplying them with the local coherent pilot, respectively. Since f here c It is twice the coherent pilot frequency 1 / T, s Ih (t) and s Qh The higher-order frequency components contained in (t) are all coherent pilot frequencies of 1 / T, which are also integer multiples of the communication symbol rate. Accumulating the frequency conversion results over 2000 symbol periods eliminates the high-frequency components, resulting in:

[0096]

[0097] The residual propagation time τ can be obtained by phase detection of the accumulated results. r The precise estimation results are as follows:

[0098]

[0099] Among them, e τ This represents the estimation error in phase detection. Utilizing... and coarse transmission delay estimation results It can obtain high-precision ranging results:

[0100]

[0101] Furthermore, based on the relationship between transmission delay and distance, the distance can be estimated:

[0102]

[0103] Where c is the speed of electromagnetic wave propagation in air, e r This represents the ranging error.

[0104] The above analysis ignores the impact of carrier synchronization on ranging accuracy. However, since precise time estimation uses phase detection as the estimation method, the accuracy of the phase detection algorithm and the remaining carrier error after carrier synchronization will affect the final estimation accuracy. In short-term UAV ad hoc network ranging, the carrier Doppler between UAV nodes is negligible. The carrier frequency offset is mainly caused by the clock difference of the local processing clock. If synchronization is performed at the start of the ad hoc network task, the clock difference can be eliminated to a certain extent. During the 1-2 hour working time of the ad hoc network task, the carrier frequency offset caused by the local clock difference can also be ignored. Therefore, in network ranging, the main carrier frequency offset is the carrier phase deviation between nodes.

[0105] This invention uses root mean square error (RMSE) to measure the estimation error e of phase detection. τ To visually represent the impact of phase detection estimation error on distance measurement, this error is converted into distance units for analysis. Figure 4 The ranging error is given under conditions of residual carrier phase error and ideal conditions. Based on... Figure 4 It can be seen that under high signal-to-noise ratio, the network ranging accuracy can reach 1mm, which can cover most of the UAV networking task requirements.

[0106] The above detailed description further illustrates the purpose, technical solution, and beneficial effects of the invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-precision bidirectional ranging method based on waveform domain orthogonality using a single carrier, characterized in that: Includes the following steps, Step 1: The UAV node generates information according to the ranging frame structure; Step 2: UAV node A modulates the information obtained in Step 1 using QPSK modulation to obtain a QPSK modulated signal; an orthogonal ranging single-tone signal is added to the QPSK modulated signal to obtain the transmitted signal s(t); the transmitted signal s(t) consists of two parts, a communication modulation signal s with a symbol period of T. QPSK (t) and pilot signal s with frequency 1 / T pilot (t), the zero phase of the pilot signal is aligned with the starting point of the communication modulation signal, thus achieving coherence; the modulation process of signal s(t) adopts quadrature modulation and quadrature up-conversion, as shown below: Where g(t-kT) is the value of a rectangular non-return-to-zero pulse with amplitude of 1 and duration of T during the duration of the kth symbol; a k b k Let I(t) be the first and second bits of the k-th symbol in the QPSK modulated signal; t is time; I(t) is the in-phase component; Q(t) is the quadrature component; By using orthogonal upconversion to shift s(t) to radio frequency, the radio frequency transmitted signal s c (t) is represented as: s c (t)=I(t)cos(2πf c t)-Q(t)sin(2πf c t) Among them, f c The frequency is radio frequency; then the DAC and antenna are used to transmit the radio frequency signal s. c (t) is transmitted, and at the same time, the local timer starts to count the bidirectional comparison delay; Step 3: Define m as the ranging initiating node and n as the ranging forwarding node; the receiving end of the ranging forwarding node receives the radio frequency transmission signal s from Step 2. c (t) Perform down-conversion and use a matched filter method to capture the pilot header in the QPSK signal; each ranging and forwarding node n needs to calculate the forwarding processing delay τ based on the capture time. mn That is, the time from capturing the ranging initiation signal from node m to the transmission from node n; the forwarding processing delay τ. mn It needs to be transmitted as control field information. The ranging and forwarding node n needs to transmit the signal according to steps one and two, which includes n-1 forwarding processing delays. Step 4: The UAV ranging initiating node acquires the transmission signal from the ranging relay node; upon acquiring the signal, it stops timing the corresponding ranging pair and obtains the total transmission delay of the corresponding ranging pair. Step 5: The UAV ranging initiation node processes the received signal and completes coarse time synchronization; Because the orthogonal pilot signals and the communication signals are orthogonal, the node receiver performs matched filtering and carrier synchronization on the received signals to losslessly demodulate the forwarding processing delay information τ contained in the communication signals. mn The coarse transmission delay estimate is obtained using the following formula: Due to total transmission delay and forwarding processing delay τ mn All use local processing clock f s Start timing, at this time The resolution is 1 / f s ; Step 6: The UAV ranging initiation node estimates the residual time delay τ using coherent pilot signals. r And combined with coarse transmission delay estimation results High-precision distance measurement can be performed using the following formula: Where c is the speed of electromagnetic wave propagation in air. For residual delay τ r The estimation results This is a high-precision distance estimation result.

