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HeavyRF Table Functions

Summary of parameters for base and optional versions
The HeavyRF package provides the following system table functions:

tf_rf_prop_max_signal (Directional Antennas and Terrain Attenuation)

Taking a set of point elevations and a set of signal source locations as input, tf_rf_prop_max_signal executes line-of-sight 2.5D RF signal propagation from the provided sources over a binned 2.5D elevation grid derived from the provided terarin locations, calculating the max signal in dBm at each grid cell, using the formula for free-space power loss. The terrain should contain columns for ground elevation, terrain elevation (which should be greater than or equal to the ground elevation height), and terrain attenuation in dbm per meter, specifying the degree to which signal will be attenuated if it passes between the terrain and ground elevations (i.e. through a tree or building). The RF source ID contributing the strongest signal is also outputted.
When geographic_coords is set to true, x and y input coordinates are assumed to be lon/lat degrees. A best-fit conversion to a meters coordinate system is executed using the change in meters per lon/lat degree at the centroid of the input terrain, using the haversine distance formula. For convenience and optimal performance, tf_rf_prop_max_signal enables filter push-down by default, such that filters on the outputs rf_source_id, x, y, and elevation_amsl_meters are pushed down to the respective inputs in the rf_sources and terrain_elevations Cursor subqueries.
SELECT * FROM TABLE(
tf_rf_prop_max_signal(
rf_sources => CURSOR(
SELECT
rf_source_id,
rf_source_x,
rf_source_y,
rf_source_z,
rf_source_signal_strength_watts,
rf_source_signal_frequency_mhz,
rf_source_antenna_azimuth_degrees,
rf_source_antenna_downtilt_degrees,
rf_source_antenna_type
FROM
rf_sources_table
),
terrain_elevations => CURSOR(
SELECT
x,
y,
ground_elevation_amsl_meters,
terrain_elevation_amsl_meters,
terrain_attenuation_dbm_per_meter
FROM
terrain_table
),
antenna_patterns => CURSOR(
SELECT
antenna_type,
antenna_gain,
antenna_horizontal_degrees,
antenna_horizontal_attenuation,
antenna_vertical_degrees,
antenna_vertical_attenuation
FROM
antennas_table
),
rf_source_z_is_relative_to_terrain => <rf_source_is_relative_to_terrain>,
geographic_coords => <geographic_coords>,
bin_dim_meters => <bin_dim_meters>,
assumed_receiver_height_agl => <assumed_receiver_height_agl>,
max_ray_travel_meters => <max_ray_travel_meters>,
initial_rays_per_source => <initial_rays_per_source>,
rays_per_bin_autosplit_threshold => <rays_per_bin_autosplit_threshold>,
min_receiver_signal_strength_dbm => <min_receiver_signal_strength_dbm>,
default_source_height_agl_meters => <default_source_height_agl_meters>,
ray_step_bin_multiple => <ray_step_bin_multiple>,
loop_grain_size => <loop_grain_size>,
)
)
Input Arguments
Parameter
Cursor
Description
Data Types
rf_source_id
rf_sources
ID of the RF source. Used in the output for each grid cell to denote the RF source contributing the strongest signal.
Column<INT | BIGINT | TEXT ENCODING DICT>
rf_source_x
rf_sources
x-coordinate of the RF source, assumed to be in longitude degrees. Whether FLOAT or DOUBLE, rf_source_x must be the same type as all other columns in the rf_sources CURSOR, excluding rf_source_z.
Column <FLOAT | DOUBLE>
rf_source_y
rf_sources
y-coordinate of the RF source, assumed to be in longitude degrees. Whether FLOAT or DOUBLE, rf_source_y must be the same type as all other columns in the rf_sources CURSOR, excluding rf_source_z.
Column <FLOAT | DOUBLE> (must be same type as rf_source_x)
rf_source_z_meters
rf_sources
z-coordinate of the RF source, in meters. If rf_source_is_relative_to_terrain is set to true, meters are relative to the terrain height; for example, an input of 20 is 20 meters above ground level. Otherwise, it is absolute height above sea level; 20 is 20 meters above mean sea level (AMSL).
Column <FLOAT | DOUBLE>
rf_source_power_watts
rf_sources
Power in Watts (W) of the transmitting antenna. rf_source_power_watts must be the same type s all other columns in the rf_sources CURSOR, excluding rf_source_z.
Column <FLOAT | DOUBLE> (must be same type as rf_source_x)
rf_source_freq_mhz
rf_sources
Frequency in megahertz (MHz) of the transmitting antenna. rf_source_freq_mhz must be the same type s all other columns in the rf_sources CURSOR, excluding rf_source_z.
Column <FLOAT | DOUBLE> (must be same type as rf_source_x)
rf_source_antenna_azimuth_degrees
rf_sources
Azimuth in degrees of the transmitting antenna. rf_source_antenna_azimuth_degrees must be the same type s all other columns in the rf_sources CURSOR, excluding rf_source_z.
Column <FLOAT | DOUBLE> (must be same type as rf_source_x)
rf_source_antenna_downtilt_degrees
rf_sources
