PTP and radio frequency fusion synchronization method for holographic sand table double-main-view stereoscopic display

Abstract

The present application belongs to the technical field of holographic display and precise synchronization, and discloses a PTP and radio frequency fusion synchronization method for holographic sand table double-main-view-angle stereoscopic display, which is suitable for multi-user collaborative decision-making scenes such as intelligent city management and control, emergency rescue cooperation, etc. The core of the present application is to generate a nanosecond unified reference clock through Beidou / GPS, so as to align the sand table radio frequency transceiver and the display screen timing; the radio frequency end transmits the synchronization signal with PTP timestamp, view ID and MAC identifier and opening and closing parameters to the glasses through 2.4GHz adaptive frequency hopping and SM4 encryption; the glasses built-in PTP slave clock compensates the transmission delay, and autonomously generates the timing control LCD shutter, which can maintain ≤300ms precise control when the signal is lost, and seamlessly reconnects after recovery. The synchronization accuracy of the method reaches sub-microsecond level, supports multi-view expansion and multi-sand table cooperation, and solves the pain points such as traditional scheme crosstalk, weak anti-interference, etc.

Description

Technical Field

[0001] This invention relates to the field of holographic display and precise synchronization technology, specifically to a PTP and radio frequency fusion synchronization method for dual-view stereoscopic display of holographic sand table, which is applicable to multi-user collaborative decision-making scenarios such as smart city management and emergency rescue coordination. Background Technology

[0002] The core requirement of the holographic sand table dual-view active stereoscopic display system is to enable users with two main viewpoints to simultaneously obtain a stereoscopic visual experience without crosstalk and with a high degree of immersion. The key lies in achieving nanosecond-level timing alignment between the display end, the radio frequency transmitter end and the dual-view shutter glasses.

[0003] Currently, the mainstream synchronization solution in the industry is traditional radio frequency (RF) synchronization, which involves sending a single trigger signal without a timestamp to the glasses via an RF transmitter. The glasses passively control the opening and closing of the LCD shutter entirely based on this real-time trigger signal. This solution has three major technical bottlenecks:

[0004] First, the synchronization accuracy is inherently limited. There is no globally unified time reference, and only coarse synchronization at the ±0.1μs level can be achieved. In the 480Hz high refresh rate display scenario, even a tiny time deviation will cause crosstalk between the left and right eyes, which will seriously affect the sense of immersion in stereo.

[0005] Secondly, passive response is susceptible to interference. Electromagnetic interference and transmission jitter in the wireless link will be directly transmitted to the shutter control, causing the timing of shutter opening and closing and the displayed image to be out of sync. Moreover, the glasses do not have the ability to automatically resume after the signal is lost, and manual restarting of pairing is required to restore synchronization.

[0006] Third, it lacks expansion and collaboration capabilities. Due to the lack of binding between view ID and device identifier, signal confusion is likely to occur when expanding multiple main views. Furthermore, the synchronization timing of each sandbox is independent of each other, and there is no global clock to support cross-domain collaboration, making it unsuitable for complex scenarios such as large-scale command and full-domain control.

[0007] Meanwhile, PTP (IEEE 1588 Precision Time Protocol), as a global clock synchronization protocol with sub-microsecond accuracy, has been successfully applied in wired scenarios such as industrial control and communication networks through optimal master clock election, hardware timestamp calibration and link delay compensation mechanisms, and can provide a unified nanosecond-level time reference for distributed multi-modules. However, existing technologies suffer from significant blind spots in technical understanding and application gaps, and an innovative integration approach of "PTP + stereoscopic display" has not yet been formed: The industry has not broken through the technological inertia of "passive triggering," generally believing that glasses can only serve as a passive response end, failing to realize that a global clock reference can be injected into the glasses through PTP, enabling them to autonomously generate synchronized timing sequences; the deep adaptation value of PTP to dual-view scenarios has not been explored, and PTP timestamps have not been deeply bound to view IDs and glasses MAC addresses, failing to translate into the crosstalk-free, scalable, and highly collaborative capabilities of stereoscopic displays; a closed-loop architecture of "global clock - wireless transmission - terminal autonomous synchronization" has not been formed, with PTP and RF synchronization remaining on independent technical tracks for a long time, resulting in the long-term inability to break through the synchronization accuracy, anti-interference capability, and scalable collaboration of holographic sand table dual-view displays.

