Satellite navigation anti-interference radio frequency assembly and double-threshold bidirectional automatic gain control method
Through the dual-threshold bidirectional automatic gain control method, the RF gain is adjusted in real time, which solves the contradiction of front-end gain needs, and achieves the effect of quickly capturing satellite signals and improving anti-interference capabilities.
Patent Information
- Application Number
- CN202411940196.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-26
- Publication Date
- 2025-04-08
AI Technical Summary
When the prior art achieves high-performance anti-interference performance, the front-end gain is too small, which leads to weak satellite signals and makes it difficult to capture satellites. At the same time, the carrier-to-noise ratio is low, which cannot effectively solve the contradiction between anti-interference and receiver performance on the front-end gain requirements.
The dual-threshold bidirectional automatic gain control method is adopted to communicate through the SPI interface of the RF chip and the anti-interference digital board, calculate the signal and count the power in real time, adjust the RF gain according to the maximum power value, and switch the large gain and small gain modes to adapt to different signal conditions.
Quickly capture satellite signals in large gain mode to ensure positioning time; improve the reception capacity of interfering signals in small gain mode to avoid ADC saturation, improve anti-interference ability, and improve the upper limit of anti-interference ability of PA-PB dB.
Smart Images
Figure CN119780969A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the field of satellite navigation confrontation and is an anti-interference radio frequency gain automatic control method. Background Art
[0002] Because the intensity of satellite navigation signals reaching the ground is very weak, satellite navigation user terminals usually have anti-interference functions.
[0003] In order to achieve high-performance anti-interference performance, the anti-interference digital board ADC sampling front-end link gain is required to be small enough (normal sampling is possible), so as to ensure that the ADC is not saturated when receiving a strong interference signal. However, too small a front-end gain will result in very weak satellite signals, making it very difficult to capture satellites using a satellite navigation receiver, and the satellite signal carrier-to-noise ratio is low. To improve capture performance and satellite carrier-to-noise ratio, the front-end gain needs to be increased. This solves the contradiction between the different requirements for front-end gain for anti-interference and receiver performance. Summary of the invention
[0004] In order to overcome the deficiencies of the prior art, the present invention provides a satellite navigation anti-interference radio frequency component and a dual-threshold bidirectional automatic gain control method.
[0005] The technical solution adopted by the present invention to solve its technical problem is:
[0006] A satellite navigation anti-interference RF component, the RF part includes L channels. In each channel, the RF signal passes through the amplifier and the filter in sequence and then enters the RF chip. After down-conversion by the RF chip, it passes through the filter again as the output of the RF part. The output signal of the RF part enters the anti-interference digital board.
[0007] The RF chip realizes the down-conversion function. The RF chip configures the internal parameters of the RF part through the SPI interface to change the channel gain and phase information;
[0008] The anti-interference digital board collects the intermediate frequency signal output by the radio frequency part to realize the anti-interference function. The anti-interference digital board is connected to the radio frequency chip through the SPI interface.
[0009] The SPI communication between the anti-interference digital board and the RF chip is divided into 3-wire or 4-wire. Select 3-wire or 4-wire according to the RF chip used, and set the RF gain according to the gain value table in the manual.
[0010] The present invention also provides a dual-threshold bidirectional automatic gain control method for a satellite navigation anti-interference radio frequency component. When the device is powered on, the radio frequency is controlled to a large gain mode by default. The anti-interference digital board calculates the statistical power of the received L-channel signal in real time. The calculation formula of the signal statistical power is shown in formula (1):
[0011]
[0012] Among them, x i is the real-time sampling data of the ADC, M is the sampling bit number of the selected ADC chip minus 1, N is the statistical average number of points, P is the statistical power of the signal, with the unit of watt (W), and P dBm is the power value obtained by converting P to dBm;
[0013] Calculate the power values of L channels respectively, and compare and select the maximum power value among the power values of L channels and denote it as P max , representing the maximum power among L channels;
[0014] The anti-interference digital board controls the gain of the RF chip through the SPI interface. The control method is to change the register configuration value in the RF chip. By modifying the register of the RF chip, the RF chip is configured with a large frequency conversion gain P A , that is, the large gain mode. Similarly, the RF chip is configured with a small frequency conversion gain P B , that is, the small gain mode;
[0015] Set the high threshold A and the low threshold B. A and B are power values, A > B, and the gain P A -P B < A - B to ensure that there will be no repeated adjustment.