Downtilt in degrees of the transmitting antenna. rf_source_antenna_gain must be the same type s all other columns in the rf_sources CURSOR, excluding rf_source_z.
Column <FLOAT | DOUBLE> (must be same type as rf_source_x)
rf_source_antenna_type
rf_sources
The type of antenna deployed. Used to lookup the antenna parameters in the antenna patterns table for the matching type entry. Must be a text type. Antenna types that are null or have no match in the antenna_patterns table will be considered omnidirectional.
Column <TEXT ENCODING DICT>
terrain_x
terrain_elevations
x-coordinate of the terrain. If geographIc_coords is true, this is assumed to be in longitude degrees, otherwise in meters. Whether FLOAT or DOUBLE, terrain_x and terrain_y must be the same type.
Column <FLOAT | DOUBLE>
terrain_y
terrain_elevations
y-coordinate of the terrain. If geographIc_coords is true, this is assumed to be in latitude degrees, otherwise in meters. Whether FLOAT or DOUBLE, terrain_x and terrain_y must be the same type.
Column <FLOAT | DOUBLE> (must be same type as terrain_x)
ground_elevation_amsl_meters
terrain_elevations
Elevation of the ground, in meters above sea level. Ground is considered to fully occlude signal
Column <FLOAT | DOUBLE (should be same type as terrain_elevation_amsl_meters and terrain_attenuation_dbm_per_meter)
terrain_elevation_amsl_meters
terrain_elevations
Maximum elevation of the terrain (could be a building, vegetation, or the ground itself), in meters above sea level. Should be greater than or equal to ground_elevation_amsl_meters
Column <FLOAT | DOUBLE (should be same type as ground_elevation_amsl_meters and terrain_attenuation_dbm_per_meter)
terrain_attenuation_dbm_per_meter
terrain_elevations
Attenuation in dBm for any ray that passes above ground_elevation_amsl_meters and below terrain_elevation_amsl_meters. If type of terrain is present in the source table, the attenuation value can be looked up from another terrain attenuation table via a join.
Column <FLOAT | DOUBLE (should be same type as ground_elevation_amsl_meters and terrain_elevation_amsl_meters)
antenna_type
antenna_patterns
Antenna type as text arguement. Used to join with rf_sources table. If antenna_type is 'default', the patterns for this type will be used for all rf_sources entry with type 'default', null, or that otherwise do not have a corresponding antenna_type entry in the antenna_patterns table.
Column <TEXT ENCODING DICT>
antenna_gain
antenna_patterns
The gain in dBm for this antenna type.
Column <FLOAT | DOUBLE> (all numeric arguments in antenna_patterns CURSOR must be the same type)
antenna_horizontal_degrees
antenna_patterns
An array specifying a set of degrees from 0 to 360, with 0 degrees representing due North, 90 degrees due East, 180 degrees due South, and 270 degrees due West. The corresponding indexed entry in the antenna_horizontal_attenuations specifies the attenuation for the degree entry. An entry will be created for each integer degree, with missing entries linearly interpolated from the closest neighbors below and above that degree. Entries can but do not have to be in order.
Column <FLOAT | DOUBLE> (all numeric arguments in antenna_patterns CURSOR must be the same type)
antenna_horizontal_attenuation
antenna_patterns
An array specifying the amount of attenuation, in dBm, for the corresponding entry with the same index in the antenna_horizontal_degrees array.
Column <FLOAT | DOUBLE> (all numeric arguments in antenna_patterns CURSOR must be the same type)
antenna_vertical_degrees
antenna_patterns
An array specifying a set of degrees from 0 to 360, with 0 degrees representing forward along the horizon along the direction of the antenna azimuth, 90 degrees directly overhead, 180 degrees in the direction opposite the antenna azimuth, and 270 degrees directly toward the ground. Entries below 0 can also be used and will be wrapped appropriately (i.e. -90 degrees = 270 degrees = directly toward the ground). The corresponding indexed entry in the antenna_vertical_attenuations specifies the attenuation for the degree entry. An entry will be created for each integer degree, with missing entries linearly interpolated from the closest neighbors below and above that degree. Entries can but do not have to be in order.
Column <FLOAT | DOUBLE> (all numeric arguments in antenna_patterns CURSOR must be the same type)
antenna_vertical_attenuation
antenna_patterns
An array specifying the amount of attenuation, in dBm, for the corresponding entry with the same index in the antenna_vertical_degrees array.
Column <FLOAT | DOUBLE> (all numeric arguments in antenna_patterns CURSOR must be the same type)
rf_source_z_is_relative_to_terrain
N/A
true specifies that rf_source_z_meters values are the height in meters above ground level. false indicates the values are height in meters above sea level.
BOOLEAN
geographic_coords
N/A
