dateStruct - see atbGetEpoch for the format of this structure dateVec - a Matlab date vector, see DATEVEC for more help timeZone - a single character string, the default is 'Z' isDST - a logical flag, the default is 0 (false) The above example corresponds to the date 1 Jan 2000, 12:30:00.00 GMT 备注：This function returns the offset in epoch seconds between the current epoch and the input date. When a Matlab format dateVec is provided as the only input, the timeZone is assumed to be 'Z' and isDST is assumed to be false. 3.1.4 atbEpochSecToDate 作用：Convert epoch seconds to an absolute date 用法：date = atbEpochSecToDate(epochSec) 说明： 备注：This function returns the absolute date corresponding to an offset in seconds from the current epoch. 3.2 坐标系转换（Coordinate Conversions） 3.2.1 atbCbfToCbi 作用：Convert CBF coordinates to CBI coordinates 用法： cbiPos = atbCbfToCbi('cbName', times, cbfPos) [cbiPos, cbiVel] = atbCbfToCbi('cbName', times, cbfPos, cbfVel) 说明：cbName - Valid central body nam, e.g. 'Earth' times - Length N vector of times for CBF pos and vel cbfPos - 3xN matrix of CBF positions cbfVel - 3xN matrix of CBF velocities cbiPos - 3xN matrix of CBI positions cbiVel - 3xN matrix of CBI velocities 备注：Converts position and velocity in the central body fixed coordinate system to a position and velocity in the default central body inertial coordinate system at the provided times. 3.2.2 atbCbfToCbiMtx 作用：Transformation matrix from CBF to CBI 用法：T = atbCbfToCbiMtx('cbName', time) 说明：time - time in seconds T - Coordinate transformation matrix 备注：Generates the transformation matrix to convert a vector in the Central Body Fixed (CBF) system to a vector in the Central Body Inertial (CBI) system. Inputs are the central body name and the time. 3.2.3 atbCbfToLhMtx 作用：Transformation matrix from CBF to local horizontal 用法：T = atbCbfToLhMtx('cbName', lat, long) 说明：lat - Geodetic latitude long - Geodetic longitude T - Coordinate transformation matrix 备注：Generates the transformation matrix to convert a vector in the Central Body Fixed (CBF) system to a vector in the local horizontal (LH) system. Inputs are the geodetic latitude and longitude of the reference location. 3.2.4 atbCbfToLla 作用：Transformation from CBF to geodetic LLA 用法： llaPos = atbCbfToLla('cbName', cbfPos) [llaPos, llaRate] = atbCbfToLla('cbName', cbfPos, cbfVel) 说明：cbName - Valid central body name cbfPos - CBF position, 3xN cbfVel - CBF velocity, 3xN llaPos - geodetic lat/long/alt, 3xN llaRate - geodetic lat/long/alt rate, 3xN 备注：Determines the geodetic latitude, longitude, and altitude and rates given a cartesian position and velocity. The cartesian vectors must be expressed in the central body fixed coordinate system. 3.2.5 atbCbfToLlr 作用：Transformation from CBF to geocentric LLR 用法： llrPos = atbCbfToLlr(cbfPos) [llrPos, llrRate] = atbCbfToLlr(cbfPos, cbfVel) 说明：cbfPos - CBF position, 3xN cbfVel - CBF velocity, 3xN llrPos - Geocentric lat/long/radius, 3xN llrRate - Geocentric lat/long/radius rate, 3xN 备注：Determines the geocentric latitude, longitude, and radius and rates given the cartesian position and velocity. The input cartesian vectors can be in any coordinate system and the output will represent the corresponding spherical coordinates. 3.2.6 atbCbfToVvlhMtx 作用：Transformation matrix from CBF to VVLH 用法：T = atbCbfToVvlhMtx(cbfPos, cbfVel) 说明：cbfPos - CBF position vector, 3x1 cbfVel - CBF velocity vector, 3x1 T - Coordinate transformation matrix, 3x3 备注：Generates the transformation matrix to convert a vector in the input cartesian system to a vector in the Vehicle Velocity Local Horizontal (VVLH) system. Inputs are the cartesian coordinate vector and velocity vector of the vehicle. The VVLH local horizontal definition is based on a spherical central body model. 3.2.7 atbCbiToCbf 作用：Convert CBI coordinates to CBF coordinates 用法： cbfPos = atbCbiToCbf('cbName', times, cbiPos) [cbfPos, cbfVel] = atbCbiToCbf('cbName', times, cbiPos, cbiVel) 说明：cbName - Valid central body name times - Length N vector of times for CBI pos and vel cbiPos - 3xN matrix of CBI positions cbiVel - 3xN matrix of CBI velocities cbfPos - 3xN matrix of CBF positions cbfVel - 3xN matrix of CBF velocities 备注：Converts position and velocity vectors in the default central body inertial coordinate system to a position and velocity in the central body fixed coordinate system at the provided time. 3.2.8 atbCbiToCbi 作用：Convert CBI coordinates to another CBI system 用法： toPos = atbCbiToCbi('fromCb', 'toCb', times, fromPos) [toPos, toVel] = atbCbiToCbi('fromCb', 'toCb', times, fromPos, fromVel) 说明：fromCb, toCb - Valid central body names times - Length N vector of times for CBF pos and vel fromPos - 3xN matrix of original CBI positions fromVel - 3xN matrix of original CBI velocities toPos - 3xN matrix of new CBI positions toVel - 3xN matrix of new CBI velocities 备注：Computes the inertial position and velocity relative to the \ velocity have been specified relative to the \ body. This computation therefore accounts for both the difference in position of the central bodies and the difference in the orientations of their default inertial coordinate systems. 