Broadcast Communication
By default, communication occurs between all satellites that are specified by the communication method. This tutorial shows how to use two classes to configure a broadcast action that must be taken for communication to occur:
Broadcast, which gives satellites an action that enables communication from them at the end of the current step.
BroadcastCommunication, which can be combined with another communication method to limit communication from broadcasters to those satellites satisfying the requirements of the other communication method.
Configuring the Environment
For this example, a multisatellite target imaging environment will be used. The goal is to maximize the value of unique images taken. This configuration is similar to the Multi-Agent Environments example.
[1]:
from bsk_rl import sats, act, obs, scene, data, comm
from bsk_rl.sim import dyn, fsw
class ImagingSatellite(sats.ImagingSatellite):
observation_spec = [
obs.OpportunityProperties(
dict(prop="priority"),
dict(prop="opportunity_open", norm=5700.0),
n_ahead_observe=4,
)
]
action_spec = [act.Broadcast(duration=15.0), act.Image(n_ahead_image=4)]
dyn_type = dyn.FullFeaturedDynModel
fsw_type = fsw.SteeringImagerFSWModel
ACTION_BROADCAST = 0
ACTION_IMAGE_0 = 1
ACTION_IMAGE_1 = 2
ACTION_IMAGE_2 = 3
ACTION_IMAGE_3 = 4
Satellite properties are set to give the satellite near-unlimited power and storage resources. To randomize some parameters in a correlated manner across satellites, a sat_arg_randomizer is set and passed to the environment. In this case, the satellites are distributed in a trivial single-plane Walker-delta constellation.
[2]:
from bsk_rl.utils.orbital import walker_delta_args
N_AGENTS = 2
sat_args = dict(
imageAttErrorRequirement=0.01,
imageRateErrorRequirement=0.01,
batteryStorageCapacity=1e9,
storedCharge_Init=1e9,
dataStorageCapacity=1e12,
u_max=0.4,
K1=0.25,
K3=3.0,
omega_max=0.087,
servo_Ki=5.0,
servo_P=150 / 5,
)
sat_arg_randomizer = walker_delta_args(
altitude=800.0, inc=60.0, n_planes=1, clustersize=N_AGENTS, clusterspacing=5.0
)
A communication type is defined that uses multidegree line-of-sight communication with broadcasting.
[3]:
class BroadcastLOS(comm.BroadcastCommunication, comm.LOSMultiCommunication):
pass
Finally, the environment can be instantiated.
[4]:
from bsk_rl import ConstellationTasking
env = ConstellationTasking(
satellites=[ImagingSatellite(f"EO-{i + 1}", sat_args) for i in range(N_AGENTS)],
scenario=scene.UniformTargets(1000),
rewarder=data.UniqueImageReward(),
communicator=BroadcastLOS(),
sat_arg_randomizer=sat_arg_randomizer,
log_level="INFO",
)
_ = env.reset()
2026-05-19 20:28:45,930 gym INFO Resetting environment with seed=3933954310
2026-05-19 20:28:45,932 scene.targets INFO Generating 1000 targets
2026-05-19 20:28:45,997 sats.satellite.EO-1 INFO <0.00> EO-1: Finding opportunity windows from 0.00 to 600.00 seconds
2026-05-19 20:28:46,029 sats.satellite.EO-2 INFO <0.00> EO-2: Finding opportunity windows from 0.00 to 600.00 seconds
2026-05-19 20:28:46,059 gym INFO <0.00> Environment reset
In the first step, both agents are tasked with an imaging action, and one successfully images a target.