true specifies that the input x and y arguments for RF sources and terrain elevations are in lon/lat degrees. false specifies that the data is already in a local meter coordinate system.
BOOLEAN
bin_dim_meters
N/A
Width and height of each binned terrain cell, which is the unit of granularity over which the RF propagation algorithm is executed.
DOUBLE
assumed_receiver_height_agl
N/A
Height in meters above ground_elevation_amsl_meters from the terrains_elevation cursor to measure the signal strength at, i.e. the modeled height of the receiving handset above ground.
DOUBLE
max_ray_travel_meters
N/A
Maximum meters for which to model RF propagation from any given source. Lower values can increase performance, but potentially miss the strongest repeater for a terrain cell that is further away than the value set.
DOUBLE
initial_rays_per_source
N/A
Number of initial 2.5D rays to propagate from each source. Since rays are automatically split as needed as they radiate out from the rf source, this can be safely set to a low number such as 64 to maximize performance.
BIGINT
rays_per_bin_autosplit_threshold
N/A
Minimum ratio of radial rays per bin, below which the ray is split into two to ensure ray coverage of terrain bins as distance increases from the rf_source. 1.5 is a safe default value to use.
DOUBLE
min_receiver_signal_strength_dbm
N/A
The minimum signal strength threshold in dBm to continue propagating a signal ray from a source. Rays stop being propagated when either the distance from the source exceeds the limit set by max_ray_travel_meters, or the signal strength (as measured by free-space power loss, assuming no obstructions in the path) drops below the value set by min_receiver_signal_strength_dbm.
DOUBLE
assumed_source_height_above_ground
N/A
The default height in meters above ground level for a source if there is no input data in the terrain_elevations for the terrain bin in which a given rf_source lies.
DOUBLE
ray_step_bin_multiple
N/A
The step, in number of bins (can be fractional), used to increment the ray propagation as the ray radiates out from the RF source. Lower values of this (below 1.0) can increase accuracy of the simulation, but decrease performance. Values above 1.0 are not recommended because they can cause gaps in the output.
DOUBLE
loop_grain_size
N/A
The size in number of rays at which to parallelize over; threads will process rays in groups of at least this size. A reasonable value might be 10, although changing this number may improve performance, depending on hardware configuration.
BIGINT
Output Columns
Name
Description
Data Type
x
x-centroid of the output terrain bin. In lon/lat degrees in longitude degrees if geographic_coords is set to true, otherwise in meters.
Column<FLOAT | DOUBLE> (same type as rf_source_x and rf_source_y input columns)
y
y-centroid of the output terrain bin. In lon/lat degrees in longitude degrees if geographic_coords is set to true, otherwise in meters.
Column<FLOAT | DOUBLE> (same type as rf_source_x and rf_source_y input columns)
elevation_amsl_meters
Maximum elevation of all input terrain data falling in the output XY terrain bin, in meters above sea level.
Column<FLOAT | DOUBLE> (same type as rf_source_z_meters input column)
rf_source_id
ID of the repeater with the strongest signal for the grid cell.
Column<INT | BIGINT | TEXT ENCODING DICT>(same type as RF sources ID input)
max_signal_strength_dbm
The maximum signal strength in dBm for a given XY-terrain bin.
Column<FLOAT | DOUBLE> (same type as rf_source_x and rf_source_y input)
Example
SELECT
rf_source_id,
ST_X(
ST_TRANSFORM(
ST_SETSRID(
ST_POINT(x, y),
32610
),
4326
)
) as lon,
ST_Y(
ST_TRANSFORM(
ST_SETSRID(
ST_POINT(x, y),
32610
),
4326
)
) as lat,
CAST(
CASE
WHEN max_rf_signal_strength_dbm IS NULL THEN -130.0
ELSE max_rf_signal_strength_dbm
END AS FLOAT
) AS rf_signal_strength_dbm
FROM
TABLE(
tf_rf_prop_max_signal(
rf_sources => CURSOR (
SELECT
id,
x,
y,
z,
power_watts,
freq_mhz,
antenna_azimuth,
antenna_downtilt,
antenna_type
FROM
seattle_rf_sources
),
terrain_elevations => CURSOR (
SELECT
CAST(x_utm AS FLOAT) AS x,
CAST(y_utm AS FLOAT) AS y,
CAST(z + 0.0001 AS float) AS elevation
FROM
seattle_expanded_lidar_tiled
),
antenna_patterns => CURSOR (
SELECT
antenna_type,
antenna_gain,
antenna_horizontal_degrees,
antenna_horizontal_attenuations,
antenna_vertical_degrees,
antenna_vertical_attenuations
FROM
seattle_antenna_types
),
rf_source_z_is_relative_to_terrain => FALSE,
geographic_coords => FALSE,
bin_dim_meters => 2.0,
assumed_receiver_height_agl => 2.0,
max_ray_travel_meters => 2500,
initial_rays_per_source => 64,
rays_per_bin_autosplit_threshold => 1.5,
min_receiver_signal_strength_dbm => -130.0,
default_source_height_agl_meters => 20.0,
ray_step_bin_multiple => 1.0,
loop_grain_size => 8
)
)
Output of RF Propagation for Seattle using HeavyRF Omniverse integration

