IL177236A - Device and method for determining a parameter of an inertial sensor of a vehicle - Google Patents

Description

S; 177236/3 κ _i_n i) v> »t-N»- i 7tt*»fl ni»-ip wv nn Device and method for determining a parameter of an inertial sensor of a vehicle 1 177236/2 FIELD OF THE INVENTION

[001] The present invention relates to devices and methods for determining a parameter of an inertial sensor of a vehicle.

BACKGROUND OF THE INVENTION

[002] Inertial sensors such as accelerometers and gyroscopes are used in navigation systems of various vehicles such as missiles, unmanned aircrafts, satellites and even underwater vehicles. These navigation systems can navigate the vehicle based only upon the inertial sensors.

[003] Some prior art vehicles include navigation systems also receive input from other sources, including but not limited to the Global Positioning System (GPS).

[004] Inertial sensors must be calibrated periodically in order to maintain their accuracy. The calibration usually includes measuring one or more inertial sensor parameters and in response setting the one or more parameters to an acceptable value.

[005] Gyroscopes are characterized by various inertial sensor parameters including their drift, random drift, scale factor and g-sensitivity. Accelerators are characterized by their bias and scale factor.

[006] Vjarious methods and devices for calibrating inertial sensors are illustrated in the following publications, all being incorporated herein by reference: U.S: patent 5421187 of Morgan, titled "Calibration of an internal sensor system", U.S. patent 6622091 of Perlmutter et al., titled "Method and system for calibrating an IG/GP navigational ¾ system", U.S. patent 6189382 of Johnson, titled "Vibratory sensor with self-calibration and low noise digital conversion", U.S. patent 5795988 of Lo et al., titled "Gyroscope noise reduction and drift compensation", PCT patent application publication serial number WO2004/046649A2 of Malvern et al., titled "Method for calibrating bias drift with temperature for a vibrating structure gyroscope", PCT patent application publication serial number WOO 1/09567 of Azuma et al., titled "Calibrating a magnetic compass with an angular rate gyroscope and a global positioning system receiver", U.S. patent 6396235 of Ellington et al., titled "Stabilized common gimbal", U.S. patent 6152403 of Fowell et al., titled 6152403 titled "Gyroscopic calibration methods for spacecrafts", U.S. patent 5562266 of 01633916X79-01 2 177236/3 Ackhar et al., titled "Rate gyro calibration method and apparatus for a three-axis stabilized satellite", "Performance evaluation of inertial navigation systems for surveying", S.A. Hewitson, J. Wang, A.H.W. Kearsley, The 6th international symposium on satellite navigation technology including mobile positioning & location services". EP patent application no. 1630562 Al discloses a device for measuring the dynamic matrix sensitivity of an inertia sensor is provided with a motion generating machine or a vibrating table for inducing a translational or rotary motion, an acceleration measuring unit, an angular velocity measuring unit or angular acceleration measuring unit, an output device for fetching an output from the unit, one or ,pre light reflectors, a displacement measuring device for seizing a multidimensional motion by using a laser interferometer radiating light from a plurality of directions to the light reflectors, a data processing unit for processing a data indicating the state of motion and obtained from the displacement measuring unit, and a displaying device to display or a transmitting device to transmit the output of the data processing unit and the output of the acceleration measuring unit,; angular velocity measuring unit or angular acceleration measuring unit. Since the accelerometer is exposed to acceleration in every conceivable direction and possibly fails to find a correct value of acceleration as encountered by the conventional one-dimensional calibration, it is actually calibrated by applying acceleration from all possible directions thereto. U.S. patent 6,876,926 discloses a method and system for processing pulse signals within an inertial device. The inertial device may have inertial sensors, such as accelerometers and gyroscopes. The inertial sensors may output signals representative of a moving body's motion. The signals may require correction due to imperfections and other errors of the inertial sensors. The inertial device may receive signals from the inertial sensors and process the signals on a signal-by-signal basis so that when processing the signals, the inertial device at least recognizes which sensor output a signal and when the signal was output. The inertial device may then correlate signals that were output from the inertial sensors at selected times in order to transform the signals into a desired navigational frame of reference.