[0008] Therefore, there is an urgent need for a precise synchronization solution that integrates the advantages of PTP and radio frequency synchronization and is suitable for dual-view scenarios of holographic sand table, in order to solve the above-mentioned technical defects. Summary of the Invention

[0009] The purpose of this invention is to overcome the shortcomings of the prior art and provide a PTP and radio frequency fusion synchronization method for dual-view stereoscopic display of holographic sand table, achieving the following core objectives: 1) improving synchronization accuracy to sub-microsecond level to ensure crosstalk-free stereoscopic display of dual-view; 2) supporting flexible expansion of multiple viewpoints and cross-domain collaboration of multiple sand tables; 3) compensating for wireless transmission delay fluctuations and improving anti-interference capability; 4) achieving seamless fault-tolerant reconnection after synchronization loss to ensure continuous and stable operation of the system.

[0010] To solve the above-mentioned technical problems, the present invention adopts the following solution:

[0011] The PTP and RF fusion synchronization method for dual-view stereoscopic display of a holographic sand table includes the following steps:

[0012] A unified reference clock source is provided. The sand table RF transceiver and the sand table display screen are respectively connected to the reference clock source through wired links to obtain synchronization timing signals, so as to achieve that the clocks of the two are from the same source and the timing is aligned.

[0013] The sand table radio frequency transceiver transmits a synchronization signal carrying a PTP timestamp and shutter opening / closing parameters to the dual main-view shutter glasses via a wireless link.

[0014] After receiving the synchronization signal, the dual main-view shutter glasses complete the clock phase-locked calibration with the sand table RF transceiver based on the PTP timestamp, thereby achieving clock synchronization between the two.

[0015] The dual-view shutter glasses autonomously generate shutter control timing based on a synchronized clock and stored shutter opening and closing parameters, and control the LCD shutter to open and close alternately according to a preset rule, without relying on real-time trigger commands from the sand table RF transceiver.

[0016] This method is specifically designed to address the crosstalk and latency issues in dual-view holographic sand table stereoscopic displays. It achieves a highly immersive visual experience through a logic of "unified benchmark + precise synchronization + autonomous control." First, a unified benchmark clock source is configured for the sand table's RF transceiver and the display screen. The two are connected via a wired link to obtain synchronization timing signals, ensuring perfect time synchronization from the source. Next, the sand table's RF transceiver transmits a synchronization signal carrying a nanosecond-level PTP timestamp, along with parameters such as shutter opening and closing frequency and phase correlation, to the dual-view shutter glasses via a wireless link. Upon receiving the signal, the glasses perform phase-locked loop calibration with the sand table based on the PTP timestamp, precisely offsetting wireless transmission latency and jitter. Finally, the glasses do not rely on real-time trigger commands from the sand table; they autonomously generate control timing based solely on the synchronized clock and pre-stored parameters, driving the LCD shutter to open and close alternately according to a preset pattern, perfectly matching the display screen's 480Hz high refresh rate. This solves the crosstalk problem of traditional solutions, enhances anti-interference capabilities and system stability during continuous operation, and is suitable for various scenarios such as military command and smart city management.

[0017] Preferably, the unified reference clock source is a nanosecond-level global reference clock generated by obtaining UTC time via BeiDou or GPS, and the optimal master clock is selected through the best master clock algorithm to provide accurate time reference for the sand table RF transceiver and sand table display screen.

