阅读说明：本技术 一种基于卫星转发器的导航地面站设备时延校准方法 (Time delay calibration method for navigation ground station equipment based on satellite transponder ) 是由 张阳 荆文芳 王沛 徐玲玲 苏瑜 卢晓春 于 2021-01-19 设计创作，主要内容包括：本发明公开了一种基于卫星转发器的导航地面站设备时延校准方法,使用伪卫星的转发器代替卫星转发器,通过地面站综合基带以及监测接收机的载波相位测量功能,地面站综合基带采用自发自收的工作模式对地面站设备时延进行标定,导航地面站向伪卫星发射信号,并接收伪卫星转发的信号,由监测接收机和时间间隔计数器SR620等构成的地面监测平台同时接收伪卫星转发的信号,对信号传输时延进行监测,通过对链路传输路径上各段时延的分析,得到导航地面站发射和接收链路设备时延,可以有效解决地面站设备时延有效校准。(The invention discloses a time delay calibration method of navigation ground station equipment based on a satellite transponder, which uses the transponder of a pseudo-satellite to replace the satellite transponder, and utilizes the carrier phase measurement functions of a ground station comprehensive baseband and a monitoring receiver, the ground station comprehensive baseband calibrates the time delay of the ground station equipment by adopting a self-sending and self-receiving working mode, the navigation ground station transmits signals to the pseudo-satellite and receives the signals forwarded by the pseudo-satellite, a ground monitoring platform formed by the monitoring receiver, a time interval counter SR620 and the like simultaneously receives the signals forwarded by the pseudo-satellite and monitors the signal transmission time delay, and the time delay of the navigation ground station transmitting and receiving link equipment is obtained by analyzing each section of time delay on a link transmission path, so that the effective calibration of the time delay of the ground station equipment can be effectively solved.)

1. A time delay calibration method for navigation ground station equipment based on a satellite transponder is characterized by comprising the following steps:

the method comprises the steps that a ground station comprehensive baseband generates a ranging signal, the ranging signal is transmitted to a pseudo satellite through an up-converter, a high-power amplifier and an antenna, a pseudo satellite receiving antenna receives the signal from a ground station and forwards the signal through a repeater, the signal forwarded by the pseudo satellite received by the ground station antenna is processed on the ground station comprehensive baseband through low-noise amplification and a down-converter, and time delay measurement of the whole loop of the ground station, the pseudo satellite and the ground station is completed;

the specific calibration is called as:

the first step is as follows: ground station-pseudolite-ground station loop link delay measurement

ΔT_loop＝ΔT1+ΔT2+ΔT3+ΔT4+ΔT5+ΔT6+ΔT7+ΔT8+ΔT4′+ΔT5′+ΔT6′+ΔT7′+ΔT8′+ΔT9+ΔT10+ΔT11

Wherein, Δ T1 is the cable delay connecting the ground atomic clock group to the first-level time-frequency distribution amplifier; the delta T2 is the cable time delay of the time frequency amplifier connecting the first-stage time frequency distribution amplifier to the navigation ground station; the delta T3 is the cable time delay from the time-frequency amplifier of the navigation ground station to the baseband; Δ T4 and Δ T4' are the integrated baseband internal transmit and receive calibration time delays, respectively; Δ T5 and Δ T5' are the navigational ground station device transmit and receive delays, respectively; Δ T6 and Δ T6' are the spatial link delays for uplink and downlink, respectively; Δ T7 and Δ T7' are the ionospheric delays of the uplink and downlink spatial links, respectively; Δ T8 and Δ T8' are the tropospheric delays of the spatial links upstream and downstream, respectively; Δ T9 is the cable delay connecting the pseudolite receive antenna to the transponder; Δ T10 is the pseudo satellite transponder delay; Δ T11 is the cable delay connecting the pseudolite transponder to the pseudolite transmit antenna;

the second step is that: ground station-pseudolite-receiver link delay measurement

The time delay value of the signal generated by the ground station integrated baseband and reaching the pseudo satellite receiving antenna through the uplink radio frequency equipment, the antenna and the space link, and directly connected to the monitoring receiver through the cable after being forwarded by the repeater is called as a one-hop time delay value T_Rec：

