Chirp signal coding and decoding method for indoor positioning

Abstract

The invention discloses a Chirp signal encoding and decoding method for indoor positioning, and relates to the technical field of communication, the method comprises the following steps: pre-constructing a Chirp code segment set of orthogonal dual channels, the set comprising independent code segments corresponding to different bit values; acquiring a serial bit stream bearing positioning and ranging information, calling a corresponding code segment according to a bit value to output an orthogonal dual-channel Chirp modulation signal, generating a time sequence latch signal, and prohibiting a new bit stream from being input in a current frame processing period; a modulation signal is collected and converted into a digital sampling signal, and the sampling signal and the code segment set are subjected to full-segment matching to obtain a matching result; restoring the serial bit stream according to a matching result, and synchronously updating the time sequence latch signal to allow a new bit stream to be input; and circularly executing the process to complete the continuous ranging frame encoding and decoding of indoor positioning. According to the method, the problems of frame processing time sequence disorder and bit stream crosstalk are relieved through time sequence closed-loop management and control, and the stability and coherence of continuous ranging encoding and decoding are improved.

Description

Technical Field

[0001] This invention relates to the field of communication technology, and in particular to a chirp signal encoding and decoding method for indoor positioning. Background Technology

[0002] Linear frequency modulation often uses chirp as a signal source. Due to its good anti-interference characteristics, chirp signals are widely used in the encoding, decoding, transmission and analysis of positioning and ranging data.

[0003] Chinese invention patent CN106411467B discloses an information transmission and reception method based on Chirp signals. The method performs channel coding on the information to be transmitted, arranges the coded data into a matrix format, completes data permutation and interleaving through preset row vectors, and then modulates the interleaved data into a Chirp signal for transmission. After demodulating the Chirp signal at the receiving end, the original information is restored through matrix rearrangement, reverse deinterleaving, and channel decoding. The interleaving process improves the system's ability to resist sudden interference.

[0004] When the aforementioned existing technologies are applied to continuous ranging scenarios for indoor wireless positioning, they only perform encoding, decoding, and interleaving operations on independent single-frame data. They do not construct a timing closed-loop control mechanism for continuous ranging frames. During the encoding and decoding of multiple sets of ranging frames, problems such as serial bit stream crosstalk and frame processing timing disorder are prone to occur. It is impossible to stably realize the encoding and decoding of continuous ranging frames for indoor wireless positioning, and it is difficult to guarantee the continuity and stability of the positioning and ranging process. Summary of the Invention

[0005] To address the technical problems of serial bit stream crosstalk and frame processing timing disorder that easily occur during the encoding and decoding of multiple sets of ranging frames in the existing technology, this invention provides a chirp signal encoding and decoding method for indoor positioning.

[0006] The technical solution adopted in this invention is:

[0007] A chirp signal encoding and decoding method for indoor positioning, comprising:

[0008] Step 1: Preconstruct an orthogonal dual-channel Chirp code segment set, wherein the Chirp code segment set contains independent code segments corresponding to different bit values;

[0009] Step 2: Obtain the serial bit stream of the positioning and ranging frame, wherein the serial bit stream is used to carry the positioning and ranging information;

[0010] Step 3: Based on the bit values ​​of the serial bit stream, call the corresponding independent code segment from the Chirp code segment set, output the orthogonal dual-channel Chirp modulation signal, and generate a timing latch signal at the same time. The timing latch signal is used to prevent new serial bit stream input during the current frame processing period.

[0011] Step 4: Acquire the orthogonal dual-channel Chirp modulated signal and convert the acquired signal into a digital sampling signal;

[0012] Step 5: Perform full-segment matching between the digital sampled signal and the Chirp code segment set to obtain the code segment matching result;

[0013] Step 6: Reconstruct the serial bit stream of the positioning and ranging frame based on the code segment matching result, and update the timing latch signal at the same time. The updated timing latch signal is used to allow the input of new serial bit streams.

[0014] Step 7: Repeat steps 2 to 6 to complete the continuous ranging frame encoding and decoding for indoor wireless positioning.