[0018] Preferably, the wireless link adopts adaptive frequency hopping transmission in the 2.4GHz band, supports 16 selectable channels, detects channel interference in real time and switches to interference-free frequency points, and the synchronization signal is transmitted after being encrypted by the SM4 algorithm, with a transmission power ≤10dBm.

[0019] Preferably, the dual-view shutter glasses have a built-in PTP slave clock unit. After receiving the synchronization signal, the dual-view shutter glasses calculate the wireless transmission delay and link jitter by "transmission timestamp - reception timestamp". The built-in PTP slave clock unit dynamically adjusts the shutter control timing to achieve delay compensation.

[0020] Preferably, when the RF synchronization signal is lost, the dual main-view shutter glasses activate the local high-precision buffer clock, fit the timing pattern based on the most recent 10 sets of PTP timestamp data, and maintain a precise shutter control timing of ≤300ms; after the signal is recovered, the local clock is calibrated through the PTP timestamp to achieve seamless reconnection with zero latency.

[0021] To further enhance synchronization stability, anti-interference capability, and timing accuracy, the wireless link preferably adopts a 2.4GHz band adaptive frequency hopping transmission design, supporting 16 selectable channels. It can detect channel interference in real time and dynamically switch to interference-free frequencies. The synchronization signal is encrypted using the SM4 algorithm before transmission, with transmission power strictly controlled to ≤10dBm, ensuring both transmission security and compliance with civilian wireless standards. Simultaneously, the dual-view shutter glasses incorporate a built-in PTP slave clock unit. After receiving the synchronization signal, it accurately calculates the wireless transmission delay and link jitter using the difference between the "transmission timestamp and reception timestamp." This PTP slave clock unit dynamically adjusts the shutter control timing, achieving real-time compensation for transmission delay. Furthermore, when the RF synchronization signal is lost due to obstruction, strong interference, or other reasons, the dual-view shutter glasses immediately activate a local high-precision buffer clock. Based on the timing pattern fitted from the most recent 10 sets of PTP timestamp data, it stably maintains a precise shutter control timing of ≤300ms. After the signal is restored, the local clock is quickly calibrated using the PTP timestamp, achieving zero latency. Seamless reconnection with minimal latency, and no video stuttering or crosstalk throughout the entire process.

[0022] Preferably, the synchronization timing signal between the sand table RF transceiver and the sand table display screen is generated by the slave clock pool module. The slave clock pool module establishes communication with the unified reference clock source through the PTP boundary clock module. The PTP boundary clock module and the unified reference clock source obtain the global reference clock signal through PTPv2 protocol phase locking, and distribute it to the slave clock pool module after link delay compensation. The slave clock pool module contains at least two sub-clock channels. Each sub-clock channel is phase-locked with the clock signal output by the PTP boundary clock module and outputs an independent synchronization timing signal.

[0023] To further ensure the timing accuracy of the sand table RF transceiver and the display screen, as well as the flexibility of system expansion, the synchronization timing signal is preferably generated by a dual master-view slave clock pool module. This slave clock pool module establishes a communication link with a unified reference clock source through a PTP boundary clock module. The PTP boundary clock module first achieves phase-locking with the unified reference clock source through the PTPv2 protocol, accurately obtains the global reference clock signal, and then distributes it to the slave clock pool module after link delay compensation processing. The slave clock pool module has at least two built-in sub-clock channels, which can be dynamically expanded to four or six channels according to the needs of multiple master-view scenarios. Each sub-clock channel achieves phase-locking with the clock signal output by the PTP boundary clock module, and finally outputs an independent and accurate synchronization timing signal, which not only ensures no crosstalk between the dual master views, but also provides stable support for multi-view expansion scenarios.

[0024] Preferably, the sand table display screen has a refresh rate of 480Hz and operates according to the logic of "alternating refresh of left / right eye images from dual main perspectives", with a refresh rate of 120Hz for each of the left / right eye images from a single main perspective.