tf_rf_prop_max_signal (Isotropic Antennas)

SELECT * FROM TABLE(
tf_rf_prop(
rf_sources => CURSOR(
SELECT
rf_source_id, x, y, z_meters
),
rf_source_z_is_relative_to_terrain,
rf_source_signal_strength_dbm,
rf_source_signal_frequency_mhz
terrain => CURSOR(
SELECT
x, y, elevation_amsl_meters
),
geographic_coords,
bin_dim_meters,
max_ray_travel_meters,
num_rays_per_source,
min_receiver_signal_strength_dbm,
default_source_height_agl_meters,
ray_step_bin_multiple,
loop_grain_size
)
)
Taking a set of point elevations and a set of signal source locations as input, tf_rf_prop_max_signal executes line-of-sight 2.5D RF signal propagation from the provided sources over a binned 2.5D elevation grid derived from the provided point locations, calculating the max signal in dBm at each grid cell, using the formula for free-space power loss. The RF source ID contributing the strongest signal is also outputted.
For the short version, where geographic_coords defaults to true, or for the long version where geographic_coords is explicitly set to true, x and y input coordinates are assumed to be lon/lat degrees. A best-fit conversion to a meters coordinate system is executed using the change in meters per lon/lat degree at the centroid of the input terrain, using the haversine distance formula. For convenience and optimal performance, tf_rf_prop_max_signal enables filter push-down by default, such that filters on the outputs rf_source_id, x, y, and elevation_amsl_meters are pushed down to the respective inputs in the rf_sources and terrain_elevations cursor subqueries.
Short Version
Long Version