[0015] Preferably, step 1 includes the following:

[0016] Each transmission channel of the orthogonal dual-channel system is configured with an independent code segment corresponding to a different bit value;

[0017] Based on the channel feature data obtained from the previous frame, the feature parameters of the current independent code segment are dynamically adjusted to form an orthogonal dual-channel Chirp code segment set adapted to the indoor channel.

[0018] Preferably, step 2 includes the following:

[0019] Receive the data stream for positioning and ranging;

[0020] Based on the temporal characteristics of the data stream itself, the frame data of different positioning nodes are distinguished to obtain the effective frame data after the distinction is completed;

[0021] Extract and obtain the serial bit stream of the positioning and ranging frame from the valid frame data that has been distinguished.

[0022] Preferably, step 3 includes the following:

[0023] Based on the current bit value, the corresponding independent code segment is called and an orthogonal dual-channel Chirp modulated signal is output;

[0024] Within the code segment output period corresponding to the current bit, a timing latch signal is generated to maintain the current frame processing period.

[0025] Preferably, step 4 includes the following:

[0026] The orthogonal dual-channel Chirp modulated signal is acquired and noise suppression preprocessing is performed to obtain the preprocessed signal;

[0027] Based on the acquisition start signal of the current frame, the preprocessed signal is subjected to analog-to-digital conversion to obtain the digital sampled signal.

[0028] Preferably, step 5 includes the following:

[0029] Based on the preset feature anchor points in the independent code segments, candidate code segment screening is performed on the digital sampled signal;

[0030] The digital sampled signal is matched with the filtered candidate code segments to obtain the code segment matching result.

[0031] Preferably, step 6 includes the following:

[0032] The serial bit stream of the positioning and ranging frame is reconstructed based on the code segment matching results;

[0033] When the bitstream reconstruction result meets the preset conditions for valid frame data, update the timing latch signal;

[0034] If the bitstream reconstruction result does not meet the preset conditions for valid frame data, update the timing latch signal and discard the current frame data.

[0035] The beneficial effects of this invention are as follows: By constructing a timing closed-loop control mechanism for continuous ranging frames, it can effectively alleviate the frame processing timing disorder problem easily caused by traditional single-frame independent encoding and decoding methods, and improve the stability of the continuous ranging frame encoding and decoding process. By uniformly controlling the encoding and decoding timing of continuous ranging frames, it can reduce crosstalk in the serial bit stream and ensure the transmission reliability of the continuously ranging frame encoded and decoded data. Compared with encoding and decoding processing methods that only target independent single-frame data, this invention can better adapt to the continuous ranging scenario requirements of indoor wireless positioning, and helps maintain the continuity of the positioning and ranging process. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the hardware architecture of the indoor positioning Chirp signal encoding and decoding system of the present invention;

[0037] Figure 2 This is a flowchart illustrating the method of the present invention. Detailed Implementation

[0038] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0039] like Figure 1As shown, the system mainly includes a main base station, Tag (mobile tag) nodes, and a host computer: The core of the main base station is a ZYNQ series chip, which includes a programmable logic unit (PL) and a processing system unit (PS), which interact through an AXI bus; the main base station is equipped with an AD9361 RF chip, which is responsible for the transmission and reception of chirp signals and analog-to-digital conversion, and also has a 433 communication module to realize auxiliary data interaction; the main base station is connected to the host computer through a UART to RS232 module to realize the uploading and configuration of positioning data; the Tag nodes and the main base station transmit chirp signals through a wireless channel to complete the interaction of positioning and ranging data.

[0040] Example 1

[0041] This embodiment is based on Figure 1 The hardware architecture shown is used to solve the technical problems of existing Chirp encoding and decoding technologies, such as the lack of timing closed-loop control and the inability to stably achieve indoor continuous ranging frame processing. Figure 2 As shown, this embodiment provides a chirp signal encoding and decoding method for indoor positioning, including:

[0042] Step 1: Preconstruct an orthogonal dual-channel Chirp code segment set, which contains independent code segments corresponding to different bit values.

[0043] Among them, orthogonal dual channels refer to two mutually orthogonal signal transmission channels used to independently transmit Chirp signals to improve the transmission anti-interference capability; Chirp code segment set refers to the sum of multiple pre-stored Chirp signal segments; independent code segment refers to a Chirp signal segment that uniquely corresponds to different bit values ​​and does not interfere with each other.

