UvAGPS

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UvAGPS Data Model

For different versions of the UvAGPS firmware different tables are used. For firmware version v0.9.3.6 till v1.0.0.X the tables UVA_ENGINEERING_DATA and UVA_TRACKING_DATA are used. But in the new firmware versions 1.0.1.4 till 1.0.2.4 so much information was added that new tables were introduced. However for the most important tracking tables a view is created so that all similar tracking for all types of firmware can be seen in one view. That is the UVA_TRACKING view.

All tables, views and functions are also in the GPS schema.

Not everybody has access to all data. For most users access is limited to "limited" views that only give access to selected devices.

UVA_TRACKING_DATA or UVA_TRACKING_LIMITED

Tracking data from UvA GPS tags for older firmware

Field Type Key Constraints Comments
device_info_serial int4 PK NOT NULL
date_time timestamp PK NOT NULL GMT
latitude float8 Decimal degrees
longitude float8 Decimal degrees
h_accuracy float8 Horizontal accuracy (m)
v_accuracy float8 Vertical accuracy (m)
altitude float8 m
x_acceleration Float8 x axis acceleration (m/s22) movement to right is + and to left is -
y_acceleration Float8 y axis acceleration (m/s22) forward movement is + and backwards is -
z_acceleration Float8 z axis acceleration (m/s22) upwards movement is + downwards is -
speed float8 m/s
course float8 Degrees
pressure float8 Pressure sensor (pascal)
temperature Float8 Degrees celcius
solar_voltage Float8 V
battery_voltage Float8 V
userflag Integer Data flagged as unacceptable by user
“"location”" geometry postgreSQL geometry

UVA_ENGINEERING_DATA

Engineering data from UvA GPS tags for older firmware

Field Type Key Constraints Comments
device_info_serial int4 PK NOT NULL
date_time timestamp PK NOT NULL GMT
t_syncsts smallint 0: not synced, 1: user synced, 2: Gps synced
t_entzt smallint 0: UCT time,1: TZT time (timezone time)
gzp_currentrategps int4
gzp_currentratecom int4
gzp_currentratepwr int4
sbm_voltagesolarpanel float8
sbm_voltagebattery float8
sbm_chargemode int2
egzp_mainrategps integer
egzp_mainratecom integer
egzp_mainratepwr integer
smg_on text
smg_off text
smg_esavegpsrate integer
smz_on text
smz_off text
smz_esavecomrate integer
gpsnavigationmode smallint
gpsfixtimeout smallint
eh text


UVA_DEVICE or UVA_DEVICE_LIMITED

To be able to track the different firmware versions and specific properties for the different devices the UVA_DEVICE table was added. This table also includes essential information needed to calibrate the accelerometers. For more information see Accelerometer calibration

Field Type Key Constraints Comments
device_info_serial integer PK NOT NULL Serial number of tag
firmware_version text NOT NULL Firmware version installed on tag
device_mass double Mass of tag (g)
x_s double Calibration sensitivity of accelerometer in the x-axis
y_s double Calibration sensitivity of accelerometer in the y-axis
z_s double Calibration sensitivity of accelerometer in the z-axis
x_o double Calibration offset of accelerometer in the x-axis
y_o double Calibration offset of accelerometer in the y-axis
z_o double Calibration offset of accelerometer in the z-axis

UVA_COMM101 or UVA_COMM_LIMITED

Communication table indicates status and result of communications with ground stations. Only for newer firmware.

Field Type Key Constraints Comments
device_info_serial integer PK NOT NULL
date_time timestamp PK NOT NULL timestamp of start communication
date_time_end timestamp timestamp of end communication
date_time_utc timestamp date_time in utc (if available)
date_time_end_utc timestamp date_time_end in utc (if available)
action text JOINED / RESCHEDULE  ??
bytes_communicated integer Number of bytes communicated (total of all bytes per DATA line)
status text READY, TIMEOUT, LOWPOWER, MISSING
network_join_time integer milliseconds
number_identical_lines integer Number identical lines in data block. Gives indication
non_ascii_char integer Number of non ascii characters (indicated by question-mark ?)
sts_time timestamp derived from S0 hh,mi
timesynced smallint TimeSynced (0=not sy:wnced, 1=user set, 2=Gps Synced)
devicemode smallint DeviceMode (0-99)
vbat float Battery voltage in V (0-~4.200V)
logb integer logged bytes, waiting for download (0-4Mbyte)
logp smallint Logged percentage (units 0.1%) of memory waiting to be downloaded (0-1000)
gpsii integer GpsIval, current (0-65535)
comii integer ComIval, current (0-65535)
accii integer AcceleroIval, current (0-65535)
swddd integer User switches, current (0-65535)
last_gps_fix timestamp timestamp of last fix
latitude float Latitude of last fix. Decimal degrees
longitude float Longitude of last fix. Decimal degrees

UVA_SETTINGS101 or UVA_SETTINGS_LIMITED

Settings are either from C0-C1-C9 lines or parsed from uplink communication lines If C0-C1 is parsed its values are compared with the previous value and if the settings are the same no new records needs to be added If uplink settings are parsed wait till the last setting has been seen, (DL command or EOF) then store all the new settings in one record. Only for newer firmware.