Input Arguments

Parameter
Details
Data Type
RF sources
Consists of rf_source_id, x (RF sources), y (RF sources), and z_meters.
CURSOR
rf_source_id
ID of the RF source. Used in the output for each grid cell to denote the RF source contributing the strongest signal.
Column<INT | BIGINT | TEXT ENCODING DICT>
x (RF sources)
x-coordinate of the RF source, assumed to be in longitude degrees. Whether FLOAT or DOUBLE, x and y must be the same type.
Column<FLOAT | DOUBLE>
y (RF sources)
y-coordinate of the RF source, assumed to be in latitude degrees. Whether FLOAT or DOUBLE, x and y must be the same type.
Column<FLOAT | DOUBLE>
z_meters
z-coordinate of the RF source, in meters. If rf_source_is_relative_to_terrain is set to true, meters are relative to the terrain height; for example, an input of 20 is 20 meters above ground level. Otherwise, it is absolute height above sea level; 20 is 20 meters above mean sea level (AMSL).
Column<FLOAT | DOUBLE>
rf_source_z_is_relative_to_terrain
true specifies that z_meters values are the height in meters above ground level. false indicates the values are height in meters above sea level.
BOOLEAN
rf_source_signal_strength_dbm
Signal strength in dBm for all RF sources.
DOUBLE
rf_source_signal_frequency_mhz
Frequency in MHZ of the RF sources.
DOUBLE
Terrain elevations
Consists of x (terrain elevations), y (terrain elevations), and elevation_amsl_meters.
CURSOR
x (terrain elevations)
x-coordinate of the terrain/building height, assumed to be in longitude degrees. Whether FLOAT or DOUBLE, x and y must be the same type.
Column<FLOAT | DOUBLE>
y (terrain elevations)
y-coordinate of the terrain/building height, assumed to be in latitude degrees. Whether FLOAT or DOUBLE, x and y must be the same type.
Column<FLOAT | DOUBLE>
elevation_amsl_meters
Elevation of the point, in meters above sea level.
Column<FLOAT | DOUBLE>
geographic_coords
true specifies that the input x and y arguments for RF sources and terrain elevations are in lon/lat degrees. false specifies that the data is already in a local meter coordinate system.
BOOLEAN
bin_dim_meters
Width and height of each binned terrain cell, which is the unit of granularity over which the RF propagation algorithm is executed.
DOUBLE
max_ray_travel_meters
Maximum meters for which to model RF propagation from any given source. Lower values can increase performance, but potentially misses the strongest repeater for a terrain cell that is further away than the value set.
DOUBLE
num_rays_per_source
Number of 2.5D rays to propagate from each source. Higher numbers potentially provide more accurate results but can decrease performance.
BIGINT
min_receiver_signal_strength_dbm
The minimum signal strength threshold in dBm to continue propagating a signal ray from a source. Rays stop being propagated when either the distance from the source exceeds the limit set by max_ray_travel_meters, or the signal strength (as measured by free-space power loss, assuming no obstructions in the path) drops below the value set by min_receiver_signal_strength_dbm.
DOUBLE

Outputs

A table of grid cells of width and height bin_dim_meters along with the maximum signal strength from any one repeater at that cell, and the ID of the repeater with the strongest signal.
Parameter
Details
Text
x
x-centroid of the output bin, in lon/lat degrees.
Column<FLOAT | DOUBLE> (same type as RF sources input)
y
y-centroid of the output bin, in lon/lat degrees.
Column<FLOAT | DOUBLE>(same type as RF sources input)
elevation_amsl_meters
Maximum elevation of all input terrain data falling in the output bin, in meters above sea level.
Column<FLOAT | DOUBLE> (same type as terrain elevations input)
rf_source_id
ID of the repeater with the strongest signal for the grid cell.
Column<FLOAT | DOUBLE>(same type as RF sources ID input)
max_signal_strength_dbm
The maximum signal strength in dBm for a given terrain bin.
Column<FLOAT | DOUBLE> (same type as RF sources coordinates input)

