A fast frequency hopping synchronization method for highly maneuverable platforms

Abstract

A fast frequency hopping synchronization method for a high-mobility platform belongs to the field of electronic communications. The main steps include: based on satellite ephemeris and high-mobility platform inertial navigation, relative position vector calculation and path delay estimation are performed to complete the coarse compensation of downlink signal capture and uplink signal transmission time; based on the satellite's time measurement error estimation and feedback of the uplink signal, the high-mobility platform performs precise compensation for the transmission time to complete the closed-loop fast time synchronization of the frequency hopping system. The method sets the capture window based on real-time path delay estimation, realizes fast capture of downlink signals, reduces the false alarm probability of capture, and accelerates the closed-loop time synchronization based on the precise compensation of the transmission time after the satellite time difference estimation.

Description

Technical Field

[0001] The invention relates to the technical field of electronic communications, and in particular to a fast frequency hopping synchronization method for a high-mobility platform. Background Art

[0002] As a supplement to the ground communication system, the satellite communication system has the characteristic of "seamless" coverage of the earth and can effectively support the communication needs of special areas on the ground such as the sky, air, sea and desert.

[0003] At present, the transmission of measurement and control information of high-mobility platforms mainly adopts ground-based measurement and control, and there are few space-based measurement and control methods, which cannot achieve global measurement and control. Therefore, it is an inevitable choice to use the global Internet satellite communication system to ensure the transmission of measurement and control information of high-mobility platforms; at the same time, due to various interferences in the channel environment, in order to ensure the reliability of information transmission of the control link, the transmission link needs to have anti-interference capabilities. Since the flight time of high-mobility platforms is short, only a few to ten minutes, the use of satellites to provide measurement and control links for high-mobility platforms can ensure the real-time control and telemetry of high-mobility platforms, and at the same time, the frequency hopping anti-interference system is used to ensure the reliability of the system.

[0004] However, since the distance and relative speed of the high-mobility platform relative to the satellite are changing in real time, how to solve the time changes caused by the relative distance changes brought about by the rapid movement of medium and high-mobility platforms has become an urgent problem in the synchronization of frequency hopping systems. Summary of the invention

[0005] In order to solve the problem of fast time synchronization when the relative distance between a satellite communication system and a high-mobility platform changes rapidly, the present invention provides a fast frequency hopping synchronization method for a high-mobility platform. The method uses satellite ephemeris and missile-borne platform inertial navigation to estimate time delay, and uses the time measurement method of frequency hopping detection signals to achieve time compensation.

[0006] The fast frequency hopping synchronization method of the high-mobility platform provided in the present disclosure mainly comprises the following steps:

[0007] S1, based on satellite ephemeris and high-mobility platform inertial navigation information, calculates the relative position vector of the satellite and the high-mobility platform and estimates the path delay;

[0008] S2, compensating the downlink signal acquisition time according to the estimated path delay to complete the downlink signal fast acquisition synchronization;

[0009] S3, based on the path delay between the satellite and the high-mobility platform, delay compensation is performed on the uplink synchronous detection signal sending time to ensure that the detection signal falls in the best position for satellite capture;

[0010] S4, the satellite estimates the time difference of the uplink synchronization detection signal and feeds back the time difference estimation result to the high mobility platform. The high mobility platform further fine-tunes the uplink signal sending time according to the time difference estimation result until the time difference meets the requirement; through this closed-loop feedback, the fast time synchronization of the frequency hopping system is completed.

[0011] Furthermore, the step S1 specifically includes:

[0012] S11, based on satellite ephemeris and high maneuverability platform inertial navigation, performs relative position vector calculation:

[0013] Based on the ephemeris position information, the high-orbit satellite position vector is obtained ;

[0014] Based on the inertial navigation position information, the position vector of the high maneuverability platform is obtained ;

[0015] Position vectors of satellites and high-mobility platforms: ,

[0016] That is, the distance between the satellite and the high mobility platform is:

[0017] ;

[0018] S12, path delay estimation based on the relative position vector of the satellite and the high-mobility platform:

[0019] The path delay between the satellite and the high mobility platform is ,Right now

[0020]

[0021] Where c is the speed of light 3e8m / s.

