Detection method and device applied to satellite signal acquisition

Abstract

The application discloses a detection method and device applied to satellite signal acquisition, comprising: detecting and judging this round of search of a current search unit according to a preset acquisition threshold and a dismissal threshold; when it is judged that this round of search of the current search unit is successful according to the acquisition threshold, the value of accumulated counting is increased, when the value of the accumulated counting reaches a preset maximum value, counting is stopped and it is judged that the current search unit successfully acquires a current satellite signal; when it is judged that this round of search of the current search unit is unsuccessful according to the dismissal threshold, the value of the counting is reset to a preset initial value, and the next search unit is entered. The application can reduce the detection times in the satellite signal acquisition process and shorten the acquisition time.

Description

Technical Field

[0001] This invention relates to the field of navigation technology, and more particularly to a detection method and apparatus for satellite signal acquisition. Background Technology

[0002] Navigation technology has played a vital role in the development of human history, and with continuous social progress, this technology, especially satellite navigation and positioning technology, is becoming increasingly intertwined with people's lives. Currently, the world's major satellite navigation systems include the Global Positioning System (GPS), BD2 (BeiDou-2), GLONASS, and Galileo. Both GPS and BD2 utilize CDMA (Code Division Multiple Access) technology, and their physical layer frame structures share many similarities. Therefore, their receiver designs are similar, both including radio frequency front-end processing, baseband digital signal processing, and positioning and navigation calculations. The baseband digital signal processing typically includes acquisition, tracking, bit synchronization, and frame synchronization.

[0003] The process of satellite navigation receivers acquiring satellite signals includes mixing, correlation, coherent / incoherent integration, and decision-making. The principle of navigation signal acquisition is as follows: Figure 1 As shown in the diagram, the decision unit compares the detected quantity obtained from the previous calculations with the decision threshold to determine whether the acquisition was successful. However, due to noise and interference, the detected quantity on the search unit where the signal is located may sometimes be weakened, while the detected quantity on other search units may sometimes show peaks, leading to missed detections or false alarms. Therefore, after a successful decision on a search unit, the navigation receiver should not immediately transition from the acquisition state to the next state, but should continue to further confirm the search unit. In other words, a confirmation mechanism needs to be added to the acquisition process.

[0004] Since the detection method in satellite signal acquisition significantly affects the receiver's time to first positioning (TTFF), a good signal acquisition detection method should have a short dwell time. However, in related technologies that include confirmation mechanisms, the time performance of satellite signal acquisition detection is not ideal, resulting in numerous detection attempts and long acquisition times. Summary of the Invention

[0005] This invention provides a detection method and apparatus for satellite signal acquisition, which can at least reduce the number of detections.

[0006] This application provides the following technical solution.

[0007] A detection method for satellite signal acquisition, comprising:

[0008] The current search unit is detected and judged in this round of search based on the pre-set capture threshold and expulsion threshold;

[0009] When the current search unit is determined to have successfully captured the satellite signal in this round of search according to the capture threshold, the count is incremented. When the count reaches the preset maximum value, the counting stops and it is determined that the current search unit has successfully captured the current satellite signal.

[0010] When the current search unit fails to capture data in this round based on the expulsion threshold, the count value is reset to a preset initial value, and the process moves to the next search unit.

[0011] The method further includes: if the count value does not reach the preset maximum value after the accumulation count, it is determined that the search needs to be continued in the current search unit.

[0012] The step of detecting and judging the current search of the current search unit based on the preset capture threshold and expulsion threshold includes: comparing the detection value of the current search unit in this round of search with the capture threshold and the expulsion threshold respectively; when the detection value is not less than the capture threshold, determining that the current search unit has successfully captured in this round of search; when the detection value is less than the expulsion threshold, determining that the current search unit has failed to capture in this round of search.

[0013] The step of detecting and judging the current search of the current search unit based on the preset capture threshold and expulsion threshold further includes: when the detected value is less than the capture threshold but not less than the expulsion threshold, keeping the current count value unchanged, and determining that it is necessary to continue the search in the current search unit.

[0014] The step of accumulating the count when determining that the current search unit has successfully captured the target in this round of search includes: adding 1 to the current count value when determining that the current search unit has successfully captured the target in this round of search.