Input Arguments

Parameter
Details
Text
RF sources
Consists of rf_source_id, x (RF sources), y (RF sources), and z_meters.
CURSOR
rf_source_id
ID of the RF source. Used in the output for each grid cell to denote the RF source contributing the strongest signal.
INT | BIGINT | TEXT ENCODING DICT
x (RF sources)
x-coordinate of the RF source. If geographic_coords is set to true, assumed to be longitude degrees; otherwise, an arbitrary meters-coordinate system. Whether FLOAT or DOUBLE, x and y must be the same type.
FLOAT | DOUBLE
y (RF sources)
y-coordinate of the RF source. If geographic_coords is set to true, assumed to be latitude degrees; otherwise, an arbitrary meters-coordinate system. Whether FLOAT or DOUBLE, x and y must be the same type.
FLOAT | DOUBLE
z_meters
z-coordinate of the RF source, in meters. If rf_source_is_relative_to_terrain is set to true, meters are relative to the terrain height; for example, an input of 20 is 20 meters above ground level. Otherwise, it is absolute height above sea level; 20 is 20 meters above mean sea level (AMSL).
FLOAT | DOUBLE
rf_source_z_is_relative_to_terrain
true specifies that z_meters values are the height in meters above ground level. false indicates the values are height in meters above sea level.
BOOLEAN
rf_source_signal_strength_dbm
Signal strength in dBm for all RF sources.
DOUBLE
rf_source_signal_frequency_mhz
Frequency in MHZ of the RF sources.
DOUBLE
Terrain elevations
Consists of x (terrain elevations), y (terrain elevations), and elevation_amsl_meters.
CURSOR
x (terrain elevations)
x-coordinate of the terrain/building height. If geographic_coords is set to true, assumed to be longitude degrees; otherwise, an arbitrary meters-coordinate system. Whether FLOAT or DOUBLE, x and y must be the same type.
FLOAT | DOUBLE
y (terrain elevations)
y-coordinate of the terrain/building height. If geographic_coords is set to true, assumed to be latitude degrees; otherwise, an arbitrary meters-coordinate system. Whether FLOAT or DOUBLE, x and y must be the same type.
FLOAT | DOUBLE
elevation_amsl_meters
Elevation of the point, in meters above sea level.
FLOAT | DOUBLE
geographic_coords
true specifies that the input x and y arguments for RF sources and terrain elevations are in lon/lat degrees. false specifies that the data is already in a local meter coordinate system.
BOOLEAN
bin_dim_meters
Width and height of each binned terrain cell, which is the unit of granularity over which the RF propagation algorithm is executed.
DOUBLE
max_ray_travel_meters
Maximum meters for which to model RF propagation from any given source. Lower values can increase performance, but potentially misses the strongest repeater for a terrain cell that is further away than the value set.
DOUBLE
num_rays_per_source
Number of 2.5D rays to propagate from each source. Higher numbers potentially provide more accurate results but can decrease performance.
BIGINT
min_receiver_signal_strength_dbm
The minimum signal strength threshold in dBm to continue propagating a signal ray from a source. Rays stop being propagated when either the distance from the source exceeds the limit set by max_ray_travel_meters, or the signal strength (as measured by free-space power loss, assuming no obstructions in the path) drops below the value set by min_receiver_signal_strength_dbm.
DOUBLE
default_source_height_agl_meters
The default height in meters above ground level for a source if there is no input data in the terrain_elevations for the terrain bin in which a given rf_source lies.
DOUBLE
ray_step_bin_multiple
The step used in number of bins (can be fractional) for the RF propagation simulation. Lower values of this (below 1.0) can increase accuracy of the simulation, but decrease performance. Values above 1.0 are not recommended because they can cause gaps in the output.
DOUBLE
loop_grain_size
The size in number of rays at which to parallelize over; threads will process rays in groups of at least this size. The default value is 40; performance may improve by changing this number, depending on hardware setup.
BIGINT

Output Columns

A table of grid cells of width and height bin_dim_meters along with the maximum signal strength from any one repeater at that cell, and the ID of the repeater with the strongest signal.
Parameter
Type
Details
Text
x
x-centroid of the output bin, in lon/lat degrees.
FLOAT | DOUBLE (same type as RF sources input)
y
y-centroid of the output bin, in lon/lat degrees.
FLOAT | DOUBLE(same type as RF sources input)
elevation_amsl_meters
Maximum elevation of all input terrain data falling in the output bin, in meters above sea level.
FLOAT | DOUBLE (same type as terrain elevations input)
rf_source_id
ID of the repeater with the strongest signal for the grid cell.
FLOAT | DOUBLE(same type as RF sources ID input)
max_signal_strength_dbm
The maximum signal strength in dBm for a given terrain bin.
FLOAT | DOUBLE (same type as RF sources coordinates input)

