Onboard compute ยท 2026-07-21
Start the capture proof on CM5; keep Orin Nano in reserve.
The first board decision is now bounded by the 15 W complete-payload ceiling, a 39.3 MB/s raw thermal stream, camera-interface compatibility, geotagging I/O, environmental evidence, and the existing USD 2k–6k integration allowance.
Decision
CM5 is the Gate-1 board, not yet a flight selection.
Evidence boundary
Published interfaces are not a capture benchmark.
Every candidate has plausible bus bandwidth, but no cited vendor closes the complete idle, peak, sustained-write, checksum, and thermal-soak case on the carrier EmberScope would fly. Missing values remain marked as missing.
Board price is not the system cost. The USD 2k–6k allowance also carries the flight carrier, storage, GNSS/IMU timing, power conditioning, cooling, harness, and integration work.
Candidate trade
Five compute paths against the same payload gates.
Physical, power, cost, and environmental screen
| Candidate | Module mass | Power vs 15 W | Price | Temperature | Disposition |
|---|---|---|---|---|---|
| NVIDIA Jetson Orin Nano 8GB GPU SoM | not published Production-module mass is not stated on the cited lineup or data-sheet index; carrier, NVMe, and thermal solution must be weighed together. | Idle: not published; peak/max: 15 W NVIDIA publishes 7-15 W for the production series. Idle is not specified. A 25 W Super mode exists but is outside this payload ceiling. Conditional pass: lock a base mode at or below 15 W; Super mode is barred, and the complete payload still needs a rail measurement. | USD 399.00 NVIDIA 1KU+ MSRP for the 8GB production module. | -25 C module minimum; keep Orin SoC below 99 C. Ambient limit depends on carrier, workload, airflow, and thermal design. | Accelerated fallback. Use if the replayable detector grows beyond CM5, without enabling a power mode above the payload ceiling. |
| NVIDIA Jetson Orin NX 16GB GPU SoM | 28 g NVIDIA support records 28 g for the production module. | Idle: not published; peak/max: 25 W NVIDIA publishes 10-25 W for the production series. Idle is not specified; 40 W Super mode is also available with redesigned power and cooling. Fail at the published upper mode: 25 W exceeds the 15 W complete-payload ceiling. A 10 W or 15 W lock still needs an integrated rail test. | USD 999.00 NVIDIA 1KU+ MSRP for the 16GB production module. | -25 C module minimum; keep Orin SoC below 99 C. Ambient limit depends on carrier, workload, airflow, and thermal design. | Do not baseline under the current ceiling. Reconsider only if measured compute demand cannot fit Orin Nano or the payload power allocation changes. |
| Raspberry Pi Compute Module 4 CPU SoM | not published Module mass is not stated in the cited product page or datasheet; carrier and thermal solution must be weighed. | Idle: not published; peak/max: not published The module datasheet specifies a 5 V rail but does not publish CM4 idle and worst-case application power. Open: measure idle, capture, detector-replay, and thermal-soak peaks. | USD 41.25 Current official starting list price; RAM/eMMC/carrier raise the total. | -20 C to +85 C; selected variants extend the lower limit to -40 C. | Low-cost fallback. Its direct USB 2 path fits ICI, but Hadron USB 3 needs extra carrier hardware and the power evidence is incomplete. |
| Raspberry Pi Compute Module 5 CPU SoM | not published Module mass is not stated in the cited product page or datasheet; carrier and cooling must be weighed. | Idle: 2 W; peak/max: not published The CM5 datasheet gives 400 mA idle and about 900 mA typical operating at 5 V (2.0 W and 4.5 W). It does not publish an application peak. Best published margin, but still conditional: measure the missing peak with camera, NVMe/eMMC, timing receiver, cooling, and detector replay active. | USD 67.50 Current official starting price; RAM/eMMC/carrier raise the total. | -20 C to +85 C non-condensing. | Preferred Gate-1 board. Prototype raw capture and RFS-049 replay here first; retain Orin Nano only if measured inference load requires acceleration. |