[0025] Preferably, the PTP timestamp is nanosecond accurate and is generated by the hardware timestamp unit of the sand table RF transceiver. The synchronization signal frame also carries the viewpoint ID and the glasses MAC address identifier to achieve unique matching of the dual main viewpoint signals. The received shutter opening and closing parameters include an alternating opening and closing frequency of 120Hz and a phase correlation rule with the displayed image.

[0026] To further ensure a high level of immersion and accurate signal matching in the 3D display, the sand table display screen preferably adopts a 480Hz total refresh rate design, operating according to the logic of "alternating refresh of left / right eye images from dual main perspectives." The refresh rate for each of the left / right eye images in a single main perspective is 120Hz, ensuring smooth, flicker-free visuals. Simultaneously, the PTP timestamp is nanosecond-level high-precision, generated by the hardware timestamp unit of the sand table RF transceiver. The synchronization signal frame also carries an additional perspective ID and glasses MAC address identifier, achieving unique matching of dual main perspective signals and avoiding signal confusion among multiple users. The shutter opening and closing parameters received by the dual main perspective shutter glasses specifically include a 120Hz alternating opening and closing frequency and a phase correlation rule with the displayed image, ensuring precise synchronization between shutter action and display screen refresh rhythm, completely eliminating crosstalk and ghosting phenomena.

[0027] Preferably, in a multi-sandbox cluster collaborative scenario, the PTP boundary clock module of each sandbox is synchronized with the unified reference clock source through a cloud collaborative platform. The cloud collaborative platform allocates an independent PTP domain to each sandbox to avoid cross-domain clock signal conflicts and achieve full-domain clock homogeneity and view collaborative scheduling.

[0028] The beneficial effects of this invention are as follows:

[0029] 1. Significantly improved synchronization accuracy: By using PTP global clock synchronization + hardware timestamp + phase-locked loop delay compensation technology, the clock phase difference of each module is ≤100ns, and the synchronization error is reduced by an order of magnitude compared with the traditional solution, completely solving the problems of ghosting and crosstalk, and improving the immersive experience of stereoscopic display.

[0030] 2. Supports multi-view expansion and multi-sandbox collaboration: Adopts a dynamic slave clock pool architecture, which can be flexibly expanded to multi-master view scenarios such as 4-way and 6-way; Through the PTP multi-domain architecture and cloud collaboration platform, it realizes cross-regional global clock synchronization and view scheduling of multiple sandboxes, expanding the application boundaries of the system.

[0031] 3. Enhanced anti-interference and fault tolerance capabilities: Adopting adaptive frequency hopping radio frequency and SM4 encrypted transmission, the anti-interference level reaches industrial-grade EMC level 4; combined with the local high-precision cached clock and PTP timestamp reconnection mechanism, seamless reconnection within ≤300ms after synchronization loss is achieved, ensuring continuous and stable operation of the system.

[0032] 4. Precise and controllable wireless transmission timing: By correcting the wireless link transmission delay through PTP timestamps, the timing deviation caused by wireless jitter in traditional RF synchronization is solved, ensuring precise alignment between the shutter and the display image. Attached Figure Description

[0033] Figure 1 This is a flowchart of the PTP and radio frequency fusion synchronization method for dual main view stereoscopic display of holographic sand table according to the present invention.

[0034] Figure 2 This is a block diagram of the architecture for generating and distributing synchronous timing signals for a holographic sand table. Detailed Implementation

[0035] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0036] like Figure 1 As shown, Figure 1 This is a flowchart illustrating the PTP and radio frequency fusion synchronization method for dual-viewpoint stereoscopic display of a holographic sand table according to the present invention. The PTP and radio frequency fusion synchronization method for dual-viewpoint stereoscopic display of a holographic sand table includes the following steps:

[0037] A unified reference clock source is provided. The sand table RF transceiver and the sand table display screen are respectively connected to the reference clock source through wired links to obtain synchronization timing signals, so as to achieve that the clocks of the two are from the same source and the timing is aligned.