tf_rf_prop

Used for generating top-k signals where 'k' represents the maximum number of antennas to consider at each geographic location. The full relevant parameter name is strongest_k_sources_per_terrain_bin. For example, if k is set to 3, the function will return up to three overlapping antenna signals based on their strength. In that case, if only 2 signals are present, they will be returned. and if 5 signals are actually present, only the strongest 3 will be recorded.
This version of the RF function can be used in optimizing antenna placements use cases or to minimize interference. For example, you might simulate repeater antenna placements on every lampost across an area, but then only plan to keep the top-performing ones. By allowing overlaps in the initial simulation, you avoid intrpducing coverage gaps when dropping out antennas, while also avoiding the requirement of multiple simulations.
SELECT * FROM TABLE(
tf_rf_prop(
data => CURSOR(
SELECT
rf_source_id, x, y, repeater_height_meters
),
rf_source_z_is_relative_to_terrain,
rf_source_signal_strength_dbm,
rf_source_signal_frequency_mhz
data => CURSOR(
SELECT
x, y, elevation_amsl_meters
),
bin_dim_meters,
strongest_k_sources_per_terrain_bin
max_ray_travel_meters,
num_rays_per_source,
min_receiver_signal_strength_dbm
default_source_height_agl_meters
ray_step_bin_multiple
loop_grain_size
)
)
Short Version
Long Version
Input Arguments
Parameter
Details
Data Type
rf_sources
Consists of rf_source_id, x (RF sources), y (RF sources), and z_meters.
CURSOR
rf_source_id
ID of the RF source. Used in the output for each grid cell to denote the RF source contributing the strongest signal.
Column<INT | BIGINT | TEXT ENCODING DICT
x (RF sources)
x-coordinate of the RF source, assumed to be in longitude degrees. Whether FLOAT or DOUBLE, x and y must be the same type.
Column<FLOAT | DOUBLE>
y (RF sources)
y-coordinate of the RF source, assumed to be in latitude degrees. Whether FLOAT or DOUBLE, x and y must be the same type.
Column<FLOAT | DOUBLE>
repeater_height_meters
.
Column<FLOAT | DOUBLE>
rf_source_z_is_relative_to_terrain
true specifies that z_meters values are the height in meters above ground level. false indicates the values are height in meters above sea level.
BOOLEAN
rf_source_signal_strength_dbm
Signal strength in dBm for all RF sources.
DOUBLE
rf_source_signal_frequency_mhz
Frequency in MHZ of the RF sources.
DOUBLE
Terrain elevations
Consists of x (terrain elevations), y (terrain elevations), and elevation_amsl_meters.
CURSOR
x (terrain elevations)
x-coordinate of the terrain/building height, assumed to be in longitude degrees. Whether FLOAT or DOUBLE, x and y must be the same type.
Column<FLOAT | DOUBLE>
y (terrain elevations)
y-coordinate of the terrain/building height, assumed to be in latitude degrees. Whether FLOAT or DOUBLE, x and y must be the same type.
Column<FLOAT | DOUBLE>
elevation_amsl_meters
Elevation of the point, in meters above sea level.
Column<FLOAT | DOUBLE>
bin_dim_meters
Width and height of each binned terrain cell, which is the unit of granularity over which the RF propagation algorithm is executed.
DOUBLE
num_top_sources_per_terrain_bin
Number of best sources ranked by signal strength for a terrain bin to be outputted in the results.
BIGINT
max_ray_travel_meters
Maximum meters for which to model RF propagation from any given source. Lower values can increase performance, buy potentially misses the strongest repeater for a terrain cell that is further away than the value set.
DOUBLE
num_rays_per_source
Number of 2.5D rays to propagate from each source. Higher numbers potentially provide more accurate results but can decrease performance.
BIGINT
min_receiver_signal_strength_dbm
The minimum signal strength threshold in dBm to continue propagating a signal ray from a source. Rays stop being propagated when either the distance from the source exceeds the limit set by max_ray_travel_meters, or the signal strength (as measured by free-space power loss, assuming no obstructions in the path) drops below the value set by min_receiver_signal_strength_dbm.
DOUBLE
Outputs
A table of grid cells of width and height bin_dim_meters along with the maximum signal strength from any one repeater at that cell, and the ID of the repeater with the strongest signal.
Parameter
Details
Text
terrain_bin_id
x
x-centroid of the output bin, in lon/lat degrees.
Column<FLOAT | DOUBLE> (same type as RF sources input)
y
y-centroid of the output bin, in lon/lat degrees.
Column<FLOAT | DOUBLE>(same type as RF sources input)
elevation_amsl_meters
Maximum elevation of all input terrain data falling in the output bin, in meters above sea level.
Column<FLOAT | DOUBLE> (same type as terrain elevations input)
rf_source_id
ID of the repeater with the strongest signal for the grid cell.
Column<FLOAT | DOUBLE>(same type as RF sources ID input)
rf_signal_strength_dbm
The signal strength in dBm for a given terrain bin.
Column<FLOAT | DOUBLE> (same type as RF sources coordinates input)
rf_signal_z_angle_degrees
The angle in degrees of the output bin with respect to the top-k signal source rf_source_id.
Column<FLOAT | DOUBLE> (same type as RF sources coordinates input)
rf_source_distance_meters
The distance of the top-k signal source rf_source_id from the output bin, in meters.
Column<FLOAT | DOUBLE> (same type as RF sources coordinates input)