2. The single-carrier high-precision bidirectional ranging method based on waveform domain orthogonality as described in claim 1, characterized in that: The estimation method involves the receiver multiplying the acquired signal by the local coherent carrier frequency generated based on the acquisition time, and then performing phase detection to obtain the estimated signal. The specific estimation method is as follows: Due to the coarse transmission delay estimation results With low time resolution, the signal r(t) captured by the receiver will have a residual transmission time τ. r There will be a phase deviation θ, and the signal r(t) is expressed as: r(t)=s c (t+τ r )e jθ Eliminate phase deviation θ according to the carrier synchronization in step five; Based on the initial phase of the coherent pilot generated at the capture time and s c (0) Aligned, and a single-tone signal with a frequency of 1 / T is represented as: For s c (t+τ r Performing orthogonal downconversion and multiplying it by the local coherent pilot signal yields: Among them, s Ih (t) and s Qh (t) are the higher-order components generated by orthogonal downconversion of I(t) and Q(t) and multiplication with the local coherent pilot; since f c Typically, the frequency of the coherent pilot is an integer multiple of 1 / T, s Ih (t) and s Qh The higher-order frequency components contained in (t) are all coherent pilot frequencies of 1 / T, which are also integer multiples of the communication symbol rate; by accumulating the frequency conversion result for N symbol periods to eliminate the high-frequency components, we get: The residual propagation time τ can be obtained by phase detection of the accumulated results. r The precise estimation results are as follows: Here, angle(·) represents phase detection of the variable, and the result takes values ​​in the range of [-π, π).

3. The single-carrier high-precision bidirectional ranging method based on waveform domain orthogonality as described in claim 1 or 2, characterized in that, The frame structure described in step one includes a pilot header, a frame synchronization header, control fields, ranging information, inertial navigation and dynamic information, and other redundant information; ◆Pilot Head: The pilot head is mainly used to detect the presence or absence of a signal and to initially determine the optimal sampling point for the received signal, thereby achieving coarse range estimation. The estimation resolution is on the order of the sampling clock. A pseudo-random sequence is used to design the pilot head. ◆Frame Synchronization Head: The frame synchronization head is used to achieve frame synchronization of communication symbols. After the receiver completes the acquisition of the pilot head, Immediately proceed with frame synchronization detection; This sequence is also used for carrier synchronization, eliminating carrier errors caused by up-conversion and down-conversion of the system, thereby enabling demodulation and decoding of subsequent information; ◆Control Fields: Control fields include the sending node information, sending timestamp information, and sending node status information of the current ranging frame. These are key information for realizing bidirectional comparison ranging and network formation. ◆Distance measurement information: Distance measurement information carries the basic information used for distance measurement and the specific distance measurement results, including node number, auxiliary distance measurement information, and specific distance measurement value; ◆Inertial Navigation and Dynamic Information: This section includes the current inertial navigation information of the device, which is used to assist nodes in converting measurement nodes into specific coordinates; the inertial navigation and dynamic information includes accelerometer parameters, gyroscope parameters, magnetic compass parameters, and barometer parameters; ◆Other redundant information: used for CRC check, encoding / decoding redundancy, and other reserved information.

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