[0022] Furthermore, in step S2, based on the downlink signal capture time compensation, the downlink signal capture window is preset as: , ,in:

[0023] ,

[0024] in, is the estimated satellite and high mobility platform path delay, is the current time; arrive Duration of the downlink synchronization signal.

[0025] Furthermore, in step S3, the uplink synchronization detection signal sending window obtained is , ,in:

[0026] ,

[0027] in, is the current time; arrive is the duration of the uplink synchronization detection signal, Path delay for satellites and highly maneuverable platforms; is the delay adjustment factor, by adjusting Make sure the detection signal falls in the best position for satellite capture.

[0028] Furthermore, the current time, the default satellite time and the high mobility platform time are all Beidou time.

[0029] Furthermore, the step S4 specifically includes:

[0030] The time difference of the satellite uplink synchronous detection signal is estimated to be ;

[0031] The time difference estimation result is fed back to the high mobility platform, and the high mobility platform makes a judgment based on the time difference estimation result:

[0032] if , then the closed-loop time synchronization of the satellite and the high-mobility platform is completed;

[0033] Otherwise, the high mobility platform further compensates the uplink signal sending time as , send an uplink signal; until .

[0034] Compared with the prior art, the present invention has the following beneficial effects: (1) by estimating the path delay based on the ephemeris and inertial navigation information and pre-compensating the receiver, the high-mobility platform receiver is prevented from performing signal capture in a long window, and only needs to perform signal capture in a small window, thereby reducing the false alarm probability of capture; (2) by adjusting the delay factor Precisely control the transmission signal window to ensure that the satellite captures the signal once and quickly estimates the time difference of the uplink synchronization signal, thereby accelerating closed-loop time synchronization; (3) Convenient calculation. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The above and other objects, features and advantages of the present disclosure will become more apparent through a more detailed description of exemplary embodiments of the present disclosure in conjunction with the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present disclosure.

[0036] Figure 1 A processing flow chart of a fast frequency hopping synchronization method for a high mobility platform according to the present disclosure;

[0037] Figure 2 It is the timing relationship between the signal transmission and reception of the highly maneuverable platform and the satellite. DETAILED DESCRIPTION

[0038] The preferred embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the preferred embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present disclosure more thorough and complete, and to fully convey the scope of the present disclosure to those skilled in the art.

[0039] The present disclosure provides a fast frequency hopping synchronization method for a high-mobility platform. In an exemplary embodiment, the processing flow is as shown in the attached Figure 1 As shown in the figure, the method includes the following steps:

[0040] (1) Calculation of relative position vector based on satellite ephemeris and high maneuverability platform inertial navigation:

[0041] The high-orbit satellite position vector of the ephemeris position information and the missile-borne platform position vector of the inertial navigation position information .

[0042] Calculate position vectors for satellites and highly maneuverable platforms , that is, the distance between the satellite and the high mobility platform is

[0043]

[0044] (2) Path delay estimation based on the relative position vector of the satellite and the highly maneuverable platform:

[0045] The path delay between the satellite and the high mobility platform is ,Right now

[0046]

[0047] Where c is the speed of light 3e8m / s.

[0048] (3) Downlink signal capture window preset based on satellite and high mobility platform path delay compensation:

[0049] The downlink signal capture window , ,Right now

[0050] [ , ]

[0051] in The current time. By default, the satellite and high-mobility platform times are both Beidou time. arrive The duration of the downlink synchronization signal.

[0052] (4) Uplink synchronous detection signal sending window preset based on satellite and high mobility platform path delay compensation:

[0053] The uplink synchronization detection signal sending window , ,Right now

[0054] [ , ]

[0055] in The current time. By default, the satellite and high-mobility platform times are both Beidou time. arrive For the uplink synchronization detection signal duration, adjust Ensure that the detection signal falls on the best position for satellite capture, such as Figure 2 .

[0056] (5) The satellite completes the time measurement error estimation of the uplink signal; the high mobility platform performs time precision compensation based on the satellite time difference estimation. Through this closed-loop feedback, the time synchronization of the satellite and the high mobility platform is completed.