Field Type Key Constraints Comments
device_info_serial int4 PK NOT NULL
date_time timestamp PK NOT NULL Derive timestamp from Hh:mi fields in C0 combined with computer timestamp in JOINED line
timesynced smallint
timezone_time smallint
swddd integer SpecialUserSwitches
gpsnavmode smallint GpsNavMode 0-7
gpsreceivermode smallint GpsReceiverNode 0-3
gpsfixtime smallint GpsFixTime 0-255
gps_ivaln_on_h smallint hours Gps IvalN on
gps_ivaln_on_m smallint minutes Gps IvalN on
gps_ivaln integer GpsIvalN (0-65530)
gps_ivale_on_h smallint hours Gps IvalE on
gps_ivale_on_m smallint minutes GpS IvalE on
gps_ivale integer GpsIvalE
com_ivaln_on_h smallint hours Com IvalN on
com_ivaln_on_m smallint minutes Com IvalN on
com_ivaln integer ComIvalN (0-65530)
com_ivale_on_h smallint hours Com IvalE on
com_ivale_on_m smallint minutes Com IvalE on
com_ivale integer ComIvalE
accii integer Accelero measurement interval
accbn integer Accelero number of blocks
accsn integer Accelero number of samples (0-65536)
f smallint Accelero sample frequency (0=20Hz, 1=10Hz, 2=5Hz, 3=1Hz)
pdp smallint PdopMsk (3-250)
pac smallint PaccMsk (10-100)
tdp smallint TdopMsk (3-250)
tac smallint TaccMsk (30-300)
ga smallint Additional Fixes GpsIval mode (3-25) before interval fix is logged
aol smallint AccMemOffLev (100 - 950) units 0.1%; if Memfull above this level all Accelero activity will be overruled and switched off untill MemFull < level - 5
eventnum text 12 eventnumbers (0-0xff) only printed if not zero, therfore converted to text


UVA_TRACKING_DATA101 or UVA_TRACKING_LIMITED

The tracking dat for newer firmware.


Field Type Key Constraints Comments
device_info_serial int4 PK NOT NULL
date_time timestamp PK NOT NULL
latitude float Decimal degrees
longitude float Decimal degrees
altitude integer heigth above sealevel meters
pressure integer in pascal (1mBar = 100Pa, 1pressuremeter = ~12Pa)
temperature float in celcius degrees
satellites_used smallint satellites used for fix
gps_fixtime float GpsFixTime in seconds
positiondop float Position DOP in units
h_accuracy float Horizontal accuracy (units of meter)
v_accuracy float Vertical accuracy (units of meter)
x_speed float Speed in x-axis (m/s)
y_speed float Speed in y-axis (m/s)
z_speed float Speed in z-axis (m/s)
speed_accuracy float Speed accuracy (m/s)
userflag Integer Data flagged as unacceptable by user
location geometry lat/long as PostGIS geometry

UVA_ACCELERATION101 or UVA_ACCELERATION_LIMITED

Acceleration entries if accelerometer was turned on. Only for newer firmware.

Field Type Key Constraints Comments
device_info_serial int4 PK NOT NULL
date_time timestamp PK NOT NULL
index smallint PK NOT NULL
x_acceleration smallint acceleration in X-axis (-2666 till 2666)
y_acceleration smallint acceleration in Y-axis (-2666 till 2666)
z_acceleration smallint acceleration in Z-axis (-2666 till 2666)

UVA_ENERGY101 or UVA_ENERGY_LIMITED

Only for newer firmware.

Field Type Key Constraints Comments
device_info_serial int4 PK NOT NULL
date_time timestamp PK NOT NULL
timesynced smallint TimeSynced (0=not synced, 1=user set, 2=Gps synced)
devicemode smallint (0-99)
vsll float Solar Voltage during charging in mV (0-~2500)
vbat float Battery Voltage in V (0-~4.200)
ssw smallint Solar Cell Switches ... (0-255) fw1022 and up
extended fields if special user switch is on
vsoo float Solar voltage open in V (0-~2.500)
vdrf float reference voltage Dac in V (0-~2.435)
vchr float charge current voltage
g smallint Gps battery threshold OK
c smallint Com battery threshold OK
m smallint Charge Mode (0,1,2 Com battery threshold OK
pressure integer in pascal (1mBar = 100Pa, 1pressuremeter = ~12Pa)
temperature float in celcius degrees


UVA_TRACKING or UVA_TRACKING_LIMITED

View to show identical fields for older and newer firmware tracking data


Field Type Key Constraints Comments
device_info_serial int4 PK NOT NULL
date_time timestamp PK NOT NULL
latitude float
longitude float
altitude float
pressure integer
temperature float
h_accuracy float
v_accuracy float
x_speed float meters/second
y_speed float meters/second
z_speed float meters/second
gps_fixtime float
location geometry

UVA_TRACKING_SPEED or UVA_TRACKING_SPEED_LIMITED

Additional view that computes with the x_speed, y_speed and z_speed components the vnorth, veast and vdown speed components as well as the absolute value speed in meters/second.