[0044] In the specific implementation process, during the system initialization phase, two orthogonal transmission channels are configured through the PL terminal of the ZYNQ chip. Chirp signal segments corresponding to bit 0 and bit 1 are generated for each channel. All signal segments are integrated into a unified code segment set and stored in the PL terminal storage unit.

[0045] For example, the system initializes the BRAM storage unit based on the PL terminal of the ZYNQ-7020 chip, configures a 56MHz system sampling clock, and constructs an I-channel cosine sine channel and a Q-channel sine sine channel respectively. For each channel, 112 sampling points and 12-bit quantization precision independent Chirp code segments are generated. The I-channel is configured with the Up-Chirp code segment corresponding to bit 1 and the Down-Chirp code segment corresponding to bit 0. The Q-channel is synchronously configured with the orthogonal independent code segments corresponding to bit 1 and bit 0. All code segments are combined to form an orthogonal dual-channel Chirp code segment set and are stored in the BRAM.

[0046] This step reduces processing delay caused by real-time signal generation and improves encoding and decoding response speed by pre-constructing a set of Chirp code segments with fixed mapping relationships. The orthogonal dual-channel structure design allows the two signals to remain independent during transmission, reducing crosstalk between signals and improving transmission stability in indoor multipath reflection environments.

[0047] Step 2: Obtain the serial bit stream of the positioning and ranging frame, which is used to carry the positioning and ranging information.

[0048] It should be noted that the positioning and ranging frame refers to the signal frame that carries the data required for indoor positioning distance calculation; the serial bit stream refers to the binary bit sequence transmitted sequentially in time.

[0049] In the specific implementation process, the PS end of the ZYNQ chip receives ranging data sent by the positioning system, converts the ranging data into a binary sequence arranged in time order, and obtains a serial bit stream used to carry positioning information; or it receives ranging data sent by the Tag node through the 433 module and converts it into a serial bit stream.

[0050] For example, in an indoor positioning system, the Tag node ID 0x01 sends a ranging request frame to the main base station. The frame structure includes a 1-byte node identifier, a 2-byte ranging instruction, and a 1-byte check bit, with a total length of 32 bits. The data is transmitted to the PS end of the ZYNQ chip at a rate of 9600bps via the 433 module. The PS end converts the parallel data into a serial bit stream that is transmitted sequentially at a rate of 0.2μs / bit.

[0051] The bitstream sequence is: 1001 0001 0010 1100 0110 1010 1110 0011, which is used for subsequent Chirp encoding.

[0052] Step 3: Based on the bit values ​​of the serial bit stream, call the corresponding independent code segment from the Chirp code segment set, output the orthogonal dual-channel Chirp modulation signal, and generate a timing latch signal. The timing latch signal is used to prevent new serial bit stream input during the current frame processing period.

[0053] It should be noted that the orthogonal dual-channel Chirp modulation signal refers to the Chirp modulation signal obtained by bit value mapping through orthogonal channels; the timing latch signal refers to the timing control signal used to control the input permissions of the bit stream; and the current frame processing period refers to the total duration from the start of encoding the current ranging frame to the completion of decoding.

[0054] During encoding, a latch signal is generated to prevent new bitstream input, which avoids crosstalk caused by new data being mixed in during the processing of the current frame and ensures the integrity of single-frame encoding and decoding.

[0055] In the specific implementation process, the PL terminal identifies the current bit value of the serial bit stream, retrieves the matching independent code segment from the pre-constructed code segment set, and outputs the modulation signal to the AD9361 RF chip through the positive channel; at the same time, the PL terminal outputs a timing latch signal to block the input of new serial bit streams within the current frame processing period.

[0056] For example, the serial bit stream of a positioning and ranging frame is represented as a binary sequence:

[0057] in to These are the bit values ​​transmitted sequentially, and can be either 0 or 1.

[0058] The orthogonal dual-channel Chirp signal uses linear frequency modulation. The expression for the I-channel Chirp signal is: The expression for the Chirp signal of the path channel is:

[0059] in For signal amplitude, , The initial frequency, This represents the frequency modulation slope.