[0015] A detection device for satellite signal acquisition, comprising:

[0016] The first comparator is used to detect and decide the current search unit in this round of search based on a pre-set capture threshold;

[0017] The second comparator is used to detect and make a decision on the current search unit in this round of search based on a pre-set expulsion threshold;

[0018] The counter is used to accumulate counts when the first comparator determines that the current search unit has successfully captured the current satellite signal in this round of search, and to stop counting when the count value reaches a preset maximum value, so as to indicate that the current search unit has successfully captured the current satellite signal; when the second comparator determines that the current search unit has failed to capture the current satellite signal in this round of search, the count value is reset to a preset initial value, so as to indicate that the search unit will move on to the next search unit.

[0019] The counter is further configured to accumulate counts after the first comparator determines that the current search unit has successfully captured the target in this round of search. If the count value does not reach the preset maximum value, the counter remains in its current state to indicate that additional searches need to be performed in the current search unit.

[0020] Specifically, the first comparator is used to compare the detection value of the current search unit in this round of search with the capture threshold; when the detection value is not less than the capture threshold, it is determined that the current search unit has successfully captured the target in this round of search.

[0021] The second comparator is specifically used to compare the detection value of the current search unit in this round of search with the expulsion threshold; when the detection value is less than the expulsion threshold, it is determined that the current search unit has failed to capture in this round of search.

[0022] Specifically, the first comparator is used to send the detection value to the second comparator when the detection value is less than the capture threshold; the second comparator is used to determine that it is necessary to continue searching in the current search unit when the detection value is not greater than the expulsion threshold; the counter is also used to keep the current count value unchanged when the second comparator determines that it is necessary to continue searching in the current search unit.

[0023] A navigation receiver includes a detection device as described above for satellite signal acquisition.

[0024] The advantages of this application include at least the following:

[0025] In this embodiment of the invention, a dual-threshold decision method is introduced in the acquisition and detection of satellite signals, thereby effectively reducing the number of detections.

[0026] In this embodiment of the invention, when it is determined that the current search unit has failed to capture, the counter is reset to its initial value and then the process moves to the next search unit. The counter only counts when the current search unit successfully captures in this round of search. It does not need to be repeatedly switched between addition and subtraction, and can be applied to the detection decision of each search unit. This can avoid counting oscillation, shorten the capture time, and improve detection performance.

[0027] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the description, claims, and drawings. Attached Figure Description

[0028] The accompanying drawings are provided to further understand the technical solutions of the present invention and constitute a part of the specification. They are used together with the embodiments of this application to explain the technical solutions of the present invention and do not constitute a limitation on the technical solutions of the present invention.

[0029] Figure 1 This is a schematic diagram illustrating the principle of navigation signal acquisition.

[0030] Figure 2 This is a schematic diagram illustrating the processing flow of the N-M strategy in related technologies;

[0031] Figure 3 This is a schematic diagram of the Tong detection process in related technologies;

[0032] Figure 4 This is a schematic diagram of the detection method applied to satellite signal acquisition in Example 1;

[0033] Figure 5 This is a schematic diagram of an exemplary processing flow for the detection method in Embodiment 1;

[0034] Figure 6 This is a schematic diagram of the processing flow of an example of detection method one in Embodiment 1;

[0035] Figure 7 This is an exemplary structural diagram of the detection device applied to satellite signal acquisition in Embodiment 2. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

[0037] The steps illustrated in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases the steps shown or described may be performed in a different order than that presented here.

[0038] In related technologies, acquisition algorithms with confirmation mechanisms can generally be divided into two types: fixed search time methods and variable search time methods. As the name suggests, the fixed search time method involves the receiver searching for a pre-set fixed time on each search unit, and then determining whether the acquisition was successful based on the multiple search results within that time period. A representative algorithm is the N×M algorithm. The variable search time method, on the other hand, involves the receiver searching for unequal amounts of time on each search unit according to certain rules and the current detection situation. Its overall acquisition performance is generally better than the fixed search time method, and a representative algorithm is the Tong algorithm.

[0039] The detection strategy of the capture algorithm that includes a confirmation mechanism in the relevant technology is explained below.

[0040] 1. The capture and detection strategy of taking M from N (hereinafter referred to as the N-M strategy).