T_Rec＝ΔT1+ΔT2+ΔT3+ΔT4+ΔT5+ΔT6+ΔT7+ΔT8+ΔT9+ΔT10+ΔT12+ΔT13

Wherein Δ T12 is the cable delay connecting the outlet of the pseudo-satellite transponder to the inlet of the pseudo-satellite ground station monitoring receiver radio frequency signal; Δ T13 is the receiver internal calibration time delay;

the one-hop delay value of the monitoring receiver is acquired by a time interval counter SR620, the 1PPS signal output by the receiver is compared with the 1PPS signal output by the main clock by the SR620, and therefore the time difference data T acquired by the time interval counter SR620_SR620Comprises the following steps:

where Δ T14 is the cable delay connecting the 1PPS signal output by the receiver to the gate signal entry of the time interval counter SR 620; the delta T15 is the cable time delay for connecting the first-stage time frequency distribution amplifier to the time frequency amplifier of the pseudolite ground station;

the third step: time delay of ground station transmitting equipment and time delay sum measurement of receiving equipment

Sum of time delays T of transmitting equipment and receiving equipment of ground station_totalComprises the following steps:

wherein Δ T1+ Δ T2+ Δ T3 is the transmission delay from the ground atomic clock group to the baseband transmission frame head of the navigation ground station; Δ T6+ Δ T7+ Δ T8 and Δ T6 ' + Δ T7 ' + Δ T8 ' are the spatial link delays from the ground station to the pseudolite, which can be calculated from the ground station antenna rotation center coordinates and the pseudolite receive and transmit antenna coordinates, respectively; the time delay of connecting the pseudolite transceiving antenna and the transponder with a cable and the processing time delay of the transponder are delta T9+ delta T10+ delta T11;

the fourth step: measurement of time delay of ground station transmitting equipment and time delay of receiving equipment

According to T_totalObtaining time delay T of navigation ground station transmitting link equipment_up：

Wherein Δ T12 is the cable delay connecting the outlet of the pseudo-satellite transponder to the inlet of the pseudo-satellite ground station monitoring receiver radio frequency signal; Δ T13 is the monitoring receiver internal time delay; Δ T14 is the cable delay from the 1PPS signal output by the monitoring receiver to the SR620 door-closing signal inlet; the delta T15 is the cable time delay for connecting the first-stage time frequency distribution amplifier to the time frequency amplifier of the pseudolite ground station; the delta T1 is the cable time delay connecting the ground atomic clock group to the first-level time-frequency distribution amplifier;

T_totalminus T_upObtaining the time delay T of the receiving link equipment_down：

Through the obtained time delay T of the navigation ground station transmitting link equipment_upAnd receiving the link equipment delay T_downAnd completing the calibration of the time delay of the navigation ground station equipment.

2. The satellite transponder based navigation ground station apparatus time delay calibration method of claim 1, wherein: and providing standard time-frequency reference signals for each device in the navigation ground station through the ground high-precision atomic clock, and transmitting signals to the pseudo satellite by the navigation ground station and receiving the signals forwarded by the pseudo satellite transponder.

3. The satellite transponder based navigation ground station apparatus time delay calibration method of claim 1, wherein: transmitting a signal to a pseudo satellite by a ground station to be detected, measuring and recording a loop time delay value by a comprehensive baseband, recording a one-hop time delay value by a monitoring receiver, recording all data once per second, and carrying out statistical analysis processing on the final observed quantity to obtain the final time delay T of the transmitting link equipment_upAnd receiving the link equipment delay T_down。

Technical Field

The invention relates to the field of time delay calibration, in particular to a time delay calibration method of navigation ground station equipment based on a satellite transponder.

Background

The accurate measurement of the time delay of the ground station equipment is a key technology for realizing high-precision time transmission by a satellite navigation system and a satellite two-way time frequency transmission technology.