[0060] In one possible example, the signal amplitude initial frequency , 2.4GHz, frequency modulation slope When the current serial bit stream has a bit value of 1, the PL terminal retrieves a 112-point, 12-bit bit-1 matching code segment from the I-channel positive channel and outputs it to the AD9361 chip to generate a Chirp modulation signal. At the same time, it outputs a high-level (3.3V) timing latch signal to prevent new bit streams from entering the encoding module. When the current serial bit stream has a bit value of 0, it retrieves the corresponding code segment from the Q-channel and outputs the modulation signal. The latch signal remains high until all 32 bits are encoded.

[0061] This step ensures a stable correspondence between the Chirp modulation signal and the original bit stream through precise mapping of bit values ​​and code segments, reducing the probability of coding errors. The timing latch signal can block new data input throughout the current frame processing, effectively avoiding problems such as inter-frame data crosstalk and timing disorder, ensuring the independent and complete operation of the single-frame encoding and decoding process, and improving the reliability of indoor positioning data processing.

[0062] Step 4: Acquire the orthogonal dual-channel Chirp modulated signal and convert the acquired signal into a digital sampling signal.

[0063] In this context, the digital sampled signal refers to the discrete digital signal obtained after acquisition and analog-to-digital conversion. Analog Chirp modulation signals cannot be directly matched with code segments and must be converted into digital sampled signals before they can be compared with pre-stored code segments.

[0064] In the specific implementation process, the AD9361 RF chip acquires the orthogonal dual-channel Chirp modulation signal sent by the Tag node and transmits the analog signal to the PL terminal of the ZYNQ chip. The PL terminal performs analog-to-digital conversion on the acquired analog signal and converts the analog signal into a discrete digital sampling signal.

[0065] For example, the AD9361 chip acquires I / Q Chirp modulated signals at a sampling frequency of 56MHz, with 112 analog sampling points for each bit, converting the analog signal with an amplitude of 0~3.3V into a 12-bit quantized (0~4095) discrete digital sampling signal; the PL terminal concatenates the two digital signals into an orthogonal digital sampling signal and stores it in a FIFO buffer, waiting for subsequent matching processing.

[0066] Step 5: Perform full-segment matching between the digital sampled signal and the Chirp code segment set to obtain the code segment matching result.

[0067] Among them, full-segment matching refers to the operation of comparing the complete digital sampled signal with the pre-stored independent code segments as a whole; code segment matching result refers to the result of the corresponding bit values ​​obtained after the comparison.

[0068] Full-segment matching can avoid errors caused by partial comparisons, improve the accuracy of bit reconstruction, and adapt to complex indoor transmission environments.

[0069] In the specific implementation process, the PL end treats the digital sampled signal as a whole and compares it with each independent code segment in the Chirp code segment set in sequence to determine the target code segment that matches the sampled signal, and outputs the corresponding matching result to the PS end.

[0070] For example, the PL terminal reads 112 points, 12-bit orthogonal digital sampling signals from the FIFO, and compares the signals with the I-way bit 1 code segment, I-way bit 0 code segment, Q-way bit 1 code segment, and Q-way bit 0 code segment in the BRAM in sequence to perform full segment correlation comparison; when the correlation between the sampling signal and the I-way bit 1 code segment is greater than the preset threshold of 0.85, the PL terminal determines the matching result as bit 1 and transmits the bit value to the PS terminal.

[0071] This step uses a full-segment overall matching method, which can avoid the problem of local feature distortion caused by indoor multipath interference, signal attenuation and other factors, and improve the accuracy of code segment matching.

[0072] Step 6: Reconstruct the serial bit stream of the positioning and ranging frame based on the code segment matching result, and update the timing latch signal at the same time. The updated timing latch signal is used to allow the input of new serial bit streams.

[0073] In the specific implementation process, the PS end determines the corresponding bit value based on the code segment matching result and restores the serial bit stream of the positioning and ranging frame in sequence; at the same time, the PS end sends control commands to the PL end through the AXI bus to change the state of the timing latch signal and allow the input of a new serial bit stream.

