A directional method based on a single GNSS satellite scenario

Abstract

The application discloses a kind of based on single GNSS satellite scene direction method, using software radio and multiple antennas to build the satellite signal receiver of multiple channels, utilize the carrier phase difference of same satellite between multiple channels to build satellite signal direction vector, the direction of satellite signal is calculated by direction vector.In this process, first, the processing delay of software radio and the propagation delay of antenna are calibrated, the relative position between multiple antennas is measured, then multiple channels satellite signal receiver is built using software radio and multiple antennas, multiple channels simultaneously process the signal of same satellite, then in the tracking process, the direction vector of satellite signal is estimated using the carrier phase difference value of multiple channels, finally, the direction of satellite signal is estimated by direction vector.The application realizes the rapid satellite signal direction estimation, calculates the dual-antenna heading information by combining satellite message information, completes the orientation function under the scene of single visible satellite.

Description

Technical Field

[0001] This invention belongs to the field of satellite signals and relates to a orientation method based on a single GNSS satellite scenario. Background Technology

[0002] With the rapid adoption of GNSS RTK technology, short-baseline lateral attitude measurement multi-antenna systems have also been widely adopted, significantly reducing heading initialization issues. However, traditional techniques require sufficient visible satellite data in open areas to calculate heading information correctly. Consequently, in challenging scenarios where visible satellite resources are scarce, conventional techniques are unsuitable.

[0003] On the other hand, traditional signal direction estimation algorithms rely on Fourier transform of spatial signals or searching for power peaks after beamforming. However, navigation satellite signals are extremely weak, making it difficult to process weak signals and unable to form effective power peaks. Meanwhile, beamforming relies on expensive phased array antennas, which is complex to implement. Summary of the Invention

[0004] To address the aforementioned issues, this invention provides a orientation method based on a single GNSS satellite scenario. The algorithm is optimized by utilizing the phase observation resources of the antenna array, enabling normal output of heading information even in scenarios with a single visible satellite and a weak signal.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A orientation method based on a single GNSS satellite scenario, the specific steps of which are as follows:

[0007] (1) The software radio processing delay and antenna transmission delay are calibrated, and the delay of each antenna is obtained as follows: Relative to antenna number 1, the relative signal phase delay between each antenna is: ,in, ;

[0008] (2) Track the signal of the same satellite in each channel to obtain multiple tracking results;

[0009] (3) Use the demodulated data signal from the tracking results to synchronize the signal and further eliminate the effects of delay;

[0010] (4) Calculate the carrier phase error by using the estimated value of the carrier phase in each tracking channel and the calibrated signal phase delay result, and use the carrier phase error to calculate the steering vector of the signal;

[0011] (5) Estimate the direction of arrival of the satellite signal based on the relative position of the antenna and the signal steering vector;

[0012] (6) Repeat steps (4) and (5) to continuously estimate the direction of the satellite signal;

[0013] (7) Calculate the heading information of the dual antennas by combining the satellite's direction of arrival and satellite coordinate information.

[0014] As a further improvement of the present invention, the specific process of step (3) is as follows:

[0015] use time Each channel data signal Calculate the cross-correlation results between channel 1 and other channels. ,in,

[0016]

[0017]

[0018]

[0019]

[0020] Then in Searching for correlation peaks in cross-correlation sequences That is, the relevant peak appears At this point, the relative delay time between channel one and other channels is obtained, and signal synchronization is completed.

[0021] As a further improvement of the present invention, the specific process of step (4) is as follows:

[0022] get Carrier phase measurement results of each channel Calculate the initial results of the carrier phase difference between channel 1 and other channels. ,

[0023]

[0024] Consider the relative signal phase delay obtained in step (1) The carrier phase difference is obtained. :

[0025]

[0026] Finally, the signal steering vector is calculated.

[0027] As a further improvement of the present invention, the specific process of step (5) is as follows:

[0028] Establish a linear equation:

[0029]

[0030] in and The first The relative distances between each antenna and the first antenna in the x and y directions of a custom coordinate system. and These are the direction angle and elevation angle of the signal, respectively. The center frequency of the signal. Represents the speed of light. Simplifying the above formula to...

[0031]

[0032] in , ;

[0033] Then, according to the least squares principle, we can calculate...

[0034]

[0035] Then the signal direction angle is calculated. Altitude angle .

[0036] As a further improvement of the present invention, in step (7), the heading angle is determined in the following manner. Value:

[0037]

[0038] Where i is the included angle of the baselines of the two antennas. It is the angle between the antenna baseline and the OC.

[0039] Compared with the prior art, the significant advantages and beneficial effects of this invention are:

[0040] This invention achieves rapid satellite signal direction estimation, which does not rely on the acquisition of satellite ephemeris or the estimation of its own position. Therefore, it can estimate the signal direction well even when the number of visible satellites is insufficient for a cold start and when the signal strength is extremely weak. Combined with satellite ephemeris, the heading information of the dual antennas can be calculated to complete the orientation function in the scenario of a single visible satellite. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the orientation method based on a single GNSS satellite scenario provided by the present invention.

[0042] Figure 2 This is a schematic diagram of heading calculation based on the guidance vector. Detailed Implementation

[0043] The technical solutions provided by the present invention will be described in detail below with reference to specific embodiments. It should be understood that the following specific embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0044] This invention provides a direction finding method based on a single GNSS satellite scenario. The method employs software-defined radio and multiple antennas to construct a multi-channel satellite signal receiver. It utilizes the carrier phase difference between multiple channels for the same satellite to construct a satellite signal steering vector, and calculates the direction of arrival of the satellite signal using this steering vector. In this process, the processing delay of the software-defined radio and the propagation delay of the antennas are first calibrated, and the relative positions between the multiple antennas are measured. Then, a multi-channel satellite signal receiver is built using the software-defined radio and multiple antennas, with multiple channels simultaneously processing signals from the same satellite. During tracking, the steering vector of the satellite signal is estimated using the carrier phase difference values ​​of the multiple channels, and finally, the direction of arrival of the satellite signal is estimated using the steering vector.