[0038] The sand table radio frequency transceiver transmits a synchronization signal carrying a PTP timestamp and shutter opening / closing parameters to the dual main-view shutter glasses via a wireless link.

[0039] After receiving the synchronization signal, the dual main-view shutter glasses complete the clock phase-locked calibration with the sand table RF transceiver based on the PTP timestamp, thereby achieving clock synchronization between the two.

[0040] The dual-view shutter glasses autonomously generate shutter control timing based on a synchronized clock and stored shutter opening and closing parameters, and control the LCD shutter to open and close alternately according to a preset rule, without relying on real-time trigger commands from the sand table RF transceiver.

[0041] Preferably, the unified reference clock source is a nanosecond-level global reference clock generated by obtaining UTC time via BeiDou or GPS, and the optimal master clock is selected through the best master clock algorithm to provide accurate time reference for the sand table RF transceiver and sand table display screen.

[0042] Preferably, the wireless link adopts adaptive frequency hopping transmission in the 2.4GHz band, supports 16 selectable channels, detects channel interference in real time and switches to interference-free frequency points, and the synchronization signal is transmitted after being encrypted by the SM4 algorithm, with a transmission power ≤10dBm.

[0043] Preferably, the dual-view shutter glasses have a built-in PTP slave clock unit. After receiving the synchronization signal, the dual-view shutter glasses calculate the wireless transmission delay and link jitter by "transmission timestamp - reception timestamp". The built-in PTP slave clock unit dynamically adjusts the shutter control timing to achieve delay compensation.

[0044] Preferably, when the RF synchronization signal is lost, the dual main-view shutter glasses activate the local high-precision buffer clock, fit the timing pattern based on the most recent 10 sets of PTP timestamp data, and maintain a precise shutter control timing of ≤300ms; after the signal is recovered, the local clock is calibrated through the PTP timestamp to achieve seamless reconnection with zero latency.

[0045] like Figure 2 As shown, Figure 2 This is a block diagram of the architecture for generating and distributing synchronization timing signals for a holographic sand table. The synchronization timing signals connected to the sand table RF transceiver and the sand table display screen are generated by a slave clock pool module. The slave clock pool module establishes communication with a unified reference clock source through a PTP boundary clock module. The PTP boundary clock module and the unified reference clock source obtain a global reference clock signal through PTPv2 protocol phase locking, and after link delay compensation, it is distributed to the slave clock pool module. The slave clock pool module contains at least two sub-clock channels. Each sub-clock channel is phase-locked with the clock signal output by the PTP boundary clock module and outputs an independent synchronization timing signal.

[0046] Preferably, the sand table display screen has a refresh rate of 480Hz and operates according to the logic of "alternating refresh of left / right eye images from dual main perspectives", with a refresh rate of 120Hz for each of the left / right eye images from a single main perspective.

[0047] Preferably, the PTP timestamp is nanosecond accurate and is generated by the hardware timestamp unit of the sand table RF transceiver. The synchronization signal frame also carries the viewpoint ID and the glasses MAC address identifier to achieve unique matching of the dual main viewpoint signals. The received shutter opening and closing parameters include an alternating opening and closing frequency of 120Hz and a phase correlation rule with the displayed image.

[0048] Preferably, in a multi-sandbox cluster collaborative scenario, the PTP boundary clock module of each sandbox is synchronized with the unified reference clock source through a cloud collaborative platform. The cloud collaborative platform allocates an independent PTP domain to each sandbox to avoid cross-domain clock signal conflicts and achieve full-domain clock homogeneity and view collaborative scheduling.