[0074] For example, the PS end receives a continuous sequence of matching results 1,0,0,1... and restores them sequentially to obtain a 32-bit positioning and ranging frame serial bit stream. After restoration, the PS end sends a low-level command to the PL end through the AXI bus. The PL end switches the timing latch signal from 3.3V high level to 0V low level, opens the bit stream input channel, and prepares to receive the next frame of data.

[0075] This step restores the bitstream in an orderly manner based on the matching results, which can completely recover the original positioning and ranging data and ensure the integrity of data parsing; timely updating of the timing latch signal can quickly remove input restrictions and smoothly connect to the processing flow of the next frame of data, avoiding process blockage.

[0076] Step 7: Repeat steps 2 to 6 to complete the continuous ranging frame encoding and decoding for indoor wireless positioning.

[0077] By repeatedly executing the encoding and decoding process, continuous processing of multiple frames of ranging data can be achieved, meeting the needs of real-time ranging for indoor positioning.

[0078] In the specific implementation process, after the current frame is processed, the PS terminal schedules back to the serial bit stream acquisition step, and sequentially triggers the PL terminal to perform subsequent encoding, acquisition, matching and decoding operations to continuously complete the encoding and decoding of multiple frames of ranging data; the PS terminal uploads the restored ranging data to the host computer through the UART to RS232 module.

[0079] For example, the indoor positioning system needs to complete the Tag node ranging every 10ms. The PS terminal schedules the encoding and decoding process in a 10ms cycle, processes multiple Tag node ranging frames with IDs 0x01, 0x02, and 0x03 in sequence, and continuously uploads the positioning results to the host computer for display via RS232.

[0080] In summary, this embodiment utilizes the collaboration between the PL and PS ends of the ZYNQ chip, combined with the AD9361 RF chip, to complete a closed-loop process of pre-stored code segments, encoding latch, acquisition conversion, full-segment matching, decoding and unlocking, and cyclic execution. This enables stable encoding and decoding of continuous ranging frames, improves the stability of indoor positioning continuous ranging frame processing, reduces data crosstalk, and ensures the continuity of the ranging process.

[0081] Example 2

[0082] Considering that in practical applications, static chirp code segments are prone to code segment matching deviations in indoor multipath and reflection-dependent channel environments, affecting encoding and decoding accuracy, in order to solve this technical problem, in one possible implementation, step 1 includes the following:

[0083] Each transmission channel of the orthogonal dual-channel system is configured with an independent code segment corresponding to a different bit value; based on the channel feature data obtained from the previous frame, the feature parameters of the current independent code segment are dynamically adjusted to form an orthogonal dual-channel Chirp code segment set adapted to the indoor channel.

[0084] In the specific implementation process, each transmission channel of the orthogonal dual-channel is first configured with an independent code segment with a different bit value; then the PS end extracts the channel feature data obtained in the encoding and decoding process of the previous frame, adjusts the feature parameters of the current independent code segment according to the channel feature data, forms an orthogonal dual-channel Chirp code segment set adapted to the indoor channel and updates it to the storage unit of the PL end.

[0085] For example, in the previous frame processing, three-path reflections and a 30% amplitude attenuation were detected in the indoor channel. The PS end extracted the attenuation feature data of this channel. When encoding the current frame, independent code segments of bits 0 and 1 were configured for the I / Q orthogonal dual channels respectively. Based on the attenuation features, the amplitude parameter of the code segment was increased by 30%, and the phase offset was corrected by 1° to form an orthogonal dual-channel Chirp code segment set adapted to the current multipath channel. This set was then updated to the BRAM at the PL end for encoding.

[0086] This embodiment dynamically adjusts the code segment parameters based on the characteristics of the preceding channel, enabling the Chirp code segment to actively adapt to the transmission characteristics of the indoor time-varying channel. This alleviates the matching deviation problem caused by environmental factors such as multipath reflection and signal attenuation, and reduces the probability of code segment mismatch in complex indoor environments. The dynamically adapted code segment set can improve the fit between the signal and the channel, improve the accuracy of the encoding and decoding results, and enable the system to maintain stable processing performance in different indoor channel environments, thereby improving the environmental adaptability of the solution.

