1. Introduction#

1.1 Context#

BIOMASS is ESA’s 7th Earth Explorer mission. The purpose of the BIOMASS is to reduce the uncertainty in the worldwide spatial distribution and dynamics of forest biomass in order to improve current assessments and future projections of the global carbon cycle. This objective will be achieved by the implementation of a P-band SAR mission, providing global maps of forest biomass stocks, forest disturbance and growth.

The BIOMASS mission will also provide 3D views of forests through the “tomographic” phase and will also support additional science needs arising from the opportunity to explore the Earth for the first time with a P-band SAR system from space offering the possibility to “see” below the vegetated areas and in beneath bare soil or icy regions.

To achieve its challenging objectives, the BIOMASS mission requires a specific data processing strategy that combines different technologies at different processing level in order to generate the final Above Ground Biomass global map.

1.2 Scope of the document#

The purpose of this document is to provide the “Forest Height Algorithms Theoretical Baseline Document (ATBD)” for the BIOMASS Processing Suite (BPS) project.

This document is organized as follows:

Section 1: Overview of the document;
Section 2: Brief introduction about BPS and Forest Height processing;
Section 3: Description of L2a Forest Height algorithms;
Section 4: Description of L2b/L3 Forest Height algorithms.

1.3 Acronyms#

Acronyms

Acronym	Description
AD	Applicable Document
ADS	Annotation datasets
AGB	Above Ground Biomass
ARESYS	Advanced Remote Sensing and Systems
ATBD	Algorithm Theoretical Baseline Document
AUX	Auxiliary
BIODEMPP	Biomass DEM Prototype Processor
BPS	BIOMASS Processing Suite
CM	Covariance Matrix
CFI	Customer Furnished Items
CoSCS	Coregistered SCS
CP	co-polarization
DEM	Digital Elevation Model
DGG	Discrete Global Grid
DTM	Digital Terrain Model
ECSS	European Cooperation for Space Standardization
EO-CFI	Earth Observation Custom Furnished Items
ESA	European Space Agency
GPP	Ground Processor Prototype
GPS	Global Positioning System
FD	Forest Disturbance
FH	Forest Height
FNF	Forest/Non-Forest Mask
IERS	International Earth Rotation Service
InSAR	Interferometric Synthetic Aperture Radar
INT	Interferometric Phase
L0	Level-0 product
L1c	Level-1c product
L2a	Level-2a product
L2b	Level-2b product
L3	Level-3 product
LOS	Line Of Sight
LUT	Look-Up Table
PF	Processing Facility
PFD	Product Format Specification Document
RD	Reference Document
SAR	Synthetic Aperture Radar
SCS	Single-look Complex Slant-range
SKP	Sum of Kronecker Products
SNR	Signal-to-Noise Ratio
TBD	To Be Defined
TBC	To Be Confirmed
TOM	Tomographic Phase
XML	`eXtended` Markup Language
XP	cross-polarization

1.4 TBD / TBC Table#

Section	TBD / TBC	Page
1.6	`BTK_WEB`: link must be defined	9

1.5 Applicable documents#

Code	Document
`[AD1]`	BIOMASS Production Model, `BIO-ESA-EOPG-EEGS-TN-0046`, issue 3.5
`[AD2]`	BIO-BPS-L1-PFD, BIOMASS L1a,b,c products format specification, I/R 1/2/2
`[AD3]`	BIO-BPS-TN-PRODMOD, BIOMASS Production Model Technical Note, I/R 1/2/1

1.6 Reference documents#

Code	Document
`[RD1]`	BIO-BPS-L1-STACK-ATBD, BIOMASS BPS L1c Stack ATBD, I/R 1/1/2
`[RD2]`	BIO-BPS-L1-SAR-ATBD, BIOMASS BPS L1 SAR ATBD, I/R 1/1/2
`[RD3]`	BIOMASS DEM Product Processor Prototype, DEM Processor Algorithm Theoretical Baseline Document, BIODEMPP-CoSCS-DEM-01, I/R 4/0
`[RD4]`	BIO-BPS-FD-ATBD, BIOMASS BPS FD ATBD, I/R 2/1/1
`[RD5]`	BIOMASS L2 Implementation Study ATBD, I/R 1/5
`[RD6]`	F. Kugler, S. Lee, I. Hajnsek and K. P. Papathanassiou, “Forest Height Estimation by Means of Pol-InSAR Data Inversion: The Role of the Vertical Wavenumber,” in IEEE Transactions on Geoscience and Remote Sensing, vol. 53, no. 10, pp. 5294-5311, Oct. 2015
`[RD7]`	BIO-BPS- AUX-FMT, BPS Auxiliary Product Format, I/R 2/1/1
`[RD8]`	BIO-BPS-PPD, BIOMASS BPS Product Performance Description, I/R 2/0/2
`[RD9]`	F. Kugler, D. Schulze, I. Hajnsek, H. Pretzsch and K. P. Papathanassiou, “TanDEM-X Pol-InSAR Performance for Forest Height Estimation,” in IEEE Transactions on Geoscience and Remote Sensing, vol. 52, no. 10, pp. 6404-6422, Oct. 2014
`[RD10]`	R. Guliaev, V. Cazcarra-Bes, M. Pardini and K. Papathanassiou, “Forest Height Estimation by Means of TanDEM-X InSAR and Waveform Lidar Data,” in IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, vol. 14, pp. 3084-3094, 2021
`[RD11]`	Y. Cui, Y. Yamaguchi, H. Yamada and S. Park, “PolInSAR Coherence Region Modeling and Inversion: The Best Normal Matrix Approximation Solution,” in IEEE Transactions on Geoscience and Remote Sensing, vol. 53, no. 2, pp. 1048-1060, Feb. 2015
`[RD12]`	BIOMASS L2 Implementation Study ARD, I/R 2/7
`[RD13]`	BIO-BPS-IODD, BIOMASS BPS IODD, I/R 1/1/3
`[RD14]`	Pinheiro, M.; Amao-Oliva, J.; Scheiber, R.; Jaeger, M.; Horn, R.; Keller, M.; Fischer, J.; Reigber, A. Dual-Frequency Airborne SAR for Large Scale Mapping of Tidal Flats. in Remote Sens., vol. 12, pag. 1827, 2020
`[RD15]`	`BTK_WEB`, official link: TBD