[0041] In the N-of-M strategy, a search unit is searched N times. For each decision, if the detection rate V exceeds a threshold, the counter value m is incremented by 1. If N searches have been completed and the number of successful searches is not less than M, the capture is considered successful in that frequency range; otherwise, the capture fails. The process is as follows: Figure 2 As shown, the N-M strategy is a detection strategy with a fixed number of searches, therefore its detection performance is worse than the Tong capture detection strategy with variable search time.

[0042] 2. Tong capture detection strategy.

[0043] The Tong capture-detection strategy is a linear search method with variable search time. In principle, it adds more search time to search units where it is difficult to determine whether the signal has been successfully captured. Its process is as follows: Figure 3 As shown in the figure. Under low carrier-to-noise ratio conditions, especially when the probability of a single detection is close to 0.5, the K value will oscillate repeatedly between adding 1 and subtracting 1, resulting in a large number of detections and a significant increase in computational load.

[0044] Since the detection method in satellite signal acquisition significantly affects the receiver's Time to First Position (TTFF), a good signal acquisition detection method should have a short dwell time. However, as the above analysis shows, the time performance of satellite signal acquisition detection in related technologies is not ideal, involving not only numerous detection attempts but also long acquisition times. To address this problem, this application proposes the following technical solution: this solution uses a dual-decision threshold to achieve detection in satellite signal acquisition, which can avoid counting oscillations, reduce acquisition time, improve detection performance, and reduce the number of detection attempts.

[0045] The implementation method of the technical solution of this application will be described in detail below.

[0046] Example 1

[0047] like Figure 3 As shown, a detection method for satellite signal acquisition may include:

[0048] Step 301: Detect and determine the current search unit's search in this round based on the preset capture threshold and expulsion threshold;

[0049] Step 302: When the current search unit is determined to have successfully captured the current satellite signal in this round of search according to the capture threshold, the count is incremented. When the count reaches the preset maximum value, the counting is stopped and it is determined that the current search unit has successfully captured the current satellite signal.

[0050] Step 303: When the current search unit fails to capture in this round according to the expulsion threshold, the count value is reset to the preset initial value and the process moves to the next search unit.

[0051] In this embodiment, after accumulating the count when the current search unit is determined to have successfully captured the target in this round of search, if the count value does not reach the preset maximum value, it is determined that the current search unit needs to continue to perform additional searches.

[0052] In this embodiment, the step of detecting and judging the current search of the current search unit in this round based on the preset capture threshold and expulsion threshold may include: comparing the detection value of the current search unit in this round with the capture threshold and the expulsion threshold respectively; when the detection value is not less than the capture threshold, determining that the current search unit has successfully captured in this round; when the detection value is less than the expulsion threshold, determining that the current search unit has failed to capture in this round.

[0053] This may further include: when the detected value is less than the capture threshold but not less than the expulsion threshold, maintaining the current count value unchanged, and determining that an additional search needs to be performed in the current search unit. In other words, when the detected value is less than the capture threshold but not less than the expulsion threshold, no counting is performed, and the current count value remains unchanged. For example, if the count value is 3 before making a decision on this round of search in the current search unit, then when the detected value in this round of search in the current search unit is less than the capture threshold but not less than the expulsion threshold, the count value remains at 3.

[0054] In this embodiment, the step of accumulating the count when the current search unit's current search capture is determined to be successful may include: incrementing the current count value by 1 when the current search unit's current search capture is determined to be successful. In practical applications, binary counting or other counting methods can also be used, and a suitable counter can be freely selected as needed. Before counting, its initial value, maximum value, etc., can be pre-configured in the counter, and the above-mentioned counting-related processing can be implemented through the counter during the detection process.

[0055] It should be noted that the initial value (hereinafter referred to as the initial value) and maximum value during counting in this embodiment can be freely set according to different actual application scenarios. In specific applications, different initial values ​​and maximum values ​​can be configured for different types of satellite signals during counting. For example, the initial value during counting can be set to 0. The maximum value during counting can be set by statistically analyzing the satellite signal acquisition situation, or it can be an empirical value. This document does not restrict the specific values ​​of the initial value and maximum value during counting.

[0056] It should be noted that, in this embodiment, the acquisition threshold and the rejection threshold are the upper and lower limits of the detection value (which can be the amplitude or energy value of the signal obtained after the integration ends after searching the current search unit; the energy value can be expressed as the square of the signal amplitude), respectively. Different acquisition thresholds and rejection thresholds can be set for different types of satellite signals, and their specific values ​​can be set based on actual needs. This document does not impose any restrictions on this.