[0057] Assume that the satellite time difference is estimated , High Mobility Platform Compensation:

[0058] ① Downlink signal receiving time compensation is ;

[0059] ② Uplink signal sending time compensation is .

[0060] in The current time. By default, the satellite and high-mobility platform times are both Beidou time. Path delay for satellite and high mobility platform; downlink signal reception time compensation and satellite time difference Not relevant, uplink signal needs to consider satellite time difference .

[0061] when At this time, the closed-loop time synchronization of the satellite and the high-mobility platform is completed.

[0062] In this embodiment, the path delay is estimated based on the ephemeris and inertial navigation information, and the receiver is pre-compensated to avoid the high-mobility platform receiver from performing signal capture in a long window, and only needs to perform signal capture in a small window, thereby reducing the false alarm probability of capture. Precisely control the transmission signal window to ensure the satellite captures the signal once and quickly estimate the time difference of the uplink synchronization signal, thereby accelerating closed-loop time synchronization.

[0063] Some parts not described in detail in this disclosure belong to the well-known technologies of those skilled in the art.

[0064] The above technical scheme is only an exemplary embodiment of the present invention. For those skilled in the art, it is easy to make various types of improvements or modifications based on the application methods and principles disclosed in the present invention, and it is not limited to the method described in the above specific embodiment of the present invention. Therefore, the method described above is only preferred and does not have a restrictive meaning.

Claims

1. A fast frequency hopping synchronization method for a high mobility platform, comprising the following steps: S1, based on satellite ephemeris and high-mobility platform inertial navigation information, calculates the relative position vector of the satellite and the high-mobility platform and estimates the path delay; S2, compensating the downlink signal acquisition time according to the estimated path delay to complete the downlink signal fast acquisition synchronization; S3, based on the path delay between the satellite and the high-mobility platform, delay compensation is performed on the uplink synchronous detection signal sending time to ensure that the detection signal falls in the best position for satellite capture; S4, the satellite estimates the time difference of the uplink synchronization detection signal and feeds back the time difference estimation result to the high mobility platform. The high mobility platform further fine-tunes the uplink signal sending time according to the time difference estimation result until the time difference meets the requirement; through this closed-loop feedback, the fast time synchronization of the frequency hopping system is completed.

2. The method according to claim 1, characterized in that The step S1 specifically includes: S11, based on satellite ephemeris and high maneuverability platform inertial navigation, performs relative position vector calculation: Based on the ephemeris position information, the high-orbit satellite position vector is obtained ; Based on the inertial navigation position information, the position vector of the high maneuverability platform is obtained ; Position vectors of satellites and high-mobility platforms: , That is, the distance between the satellite and the high mobility platform is: ； S12, path delay estimation based on the relative position vector of the satellite and the high-mobility platform: The path delay between the satellite and the high mobility platform is ,Right now Where c is the speed of light 3e8m / s.

3. The method according to claim 1, characterized in that In step S2, based on the downlink signal capture time compensation, the downlink signal capture window is preset as: , ,in: ， in, is the estimated satellite and high mobility platform path delay, is the current time; arrive The duration of the downlink synchronization signal.

4. The method according to claim 1, characterized in that: In step S3, the uplink synchronization detection signal sending window obtained is , ,in: ， in, is the current time; arrive is the duration of the uplink synchronization detection signal, Path delay for satellites and highly maneuverable platforms; is the delay adjustment factor, by adjusting Make sure the detection signal falls in the best position for satellite capture.

5. The method according to claim 3 or 4, characterized in that: The current time, by default, the satellite and high mobility platform times are all Beidou time.

6. The method according to claim 4, characterized in that The step S4 specifically includes: The time difference of the satellite uplink synchronous detection signal is estimated to be ; The time difference estimation result is fed back to the high mobility platform, and the high mobility platform makes a judgment based on the time difference estimation result: if , then the closed-loop time synchronization of the satellite and the high-mobility platform is completed; Otherwise, the high mobility platform further compensates the uplink signal sending time as , send an uplink signal; until .

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