| AMD Kria K26C FPGA/CPU SoM | not published AMD publishes 77 x 60 x 11 mm with heat spreader, but module mass is not stated on the cited product page; carrier and thermal solution must be weighed. | Idle: not published; peak/max: 15 W Idle is not published because AMD requires application-specific PDM/Vivado estimation. Its thermal guide shows 8.7 W at 52 C and 9.7 W worst-case at 85 C; the module maximum is 15 W. Conditional to failing: a 15 W module maximum leaves no complete-payload margin. Close only with workload-specific PDM and rail measurements. | USD 325.00 AMD MSRP for the commercial production SoM. | Commercial grade: 0 C to 85 C MPSoC junction; industrial K26I: -40 C to 100 C junction. Ambient is system-thermal-design dependent. | Specialist accelerator, not the first baseline. Use only if deterministic sensor preprocessing justifies FPGA development and a custom carrier. |
Camera, storage, and geotagging integration
| Candidate and exposed buses | Camera-path match | Storage vs 50 MiB/s | GNSS / IMU interfaces |
|---|---|---|---|
| NVIDIA Jetson Orin Nano 8GB USB 3.2, USB 2.0, MIPI CSI-2, Gigabit Ethernet via carrier | Boson+: Direct MIPI CSI-2 or USB path on a suitable carrier. ICI 8640 P: Direct USB 2.0 host path on a suitable carrier. Hadron 640R: Direct USB 3 or two-lane MIPI path on a suitable carrier. | External NVMe over PCIe or USB storage; the module has no onboard eMMC. Bus headroom is ample, but no vendor sustained-write guarantee closes the 50 MiB/s checksummed capture gate. | UART, I2C, SPI, USB, CAN via carrier |
| NVIDIA Jetson Orin NX 16GB USB 3.2, USB 2.0, MIPI CSI-2, Gigabit Ethernet via carrier | Boson+: Direct MIPI CSI-2 or USB path on a suitable carrier. ICI 8640 P: Direct USB 2.0 host path on a suitable carrier. Hadron 640R: Direct USB 3 or two-lane MIPI path on a suitable carrier. | External NVMe over PCIe or USB storage. Bus headroom is ample, but the selected carrier and drive must sustain 50 MiB/s with checksums and thermal soak. | UART, I2C, SPI, USB, CAN via carrier |
| Raspberry Pi Compute Module 4 USB 2.0, MIPI CSI-2, Gigabit Ethernet PHY, PCIe Gen 2 x1 | Boson+: MIPI CSI-2 is direct; USB 2 is available; USB 3 needs a PCIe carrier controller. ICI 8640 P: Direct USB 2.0 host path. Hadron 640R: MIPI is direct; the USB 3 path needs a PCIe carrier controller. | Up to 32GB eMMC, or SD on Lite; PCIe permits external NVMe on a carrier. Interface capacity is plausible, but neither eMMC nor carrier storage has a vendor sustained-write guarantee for the 50 MiB/s gate. | UART, I2C, SPI, USB, Gigabit Ethernet |
| Raspberry Pi Compute Module 5 USB 3.0, USB 2.0, 2 x 4-lane MIPI, Gigabit Ethernet PHY | Boson+: Direct MIPI CSI-2 or USB path on a suitable carrier. ICI 8640 P: Direct USB 2.0 host path. Hadron 640R: Direct USB 3 or two-lane MIPI path on a suitable carrier. | Up to 64GB eMMC, or SD on Lite; PCIe Gen 2 x1 permits external NVMe. Interface capacity is plausible, but the selected eMMC/NVMe path must demonstrate 50 MiB/s checksummed writes under thermal soak. | UART, I2C, SPI, USB, Gigabit Ethernet, RTC on carrier |
| AMD Kria K26C MIPI/USB 3/Gigabit Ethernet are carrier dependent, Programmable I/O | Boson+: Needs a custom or KV260-class carrier for MIPI or USB. ICI 8640 P: Needs a carrier exposing a USB 2 host path. Hadron 640R: Needs a carrier exposing USB 3 or two-lane MIPI. | 16GB eMMC on module; PCIe and additional storage depend on the carrier. The architecture can stream data, but the exact FPGA design, carrier, and storage path must prove the 50 MiB/s checksummed gate. | UART, I2C, SPI, CAN via programmable logic/carrier |
Interface finding
The camera branches do not share one native link.
Boson+
MIPI or USB depending on the exact core and interface configuration.
ICI 8640 P
USB Mini-B / USB 2.0 for 30 Hz, 14-bit raw streaming; its data sheet does not claim direct GigE.
Hadron 640R
USB 3.0 or two-lane MIPI.
Gigabit Ethernet
Useful for a bridge, payload network, or ground export; not a native link on these exact three cited camera modules.
Next proof
One carrier must close capture, replay, power, and heat together.
Run the CM5 with the selected camera path and storage while writing at least 50 MiB/s with checksums and RFS-047 metadata, then replay the RFS-049 detector without dropped frames.
Measure complete-rail idle and peak power, timestamp alignment, storage temperature, throttling, and recovery after a sustained thermal soak. Promote Orin Nano only if that test shows a measured compute shortfall.
Sources