In a satellite navigation system, a radio bidirectional pseudo range time synchronization method is generally adopted to realize satellite-to-ground time synchronization and inter-station time synchronization, and a time delay measurement error of time synchronization equipment is a main error of system time synchronization; in a forwarding type satellite navigation system, a navigation signal is generated on the ground, is sent to a satellite through a ground navigation station and is forwarded to a user, the equipment time delay of the ground station is contained in pseudo code distance measurement observation quantity of a user receiver and influences the distance measurement result of the navigation signal, so that the measurement error of the equipment time delay of the ground station is one of important factors influencing the positioning time service precision of the system; in the satellite bidirectional time frequency transfer system, because the transmitting and receiving paths of two ground station signals are basically the same and opposite in direction, the path error influence in the ranging process can be greatly eliminated, but the time delay error of ground station equipment still influences the time comparison precision. In summary, the ground station time delay calibration technology is one of the key technologies of a satellite navigation system and a satellite two-way time comparison method, and is vital to the establishment of high-precision space reference and time-frequency reference.

The original pseudo-range observed quantity of the integrated base band of the monitoring receiver and the ground station comprises the time delay of the ground station equipment, the accurate pseudo-range observed quantity of a link is obtained by measuring the time delay of the ground station equipment and deducting the time delay in the pseudo-range observed quantity, and the time delay calibration error of the ground station equipment can influence the final ranging precision, so that the improvement of the time delay calibration precision of the ground station equipment is the key for improving the service performance of a satellite navigation system and the precision of the two-way time comparison of a satellite. How to accurately calibrate the time delay of the ground station equipment and how to verify the accuracy of the time delay calibration result between the ground stations after calibration is finished need further research.

Disclosure of Invention

Aiming at the problems in the prior art, the invention aims to provide a method for calibrating the time delay of navigation ground station equipment based on a satellite transponder, and solves the problem that the time delay of the ground station equipment is difficult to calibrate effectively.

In order to solve the technical problems, the invention adopts the following technical scheme:

a time delay calibration method of navigation ground station equipment based on a satellite transponder is characterized in that a ground station comprehensive baseband generates a ranging signal, the ranging signal is transmitted to a pseudo satellite through an up-converter, a high-power amplifier and an antenna, a pseudo satellite receiving antenna receives the signal from a ground station and forwards the signal through the transponder, the signal forwarded by the pseudo satellite received by the ground station antenna is processed on the ground station comprehensive baseband through a low-noise amplifier and a down-converter, and time delay measurement of the whole loop of the ground station, the pseudo satellite and the ground station is completed;

the specific calibration is called as:

the first step is as follows: ground station-pseudolite-ground station loop link delay measurement

ΔT_loop＝ΔT1+ΔT2+ΔT3+ΔT4+ΔT5+ΔT6+ΔT7+ΔT8+ΔT4′+ΔT5′+ΔT6′+ΔT7′+ΔT8′+ΔT9+ΔT10+ΔT11

Wherein, Δ T1 is the cable delay connecting the ground atomic clock group to the first-level time-frequency distribution amplifier; the delta T2 is the cable time delay of the time frequency amplifier connecting the first-stage time frequency distribution amplifier to the navigation ground station; the delta T3 is the cable time delay from the time-frequency amplifier of the navigation ground station to the baseband; Δ T4 and Δ T4' are the integrated baseband internal transmit and receive calibration time delays, respectively; Δ T5 and Δ T5' are the navigational ground station device transmit and receive delays, respectively; Δ T6 and Δ T6' are the spatial link delays for uplink and downlink, respectively; Δ T7 and Δ T7' are the ionospheric delays of the uplink and downlink spatial links, respectively; Δ T8 and Δ T8' are the tropospheric delays of the spatial links upstream and downstream, respectively; Δ T9 is the cable delay connecting the pseudolite receive antenna to the transponder; Δ T10 is the pseudo satellite transponder delay; Δ T11 is the cable delay connecting the pseudolite transponder to the pseudolite transmit antenna;

the second step is that: ground station-pseudolite-receiver link delay measurement

The time delay value of the signal generated by the ground station integrated baseband and reaching the pseudo satellite receiving antenna through the uplink radio frequency equipment, the antenna and the space link, and directly connected to the monitoring receiver through the cable after being forwarded by the repeater is called as a one-hop time delay value T_Rec：