[0057] Figure 5 As an exemplary processing flow in this embodiment, each relevant branch of a pair of I and Q branches corresponds to a dual-threshold searcher (not shown in the figure). This dual-threshold searcher (equivalent to the detection device applied to satellite signal acquisition described below) mainly includes an amplitude comparator 1 (equivalent to the first comparator below), an amplitude comparator 2 (equivalent to the second comparator below), and a counter. The two amplitude comparators each correspond to an acquisition threshold V. H (High threshold) and an expulsion threshold V L (Low threshold). Wherein, the capture threshold V H This refers to the lower limit of the amplitude at which a successful capture can be determined; that is, at least this threshold must be reached to determine that the capture in this round is successful. The threshold V is the exclusion threshold. L This refers to the upper limit of the amplitude at which the current capture fails; that is, as long as it is less than this threshold, the capture in this round can be judged as a failure. The counter counts the number of times a search unit is successfully captured. The value of the counter is incremented by 1 for each successful capture of a search unit.

[0058] like Figure 5As shown, this exemplary process may include: when the receiver begins searching for a signal in a certain search unit, the value of the counter is first preset to an initial value; then, the search unit is searched, and after each integration of the current signal, the integrated detection value is fed into amplitude comparator 1, which, based on the detection value and the acquisition threshold V, performs a search. H If the search is successful, the counter value is incremented by 1. Then, it is checked whether the counter has reached a preset maximum value. If the counter reaches the preset maximum value, counting stops to determine whether the search for the current search unit needs to continue. If the current counter stops counting, it indicates that the receiver has successfully acquired the current satellite signal in the current search unit, and the two-dimensional search ends. If the counter has not stopped after this round of searching (i.e., has not reached the preset maximum value), the receiver continues the search in the current search unit. When entering amplitude comparator 1, if a failure is detected, it further enters amplitude comparator 2. Amplitude comparator 2 is based on the above detection value and the removal threshold V. L The detection and judgment are performed. If the amplitude comparator 2 determines that the detection is successful, the search is added to the current search unit. If the amplitude comparator 2 determines that the detection is unsuccessful, the receiver determines that the satellite signal has failed to be acquired in the current search unit, resets the counter to the initial value, and moves to the next search unit to continue searching and perform the above processing.

[0059] First, this embodiment introduces a dual-threshold decision method in satellite signal acquisition and detection, effectively reducing the number of detection attempts. Second, when the current search unit fails to acquire the signal, this embodiment resets the counter to its initial value before moving to the next search unit. The counter only counts when the current search unit successfully acquires the signal in this round, eliminating the need for repeated addition and subtraction. This allows it to be applied to the detection decisions of each search unit, avoiding counting oscillations, shortening the acquisition time, and thus improving detection performance.

[0060] The following examples illustrate the specific implementation of the method in this embodiment. It should be noted that the following examples are merely exemplary implementations of the method in this embodiment. In practical applications, the specific implementation of the method in this embodiment is not limited to these examples, and other specific implementations can be adopted in combination with specific application scenarios.

[0061] Example 1

[0062] like Figure 6 The diagram shows the detection process for satellite signal acquisition in this example, which may include:

[0063] Step 600: When the receiver starts searching for a signal in a certain search unit, the variable K of the preset counter is initialized to 0.

[0064] Step 601: After the receiver performs a search in the current search unit, after each integration of the signal (i.e., calculation of the signal amplitude), it compares the detected quantity V with the acquisition threshold V. H The size of V, if V exceeds or equals the capture threshold of 606V H Then proceed to step 602; if V is less than the capture threshold V H Then proceed to step 606;

[0065] Step 602, increment the K value by 1;

[0066] Step 603: Check the value of K to determine whether to continue searching the current search unit. If the current value of K, after the previous accumulation, is equal to its maximum value A, proceed to step 604; if the current value of K is less than its maximum value A, proceed to step 605.

[0067] Step 604: Declare that the receiver has successfully acquired the current satellite signal in the current search unit, and the two-dimensional search ends thereafter.