[0045] Specifically, this invention provides a orientation method based on a single GNSS satellite scenario, the process of which is as follows: Figure 1 As shown, it includes:

[0046] Step 1: Calibrate the software radio processing delay and antenna transmission delay, and obtain the delay of each antenna. The time delay difference between each antenna relative to antenna number 1 is: ,in, .

[0047] Step 2: Track the signal of the same satellite in each channel to obtain multiple tracking results.

[0048] Step 3: Use the demodulated data signal from the tracking results to synchronize the signal and further eliminate the impact of delay.

[0049] The specific process of signal synchronization is as follows:

[0050] use time Each channel data signal Calculate the cross-correlation results between channel 1 and other channels. ,in,

[0051]

[0052]

[0053]

[0054]

[0055] Then in Searching for correlation peaks in cross-correlation sequences That is, the relevant peak appears At this point, the relative delay time between channel one and other channels is obtained, and signal synchronization is completed.

[0056] Step 4: Using the estimated carrier phase values ​​from each tracking channel, combined with the calibrated signal phase delay results, calculate the carrier phase error, and then use the carrier phase error to calculate the signal's steering vector. The specific process is as follows:

[0057] get Carrier phase measurement results of each channel Calculate the initial results of the carrier phase difference between channel 1 and other channels. ,

[0058]

[0059] Consider the relative signal phase delay obtained in step (1) The carrier phase difference is obtained. :

[0060]

[0061] Finally, the signal steering vector is calculated.

[0062] Step 5: Estimate the satellite signal direction of arrival based on the relative position of the antenna and the signal steering vector. The specific process is as follows:

[0063] Establish a linear equation:

[0064]

[0065] in and The first The relative distances between each antenna and the first antenna in the x and y directions of a custom coordinate system. and These are the direction angle and elevation angle of the signal, respectively. The center frequency of the signal. Represents the speed of light. The above formula simplifies to:

[0066]

[0067] in , .

[0068] Then, according to the least squares principle, we can calculate...

[0069]

[0070] Then the signal direction angle is calculated. Altitude angle

[0071] Step 6: Repeat steps 4 and 5 to continuously estimate the direction of the satellite signal until the satellite leaves the field of view.

[0072] Step 7, as follows Figure 2 As shown, given the satellite azimuth angle, elevation angle calculated from the satellite ephemeris, and the angle i between the satellite and the dual-antenna baseline, the heading angle can be calculated.

[0073]

[0074] Where O is the center point of antenna 1, A is any point on the line connecting the satellite and O, B is the vertical projection of OA onto the baseline of antennas 1 and 2, and C is the projection of OA onto the northeast horizon. It is the angle between the baseline of antenna 1,2 and OC.

[0075] The technical means disclosed in this invention are not limited to those disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications are also considered within the scope of protection of this invention.

Claims

1. A orientation method based on a single GNSS satellite scenario, characterized in that, Includes the following steps: (1) The software radio processing delay and antenna transmission delay are calibrated, and the delay of each antenna is obtained as follows: Relative to antenna number 1, the relative signal phase delay between each antenna is... ,in, ; (2) Track the signal of the same satellite in each channel to obtain multiple tracking results; (3) Use the demodulated data signal from the tracking results to synchronize the signal and further eliminate the effects of delay; (4) Using the estimated carrier phase values ​​in each tracking channel and the calibrated signal phase delay results, calculate the carrier phase error, and use the carrier phase error to calculate the signal steering vector; specifically, the following process is included: get Carrier phase measurement results of each channel Calculate the initial results of the carrier phase difference between channel 1 and other channels. , Consider the relative signal phase delay obtained in step (1) The carrier phase difference is obtained. : Finally, the signal steering vector is calculated. ; (5) Estimate the direction of arrival of the satellite signal based on the relative position of the antenna and the signal steering vector; specifically, this includes the following process: Establish a linear equation: in and The first The relative distances between each antenna and the first antenna in the x and y directions of a custom coordinate system. and These are the direction angle and elevation angle of the signal, respectively. The center frequency of the signal. Representing the speed of light; simplifying the above formula to: in , ; Then, according to the least squares principle, we can calculate... Then the signal direction angle is calculated. elevation angle ; (6) Repeat steps (4) and (5) to continuously estimate the direction of the satellite signal; (7) Calculate the heading information of antenna 1 and 2 by combining the satellite's direction of arrival and satellite coordinate information.

2. The orientation method based on a single GNSS satellite scenario according to claim 1, characterized in that, Step (3) specifically includes the following process: use time Each channel data signal Calculate the cross-correlation results between channel 1 and other channels. ,in, Then in Searching for correlation peaks in cross-correlation sequences That is, the relevant peak appears At this point, the relative delay time between channel one and other channels is obtained, and signal synchronization is completed.

3. The orientation method based on a single GNSS satellite scenario according to claim 1, characterized in that, Step (7) specifically includes the following process: The heading angle is determined using the following method. Value: Where i is the angle between the satellite and the baseline of the dual antennas, O is the center point of antenna 1, A is any point on the line connecting the satellite and O, B is the vertical projection point of OA onto the baseline of antennas 1 and 2, and C is the projection point of OA onto the northeast horizon. It is the angle between the antenna baseline and the OC.

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