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DE-112022005166-B4 - Protection level calculation device, protection level calculation system, position determination system and protection level calculation method

DE112022005166B4DE 112022005166 B4DE112022005166 B4DE 112022005166B4DE-112022005166-B4

Abstract

Protection level calculation device (3), comprising: a distortion error model unit (13) to output an upper and lower limit of a distortion error that is assumed to be contained in a measurement obtained from a position determination signal; and a protection level calculation unit (14) to calculate a protection level for determining the validity of a position determination solution calculated on the basis of measurement, using the upper limit and the lower limit.

Inventors

  • Yuki Sato
  • Akinori Taira
  • Rui Hirokawa

Assignees

  • MITSUBISHI ELECTRIC CORPORATION

Dates

Publication Date
20260513
Application Date
20220106

Claims (13)

  1. Protection level calculation device (3), comprising: a distortion error model unit (13) for outputting an upper limit and a lower limit of a distortion error assumed to be contained in a measurement obtained from a position determination signal; and a protection level calculation unit (14) for calculating a protection level for determining the validity of a position determination solution calculated on the basis of the measurement, using the upper limit and the lower limit.
  2. Protection level calculation device (3A, 3B) according to Claim 1 , wherein the distortion error model unit (13A, 13B) determines both the upper and lower bounds based on an environment model which is a model of an environment around a position determination object (101).
  3. Protection level calculation device (3B) according to Claim 2 , comprising a map information unit (17) to reference map information using the positioning solution or positioning information about the positioning object (101) to determine a class that represents a magnitude or occurrence frequency of the distortion error due to the environment for the environment around the positioning object (101), wherein the distortion error model unit (13B) determines the upper and lower bounds using the environment model corresponding to the class determined by the map information unit (17).
  4. Protection level calculation device (3C) according to one of the Claims 1 until 3 , wherein the protection level calculation unit (14C) further calculates the protection level using an upper limit and a lower limit of a distortion error assumed to be contained in a measurement of a carrier phase, and both the upper limit and the lower limit of the distortion error assumed to be contained in the measurement of the carrier phase are a value obtained from a model of an integer error in an ambiguity of the carrier phase.
  5. Protection level calculation device (3C) according to Claim 1 , wherein the protection level calculation unit (14C) further calculates the protection level using an upper limit and a lower limit of a distortion error assumed to be contained in a measurement of a carrier phase, both the upper limit and the lower limit of the distortion error assumed to be contained in the measurement used to calculate the position determination solution, and the measurement of a pseudo-path between a signal source of the position determination signal and a position determination object (101), are a value obtained from a model of an environment around the position determination object (101), and both the upper limit and the lower limit of the distortion error assumed to be contained in the measurement of the carrier phase are a value obtained from a model of an integer error in an ambiguity of the carrier phase.
  6. Protection level calculation device (3A, 3B) according to Claim 2 , 3 or 5 , where the environment model is a geometric model obtained from three-dimensional map information.
  7. Protection level calculation device (3) according to one of the Claims 1 until 6 , wherein the protection level calculation unit (14) further determines the protection level using a weighting of a previous The predicted value is calculated as a state variable, which is a weight used in calculating the position determination solution, and an upper and lower limit of a distortion error, which is assumed to be contained in the previous predicted value.
  8. Protection level calculation device (3) according to Claim 7 , where the previous predicted value is calculated using a measurement from an inertial sensor.
  9. Protection degree calculation device (3A) according to one of the Claims 1 until 6 , wherein the protection degree calculation unit (14A) further calculates the protection degree using a standard distortion error in a correction value to correct the measurement.
  10. Protection level calculation system (1), comprising: a position determination calculation unit (11) for calculating a position determination solution based on a measurement obtained from a position determination signal; a distortion error model unit (13) for outputting an upper limit and a lower limit of a distortion error assumed to be contained in the measurement; and a protection level calculation unit (14) for calculating a protection level to determine a validity of the position determination solution using the upper limit and the lower limit.
  11. Protection level calculation system (1) according to Claim 10 , wherein the position determination calculation unit (11) is contained in a first device (102) and the distortion error model unit (13) and the protection level calculation unit (14) are contained in a second device (105) which can communicate with the first device (102).
  12. Position determination system (100, 200), comprising the protection level calculation system (1) according to Claim 10 or 11 .
  13. Protection level calculation method, comprising: a step for outputting an upper limit and a lower limit of a distortion error assumed to be contained in a measurement obtained from a positioning signal; and a step for calculating a protection level to determine a validity of a positioning solution calculated on the basis of the measurement, using the upper limit and the lower limit.