[0068] Step 605: The receiver continues to search in the current search unit and returns to step 601;

[0069] Step 606: Compare the detection quantity V with the rejection threshold V L Compare; if V exceeds or equals the expulsion threshold V L If V is less than the expulsion threshold V, then return to step 605 and continue the search in the current search unit; L Then proceed to step 607;

[0070] Step 607: The receiver determines that the signal has failed to be captured in the current search unit, but determines that the signal has not yet been captured. It then moves to the next search unit to continue searching, returns to step 600, resets the variable K of the counter to the initial value 0, and repeats the process for the next search unit.

[0071] The method of this embodiment can be applied to a navigation receiver, specifically through a baseband digital signal processing module. In one implementation, the method described above can be applied to the acquisition of GPS satellite signals.

[0072] Example 2

[0073] A detection device for satellite signal acquisition, such as Figure 7 As shown, it may include:

[0074] The first comparator 71 is used to detect and decide the current search of the current search unit in this round according to the preset capture threshold;

[0075] The second comparator 72 is used to detect and make a decision on the current search of the current search unit based on a preset expulsion threshold.

[0076] Counter 73 is used to accumulate a count when the first comparator determines that the current search unit has successfully captured the current satellite signal in this round of search, and to stop counting when the count value reaches a preset maximum value, so as to indicate that the current search unit has successfully captured the current satellite signal; when the second comparator determines that the current search unit has failed to capture the current satellite signal in this round of search, the count value is reset to a preset initial value, so as to indicate that the search unit will move on to the next search unit.

[0077] In this embodiment, the counter 73 can also be used to maintain its current state (i.e., not stop counting) when the count value has not reached a preset maximum value, to indicate that additional searches need to be added to the current search unit. In other words, the counter 73 can also be used to maintain its working state (i.e., not stop counting) after the first comparator determines that the current search unit has successfully captured the target in this round of search, to indicate that additional searches need to be added to the current search unit.

[0078] In this embodiment, the first comparator 71 is specifically used to compare the detection value of the current search unit in this round of search with the capture threshold respectively; when the detection value is not less than the capture threshold, it is determined that the current search unit has successfully captured in this round of search; the second comparator 72 is specifically used to compare the detection value of the current search unit in this round of search with the expulsion threshold respectively; when the detection value is less than the expulsion threshold, it is determined that the current search unit has failed to capture in this round of search.

[0079] Here, the first comparator 73 is specifically used to send the detection value to the second comparator when the detection value is less than the capture threshold; the second comparator 74 is specifically used to determine that an additional search needs to be added to the current search unit when the detection value is not greater than the expulsion threshold; the counter 73 can also be used to keep the current count value unchanged when the second comparator determines that an additional search needs to be added to the current search unit. In other words, no counting is performed when the detection value is less than the capture threshold but not less than the expulsion threshold, and the current count value remains unchanged. For example, if the counter count is 3 before making a decision on this round of search in the current search unit, then when the detection value of this round of search in the current search unit is less than the capture threshold but not less than the expulsion threshold, the counter count value will still remain at 3.

[0080] In this embodiment, the counter 73 is used to count when the current search unit's current search capture is determined to be successful. This can include incrementing the current count by 1 when the current search unit's current search capture is determined to be successful. In practical applications, this counter can be of various types, such as a binary counter or a decimal counter, and can be freely selected as needed.

[0081] It should be noted that the initial value (hereinafter referred to as the initial value) and maximum value of the counter in this embodiment can be freely set according to different actual application scenarios. In specific applications, different initial values ​​and maximum values ​​can be configured for different types of satellite signals. For example, the initial value of the counter can be set to 0. The maximum value of the counter can be set by statistically analyzing the acquisition of satellite signals, or it can be an empirical value. This document does not restrict the specific values ​​of the initial value and maximum value of the counter.

[0082] It should be noted that, in this embodiment, the acquisition threshold and the rejection threshold are the upper and lower limits of the detection value (which can be the amplitude or energy value of the signal obtained after the integration ends after searching the current search unit; the energy value can be expressed as the square of the signal amplitude), respectively. Different acquisition thresholds and rejection thresholds can be set for different types of satellite signals, and their specific values ​​can be set based on actual needs. This document does not impose any restrictions on this.