[0016] When the device is powered on, the RF chip is default-configured in the large gain mode, and the gain value is P A . When it is detected that the power value P max is greater than the threshold A, the RF gain is configured to the small gain, and the gain value is P B ; when the RF is working in the small gain mode and it is detected that the power value P max drops below the threshold B, the RF gain is configured to the large gain, and the gain value is P A .
[0017] The beneficial effect of the present invention is that when the RF is working in the large gain mode, the satellite signal is amplified to meet the requirements of the satellite navigation receiver for quick acquisition, ensuring the acquisition speed and positioning time; when the RF is working in the small gain mode, the satellite navigation receiver is working in the tracking mode, and the satellite signal can still be normally resolved. At this time, the RF gain is reduced, and the upper limit of the interference signal received by the device is increased, and the increased value is P A -P B . When the ADC is not saturated and the anti-interference can work normally, the upper limit of the anti-interference ability is increased by P A -P B dB.
[0018] Usually, a single-chip microcomputer is configured for the RF chip during design. The RF gain control is performed by the single-chip microcomputer. The gain is controlled by changing the single-chip microcomputer program. The scheme of the present invention can save the single-chip microcomputer and save costs. In addition, the scheme of the present invention can monitor the channel power in real time and adjust the RF gain according to the channel power, and the control method is more flexible. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 This is the architecture diagram of the anti-interference RF component.
[0020] Figure 2 It is a schematic diagram of the anti-interference RF gain control method. DETAILED DESCRIPTION
[0021] The present invention is further described below in conjunction with the accompanying drawings and embodiments.
[0022] A satellite navigation anti-interference radio frequency component. The current framework of the satellite navigation anti-interference radio frequency component is as follows: Figure 1 As shown, the RF part includes L channels. In each channel, the RF signal passes through the amplifier and the filter in turn and then enters the RF chip. After down-conversion by the RF chip, it passes through the filter again as the output of the RF part. The output signal of the RF part enters the anti-interference digital board.
[0023] The RF chip realizes the down-conversion function. The RF chip configures the internal parameters of the RF part through the SPI interface to change the channel gain and phase information;
[0024] The anti-interference digital board collects the intermediate frequency signal output by the radio frequency part to realize the anti-interference function. The anti-interference digital board is connected to the radio frequency chip through the SPI interface.
[0025] The SPI communication between the anti-interference digital board and the RF chip is divided into 3-wire or 4-wire. Select 3-wire or 4-wire according to the RF chip used, and set the RF gain according to the gain value table in the manual.
[0026] The present invention also provides a control method for an anti-interference radio frequency component. When the device is powered on, the radio frequency is controlled to a large gain mode by default. The anti-interference digital board calculates the statistical power of the received L-channel signals in real time. The calculation formula of the signal statistical power is shown in formula (1):
[0027]
[0028] Among them, x i is the real-time sampling data of the ADC, M is the sampling bit number of the selected ADC chip minus 1, N is the number of statistical average points, P is the signal statistical power in watts (W), P dBm To convert P into a power value in dBm;
[0029] Calculate the power values of L channels respectively, and compare and select the maximum power value among the power values of L channels, denoted as P max , representing the maximum power among L channels;
[0030] The anti-interference digital board controls the gain of the RF chip through the SPI interface. The control method is to change the register configuration value in the RF chip. The RF chip is configured as a large frequency conversion gain P by modifying the registers of the RF chip A , that is, the large gain mode. Similarly, the RF chip is configured as a small frequency conversion gain P B , that is, the small gain mode;
[0031] Set the high threshold A and the low threshold B. A and B are power values, A > B, and the gain P A -P B < A - B, ensuring that there will be no repeated adjustment.
[0032] When the device is powered on, the RF chip is default configured to the large gain mode, and the gain value is P A , when the detected power value P max is greater than the threshold A, the RF gain is configured to the small gain, and the gain value is P B ; when the RF is working in the small gain mode and the detected power value P max drops below the threshold B, the RF gain is configured to the large gain, and the gain value is P A .