Description

Technical field The present disclosure relates to a protection level calculation device, a protection level calculation system, a position determination system and a protection level calculation method for calculating a protection level to determine the validity of a position determination solution. State of the art For advanced applications, such as autonomous driving, positioning systems exist that determine the application's position using signals transmitted by Global Positioning System (GPS) satellites, wireless communication base stations, or similar devices. To enable the safe, application-controlled use of a position solution calculated from measurements, these positioning systems use a level of protection to determine whether the calculated position solution is valid. For example, a protection level calculation device described in patent reference 1 derives a multivariate probability distribution model in advance, which includes distance measurement errors and measurement quality indicators of distance measurements. When performing a position determination, the protection level calculation device described in patent reference 1 determines the conditional probability density of a measurement error with respect to values of the simultaneously obtained measurement quality indicators for a distance measurement from each of a plurality of signal sources transmitting a position determination signal and calculates the protection level of a position determination solution based on the relationship between the measurement errors and a position determination error. Patent reference 2 describes a method for vector phase tracking of a plurality of global positioning satellite carrier signals, in which, for a tracked satellite, a discriminator generates phase tracking error signals at different frequencies associated with the different carrier signals of the tracked satellite, and in which a multi-frequency estimation of the disturbances is performed based on the phase tracking error signal supplied by the discriminator unit. The method takes the ionospheric error into account when determining the output phase error signals. Patent reference 3 discloses a pseudorange-based reliable positioning method for a multimode GNSS receiver. The multimode GNSS receiver receives GNSS satellite signals, primarily to obtain pseudoranges and navigation messages from the GNSS satellite signals. Different types of pseudoranges and navigation messages are unified to the same time and space coordinate, and the pseudoranges and the navigation messages transformed into coordinates are subjected to error correction. Patent literature 4 discloses a method for predicting the performance of a satellite navigation system comprising at least one constellation of satellites for a GNSS receiver. The method is characterized in that it additionally includes the steps of acquiring third-party data (Pfa, Pmd) from the receiver, which indicate the probability of a false alarm and the probability of a false message according to the requirements for the predetermined RAIM method, and creating a database (7) of this third-party data according to predetermined scenarios. Patent reference 5 discloses a method for determining the reliability of position information based on a smart device, which determines the reliability of the accuracy of position information provided to a smart device for this purpose, as well as a system for determining the same. To achieve this purpose, the method for determining the reliability of position information based on a smart device according to the present invention comprises: a first step that enables an analysis unit to analyze a navigationally hazardous environment at sea; a second step that enables a computation unit to calculate a level of protection based on the data analyzed by the analysis unit; a third step in which a fault modeling unit models a fault generated from a satellite navigation signal and an inertial sensor of the smart device; and a fourth step in which a comparison unit compares an alarm threshold (AL) that prevents a user's navigation solution, to which the calculated level of protection and the fault modeled by the fault modeling unit are applied, from being exceeded. List of quotations Patent literature Patent literature 1: Japanese Patent No. 6855580Patent literature 2: WO 2009 / 125 011 A1Patent literature 3: CN 1 04 035 113 APatent literature 4: EP 1 965 219 A1Patent literature 5: KR 10 2023 0 083 466A Brief description of the invention Problem to be solved by the invention According to the conventional technique disclosed in patent literature 1, if an abnormal measurement is present at the time of using the multivariate probability distribution model, the protection level calculation device rejects the abnormal measurement for calculating the protection level. Therefore, the conventional technique has a problem in that the protection level calculation device cannot calculate the effective