T_Rec＝ΔT1+ΔT2+ΔT3+ΔT4+ΔT5+ΔT6+ΔT7+ΔT8+ΔT9+ΔT10+ΔT12+ΔT13

Wherein Δ T12 is the cable delay connecting the outlet of the pseudo-satellite transponder to the inlet of the pseudo-satellite ground station monitoring receiver radio frequency signal; Δ T13 is the receiver internal calibration time delay;

the one-hop delay value of the monitoring receiver is acquired by a time interval counter SR620, the 1PPS signal output by the receiver is compared with the 1PPS signal output by the main clock by the SR620, and therefore the time difference data T acquired by the time interval counter SR620_SR620Comprises the following steps:

where Δ T14 is the cable delay connecting the 1PPS signal output by the receiver to the gate signal entry of the time interval counter SR 620; the delta T15 is the cable time delay for connecting the first-stage time frequency distribution amplifier to the time frequency amplifier of the pseudolite ground station;

the third step: time delay of ground station transmitting equipment and time delay sum measurement of receiving equipment

Sum of time delays T of transmitting equipment and receiving equipment of ground station_totalComprises the following steps:

wherein Δ T1+ Δ T2+ Δ T3 is the transmission delay from the ground atomic clock group to the baseband transmission frame head of the navigation ground station; Δ T6+ Δ T7+ Δ T8 and Δ T6 ' + Δ T7 ' + Δ T8 ' are the spatial link delays from the ground station to the pseudolite, which can be calculated from the ground station antenna rotation center coordinates and the pseudolite receive and transmit antenna coordinates, respectively; the time delay of connecting the pseudolite transceiving antenna and the transponder with a cable and the processing time delay of the transponder are delta T9+ delta T10+ delta T11;

the fourth step: measurement of time delay of ground station transmitting equipment and time delay of receiving equipment

According to T_totalObtaining time delay T of navigation ground station transmitting link equipment_up：

Wherein Δ T12 is the cable delay connecting the outlet of the pseudo-satellite transponder to the inlet of the pseudo-satellite ground station monitoring receiver radio frequency signal; Δ T13 is the monitoring receiver internal time delay; Δ T14 is the cable delay from the 1PPS signal output by the monitoring receiver to the SR620 door-closing signal inlet; the delta T15 is the cable time delay for connecting the first-stage time frequency distribution amplifier to the time frequency amplifier of the pseudolite ground station; the delta T1 is the cable time delay connecting the ground atomic clock group to the first-level time-frequency distribution amplifier;

T_totalminus T_upObtaining the time delay T of the receiving link equipment_down：

Through the obtained time delay T of the navigation ground station transmitting link equipment_upAnd receiving the link equipment delay T_downAnd completing the calibration of the time delay of the navigation ground station equipment.

Furthermore, a standard time-frequency reference signal is provided for each device in the navigation ground station through the ground high-precision atomic clock, and the navigation ground station transmits a signal to the pseudo satellite and receives a signal forwarded by the pseudo satellite transponder.

Further, the ground station to be tested transmits signals to the pseudo satellite, the comprehensive baseband measures and records the loop time delay value, the monitoring receiver records the one-hop time delay value, all data are recorded once per second, and the final data are recordedThe observed quantity is subjected to statistical analysis processing to obtain the final time delay T of the transmitting link equipment_upAnd receiving the link equipment delay T_down。

The invention relates to a time delay calibration method of navigation ground station equipment based on a satellite transponder, which uses the transponder of a pseudo-satellite to replace the satellite transponder, and utilizes the carrier phase measurement functions of a ground station comprehensive baseband and a monitoring receiver, the ground station comprehensive baseband calibrates the time delay of the ground station equipment by adopting a self-transmitting and self-receiving working mode, the navigation ground station transmits signals to the pseudo-satellite and receives the signals forwarded by the pseudo-satellite, a ground monitoring platform formed by the monitoring receiver, a time interval counter SR620 and the like simultaneously receives the signals forwarded by the pseudo-satellite, monitors the signal transmission time delay, and analyzes the time delay of each section on a link transmission path to obtain the time delay of the transmission and reception link equipment of the navigation ground station.