[0087] Example 3

[0088] Considering that in practical applications, the above embodiments still have the problem of data stream aliasing and inability to distinguish valid frame data when multiple positioning nodes transmit concurrently, and invalid data occupying system processing resources, in order to solve this technical problem, in one possible implementation, step 2 includes the following:

[0089] Receive the positioning and ranging data stream; distinguish the frame data of different positioning nodes based on the timing characteristics of the data stream itself, and obtain the valid frame data after the distinction is completed; extract and obtain the serial bit stream of the positioning and ranging frame from the valid frame data after the distinction is completed.

[0090] In the specific implementation process, firstly, the PS end of the ZYNQ chip receives all the data streams for positioning and ranging through the 433 module; then, based on the transmission timing interval characteristics of the data stream, it distinguishes the frame data sent by different tag nodes and filters out the valid frame data; finally, it extracts the serial bit stream of the positioning and ranging frame from the valid frame data.

[0091] For example, three tag nodes (ID: 0x01 / 0x02 / 0x03) in the room simultaneously send ranging data with frame intervals of 0.2μs, 0.4μs, and 0.6μs, respectively. The PS end detects the temporal interval characteristics of the data stream, classifies frames with an interval of 0.2μs as node 0x01, 0.4μs as node 0x02, and 0.6μs as node 0x03, removes fragmented interference data with abnormal intervals, and extracts a 32-bit serial bit stream from the valid frames of node 0x01 for encoding.

[0092] This embodiment distinguishes multi-node frame data by using time interval features, which can accurately separate ranging data of different nodes in multi-node concurrent transmission scenarios and avoid frame recognition errors caused by data stream aliasing. Preemptively removing invalid fragment data can reduce the occupation of system processing resources by invalid data and improve the processing priority of valid data. The optimized bit stream acquisition method can improve the purity of data processing in multi-node scenarios and ensure the stable operation of multi-node indoor positioning system.

[0093] Example 4

[0094] Considering that the above embodiments still have the problem of bit-level crosstalk easily occurring when outputting intra-frame bit code segments during frame-level latch control in practical applications, affecting the encoding and decoding synchronization accuracy, in order to solve this technical problem, in one possible implementation, step 3 includes the following:

[0095] Based on the current bit value, the corresponding independent code segment is called and an orthogonal dual-channel Chirp modulation signal is output; within the output period of the code segment corresponding to the current bit, a timing latch signal is generated to maintain the current frame processing period.

[0096] In the specific implementation process, the PL terminal calls the corresponding independent code segment according to the current bit value and outputs the quadrature dual-channel Chirp modulation signal to the AD9361 chip; within the output period of the code segment corresponding to the current bit, a timing latch signal is generated, which continuously maintains the control state of the current frame processing period.

[0097] For example, the current bit code segment output period is 0.2μs, corresponding to the output duration of 112 sampling points; the PL terminal generates a high-level timing latch signal within this 0.2μs period to protect the current bit output from crosstalk; this latch signal is maintained until the current frame processing of 32 bits and a total duration of 6.4μs is completed, thus avoiding single-bit crosstalk and maintaining the timing control of the entire frame.

[0098] This embodiment refines the control granularity of timing latch from the frame level to the bit level, which can accurately protect the output process of a single bit code segment, reduce crosstalk between bits within a frame, and improve the timing synchronization accuracy of encoding and decoding. The refined timing control can further optimize the frame processing timing logic, improve the stability of data processing within a single frame while maintaining the continuous processing capability at the frame level, and improve the timing control effect of indoor positioning encoding and decoding.

[0099] Example 5

[0100] Considering that in practical applications of the above embodiments, there is still the problem that the acquired Chirp modulation signal contains noise interference in indoor weak signal environments, and direct conversion will reduce the subsequent matching accuracy, in order to solve this technical problem, in one possible implementation, step 4 includes the following:

[0101] The orthogonal dual-channel Chirp modulation signal is acquired and noise suppression preprocessing is performed to obtain a preprocessed signal; based on the acquisition start signal of the current frame, the preprocessed signal is subjected to analog-to-digital conversion processing to obtain the digital sampling signal.