In addition to the fields in the UVA_TRACKING view this view adds :

Field Type Key Constraints Comments
vnorth float - vx * sin(lat) * cos(long) - vy * sin(lat) * sin (long) + vz * cos(lat)
veast float - vx * sin(lon) + vy * cos(lon)
vdown float - vx * cos(lat) * cos(lon) - vy * cos(lat) * sin(lon) - vz * sin(lat)
speed float sqrt(vx^2 + vy^2 + vz^2)

UvAGPS functions

get_uvagps_track_speed

Compute distance (meters), time-interval, speed (meters/second) and heading (degrees) for a series of subsequent tracking entries with specific device_info_serial. For the first entry in the sequence these values will always be missing because they are computed as the difference between subsequent rows.

Usage examples : 

select * from gps.get_uvagps_track_speed(119, '2008-01-01 00:00:00', '2010-01-01 00:00:00');

select * from gps.get_uvagps_track_speed(119);

select t.*, a.distance, a.interval, a.speed, a.direction from gps.get_uvagps_track_speed(119, '2008-01-01 00:00:00', '2010-01-01 00:00:00') a join gps.uva_tracking t using(device_info_serial, date_time);

Distances and heading are calculated with spherical correction with the Haversine formula as described here. The heading is the initial heading. PostGIS does not calculate the heading, so therefore we don't use PostGIS.

In these functions the records that have been flagged as invalid by setting the userflag are not token into account and discarded. If it is required get the speed for all records a additional boolean argument for get raw data can be given. i.e. 

select * from gps.get_uvagps_track_speed(119, '2008-01-01 00:00:00', '2010-01-01 00:00:00', true);

select * from gps.get_uvagps_track_speed(119, true);

get_uvagps_track_distance

Compute distance (meters) for UvAGPS tracks to arbitrary point in lat/long or geometry location

Example usage : 

select * from gps.get_uvagps_track_distance(119, 52.1897017, 6.1996606); 

select * from gps.get_uvagps_track_distance(119, (select location from gps.uva_tracking where device_info_serial = 119 and date_time = '2009-05-07 19:55:08'));

Here the distance is calculated with the PostGIS distance_sphere function which uses spherical correction.


get_uvagps_track_distance_direction

Compute distance (meters) and direction (degrees) for UvAGPS tracks from arbitrary point in lat/long or geometry location

Example usage: 

select * from gps.get_uvagps_track_distance_direction(119, 52.1897017, 6.1996606);

Distances and direction are calculated with spherical correction with the Haversine formula as described here. The direction is the direction from the given point.

In this function the records where the userflag has been set are discarded. To see these records a additional boolean argument for show raw data should be added like : 

select * from gps.get_uvagps_track_distance_direction(119, 52.1897017, 6.1996606, true);

Accelerometer calibration

The accelerometer measures the acceleration in 3D (20 times per second). Acceleration is caused by gravity (static component) and by a change in speed (dynamic component). When the logger is static in horizontal position (solar cells up), gravity (green arrow) shows a heave (vertical acceleration, z) of +1 g (1 g = 9.81 m.s-2) while surge and heave are both 0. When the front of the logger is vertically pointing down (forward acceleration, x), surge is +1g and when it is rolled to the right (sidewards acceleration, y) sway is +1g. Due to gravity, the pitch of a logger is thus translated into the values of heave, surge and sway (or z, x, y).

However, the values are measured in mV instead of g. Before delivering the GPS-loggers, they have been calibrated at UvA. The acceleration (A) expressed in g is calculated from the measured value (M) and the calibration factors offset (O) and sensitivity (S).

Thus acceleration for heave (z), surge (x) and sway (y) is calculated as: Az = (Mz-Oz)/Sz ; Ax = (Mx-Ox)/Sx; Ay = (My-Oy)/Sy ;

The values of O (in general ranging from 0-60, sometimes even 300) and S (ranging from 1300-1450) are available in the device table of the data base. If not available, use the factory defaults O = 0 and S = 1365.

Accelero1.png Accelero2.png|

In the figure above heave (z) is shown in green, surge(x) in red and sway (y) in blue, all values are expressed in g (on the y-axis).

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