[007] In vehicles such as missiles or unmanned aircrafts the navigation system is taken off the vehicle and sent to a remote laboratory for routine checks and 01633916X87-01 177236/1 2a calibration. In many cases the laboratory determines that the disassembled navigation system is operational and merely returns the navigation system to the vehicle.

[008] During this time-consuming session the vehicle is not operational.

[009] There is a need to provide an efficient method and system for determining at least one parameter of an inertial sensor.

SUMMARY OF THE INVENTION

[0010] According to one aspect of the presently disclosed subject matter, there is provided a method for measuring at least one parameter of at least one inertial sensor of a vehicle, the method comprising: moving a testing device connected to the vehicle, and receiving inertial sensor information provided by the at least one inertial sensor; wherein the vehicle comprises the at least one inertial sensor and wherein the stage of moving the testing device comprises positioning the vehicle at multiple positions that differ from each other and receiving inertial sensor information provided when at least substantial portion of the vehicle is positioned in at least two different positions; and determining at least one parameter of the at least one inertial sensor in response to the received inertial sensor information, wherein at least one of the parameters is usable for calibrating said at least one inertial sensor.

[0011] According to another aspect of the presently disclosed subject matter, there is provided a testing device, comprising: a mechanical unit adapted to support a vehicle and to move the vehicle; wherein the vehicle comprises at least one inertial sensor; and wherein the testing device is adapted to position the vehicle at multiple positions that differ from each other and receive inertial sensor information provided when at least substantial portion of the vehicle is positioned in at least two different positions; a processing unit, adapted to receive inertial sensor information and calculate at least one parameter of the at least one inertial sensor in response to received inertial sensor information, wherein at least one of the parameters is usable for calibrating said at least one inertial sensor. 01633916\87-01 3 177236/2 BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The present invention will be understood and appreciated more folly from the following detailed description taken in conjunction with the drawings in which:

[0013] Figure 1 illustrates a portion of a testing device, according to an embodiment of the invention;

[0014] Figures 2-8 illustrate various positions of a canister that is connected to a portion of the testing device, according to an embodiment of the invention;

[0015] Figure 9 illustrates various portions of a testing device, a canister and a vehicle, according to an embodiment of the invention; and

[0016] Figures 10-11 are flow charts of methods for determining a parameter of an inertial sensor of a vehicle, according to various embodiments of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

[0017] The invention provides a method for determining one or more parameters of one or more inertial sensors. A vehicle is positioned in various positions and is moved along predefined movement patterns while inertial sensor information from one or more inertial sensors within the vehicle is received. The inertial sensor information can indicate whether one or more inertial sensors of the vehicle are operational, whether a calibration process is required and optionally if one or more dnertial sensojrs should be replaced.

[0018] Conveniently, the vehicle can remain folly operational or substantially folly operational during the testing process. Conveniently, a testing device can be located at the launching site of the vehicle.

[0019] Conveniently, the vehicle or the substantial portion of the vehicle is connected to:! a testing device via an intermediate element such as a canister. The canister can be accurately moved by the testing device and placed in predefined positions that differ from each other.

[0020] The inertial sensor information can be received during the movement of the vehicle (by the testing device) and/or when the vehicle is positioned in one or more of these predefined positions. [0021 ] According to an embodiment of the invention the vehicle does not move in relation to the intermediate element during the testing process, but this is not i 01633916X79-01 4 177236/2 necessarily so. Conveniently, any relative movement between the vehicle and the intermediate , entity can also be determined based upon gathered inertial sensor information. \

[0022] Conveniently, the vehicle is moved according to a movement scheme. The movement scheme is usually defined in response to the one or more parameters of the inertial sensors that should be calculated.