Input Arguments
Parameter
Details
Data Type
RF sources
Consists of rf_source_id, x (RF sources), y (RF sources), and z_meters.
CURSOR
rf_source_id
ID of the RF source. Used in the output for each grid cell to denote the RF source contributing the strongest signal.
INT | BIGINT | TEXT ENCODING DICT
x (RF sources)
x-coordinate of the RF source. If geographic_coords is set to true, assumed to be longitude degrees; otherwise, an arbitrary meters-coordinate system. Whether FLOAT or DOUBLE, x and y must be the same type.
FLOAT | DOUBLE
y (RF sources)
y-coordinate of the RF source. If geographic_coords is set to true, assumed to be latitude degrees; otherwise, an arbitrary meters-coordinate system. Whether FLOAT or DOUBLE, x and y must be the same type.
FLOAT | DOUBLE
repeater_height_meters
FLOAT | DOUBLE
rf_source_z_is_relative_to_terrain
true specifies that z_meters values are the height in meters above ground level. false indicates the values are height in meters above sea level.
BOOLEAN
rf_source_signal_strength_dbm
Signal strength in dBm for all RF sources.
DOUBLE
rf_source_signal_frequency_mhz
Frequency in MHZ of the RF sources.
DOUBLE
Terrain elevations
Consists of x (terrain elevations), y (terrain elevations), and elevation_amsl_meters.
CURSOR
x (terrain elevations)
x-coordinate of the terrain/building height. If geographic_coords is set to true, assumed to be longitude degrees; otherwise, an arbitrary meters-coordinate system. Whether FLOAT or DOUBLE, x and y must be the same type.
FLOAT | DOUBLE
y (terrain elevations)
y-coordinate of the terrain/building height. If geographic_coords is set to true, assumed to be latitude degrees; otherwise, an arbitrary meters-coordinate system. Whether FLOAT or DOUBLE, x and y must be the same type.
FLOAT | DOUBLE
elevation_amsl_meters
Elevation of the point, in meters above sea level.
FLOAT | DOUBLE
bin_dim_meters
Width and height of each binned terrain cell, which is the unit of granularity over which the RF propagation algorithm is executed.
DOUBLE
strongest_k_sources_per_terrain_bin
max_ray_travel_meters
Maximum meters for which to model RF propagation from any given source. Lower values can increase performance, but potentially misses the strongest repeater for a terrain cell that is further away than the value set.
DOUBLE
num_rays_per_source
Number of 2.5D rays to propagate from each source. Higher numbers potentially provide more accurate results but can decrease performance.
BIGINT
min_receiver_signal_strength_dbm
The minimum signal strength threshold in dBm to continue propagating a signal ray from a source. Rays stop being propagated when either the distance from the source exceeds the limit set by max_ray_travel_meters, or the signal strength (as measured by free-space power loss, assuming no obstructions in the path) drops below the value set by min_receiver_signal_strength_dbm.
DOUBLE
default_source_height_agl_meters
The default height in meters above ground level for a source if there is no input data in the terrain_elevations for the terrain bin in which a given rf_source lies.
DOUBLE
ray_step_bin_multiple
The step used in number of bins (can be fractional) for the RF propagation simulation. Lower values of this (below 1.0) can increase accuracy of the simulation, but decrease performance. Values above 1.0 are not recommended because they can cause gaps in the output.
DOUBLE
loop_grain_size
The size in number of rays at which to parallelize over; threads will process rays in groups of at least this size. The default value is 40; performance may improve by changing this number, depending on hardware setup.
BIGINT

Outputs

A table of grid cells of width and height bin_dim_meters along with the maximum signal strength from any one repeater at that cell, and the ID of the repeater with the strongest signal.
Parameter
Details
Data Type
terrain_bin_id
x
x-centroid of the output bin, in lon/lat degrees.
FLOAT | DOUBLE (same type as RF sources input)
y
y-centroid of the output bin, in lon/lat degrees.
FLOAT | DOUBLE(same type as RF sources input)
elevation_amsl_meters
Maximum elevation of all input terrain data falling in the output bin, in meters above sea level.
FLOAT | DOUBLE (same type as terrain elevations input)
rf_source_id
ID of the repeater with the strongest signal for the grid cell.
FLOAT | DOUBLE(same type as RF sources ID input)
rf_signal_strength_dbm
The signal strength in dBm for a given terrain bin.
FLOAT | DOUBLE (same type as RF sources coordinates input)
rf_signal_z_angle_degrees