[0102] In the specific implementation process, the AD9361 chip acquires orthogonal dual-channel Chirp modulation signals, and the PL terminal performs noise suppression preprocessing on the signals to remove environmental interference and obtain preprocessed signals. Based on the acquisition start signal of the current frame, analog-to-digital conversion processing is triggered to convert the preprocessed signals into digital sampling signals.

[0103] For example, the indoor environment has -60dBm electromagnetic interference noise, and the chirp signal acquired by AD9361 is superimposed with noise components; the PL terminal performs mean filtering and noise suppression on the signal to filter out high-frequency noise; the rising edge of the frame acquisition start signal is used as the trigger time to synchronously perform analog-to-digital conversion, converting the filtered signal into a 12-bit digital sampling signal to ensure that there is no offset in the sampling timing.

[0104] This embodiment adds noise suppression preprocessing before analog-to-digital conversion, which can effectively filter out noise components such as electromagnetic interference and clutter in the indoor environment, and improve the purity of the sampled signal. Based on the synchronous triggering of the acquisition start signal, the timing of analog-to-digital conversion can be kept consistent with the timing of signal acquisition, avoiding signal distortion caused by timing offset. The pure and timing-synchronized digital sampled signal can provide a more reliable data foundation for subsequent code segment matching, and improve the robustness of encoding and decoding in weak signal and high interference environments.

[0105] Example 6

[0106] Considering that the above embodiments still have the problem of directly performing full-segment matching on all code segments in practical applications, which is time-consuming and consumes hardware processing resources, in order to solve this technical problem, in one possible implementation, step 5 includes the following:

[0107] Based on the preset feature anchor points in the independent code segments, candidate code segments are filtered on the digital sampled signal; the digital sampled signal is then matched with the filtered candidate code segments to obtain the code segment matching result.

[0108] In the specific implementation process, the PL end extracts the preset feature anchor points in the independent code segment, compares the digital sampling signal based on the feature anchor points, and selects candidate code segments; the digital sampling signal and the candidate code segments are matched in full segment to obtain the final code segment matching result.

[0109] For example, the code segment set contains 4 independent code segments, and each code segment presets the 10th point, the 56th point, and the 100th point as feature anchor points; the PL end extracts the 3 anchor point values ​​of the sampled signal and compares them with the 4 code segment anchor points to select two candidate code segments, I-way bit 1 and Q-way bit 1; full segment matching is performed only on the two candidate code segments, reducing the matching calculation by 50%.

[0110] This embodiment pre-screens candidate code segments using feature anchor points, which can significantly reduce the comparison range of the entire segment matching, reduce unnecessary traversal calculations, and effectively improve the processing efficiency of code segment matching. The smaller matching range can reduce the amount of hardware computing resources occupied by the PL terminal and alleviate the hardware processing pressure. While ensuring matching accuracy, it can improve the processing speed of continuous ranging frames and adapt to the real-time requirements of indoor positioning.

[0111] Example 7

[0112] Considering that in practical applications, the above embodiments also have the problem of invalid frame data entering the subsequent positioning calculation process and causing data pollution due to the unified update of latch signals, in order to solve this technical problem, in one possible implementation, step 6 includes the following:

[0113] The serial bit stream of the positioning and ranging frame is reconstructed based on the code segment matching results;

[0114] When the bitstream reconstruction result meets the preset conditions for valid frame data, update the timing latch signal;

[0115] If the bitstream reconstruction result does not meet the preset conditions for valid frame data, update the timing latch signal and discard the current frame data.

[0116] In the specific implementation process, the PS end restores the serial bit stream of the positioning and ranging frame based on the code segment matching result; it determines whether the bit stream restoration result meets the frame data validity preset conditions. If the conditions are met, it directly sends an instruction to the PL end to update the timing latch signal; if the conditions are not met, it sends an instruction to update the timing latch signal and discards the current frame data, and does not pass invalid data into the positioning calculation module.

[0117] For example, the PS end restores a 32-bit bit stream. If the result of the check bit calculation does not match the preset value, it is determined to be an invalid frame. The PS end immediately sends an instruction to the PL end to update the timing latch signal to a low level, and simultaneously discards the 32-bit invalid bit stream. The data is not transmitted to the host computer, and the process directly enters the next frame processing flow.