[0023] According to an embodiment of the invention the received inertial sensor information is processed in order to determine at least one parameter of at least one inertial sensor. It is noted that the processing can be executed in parallel to the movements of the vehicle, partially in parallel to the movement or after the movements.

[0024] According to an embodiment of the invention the measurements process can be stopped once inertial sensor information that is received during the testing process indicates that the inertial sensor should be calibrated or replaced. '[0025] According to yet another embodiment of the invention a substantial portion of the vehicle and not the whole vehicle is provided to the testing device. Thus, the measurement process includes moving a substantial portion of the vehicle and/or positioning the substantial portion of the vehicle in predefined positions and receiving inertial sensor information. :[0026] The following description relates to a missile that includes three substantially perpendicular gyroscopes and three substantially perpendicular accelerometers. The inertial sensor parameters that were determined include the scale factor and bias of each accelerometer, the drift, random drift, scale factor, and g-sensitivity of each gyroscope. The movement scheme was defined such as to allow a measurement of the mentioned above inertial sensor parameters. Those of skill in the art will appreciate that other parameters can be measured, and that different movement schemes can be defined for vehicles that have different inertial systems.

[0027] Figure 1 illustrates a mechanical unit 100 of a testing device according to an embodiment of the invention. Figures 2-8 illustrate a canister 200 that is connected to mechanical unit 100, and is positioned in various positions, according to an embodiment of the invention. 01633916V79-01 177236/2

[0028] It is noted that the testing device 90 accurately monitors the movements of canister 200. This can be achieved by applying various prior art motion control and exact movement methods and devices. Closed loop as well as open loop control schemes can be applied in order to maintain a certain movement accuracy level. The testing device 90 can include sensors for monitoring the movement of the canister 200 but this is not necessarily so.

[0029] The inventors used a testing device 90 that has a rotation accuracy of less then 0.5 miliTRadian. The testing device, 90 and especially a first rotating element 130 were parallel to the ground (positioned in a horizontal position) with an accuracy of less than 0.5 mili-Radian. Testing device 90 was able to rotate the vehicle in few seconds. The whole testing process was completed within a few minutes.

[0030] Cylinder-shaped canister 200 is rigidly connected to a vehicle such as missile 210 (not shown). It is noted that the canister 200 is usually tailored to the vehicle it holds. Thus, for example, larger missiles will have larger canisters. Canisters that have a different shape and size from canister 200 will hold unmanned aircrafts.

[0031] Testing device 90 includes mechanical unit 100. Mechanical unit 100 can be controlled by an electrical unit 92 that is further illustrated in Figure 9.

[0032] Fig. 1 illustrates mechanical unit 100 of testing device 90 and an optional fence 110. Control unit 94 that belongs to the electrical unit 92 conveniently controls mechanical unit 100.

[0033] The mechanical unit 100 is capable of accurately positioning the canister 200 in multiple predefined positions, as well as to rotate the canister about a vertical axis and a horizontal axis.

[0034] Conveniently, a testing device 90 can also rotate the canister along a third axis that is traverse to the vertical and horizontal axis. This additional rotation can be replaced by positioning the canister in a vertical position (or in a position that has vertical components) and receiving inertial sensor information.

[0035] Mechanical unit 100 includes a base 120, a first rotating element 130 and a second rotating element 140.

[0036] The first rotating element 130 is connected to base 120 via a first axis. The first rotating element 130 conveniently includes a rotating motor (not shown) that can 01633916X79-01 6 177236/2 accurately rotate the first rotating element 130. It is noted that the rotational velocity, the position ; of the first rotating element 130 and even its acceleration can be accurately controlled using open loop or closed loop mechanisms known in the art.

[0037] The second rotating element 140 is connected to the first rotating element 130 via a second axis. The second axis is connected to a rotating motor 170 that can rotate the second rotating element 140 about a horizontal axis. It is noted that the rotational velocity, position of the second rotating element 140 and even its acceleration can be accurately controlled using open loop or closed loop mechanisms known in the art.