The equipment used in the calibration scheme, such as a navigation ground station, a calibration pseudo-satellite transponder, a monitoring receiver and a test SR620, is connected with an external system reference clock source, all standard cables are matched by using a universal instrument to complete accurate initial calibration, and after the calibration is completed, effective time delay calibration of ground station equipment can be effectively solved.

The method has the advantages that the precision reaches subnanosecond magnitude, the method has important significance for establishing a virtual clock model of a forwarding satellite navigation system, and meanwhile, the method has important significance for calibrating the time delay of ground station equipment of a time transfer system with equal time ratio of the navigation function and time service of the forwarding satellite navigation system and the bidirectional time frequency of a satellite. The time delay calibration test of the ground station equipment is completed through the pseudo-satellite transponder, and the test result shows that the method is feasible and is a convenient and effective time delay calibration method of the ground station equipment.

Drawings

FIG. 1 is a schematic diagram of a time delay calibration for ground station equipment;

FIG. 2 is a device connection diagram;

FIG. 3 is a ground station equipment connectivity diagram;

FIG. 4 is a statistical plot of loop delay for integrated baseband measurements at a ground station;

FIG. 5 is a one-hop latency statistic plot of pseudolite ground station monitor receiver measurements;

FIG. 6 is a time delay statistics diagram for a ground station transmitting device;

figure 7 is a time delay statistical chart for a ground station receiving device.

Detailed Description

The present invention will be described in further detail with reference to the following examples, which are not intended to limit the invention thereto.

And assuming that the ground station needing calibration is the station A, the ground high-precision atomic clock provides standard time-frequency reference signals for each device in the navigation ground station, and the navigation ground station transmits signals to the pseudo satellite and receives the signals forwarded by the pseudo satellite transponder.

The ground station comprehensive baseband generates a ranging signal, the ranging signal is transmitted to a pseudo satellite through an up-converter, a high-power amplifier and an antenna, a pseudo satellite receiving antenna receives the signal from the ground station and forwards the signal through a repeater, the signal forwarded by the pseudo satellite received by the ground station antenna is processed on the ground station comprehensive baseband through low-noise amplification and a down-converter, and time delay measurement of the whole loop of the ground station, the pseudo satellite and the ground station is completed.

The specific calibration process is as follows:

referring to fig. 1 and 3, a navigation ground station-pseudolite-ground station loop delay is measured.

Navigation ground station integrated baseband measurement to obtain loop time delay value delta T_loopComprises the following steps:

ΔT_loop＝ΔT1+ΔT2+ΔT3

ΔT4+ΔT5+ΔT6+ΔT7+ΔT8+ΔT4′+ΔT5′+ΔT6′+ΔT7′+ΔT8′+ΔT9+ΔT10+ΔT11

wherein, Δ T1 is the cable delay connecting the ground atomic clock group to the first-level time-frequency distribution amplifier; the delta T2 is the cable time delay of the time frequency amplifier connecting the first-stage time frequency distribution amplifier to the navigation ground station; the delta T3 is the cable time delay from the time-frequency amplifier of the navigation ground station to the baseband; Δ T4 and Δ T4' are the baseband internal transmit and receive calibration time delays, respectively; Δ T5 and Δ T5' are the navigational ground station device transmit and receive delays, respectively; Δ T6 and Δ T6' are the spatial link delays for uplink and downlink, respectively; Δ T7 and Δ T7' are the ionospheric delays of the uplink and downlink spatial links, respectively; Δ T8 and Δ T8' are the tropospheric delays of the spatial links upstream and downstream, respectively; Δ T9 is the cable delay connecting the pseudolite receive antenna to the transponder; Δ T10 is the pseudo satellite transponder delay; at 11 is the cable delay connecting the pseudolite transponder to the pseudolite transmit antenna.

Referring to fig. 1 and 3, the measurement monitors the receiver one-hop delay value.