[0049] This embodiment is applied to an emergency rescue command center in a certain city. It needs to support two main-view personnel (commander and technical staff) to simultaneously observe the three-dimensional situation of the urban disaster area using a holographic sand table (such as the flood inundation range and the distribution of rescue channels). It requires no crosstalk and resistance to on-site electromagnetic interference (interference from walkie-talkies and rescue equipment). The core components of the system are as follows:

[0050] I. Implementation Scenarios and System Composition

[0051] Unified reference clock source: Using BeiDou-2 timing module + GPS dual-mode timing, a nanosecond-level global reference clock (accuracy ±5ns) is generated, and the optimal master clock is selected through the best master clock algorithm;

[0052] Synchronization control unit: 1 PTP boundary clock module (supports PTPv2 protocol), 1 slave clock pool module (with built-in 2 sub-clock channels);

[0053] Display and transmission unit: 1 480Hz holographic sand table display screen, 1 sand table RF transceiver;

[0054] Terminal unit: 2 pairs of dual master-view shutter glasses (built-in PTP slave clock unit, MAC address: MAC-001, MAC-002);

[0055] Auxiliary modules: SM4 encryption chip, 2.4GHz adaptive frequency hopping module.

[0056] II. Specific Implementation Steps

[0057] Global clock synchronization: A unified reference clock source is connected to the PTP boundary clock module via a wired link. Through PTPv2 protocol phase-locked loop and link delay compensation (compensating for 12ns wired delay), the global reference signal is distributed to the slave clock pool module. The slave clock pool module outputs synchronization timing signals through two sub-clock channels, which are connected to the sand table display screen and RF transceiver via wired links. The timing deviation between the two is ≤25ns.

[0058] Parameter configuration: The total refresh rate of the display screen is 480Hz. The refresh rate for the left and right eyes of the commander (view ID=001) is 120Hz each (refresh window: 0-4.167ms for the left eye, 4.167-8.333ms for the right eye); the refresh window of the technical staff (view ID=002) is offset by 2.083ms (refresh window: 2.083-6.25ms for the left eye, refresh window: 6.25-10.417ms for the right eye). The offset is to avoid the windows of the two main viewpoints overlapping; the RF transceiver enables 16-channel adaptive frequency hopping, and switches to channel 12 when the interference intensity of channel 5 is detected to be -68dBm. The synchronization signal is encrypted with SM4 and transmitted at a power of 9dBm.

[0059] Signal transmission and calibration: The RF transceiver transmits a synchronization signal containing a nanosecond-level PTP timestamp, view ID, MAC address, and 120Hz shutter opening and closing parameters to the glasses; after receiving the signal, the commander's glasses calculate the transmission delay of 32ns by subtracting the receiving timestamp from the transmission timestamp, and dynamically compensate for it using the built-in PTP clock unit.

[0060] Autonomous control and fault tolerance: When the glasses are disconnected from the real-time trigger, they autonomously generate timing control shutters to precisely align with the display refresh rate; when signal loss is caused by simulated field obstruction, the glasses activate the local cache clock, fit the timing based on the most recent 10 PTP timestamps, maintain precise control for 290ms, and seamlessly reconnect with zero latency after the signal is restored.

[0061] Extended Adaptation: If a new rescue site sand table is added, an independent PTP domain will be allocated through the cloud collaboration platform and synchronized with the global reference clock to achieve cross-regional situational coordination.

[0062] III. Implementation Results

[0063] With synchronization accuracy down to the sub-microsecond level, crosstalk is completely eliminated: Tested with professional equipment, the clock phase difference between the sand table display, the RF transceiver, and the shutter glasses is stably controlled within ≤90ns, reducing synchronization error by an order of magnitude compared to traditional solutions (±0.1μs). In emergency rescue scenarios, the commander and technical staff observe the flood-inundated boundaries, the real-time location of rescue vehicles, and other three-dimensional situational awareness without any ghosting or crosstalk. Even millimeter-level details of the disaster area are accurately presented, avoiding decision-making errors in rescue route planning and the location of trapped personnel due to visual biases, providing precise visual support for the rapid formulation of rescue plans.