[0038] The second rotating element 140 is firmly connected to canister 200 during the testing process. The second rotating element 140 can be connected to canister 200 in various prior art methods that can be applied in order to minimize and eyen eliminate relative movement between canister and second rotating element 140 during the testing process while allowing the removal of canister 200 from the mechanical unit 100 once the measurement ends.

[0039] The first rotating element 130 includes a first rotating element base 132 that is located between two vertical walls 134 and 136. The vertical walls 134 and 136 are higher than the radius of canister 200, thus allowing canister 200 to rotate about a horizontal axis while being held by second rotating element 140 that in turn is connected to walls 134 and 136.

[0040] Those of skill in the art will appreciate that mechanical unit 100 can have a fixed configuration that is tailored to a certain type of vehicle, but this is not necessarily so.

[0041] For example, mechanical unit 100 can include adjustable components that will enable a single testing device 90 to test different vehicles.

[0042] It is noted that testing device 90 tests the vehicles while canister 200 is substantially parallel to the ground. This feature reduces the complexity of testing device 90 and also enables testing device 90 to test relatively large vehicles without including complex and costly mechanical elements.

[0043] Figure 9 illustrates various portions of testing device 90, canister 200 and vehicle 210, according to an embodiment of the invention. 01633916X79-01 7 177236/2

[0044] Canister 200 is connected to the vehicle 210 via a first cable 205 that enables the canister 200 and the vehicle 210 to exchange information. Canister 200 can receive inertial sensor information from vehicle 210 via first cable 205. The first cable 205 can also be used to activate various components of ! vehicle 210. In operational mode the first cable 205 can send ignition instructions to vehicle 210.

[0045] Canister 200 is connected via a second cable 215 to the testing device 90. Second cable 215 is illustrated as being connected to control unit 94 that belongs to the testing device 90.

[0046] Second cable 215 can be a part of an interface that receives inertial sensor information. Interface can also include receivers and transmitters that send the inertial sensor information from control unit 94 to processing unit 96.

[0047] The second cable 215 conveniently differs from an operational cable that is connected to canister 200, by not having one or more lines that are used for igniting vehicle 210. ;[0048] Control unit 94 can includes various motor controllers, such as motor controller 93 that control the rotation of the first and second rotating elements 130 and 140. The control unit 94 also includes a local controller 95 that can control the exchange of information with the vehicle 210, store received inertial sensor information and also control the exchange of information with a remote processing unit 96.

[0049] It: is noted that according to various embodiments of the invention the processing unit 96 can be included within the control unit 94. It is further noted that the communication between the vehicle 210 and the processing unit 96 can be controlled in various manners.

[0050] The processing unit 96 can receive the inertial sensor information from vehicle 210 (via contrpl unit 94), and calculate one or more inertial sensor parameters of one or more inertial sensors that are included within vehicle 210.

[0051] The processing unit 96 can include (or be connected to) one or more memory units that store previously received inertial sensor information, previous test results, and the like. The processing unit 96 can also send the received inertial sensor information or calculated inertial sensor parameters to a remote calibration entity, such as a calibration laboratory. 01633916Y79-01 8 177236/2

[0052] According to an embodiment of the invention the control unit 94 and/or the processing unit 96 can include (or be connected to) a display 97 or other means for providing visual an/or audio indications to an operator. The former can be used to indicate that an inertial sensor is functional, that it should be replaced, and the like. The processing unit 96 can also include various input components such as a keyboard, a mouse and the like.

[0053] The testing device 90 can automatically perform the various movements and measurements but it can also be controlled by or assisted by an operator. The operator can be requested to approve each movement, each measurement, a set of movements, a set of measurements, and even add additional movements or measurements. The operator can also select not to perform various movements and/or measurements.