[5]:
_ = env.step({"EO-1": ACTION_IMAGE_3, "EO-2": ACTION_IMAGE_2})
2026-05-19 20:28:46,064 gym INFO <0.00> === STARTING STEP ===
2026-05-19 20:28:46,065 sats.satellite.EO-1 INFO <0.00> EO-1: target index 3 tasked
2026-05-19 20:28:46,065 sats.satellite.EO-1 INFO <0.00> EO-1: Target(tgt-150) tasked for imaging
2026-05-19 20:28:46,066 sats.satellite.EO-1 INFO <0.00> EO-1: Target(tgt-150) window enabled: 487.4 to 600.0
2026-05-19 20:28:46,067 sats.satellite.EO-1 INFO <0.00> EO-1: setting timed terminal event at 600.0
2026-05-19 20:28:46,068 sats.satellite.EO-2 INFO <0.00> EO-2: target index 2 tasked
2026-05-19 20:28:46,068 sats.satellite.EO-2 INFO <0.00> EO-2: Target(tgt-642) tasked for imaging
2026-05-19 20:28:46,069 sats.satellite.EO-2 INFO <0.00> EO-2: Target(tgt-642) window enabled: 107.4 to 193.4
2026-05-19 20:28:46,070 sats.satellite.EO-2 INFO <0.00> EO-2: setting timed terminal event at 193.4
2026-05-19 20:28:46,091 sats.satellite.EO-2 INFO <110.00> EO-2: imaged Target(tgt-642)
2026-05-19 20:28:46,092 data.base INFO <110.00> Total reward: {'EO-2': 0.020813305978741536}
2026-05-19 20:28:46,093 sats.satellite.EO-2 INFO <110.00> EO-2: Satellite EO-2 requires retasking
2026-05-19 20:28:46,095 gym INFO <110.00> Step reward: {'EO-2': 0.020813305978741536}
When both select the broadcast action, data is shared in both directions. This is subject to line-of-sight availability as well as selecting the correct action.
[6]:
_ = env.step({"EO-1": ACTION_BROADCAST, "EO-2": ACTION_BROADCAST})
2026-05-19 20:28:46,100 gym INFO <110.00> === STARTING STEP ===
2026-05-19 20:28:46,101 sats.satellite.EO-1 INFO <110.00> EO-1: setting timed terminal event at 125.0
2026-05-19 20:28:46,101 sats.satellite.EO-2 INFO <110.00> EO-2: setting timed terminal event at 125.0
2026-05-19 20:28:46,106 sats.satellite.EO-1 INFO <125.00> EO-1: timed termination at 125.0 for broadcast
2026-05-19 20:28:46,106 sats.satellite.EO-2 INFO <125.00> EO-2: timed termination at 125.0 for broadcast
2026-05-19 20:28:46,107 data.base INFO <125.00> Total reward: {}
2026-05-19 20:28:46,108 comm.communication INFO <125.00> Communicating data in 2 directions.
2026-05-19 20:28:46,108 comm.communication INFO <125.00> Optimizing data communication between all pairs of satellites
2026-05-19 20:28:46,109 sats.satellite.EO-1 INFO <125.00> EO-1: Satellite EO-1 requires retasking
2026-05-19 20:28:46,109 sats.satellite.EO-2 INFO <125.00> EO-2: Satellite EO-2 requires retasking
2026-05-19 20:28:46,112 gym INFO <125.00> Step reward: {}
One agent can broadcast while the others are completing a different task.
[7]:
_ = env.step({"EO-1": ACTION_IMAGE_2, "EO-2": ACTION_BROADCAST}) # Agent 1 broadcasts
2026-05-19 20:28:46,117 gym INFO <125.00> === STARTING STEP ===
2026-05-19 20:28:46,118 sats.satellite.EO-1 INFO <125.00> EO-1: target index 2 tasked
2026-05-19 20:28:46,118 sats.satellite.EO-1 INFO <125.00> EO-1: Target(tgt-396) tasked for imaging
2026-05-19 20:28:46,119 sats.satellite.EO-1 INFO <125.00> EO-1: Target(tgt-396) window enabled: 501.7 to 600.0
2026-05-19 20:28:46,119 sats.satellite.EO-1 INFO <125.00> EO-1: setting timed terminal event at 600.0
2026-05-19 20:28:46,121 sats.satellite.EO-2 INFO <125.00> EO-2: setting timed terminal event at 140.0
2026-05-19 20:28:46,125 sats.satellite.EO-2 INFO <140.00> EO-2: timed termination at 140.0 for broadcast
2026-05-19 20:28:46,125 data.base INFO <140.00> Total reward: {}
2026-05-19 20:28:46,126 comm.communication INFO <140.00> Communicating data in 1 direction.
2026-05-19 20:28:46,127 sats.satellite.EO-2 INFO <140.00> EO-2: Satellite EO-2 requires retasking
2026-05-19 20:28:46,129 gym INFO <140.00> Step reward: {}