3.2.9 atbCbiToCbiMtx 作用：Transformation matrix from CBI to another CBI system 用法：T = atbCbiToCbiMtx('fromCB', 'toCB') 说明：T - Coordinate transformation matrix 备注：Generates the transformation matrix to convert a vector in one Central Body Fixed (CBF) system to a vector in another Central Body Inertial (CBI) system. Inputs are the two central body names 3.2.10 atbLlaToCbf 作用：Transformation from geodetic LLA to CBF 用法： cbfPos = atbLlaToCbf('cbName', llaPos) [cbfPos, cbfVel] = atbLlaToCbf('cbName', llaPos, llaRate) 说明：cbName - Valid central body name llaPos - Geodetic lat/long/alt, 3xN llaRate - Geodetic lat/long/alt rate, 3xN cbfPos - CBF position, 3xN cbfVel - CBF velocity, 3xN 备注：Converts the geodetic latitude, longitude, and altitude and rates to a cartesian position and velocity. The cartesian vectors will be expressed in the central body fixed coordinate system. 3.2.11 atbLlrToCbf 作用：Transformation from geocentric LLR to CBF 用法： cbfPos = atbLlrToCbf(llrPos) [cbfPos, cbfVel] = atbLlrToCbf(llrPos, llrRate) 说明：llrPos - Geodetic lat/long/radius, 3xN llrRate - Geodetic lat/long/radius rate, 3xN cbfPos - CBF position, 3xN cbfVel - CBF velocity, 3xN 备注：Converts the geocentric latitude, longitude, and radius and rates to a cartesian position and velocity. The cartesian vectors will be expressed in the central body fixed coordinate system. 3.2.12 atbCbCoordinates 作用：Coordinate system names associated with a central body 用法：[names, descrips]= atbCbCoordinates('cb') 说明：cb - central body name names - cell array of coordinate system names descrips - cell array of coordinate system descriptions 备注：This function outputs the possible coordinate systems which may be converted between using atbCoordXForm and atbCoordXFormMtx 3.2.13 atbCoordXForm 作用：General coordinate system transformation 用法：[ToPos, ToVel]= atbCoordXForm(time, 'FromCb', 'FromSystemName', FromEpoch,... 'ToCb', 'ToSystemName', ToEpoch,... FromPos, FromVel) 说明：time - time offset from epoch in seconds of the FromPos and FromVel Cb - central body names SystemName - valid coordinate system name, obtained via atbCbCoordinates Epoch - epochs for coordinate systems, may be ignored (see below) Pos - 3x1 position vector (meters) Vel - 3x1 velocity vector (meters) (optional) 备注：This function converts from one coordinate system of one central body to another system of another central body. Some coordinate systems require an epoch to fully define them, in these cases, the Epoch inputs will be used, otherwise the Epoch inputs will be ignored. For example, the J2000 epoch is intrinsic to the definition of the coordinate system and therefore any input epoch will be ignored. The various ...OfEpoch coordinate systems are examples of systems that need an epoch. 3.2.14 atbCoordXFormMtx 作用：General coordinate system transformation 用法：[TfmMtx, AngVelSysName, AngVel]= atbCoordXFormMtx('cb', 'FromSystemName', FromEpoch,'ToSystemName', ToEpoch) 说明：cb - central body name SystemName - valid coordinate system name, obtained via atbCbCoordinates Epoch - epochs for coordinate systems, may be ignored (see below) TfmMtx - transformation matrix AngVelSysName - name of the coordinate system in which the angular velocity is defined (optional) AngVel - angular velocity of the two systems (3x1) (optional) 备注：This function generates the rotation matrix from one coordinate system of a central body to another system of the same central body. Some coordinate systems require an epoch to fully define them, in these cases, the Epoch inputs will be used, otherwise the Epoch inputs will be ignored. For example, the J2000 epoch is intrinsic to the definition of the coordinate system and therefore any input epoch will be ignored. The various ...Of Epoch coordinate systems are examples of systems that need an epoch. 3.3 转动与四元数（Rotations and Quaternions） 3.3.1 atbAlignVecQuat 作用：Quaternion for coordinate system transformation 用法：rotQuat = atbAlignVecQuat(vec1A, vec1B) rotQuat = atbAlignVecQuat(vec1A, vec1B, vec2A, vec3B)