[0054] Conveniently, only a portion of the gathered inertial sensor information is used during the testing process. For example, the inertial sensor information provided by an x-axis gyroscope should be taken into account only during various movements or positions of canister 200. Accordingly, this information can be selectively transmitted from vehicle 210, can be filtered by canister 200 or by control unit 94 and even filtered by the processing unit 96. Unnecessary information can also be provided to various components, stored, analyzed and the like. {0055] Testing device 90 can calculate the accelerometer bias of the accelerators of vehicle 210 by processing inertial sensor information gained when vehicle 210 is positioned at' a first position and at a second position that are at the same plane but opposite to each other.

[0056] This can be achieved by: (i) receiving inertial information from one or more accelerometers when the canister 200 is positioned at a first horizontal position, (ii) rotating the first rotating element 130 by 180°, (iii) receiving inertial information from one or more accelerometers and (iv) processing inertial sensor information.

[0057] Yet for another example, testing device 90 can calculate the scale factor of an accelerometer by processing inertial sensor information gained (i) when a gravitational force of g(m/sec2) is applied approximately along the accelerometer sensitive axis and (ii) when a gravitational force of -g(m/sec2) is applied approximately along the accelerometer sensitive axis. 01633916X79-01 9 177236/2

[0058] This can be achieved by rotating canister 200 by second rotating element 140 by 180°, If, for example, the vehicle 210 includes two accelerometers that are perpendicular to each other their scale factors can be measured by rotating the second rotating element 140 such as to place canister 200 at four positions that are substantially perpendicular to each other.

[0059] Conveniently, the gyroscope drifts are calculated by processing inertial sensor information received when the vehicle 210 is positioned such that the sensitive axis of the gyroscope is in a direction that has no inertial rotation.

[0060] The scale factor of the gyroscope can be calculated by processing inertial sensor information that is gained while rotating vehicle 210 by the second rotating element.

[0061] The g-sensitivity of a . gyroscope of vehicle 210 can be calculated by processing inertial sensor information received when the vehicle 210 is rotated by the second rotating element 140 such as to be positioned in different positions in relation to the direction earth's gravity.

[0062] Figure 10 illustrates a method 300 for testing a parameter of an inertial sensor, according to an embodiment of the invention.

[0063] For convenience of explanation two coordinate systems are defined. The first coordinate system is the coordinate system of the testing device 90 while the ;second coordinate system is the vehicle's coordinate system. The first coordinate system includes an n-axis, a d-axis and an e-axis. The n-axis is a horizontal axis that points to the north. The d-axis is a vertical axis that points to the ground. The e-axis is f perpendicular to both n-axis and d-axis and forms, with the e-axis and the n-axis, a right handed coordinate system.

[0064] The second coordinate system includes an x-axis, a y-axis and a z-axis. The x-axis is substantially parallel to a longitudinal axis of the vehicle 210. The z-axis is perpendicular to the x-axis and points to the right side of vehicle 210 (when vehicle 210 is placed on testing device 90). The y-axis is perpendicular to both x-axis and z-axis and forms, with the x-axis and the z-axis, a right handed coordinate system.

[0065] It is assumed that vehicle 210 includes x-axis gyroscope (referred to as x-gyro), y-axis gyroscope (referred to as y-gyro), z-axis gyroscope (referred to as z- 01633916X79-01 177236/2 gyro), x-axis iaccelerometer (referred to as x-acc), y-axis accelerometer (referred to as y-acc) and z-axis accelerometer (referred to as z-acc).

[0066] The angular velocity of the earth is denoted co, the gravitational force of the earth is denoted g, and the latitude line of the testing device 90 is denoted λ.

[0067] TABLE 1 illustrates the relevant inertial sensor information that is gathered during the various stages of method 300. It includes four columns. The first column indicates the serial number of the measured inertial sensor information (which is also the serial number of the associated equation). The second column includes an equation that illustrates the mathematical relationship between the measured inertial sensor information and one or more inertial sensor parameters (or angular orientations). The third column indicates the stage of method 300 during which the inertial sensor information is received. The fourth column includes remarks, especially relating to the position of canister 200 during a certain stage of method 300.