[0033] The present invention is applicable to the suppression of jamming signals in the downlink frequency band of all satellite navigation systems using anti-interference RF chips. The specific implementation manner of the present invention is described by taking the BDS-B3 frequency point jamming signal as an example.
[0034] In the embodiment, a 16bit ADC chip is used. The peak-to-peak value of the ADC sampling signal is set to 2V. At this time, the ADC sampling upper limit is 10dBm. The threshold A is set to -10dBm, the threshold B is set to -20dBm, the PA is set to 20dB, and the PB is set to 13dB.
[0035] The RF chip adopts RF1947, and the SPI is a three-wire system.
[0036] Step 1: The device is powered on. By default, the anti-interference digital board controls the RF to work in the large gain mode PA 20dB. At this time, if Pmax is less than the threshold A - 10dBm, the RF still works in the large gain. If Pmax is greater than the threshold A - 10dBm, the RF is adjusted to the small gain mode PB 13dB through the SPI.
[0037] Step 2: When the RF is working in the large gain mode, an interference signal is applied. The interference increases from small to large and exceeds the threshold A. At this time, the RF is adjusted to the small gain mode, and after adjustment, Pmax is greater than the threshold B.
[0038] Step 3: When the radio frequency works in the low gain mode, adjust the interference signal size. When Pmax is less than the threshold B, readjust the radio frequency to the high gain mode.
Claims
1. A satellite navigation anti-interference radio frequency component, characterized in that: The satellite navigation anti-interference RF component has an RF part which includes L channels. In each channel, the RF signal passes through the amplifier and the filter in sequence and then enters the RF chip. After down-conversion by the RF chip, it passes through the filter again as the output of the RF part. The output signal of the RF part enters the anti-interference digital board.
2. The satellite navigation anti-interference radio frequency component according to claim 1, characterized in that: The radio frequency chip realizes the down-conversion function. The radio frequency chip configures the internal parameters of the radio frequency part through the SPI interface to change the channel gain and phase information.
3. The satellite navigation anti-interference radio frequency component according to claim 1, characterized in that: The anti-interference digital board collects the intermediate frequency signal output by the radio frequency part to realize the anti-interference function. The anti-interference digital board is connected to the radio frequency chip through the SPI interface.
4. The satellite navigation anti-interference radio frequency component according to claim 1, characterized in that: The SPI communication between the anti-interference digital board and the RF chip is divided into 3-wire or 4-wire. Select 3-wire or 4-wire according to the RF chip used, and set the RF gain according to the gain value table in the manual.
5. A dual-threshold bidirectional automatic gain control method using the satellite navigation anti-interference radio frequency component of claim 1, characterized in that The steps include: When the device is powered on, the default control radio frequency is set to high gain mode. The anti-interference digital board calculates the statistical power of the received L-channel signals in real time. The calculation formula of the signal statistical power is shown in formula (1): Among them, x i is the real-time sampling data of the ADC, M is the sampling bit number of the selected ADC chip minus 1, N is the number of statistical average points, P is the signal statistical power in watts (W), P dBm To convert P into a power value in dBm; Calculate the power values of L channels respectively, and compare and select the largest power value among the L channel power values, denoted as P max , represents the maximum power among L channels; The anti-interference digital board controls the gain of the RF chip through the SPI interface. The control method is to change the register configuration value in the RF chip. By modifying the register of the RF chip, the RF chip is configured to a large frequency conversion gain P. A , that is, large gain mode. Similarly, the RF chip is configured to a small frequency conversion gain P B , i.e. small gain mode; Set a high threshold A and a low threshold B, where A and B are power values, A > B, and the gain is P A -P B < A - B to ensure that there will be no repeated adjustments.
6. The dual-threshold bidirectional automatic gain control method for satellite navigation anti-interference radio frequency components according to claim 5, characterized in that: When the device is powered on, the RF chip is configured to high gain mode by default, and the gain value is P A , when the power value P is detected max When the value is greater than the threshold A, the RF gain is configured as a small gain, and the gain value is P B ; When the RF operates in low gain mode, the power value P is detected max When the value drops below threshold B, the RF gain is configured as high gain, and the gain value is P A .