[0083] In practical applications, the detection device for satellite signal acquisition in this embodiment can be implemented through a navigation receiver or integrated within it. In one implementation, the detection device can be implemented using the baseband digital signal processing module of the navigation receiver. The first comparator 71, the second comparator 72, and the counter 73 can be software, hardware, or a combination of both. In another implementation, the detection device can serve as… Figure 1 The decision device shown or set in Figure 1 The decision-making device shown.

[0084] Other technical details of this embodiment can be found in Embodiment 1.

[0085] Example 3

[0086] This application also provides a navigation receiver that includes the detection device described above for satellite signal acquisition. Specific technical details can be found in Embodiments 1 and 2.

[0087] While the embodiments disclosed in this invention are as described above, the content is merely for the purpose of facilitating understanding of the invention and is not intended to limit the invention. Any person skilled in the art to which this invention pertains may make any modifications and changes to the form and details of the implementation without departing from the spirit and scope disclosed herein; however, the scope of patent protection of this invention shall still be determined by the scope defined in the appended claims.

Claims

1. A detection method for satellite signal acquisition, comprising: The current search unit is detected and judged in this round of search based on the pre-set capture threshold and expulsion threshold; When the current search unit is determined to have successfully captured the satellite signal in this round of search according to the capture threshold, the count is incremented. When the count reaches the preset maximum value, the counting stops and it is determined that the current search unit has successfully captured the current satellite signal. When the current search unit fails to capture in this round according to the expulsion threshold, the count value is reset to the preset initial value, and the process moves to the next search unit. The step of detecting and judging the current search of the current search unit according to the preset capture threshold and expulsion threshold includes: when the detection value is less than the capture threshold but not less than the expulsion threshold, keeping the current count value unchanged, and determining that it is necessary to continue the search in the current search unit.

2. The detection method according to claim 1, characterized in that, The method further includes: If the count value does not reach the preset maximum value after the cumulative count, it is determined that the search needs to be continued in the current search unit.

3. The detection method according to claim 1 or 2, characterized in that, The step of detecting and judging the current search of the current search unit based on the preset capture threshold and expulsion threshold also includes: The detection value of this round of search by the current search unit is compared with the capture threshold and the expulsion threshold respectively; When the detected value is not less than the capture threshold, the current search unit is determined to have successfully captured the target in this round; when the detected value is less than the expulsion threshold, the current search unit is determined to have failed to capture the target in this round.

4. The detection method according to claim 1, characterized in that, The step of accumulating the count when it is determined that the current search unit has successfully captured the target in this round of search includes: adding 1 to the current count value when it is determined that the current search unit has successfully captured the target in this round of search.

5. A detection device for satellite signal acquisition, characterized in that, include: The first comparator is used to detect and decide the current search unit in this round of search based on a pre-set capture threshold; The second comparator is used to detect and make a decision on the current search unit in this round of search based on a pre-set expulsion threshold; A counter is used to accumulate counts when the first comparator determines that the current search unit has successfully captured the current satellite signal in this round of search, and to stop counting when the count value reaches a preset maximum value, so as to indicate that the current search unit has successfully captured the current satellite signal; when the second comparator determines that the current search unit has failed to capture the current satellite signal in this round of search, the count value is reset to a preset initial value, so as to indicate that the next search unit will be started. Specifically, the first comparator is used to send the detection value to the second comparator when the detection value is less than the capture threshold; The second comparator is specifically used to determine that an additional search needs to be performed in the current search unit when the detected value is not greater than the expulsion threshold; The counter is also used to keep the current count value unchanged when the second comparator determines that it is necessary to continue the search in the current search unit.

6. The detection device according to claim 5, characterized in that, The counter is also used to accumulate counts after the first comparator determines that the current search unit has successfully captured the target in this round of search. If the count value does not reach the preset maximum value, the counter remains in its current state to indicate that the current search unit needs to continue to perform additional searches.

7. The detection device according to claim 5, characterized in that, The first comparator is specifically used to compare the detection value of the current search unit in this round of search with the capture threshold; when the detection value is not less than the capture threshold, it is determined that the current search unit has successfully captured the target in this round of search. The second comparator is specifically used to compare the detection value of the current search unit in this round of search with the expulsion threshold; when the detection value is less than the expulsion threshold, it is determined that the current search unit has failed to capture in this round of search.

8. A navigation receiver, characterized in that, The navigation receiver includes the detection device for satellite signal acquisition as described in any one of claims 5 to 7.

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