[0068] Method 300 starts by stage 310 of attaching an intermediate entity such as canister 200 to testing device 90. The canister 200 is placed in a horizontal position and faces the east. Stage 320 can include a leveling stage of canister 200. It is assumed that the x-axis accelerometer is positioned at a small angle β in relation to the horizon and that the y-axis accelerometer is positioned at a small angle -a in relation to the horizon.

[0069] Stage 320 includes static measurements of x-axis, y-axis and z-axis accelerations as well as x-axis, y-axis and z-axis angular velocities.

[0070] Stage 320 is followed by stage 330 of rotating the canister 200 by 180° about the d-axis for t2 seconds, and receiving the angle that is measured by the z-axis gyroscope. This rotation is relatively fast. The inventors used a rotation period (t2) of 10 seconds.

[0071] Stage 330 is followed by stage 340 of performing a static measurement of the y-axis acceleration.

[0072] Stage 340 is followed by stage 350 of rotating canister 200 by 180° about the n-axis for t3 seconds, and receiving the angle that is measured by the x-axis gyroscope. This rotation is relatively fast. The inventors used a rotation period (t3) of S ■ ' · ■ seconds. 01633916X79-01 11 177236/2

[0073] Stage 350 is followed by stage 360. of performing static measurements of x-axis, y-axis and z-axis accelerations as well as x-axis, y-axis and z-axis angular velocities.

[0074] Stage 360 is followed by stage 370 of rotating canister 200 by 90° about the n-axis, rotating the canister 200 by 180° about the d-axis for t5 seconds and receiving the angle that is measured by the y-axis gyroscope during the former rotation.

[0075] Stage 370 is followed by stage 380 of performing static measurements of x-axis, y-axis and z-axis accelerations as well as x-axis, y-axis and z-axis angular velocities.

[0076] Stage 380 is followed by stage 390 of removing canister 200 from testing device and positioning it at an erect portion when the z-axis of the vehicle is at about ψ to the north. Stage 390 also includes performing static measurements of x-axis acceleration as well as x-axis, y-axis and z-axis angular velocities. 01633916X79-01 12 177236/2 TABLE 1

[0077] Stage 390 is followed by stage 400 of determining at least one parameter of the at least one inertial sensor in response to the inertial sensor information.

[0078] An example of stage 400 is provided in TABLE 2. TABLE 2 illustrates exemplary inertial sensor parameters that can be calculated from the accelerations, angular velocity and angles that are measured during stages 320-390.

[0079] TABLE 2 includes three columns. The first column indicates the calculated inertial sensor parameter. The second column includes, an equation that illustrates the mathematical relationship between the inertial sensor parameter and the s ■ " ; previously measured inertial sensor information. The third column indicates the equations (of TABLE 1) from which the inertial sensor parameter was extracted. 01633916X79-01 13 177236/2 01633916Y79-01 14 177236/2 TABLE 2

[0080] Figure 11 illustrates a method 500 for testing a parameter of an inertial sensor, according to an embodiment of the invention.

[0081] Method 500 starts by stage 510 of defining a movement scheme in response to at least one parameter of the at least one inertial sensor to be measured. The movement scheme conveniently includes multiple accurate movements that ^position the at least substantial portion of the vehicle at predefined positions.

[0082] Stage 510 is followed by stage 520 of moving at least a substantial portion of the vehicle, by a testing device, and receiving inertial sensor information provided by the at least one inertial sensor. The at least substantial portion includes the at least one inertial sensor.

[0083] Stage 520 can include various stages, such as but not limited to various stages of method 300.

[0084] Conveniently, the at least a substantial portion of the vehicle is moved according to ¾he movement scheme.

[0085] The moving results in positioning the at least substantial portion of the vehicle at predefined positions. The receiving can be done during the movements, when the at ileast substantial portion of the vehicle is placed in one or more of said various positions or during both. 01633916X79-01 177236/2

[0086] Conveniently, stage 520 includes rotating the at least substantial portion of the vehicle about two measurement axes that are traverse to each other.