[0118] This embodiment uses frame data validity determination linked to time-series latch updates to promptly identify and remove invalid frame data, preventing erroneous data from entering subsequent processes such as positioning calculation and data uploading, and preventing invalid data from contaminating the system. The logic of synchronously releasing invalid frames ensures that the continuous processing flow is not interrupted, avoiding process blockage caused by invalid data, and improving the reliability and smoothness of continuous ranging processing. Precise invalid data filtering can improve the validity of output positioning data and improve the accuracy of indoor positioning results.

[0119] The embodiments described above are merely illustrative of specific implementations of the present invention, and while the descriptions are detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A chirp signal encoding and decoding method for indoor positioning, characterized in that, include: Step 1: Preconstruct a set of orthogonal dual-channel Chirp code segments, wherein the set of Chirp code segments contains independent code segments corresponding to different bit values; Step 2: Obtain the serial bit stream of the positioning and ranging frame, wherein the serial bit stream is used to carry the positioning and ranging information; Step 3: Based on the bit values ​​of the serial bit stream, call the corresponding independent code segment from the Chirp code segment set, output the orthogonal dual-channel Chirp modulation signal, and generate a timing latch signal at the same time. The timing latch signal is used to prevent new serial bit stream input during the current frame processing period. Step 4: Acquire the orthogonal dual-channel Chirp modulated signal and convert the acquired signal into a digital sampling signal; Step 5: Perform full-segment matching between the digital sampled signal and the Chirp code segment set to obtain the code segment matching result; Step 6: Reconstruct the serial bit stream of the positioning and ranging frame based on the code segment matching result, and update the timing latch signal at the same time. The updated timing latch signal is used to allow the input of new serial bit streams. Step 7: Repeat steps 2 to 6 to complete the continuous ranging frame encoding and decoding for indoor wireless positioning.

2. The chirp signal encoding and decoding method for indoor positioning according to claim 1, characterized in that, Step 1 includes the following: Each transmission channel of the orthogonal dual-channel system is configured with an independent code segment corresponding to a different bit value; Based on the channel feature data obtained from the previous frame, the feature parameters of the current independent code segment are dynamically adjusted to form an orthogonal dual-channel Chirp code segment set adapted to the indoor channel.

3. The chirp signal encoding and decoding method for indoor positioning according to claim 1, characterized in that, Step 2 includes the following: Receive the data stream for positioning and ranging; Based on the temporal characteristics of the data stream itself, the frame data of different positioning nodes are distinguished to obtain the effective frame data after the distinction is completed; Extract and obtain the serial bit stream of the positioning and ranging frame from the valid frame data that has been distinguished.

4. The chirp signal encoding and decoding method for indoor positioning according to claim 1, characterized in that, Step 3 includes the following: Based on the current bit value, the corresponding independent code segment is called and an orthogonal dual-channel Chirp modulated signal is output; Within the code segment output period corresponding to the current bit, a timing latch signal is generated to maintain the current frame processing period.

5. A chirp signal encoding and decoding method for indoor positioning according to claim 1, characterized in that, Step 4 includes the following: The orthogonal dual-channel Chirp modulated signal is acquired and noise suppression preprocessing is performed to obtain the preprocessed signal; Based on the acquisition start signal of the current frame, the preprocessed signal is subjected to analog-to-digital conversion to obtain the digital sampled signal.

6. A chirp signal encoding and decoding method for indoor positioning according to claim 1, characterized in that, Step 5 includes the following: Based on the preset feature anchor points in the independent code segments, candidate code segment screening is performed on the digital sampled signal; The digital sampled signal is matched with the filtered candidate code segments to obtain the code segment matching result.

7. A chirp signal encoding and decoding method for indoor positioning according to claim 1, characterized in that, Step 6 includes the following: The serial bit stream of the positioning and ranging frame is reconstructed based on the code segment matching results; When the bitstream reconstruction result meets the preset conditions for valid frame data, update the timing latch signal; If the bitstream reconstruction result does not meet the preset conditions for valid frame data, update the timing latch signal and discard the current frame data.

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