[0064] Anti-interference capability adaptable to complex field environments: Relying on the 2.4GHz band 16-channel adaptive frequency hopping design, the system can avoid electromagnetic interference generated by walkie-talkies, emergency lighting equipment, and drone communications at the rescue site in real time. The channel switching response time is ≤2ms, and the synchronization signal bit error rate is ≤10% even in complex environments with interference intensity up to -40dBm. -6 No signal interruption or transmission delay was observed. Meanwhile, the SM4 encryption algorithm ensured that the synchronization signal was not stolen or tampered with, effectively protecting sensitive information such as disaster situation and rescue deployment, and meeting the requirements for emergency rescue information security.

[0065] The fault-tolerant reconnection performance ensures continuous operation of the system: When command personnel wearing shutter glasses move to an area obstructed by the rescue command vehicle, or when strong electromagnetic pulse interference causes RF signal loss, the glasses' local high-precision cache clock can be activated immediately. Based on the most recent 10 sets of PTP timestamp data, it fits the timing pattern (fitting error ≤10ns) and stably maintains precise shutter control at 290ms, far below the design threshold of 300ms. During this period, the image is smooth and flicker-free, allowing command personnel to continuously observe the situation. After the signal is restored, the local clock is quickly calibrated using the PTP timestamp, achieving seamless reconnection with zero latency and imperceptible switching throughout the process. This avoids command process interruptions due to signal interruption and ensures the continuity of rescue command.

[0066] Flexible multi-view expansion adapts to multi-person collaborative decision-making: The clock pool module supports dynamic expansion of sub-clock channels. When a rescue scenario requires adding a third primary viewpoint for the on-site rescue team leader, only one sub-clock channel needs to be added to the clock pool module (no system architecture reconstruction required), an independent viewpoint ID=003 assigned, and the refresh window offset from the original viewpoint by 2.083ms. The new glasses can be quickly integrated into the system by binding their MAC address to the viewpoint ID. After expansion, there is no signal confusion among the three primary viewpoint personnel, and their individual visual experiences are unaffected, enabling multi-person collaborative decision-making between the command center and the on-site rescue team, and improving the efficiency of rescue command transmission and execution.

[0067] Cross-regional collaborative capabilities support comprehensive rescue and dispatch: When the disaster area expands and requires coordinated operations using a holographic sand table at suburban rescue branches, an independent PTP domain (domain ID=02) is allocated to the suburban sand table through a cloud-based collaborative platform. The PTP boundary clock modules of each sand table are synchronized with a unified reference clock source via a 5G network, with a cross-regional clock source deviation of ≤50ns. The command center can dispatch the rescue situation at the suburban sand table in real time, with a collaborative response time of ≤50ms between the two locations, achieving unified allocation of rescue resources across the entire "urban-suburban" region and avoiding conflicts or deployment delays in rescue forces due to cross-regional time synchronization issues.

[0068] High refresh rate adaptation enhances visual immersion and operational precision: The sand table display boasts a total refresh rate of 480Hz, coupled with a 120Hz refresh rate for each eye (left / right eye), resulting in smoother visuals than traditional 60Hz displays, with no ghosting or flickering. Commanders can observe for extended periods (over 2 hours continuously) without visual fatigue, and the shutter timing precisely matches the phase of the displayed image. When technical staff adjust the sand table zoom or switch disaster scene layers via interactive devices, the glasses' shutter responds in real-time, with no delay in image switching, ensuring consistency between operation and visual feedback and improving the accuracy of decision-making.