[0087] Conveniently, stage 520 includes positioning the at least substantial portion of the vehicle at multiple positions that differ from each other and monitoring inertial sensor information provided when the at least substantial portion of the vehicle is positioned in these positions.

[0088] Conveniently, stage 520 starts by attaching the vehicle to the testing device. It is noted that at least one measurement (for example the measurement of stage 390) can be done before (or after) the attachment.

[0089] Conveniently, stage 520 is preceded by attaching an intermediate element to the testing device. The intermediate element (such as canister 200) is connected to the at least substantial portion of the vehicle.

[0090] Conveniently, stage 520 includes rotating the at least substantial portion of the vehicle about a horizontal axis and rotating the at least substantial portion of the vehicle about a vertical axis.

[0091] Stage 520 is followed by stage 530 of determining at least one parameter of the at least one inertial sensor in response to the received inertial sensor information.

[0092] Conveniently, stage 530 further includes determining relative movements between the intermediate element and the at least substantial portion of the vehicle.

[0093] Conveniently, stage 530 is followed by stage 540 of determining whether to disassemble an inertial sensor. One or more inertial sensors can be located within a housing. The housing and not the inertial sensor itself are usually disassembled. It is noted that if the calculated inertial sensor parameters indicate that the inertial sensors of the vehicle are functional then stage 540 is followed by stage 560 of defining the inertial system of the vehicle as operational. The vehicle can be returned to its location prior to the test. Else, stage 540 is followed by stage 570 of disassembling one or more defective (or non-operational) inertial sensors (or disassembling the whole inertial system) in order to enable calibration and/or replacement of the nonfunctional inertial sensor.

[0094] Conveniently, method 500 includes an optional stage 525 of monitoring inertial sensor information provided by the at least one inertial sensor when the at 01633916X79-01 16 177236/2 least substantial portion of the vehicle is positioned outside the testing device. Stage 525 can precede stage 520, although it is illustrated as following stage 520. Stage 525 can include stage 390.

[0095] Conveniently, stage 520 includes positioning the at least substantial portion of the vehicle at multiple positions and stage 525 includes positioning the at least substantial portion of the vehicle at one or more additional positions that differs from the positions during which the vehicle is positioned at stage 520.

[0096] Conveniently, stage 520 includes rotating the at least substantial portion of the vehicle about a horizontal axis and rotating the at least substantial portion of the vehicle about a vertical axis.

[0097] Conveniently, stage 520 can include transmitting the inertial sensor information to a processing unit. The processing unit can be located near the tested vehicle but this is not necessarily so. 01633916X79-01 17 177236/3

Claims (27)

1. A method for measuring at least one parameter of at least one inertial sensor of a vehicle, the method comprising: moving a testing device connected to the vehicle, and receiving inertial sensor information provided by the at least one inertial sensor; wherein the vehicle comprises the at least one inertial sensor and wherein the stage of moving the testing device comprises positioning the vehicle at multiple positions that differ from each other and receiving inertial sensor information provided when at least substantial portion of the vehicle is positioned in at least two different positions; and determining at least one parameter of the at least one inertial sensor in response to the received inertial sensor information, wherein at least one of the parameters is usable for calibrating said at least one inertial sensor.

2. The method according to claim 1 wherein the moving comprises rotating the at least substantial portion of the vehicle about two measurement axes; whereas the two measurement axes are traverse to each other.

3. .3. The method according to any one of the preceding claims wherein the method further comprises defining a movement scheme in response to the at least one parameter of the at least one inertial sensor, wherein the moving is responsive to the movement scheme.

4. The method according to any one of the preceding claims wherein the method further comprises disassembling an inertial sensor if at least one parameter associated with the inertial sensor indicates that the inertial sensor is not functional.

5. The method according to any one of the preceding claims wherein the moving is preceded by attaching the vehicle to the testing device.

