from ..message_base import MessageBase from ..constants import Subaddress, TrackAccuracy, NormFactorXY, NormFactorZ from ..fields import BitField, EnumField, ScaledField class MsgB4(MessageBase): """ Message B4: SPT Target Message ID: B4 Direction: RT -> BC (Transmit) Subaddress: 14 Rate: 50 Hz Document Ref: 7.2.4 Contains detailed tracking data for the Secondary Priority Target (SPT). """ SUBADDRESS = Subaddress.TX_SPT IS_TRANSMIT = True # --- Word 01: Track Validity and Status Word #1 (Ref 7.2.4.1) --- range_valid = BitField(word_index=0, start_bit=0, width=1) pos_xyz_valid = BitField(word_index=0, start_bit=1, width=1) range_rate_valid = BitField(word_index=0, start_bit=2, width=1) velocity_valid = BitField(word_index=0, start_bit=3, width=1) accel_valid = BitField(word_index=0, start_bit=4, width=1) aspect_angle_valid = BitField(word_index=0, start_bit=5, width=1) cas_mach_valid = BitField(word_index=0, start_bit=6, width=1) # Bit 7 Spare display_coords_valid = BitField(word_index=0, start_bit=8, width=1) pos_accuracy = EnumField(word_index=0, start_bit=9, width=2, enum_cls=TrackAccuracy) vel_accuracy = EnumField(word_index=0, start_bit=11, width=2, enum_cls=TrackAccuracy) acc_accuracy = EnumField(word_index=0, start_bit=13, width=2, enum_cls=TrackAccuracy) # Bit 15 Spare # --- Word 02: Track Validity and Status Word #2 (Ref 7.2.4.2) --- reacquisition = BitField(word_index=1, start_bit=0, width=1) target_coast = BitField(word_index=1, start_bit=1, width=1) hoj_active = BitField(word_index=1, start_bit=2, width=1) aoj_active = BitField(word_index=1, start_bit=3, width=1) norm_factor_x = EnumField(word_index=1, start_bit=4, width=3, enum_cls=NormFactorXY) norm_factor_y = EnumField(word_index=1, start_bit=7, width=3, enum_cls=NormFactorXY) norm_factor_z = EnumField(word_index=1, start_bit=10, width=2, enum_cls=NormFactorZ) # Bits 12-15 Spare # --- Word 03: Time Tag (Ref 7.2.4.3) --- # LSB 64 us time_tag = ScaledField(word_index=2, start_bit=0, width=16, lsb_value=64.0) # --- Word 04: Target Range (Ref 7.2.4.4) --- # LSB 8 ft target_range = ScaledField(word_index=3, start_bit=0, width=16, lsb_value=8.0) # --- Word 05: Normalized Target Position X (Ref 7.2.4.5) --- # 2's complement. Actual value = Raw * Multiplier (from Word 02) # We treat it as raw signed integer here. norm_pos_x = ScaledField(word_index=4, start_bit=0, width=16, lsb_value=1.0, signed=True) # --- Word 06: Normalized Target Position Y (Ref 7.2.4.6) --- norm_pos_y = ScaledField(word_index=5, start_bit=0, width=16, lsb_value=1.0, signed=True) # --- Word 07: Normalized Target Position Z (Ref 7.2.4.7) --- norm_pos_z = ScaledField(word_index=6, start_bit=0, width=16, lsb_value=1.0, signed=True) # --- Word 08: Target Range Rate (Ref 7.2.4.8) --- # LSB 1.0 ft/s, 2's comp range_rate = ScaledField(word_index=7, start_bit=0, width=16, lsb_value=1.0, signed=True) # --- Word 09: Target Velocity Magnitude (Ref 7.2.4.9) --- # LSB 0.0625 ft/s vel_magnitude = ScaledField(word_index=8, start_bit=0, width=16, lsb_value=0.0625) # --- Word 10-12: Target Velocity X, Y, Z (Ref 7.2.4.10 - 12) --- # LSB 0.125 ft/s, 2's comp vel_x = ScaledField(word_index=9, start_bit=0, width=16, lsb_value=0.125, signed=True) vel_y = ScaledField(word_index=10, start_bit=0, width=16, lsb_value=0.125, signed=True) vel_z = ScaledField(word_index=11, start_bit=0, width=16, lsb_value=0.125, signed=True) # --- Word 13: Target Acceleration Magnitude (Ref 7.2.4.13) --- # LSB 0.015625 ft/s^2 acc_magnitude = ScaledField(word_index=12, start_bit=0, width=16, lsb_value=0.015625) # --- Word 14-16: Target Acceleration X, Y, Z (Ref 7.2.4.14 - 16) --- # LSB 0.03125 ft/s^2, 2's comp acc_x = ScaledField(word_index=13, start_bit=0, width=16, lsb_value=0.03125, signed=True) acc_y = ScaledField(word_index=14, start_bit=0, width=16, lsb_value=0.03125, signed=True) acc_z = ScaledField(word_index=15, start_bit=0, width=16, lsb_value=0.03125, signed=True) # --- Word 17: Target Aspect Angle (Ref 7.2.4.17) --- # Semicircles, 2's comp aspect_angle = ScaledField(word_index=16, start_bit=0, width=16, lsb_value=3.05176e-5, signed=True) # --- Word 18: Target CAS (Ref 7.2.4.18) --- # LSB 3.0518e-2 knots target_cas = ScaledField(word_index=17, start_bit=0, width=16, lsb_value=3.0518e-2) # --- Word 19: Target Mach Number (Ref 7.2.4.19) --- # LSB 2.4414e-4 Mach target_mach = ScaledField(word_index=18, start_bit=0, width=16, lsb_value=2.4414e-4) # --- Word 20: Target X Display Coordinate (Ref 7.2.4.20) --- # Pixels (0-1023) display_x = BitField(word_index=19, start_bit=0, width=10) # --- Word 21: Target Y Display Coordinate (Ref 7.2.4.21) --- # Pixels (0-1023) display_y = BitField(word_index=20, start_bit=0, width=10) # --- Word 22-24: Standard Deviation Position X, Y, Z (Ref 7.2.4.22 - 24) --- # LSB 0.42725 ft std_dev_x = ScaledField(word_index=21, start_bit=0, width=16, lsb_value=0.42725) std_dev_y = ScaledField(word_index=22, start_bit=0, width=16, lsb_value=0.42725) std_dev_z = ScaledField(word_index=23, start_bit=0, width=16, lsb_value=0.42725)