[0069] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Based on the technical essence of the present invention, any simple modifications, equivalent substitutions, and improvements made to the above embodiments within the spirit and principles of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for PTP and radio frequency fusion synchronization of holographic sand table dual-view stereoscopic display, characterized in that, Includes the following steps: A unified reference clock source is provided, which is a nanosecond-level global reference clock generated by obtaining UTC time via BeiDou or GPS, and the optimal master clock is selected through the best master clock algorithm to provide accurate time reference for the sand table radio frequency transceiver and sand table display screen. The sand table RF transceiver and the sand table display screen are respectively connected to the reference clock source through wired links to obtain synchronization timing signals, so as to realize that the sand table RF transceiver and the sand table display screen have the same clock source and timing alignment. The sand table radio frequency transceiver transmits a synchronization signal carrying a PTP timestamp and shutter opening / closing parameters to the dual main-view shutter glasses via a wireless link. The PTP timestamp is nanosecond accurate and is generated by the hardware timestamp unit of the sand table RF transceiver. The synchronization signal frame also carries the view ID and glasses MAC address identifier to achieve unique matching of dual main view signals. The received shutter opening and closing parameters include an alternating opening and closing frequency of 120Hz and a phase correlation rule with the display screen. After receiving the synchronization signal, the dual main-view shutter glasses complete the clock phase-locked calibration with the sand table RF transceiver based on the PTP timestamp, thereby achieving clock synchronization between the dual main-view shutter glasses and the sand table RF transceiver. The dual-view shutter glasses autonomously generate shutter control timing based on a synchronized clock and stored shutter opening and closing parameters, and control the LCD shutter to open and close alternately according to a preset rule, without relying on real-time trigger commands from the sand table RF transceiver.

2. The PTP and radio frequency fusion synchronization method for holographic sand table dual-view stereoscopic display according to claim 1, characterized in that, The wireless link uses adaptive frequency hopping transmission in the 2.4GHz band, supports 16 selectable channels, detects channel interference in real time and switches to interference-free frequency points, and the synchronization signal is transmitted after being encrypted by the SM4 algorithm, with a transmission power ≤10dBm.

3. The PTP and radio frequency fusion synchronization method for holographic sand table dual-view stereoscopic display according to claim 1, characterized in that, After receiving the synchronization signal, the dual-view shutter glasses calculate the wireless transmission delay and link jitter by using the "transmission timestamp - reception timestamp". The built-in PTP dynamically adjusts the shutter control timing from the clock unit to achieve delay compensation.

4. The PTP and radio frequency fusion synchronization method for holographic sand table dual-view stereoscopic display according to claim 1, characterized in that, When the RF synchronization signal is lost, the dual main view shutter glasses activate the local high-precision buffer clock, fit the timing pattern based on the most recent 10 sets of PTP timestamp data, and maintain a precise shutter control timing of ≤300ms. After the signal is restored, the local clock is calibrated using the PTP timestamp to achieve seamless reconnection with zero latency.

5. The PTP and radio frequency fusion synchronization method for holographic sand table dual-view stereoscopic display according to claim 1, characterized in that, The synchronization timing signal between the sand table RF transceiver and the sand table display screen is generated by the slave clock pool module. The slave clock pool module establishes communication with the unified reference clock source through the PTP boundary clock module. The PTP boundary clock module and the unified reference clock source obtain the global reference clock signal through the PTPv2 protocol phase-locked loop, and distribute it to the slave clock pool module after link delay compensation. The slave clock pool module includes at least two sub-clock channels. Each sub-clock channel is phase-locked with the clock signal output by the PTP boundary clock module and outputs an independent synchronization timing signal.

6. The PTP and radio frequency fusion synchronization method for holographic sand table dual-view stereoscopic display according to claim 1, characterized in that, The sand table display screen has a refresh rate of 480Hz and operates according to the logic of "alternating refresh of left / right eye images in dual main view". The refresh rate of left / right eye images in a single main view is 120Hz each.

7. The PTP and radio frequency fusion synchronization method for holographic sand table dual-view stereoscopic display according to claim 1, characterized in that, In a multi-sandbox cluster collaboration scenario, the PTP boundary clock module of each sandbox is synchronized with the unified reference clock source through the cloud collaboration platform. The cloud collaboration platform allocates an independent PTP domain to each sandbox to avoid cross-domain clock signal conflicts and achieve global clock homogeneity and view collaborative scheduling.

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