6. The method according to any one of the preceding claims wherein the moving is preceded by attaching an intermediate element to the testing device; whereas the intermediate (element is connected to the at least substantial portion of the vehicle. 01633916X73-01 18 177236/3

7. The method according to claim 6 wherein the stage of determining further comprises determining relative movements between the intermediate element and the at least substantial portion of the vehicle.

8. The method according to any one of the preceding claims wherein the moving comprises moving the testing device connected to a missile.

9. The method according to any one of the preceding claims wherein the moving comprises moving the testing device connected to an unmanned aircraft.

10. The method according to any one of the preceding claims further comprising receiving inertial sensor information provided by the at least one inertial sensor when the at least substantial portion of the vehicle is positioned outside the testing device.

11. The method according to any one of the preceding claims wherein the moving comprises positioning the at least substantial portion of the vehicle at multiple positions and whereas the method further comprises positioning the at least substantial portion of the vehicle at an additional position that differs from positions that belong to the multiple positions.

12. The method according to any one of the preceding claims wherein the moving comprises rotating the at least substantial portion of the vehicle about a horizontal axis and rotating the at least substantial portion of the vehicle about a vertical axis.

13. The method according to any one of the preceding claims further comprising transmitting the inertial sensor information to a processing unit.

14. A testing device, comprising: a mechanical 'unit adapted to support a vehicle and to move the vehicle; wherein the vehicle comprises at least one inertial sensor; and wherein the testing device is adapted to position the vehicle at multiple positions that differ from each other and receive inertial sensor information provided when at least substantial portion of the vehicle is positioned in at least two different positions; 01633916X73-01 19 177236/3 a processing unit, adapted to receive inertial sensor information and calculate at least one parameter of the at least one inertial sensor in response to received inertial sensor information, wherein at least one of the parameters is usable for calibrating said at least one inertial sensor.

15. The device according to claim 14 whereas the mechanical unit is adapted to rotate the at least substantial portion of the vehicle about two measurement axes; wherein the two measurement axes are traverse to each other.

16. The device according to any one of claims 14 or 15, wherein the device is adapted to define a movement scheme in response to the at least one parameter of the at least one inertial sensor, whereas the mechanical unit is adapted to rotate the at least substantial portion of the vehicle in response to the movement scheme.

17. The device according to any one of claims 14 to 16, wherein the device is further adapted to provide a disassembling indication indicating that an inertial sensor of the vehicle, if at least one parameter associated with the inertial sensor indicates that the inertial sensor is not functional.

18. The device according to any one of claims 14 to 17, wherein the vehicle is connected to the mechanical unit via an intermediate entity and whereas the device is adapted to determine relative movements between the intermediate element and the at least substantial portion of the vehicle.

19. The device according to any one of claims 14 to 18, wherein the mechanical unit is adapted to support and move a missile.

20. The device according to any one of claims 14 to 19, wherein the mechanical unit is adapted to support and move an unmanned aircraft.

21. The device according to any one of claims 14 to 20, further adapted to receive inertial sensor information provided by the at least one inertial sensor when the at least substantial portion of the vehicle is positioned outside the testing device. 01633916X73-01 20 177236/3

22. The device according to any one of claims 14 to 21, wherein the mechanical unit is adapted to rotate the at least substantial portion of the vehicle about a horizontal axis and rotating the at least substantial portion of the vehicle about a vertical axis.

23. The device according to any one of claims 14 to 22 comprising a mechanical unit, a control unit and a processing unit; wherein the control unit is adapted to transmit the inertial sensor information to a processing unit.

24. The device according to any one of claims 14 to 23, wherein the mechanical unit is adapted to accurately monitor the movement of the vehicle

25. The device according to any one of claims 14 to 24 further comprising an interface, adapted to receive inertial sensor information from the at least substantial portion of the vehicle and to provide the inertial sensor information to the processing unit.

26. A method according to any one of claims 1 to 13, substantially as described herein with reference to the accompanying drawings.

27. A testing device, according to any one of claims 14 to 25, substantially as described herein with reference to the accompanying drawings. For the Applicants, 01633916X73-01