One-hop delay value T measured by a monitoring receiver is collected at a pseudolite ground station by using a time interval counter SR620_SR620Comprises the following steps:

wherein Δ T12 is the cable delay connecting the outlet of the pseudo-satellite transponder to the inlet of the pseudo-satellite ground station monitoring receiver radio frequency signal; Δ T13 is the receiver internal calibration time delay; Δ T14 is the cable delay from the 1PPS signal at the receiver output to the SR620 door-closing signal entrance; at 15 is the cable delay connecting the first stage time frequency distribution amplifier to the time frequency amplifier of the pseudolite ground station.

Referring to fig. 1, the time delay of the ground station transmitting device and the time delay of the receiving device are calculated.

The sum T of the time delays of the transmitting equipment and the receiving equipment of the ground station can be obtained by calculation_totalComprises the following steps:

wherein Δ T_loopThe loop delay value of the navigation ground station, the pseudo satellite and the ground station measured by the ground station comprehensive baseband; Δ T1+ Δ T2+ Δ T3 is the transmission delay from the ground atomic clock group to the ground station baseband transmission frame header, which is known to be measurable; Δ T6+ Δ T7+ Δ T8 and Δ T6 ' + Δ T7 ' + Δ T8 ' are the spatial link delays from the ground station to the pseudolite, which can be calculated from the coordinates of the ground station antenna rotation center and the pseudolite receive and transmit antenna coordinates, respectively, since the ground station is closer to the pseudolite, the convection currents in the spatial link occurThe time delay of the stratum, the ionosphere and the like can be ignored, so that the time delay is known; Δ T9+ Δ T10+ Δ T11 are the pseudolite antenna to transponder connection cable delays and the transponder's own processing delays, which are measurable and known, so that the sum T of the ground station equipment delays is obtained_total。

Calculating time delay T of ground station transmitting link equipment_up：

Wherein Δ T12 is the cable delay connecting the outlet of the pseudo-satellite transponder to the inlet of the pseudo-satellite ground station monitoring receiver radio frequency signal, the test cable delay can be calibrated in advance and is known; the delta T13 is the internal time delay of the monitoring receiver, and the monitoring receiver is calibrated before testing, so the time delay of the part is negligible; Δ T14 is the cable delay from the monitoring receiver output 1PPS signal to the SR620 door-closing signal entrance, which can be calibrated in advance and is known; Δ T15 is the cable delay connecting the first stage time frequency distribution amplifier to the pseudolite ground station time frequency amplifier, which can be calibrated in advance and is known; at 1 is the cable delay connecting the ground atomic clock group to the first-stage time-frequency distribution amplifier, which can be calibrated in advance and is known.

Therefore, the time delay of the ground station transmitting link equipment can be calculated.

Through T_down＝T_total-T_upCalculating to obtain the time delay T of the receiving link equipment_down。

The equipment used in the calibration scheme, such as a navigation ground station, a calibration pseudo-satellite transponder, a monitoring receiver and a test SR620, is connected with an external system reference clock source, all standard cables are matched by using a universal instrument to complete accurate initial calibration, and after the calibration is completed, effective time delay calibration of ground station equipment can be effectively solved.

Figures 4-7 show graphs of the results of calibrating the time delay of the ground station equipment using pseudolites. The ground station to be measured transmits signals to the pseudo satellite, the comprehensive baseband measurement is carried out, a loop time delay value is recorded, a one-hop time delay value is recorded by the monitoring receiver, all data are recorded once per second, and the final observed quantity is subjected to statistical analysis processing.

The result shows that the maximum value of the time delay of the ground station transmitting equipment is 197.25ns, the minimum value is 196.0ns, and the statistical standard deviation is 0.18 ns; the maximum value of the time delay of the receiving equipment of the ground station is 348.53ns, the minimum value is 348.40ns, and the statistical standard deviation is 0.018 ns; the precision of time delay calibration of ground station equipment can reach subnanosecond order. The method has important significance for improving the precision of a satellite navigation system and a satellite bidirectional time comparison method. The time delay calibration test of the ground station equipment is completed through the pseudo-satellite transponder, and the test result shows that the method is feasible and is an effective time delay calibration method of the ground station equipment.

The present invention is described in detail with reference to the above embodiments, and those skilled in the art will understand that: modifications and equivalents may be made to the embodiments of the invention without departing from the spirit and scope of the invention, which is to be covered by the claims.